Dosing regimen for a treatment of hunter syndrome

Abstract

Certain embodiments provide methods and dosing regimens for the treatment of Hunter syndrome.

Description

[0001] DNL-016-14-WO - 02900.064WO1

[0002] DOSING METHODS FOR THE TREATMENT OF HUNTER SYNDROME

[0003] CROSS-REFERENCE TO RELATED APPLICATION This application claims priority to U.S. Provisional Application Serial No. 63 / 754,364, filed February 5, 2025. The entire content of the application referenced above is hereby incorporated by reference herein.

[0004] BACKGROUND

[0005] Hunter syndrome, or MPS II, is a rare, X-linked recessive disorder caused by IDS gene mutations. Insufficient iduronate 2-sulfatase (IDS) activity leads to accumulation of the glycosaminoglycans (GAGs) heparan sulfate (HS) and dermatan sulfate (DS) and to lysosomal dysfunction in multiple organs and tissues. Approximately two-thirds of patients display a neuronopathic phenotype (nMPS II). A recombinant form of IDS has been approved to treat Hunter syndrome, but intravenous administration of the same has little effect on the brain due to difficulties in delivering the recombinant enzyme across the blood-brain barrier (BBB).

[0006] Tividenofusp alfa is an enzyme replacement therapy that is being investigated as a treatment for patients with MPS II to address both the peripheral and central nervous system (CNS) symptoms of disease. Tividenofusp alfa is administered by intravenous infusion to patients, which may result in infusion-related reaction (IRR) events in the patients.

[0007] Accordingly, there is a need for methods (e.g., dosing regimens) for reducing the risk of dose reductions due to IRRs during tividenofusp alfa initiation.

[0008] SUMMARY

[0009] Accordingly, certain embodiments provide a method of treating Hunter syndrome in a subject in need thereof, comprising administering tividenofusp alfa by intravenous infusion to the subject according to a dosing regimen, wherein the dosing regimen of tividenofusp alfa (mg / kg of body weight) to be administered comprises: about 3 mg / kg QW for at least about 4 weeks, which is followed by about 7.5 mg / kg QW for at least about 4 weeks, and which is followed by about 15 mg / kg QW.

[0010] Certain embodiments provide tividenofusp alfa for use in a method of treating Hunter syndrome, the method comprising administering tividenofusp alfa by intravenous infusion to a subject in need thereof according to a dosing regimen, wherein the dosing regimen ofDNL-016-14-WO - 02900.064WO1

[0011] tividenofusp alfa (mg / kg of body weight) to be administered comprises: about 3 mg / kg QW for at least about 4 weeks, which is followed by about 7.5 mg / kg QW for at least about 4 weeks, and which is followed by about 15 mg / kg QW.

[0012] Certain embodiments provide the use of tividenofusp alfa in the preparation of a medicament for the treatment of Hunter syndrome by administering the medicament by intravenous infusion to a subject in need thereof according to a dosing regimen, wherein the dosing regimen of the medicament to be administered comprises: about 3 mg / kg QW for at least about 4 weeks, which is followed by about 7.5 mg / kg QW for at least about 4 weeks, and which is followed by about 15 mg / kg QW, wherein the dose is mg of tividenofusp alfa per kg of body weight.

[0013] Certain embodiments also provide a kit for treatment of Hunter syndrome in a subject in need thereof, the kit comprising a pharmaceutically acceptable dosage form comprising tividenofusp alfa configured for intravenous administration at a dose of 3 mg / kg to 15 mg / kg, and instructions for administering the pharmaceutically acceptable dosage form at about 3 mg / kg QW for at least about 4 weeks, followed by about 7.5 mg / kg QW for at least about 4 weeks, and followed by about 15 mg / kg QW, wherein the dose is mg of tividenofusp alfa per kg of body weight.

[0014] Certain embodiments also provide a method of administering tividenofusp alfa to a subject in need thereof, comprising reconstituting a tividenofusp alfa lyophilized product in 5.2 mL of sterile water to provide a reconstituted tividenofusp alfa solution that contains tividenofusp alfa at a concentration of about 30 mg / mL; diluting the reconstituted tividenofusp alfa solution in 0.9% sodium chloride to provide a diluted tividenofusp alfa solution having a final concentration of from about 0.6 mg / mL to about 15 mg / mL; and administering the diluted tividenofusp alfa solution by intravenous infusion to the subject. In certain embodiments, the diluted tividenofusp alfa solution is administered according to an infusion schedule described herein.

[0015] Certain embodiments provide tividenofusp alfa for use in a method of administration to a subject in need thereof, the method comprising reconstituting a tividenofusp alfa lyophilized product in 5.2 mL of sterile water to provide a reconstituted tividenofusp alfa solution that contains tividenofusp alfa at a concentration of about 30 mg / mL; diluting the reconstituted tividenofusp alfa solution in 0.9% sodium chloride to provide a diluted tividenofusp alfa solution having a final concentration of from about 0.6 mg / mL to about 15 mg / mL; andDNL-016-14-WO - 02900.064WO1

[0016] administering the diluted tividenofusp alfa solution by intravenous infusion to the subject. In certain embodiments, the diluted tividenofusp alfa solution is administered according to an infusion schedule described herein.

[0017] Certain embodiments provide the use of tividenofusp alfa in the preparation of a medicament for the administration of the medicament by intravenous infusion to a subject in need thereof, wherein the medicament is prepared by reconstituting a tividenofusp alfa lyophilized product in 5.2 mL of sterile water to provide a reconstituted tividenofusp alfa solution that contains tividenofusp alfa at a concentration of about 30 mg / mL; diluting the reconstituted tividenofusp alfa solution in 0.9% sodium chloride to provide the medicament having a final concentration of from about 0.6 mg / mL to about 15 mg / mL. In certain embodiments, the administration of the medicament by intravenous infusion is according to an infusion schedule described herein.

[0018] Certain embodiments also provide a method of treating an infusion-associated reaction (IAR) in a subject receiving a tividenofusp alfa infusion according to an infusion schedule, the method comprising 1) stopping the tividenofusp alfa infusion and / or reducing the tividenofusp alfa infusion rate by at least 50% from the subject’s current rate of infusion; 2) subsequently, restarting the administration of the tividenofusp alfa infusion if needed and increasing the infusion rate, in a step-wise manner, to the rate of infusion the subject had been receiving prior to the implementation of step 1); and 3) continuing the administration of the tividenofusp alfa infusion by resuming the infusion schedule, wherein the infusion schedule is as follows: (a) For a total infusion volume of about 25 mL, infuse for the first hour at about 2.5 mL / hour, infuse for the second hour at about 5 mL / hour, and then infuse at about 10 mL / hour from the third hour until completion of infusion; or (b) For a total infusion volume of about 50 mL, infuse for the first hour at about 5 mL / hour, infuse for the second hour at about 10 mL / hour, and then infuse at about 20 mL / hour from the third hour until completion of infusion; or (c) For a total infusion volume of about 100 mL, infuse for the first hour at about 10 mL / hour, infuse for the second hour at about 20 mL / hour, and then infuse at about 40 mL / hour from the third hour until completion of infusion; or (d) For a total infusion volume of about 250 mL, infuse for the first hour at about 25 mL / hour, infuse for the second hour at about 50 mL / hour, and then infuse at about 100 mL / hour from the third hour until completion of infusion.DNL-016-14-WO - 02900.064WO1

[0019] BRIEF DESCRIPTION OF THE FIGURES

[0020] Figure 1. Scheme showing dosing for a Phase 1 / 2 study of patients diagnosed with MPS II.

[0021] Figure 2. Proportion of participants with at least one IRR by severity by 4-week intervals. Proportions were calculated based on the number of participants who had an IRR / the number of participants exposed to tividenofusp alfa at any point during that time interval (maximum of one IRR per participant, per interval; the IRR with the highest severity was included for each participant per time interval; ongoing IRRs were counted once in the interval of onset). nbrefers to the number of participants entering a given time interval.

[0022] Figure 3. Kaplan-Meier Plot of Time to First IRR by Prior ERT Status (up to Week 24). Abbreviations: ERT, enzyme replacement therapy; W, week.

[0023] DETAILED DESCRIPTION

[0024] Provided are methods of treating Hunter syndrome in a subject in need thereof by administering tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), according to an escalating dosing regimen described herein. Tividenofusp alfa is an enzyme replacement therapy that is designed to cross the BBB and is for treating both the peripheral and CNS manifestations of Hunter syndrome (see, Recommended INN: List 90, WHO Drug Information, Vol. 37, No. 3, 868-870 (2023); and CAS Registry No. 2641020-57-5). As described in the Examples, a subset of subjects receiving intravenous tividenofusp alfa have experienced IRRs associated with the administration of this therapy, wherein a majority of these subjects experienced their first IRR within the first 4 weeks of treatment. Accordingly, a dose escalation scheme for initiation of tividenofusp alfa has been developed, which may minimize the risk of dose reductions resulting from IRRs.

[0025] Accordingly, certain embodiments provide a method of treating Hunter syndrome in a subject in need thereof, comprising administering tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), by intravenous infusion to the subject according to a dosing regimen, wherein the dosing regimen of tividenofusp alfa (mg / kg of body weight) to be administered comprises: about 3 mg / kg QW for at least about 4 weeks, which is followed by about 7.5 mg / kg QW for at least about 4 weeks, and which is followed by about 15 mg / kg QW. In certain embodiments, 15 mg / kg QW is a maintenance dose. In certain embodiments, such a method may further comprise steps as described herein for preparing a tividenofusp alfa solutionDNL-016-14-WO - 02900.064WO1

[0026] suitable for intravenous infusion ( / .< ., a diluted tividenofusp alfa solution). In certain embodiments, a subject may experience an adverse event, such as an infusion related reaction (IRR), and as such, a method of treating Hunter syndrome as described herein may further comprise steps for treating the IRR (e.g., steps as described herein, such as in Example 2).

[0027] As described herein, the subject is dose escalated after at least 4 weekly doses of a given dose (e.g., from about 3 mg / kg to about 7.5 mg / kg or from about 7.5 mg / kg to about 15 mg / kg) based on treatment tolerability. In certain embodiments, the subject is dose escalated after at least 4 consecutive weekly doses of a given dose based on treatment tolerability. As used herein, a subject is considered to have tolerated a given administered dose when 1) the given administration does not result in an IRR; or 2) the administration results in an IRR that may be managed by medications (e.g., one or more agents useful for the treatment of an IRR as described herein) and / or slowing down the infusion but the IRR management does not include a dose reduction (e.g., at least about 85%, 90%, 95%, or 100% of the dose is administered). In certain other embodiments, a subject is considered to have tolerated a given administered dose when the given administration does not result in an IRR. In certain embodiments, a subject is considered to have tolerated a given administered dose when the administration results in an IRR, but the IRR may be managed by medications and / or slowing down the infusion, but the IRR management does not include a dose reduction. In certain embodiments, a subject that experiences an IRR during an administration event, which necessitates a dose reduction for management, would continue to be administered the given dose level for at least 4 more weeks before escalating to the next dose level (e.g., a subject that experienced an IRR that was associated with a third dose at the 7.5 mg / kg level, wherein the IRR resulted in a dose reduction for that administration event, would be administered at least four additional doses at the 7.5 mg / kg level before escalating to the 15 mg / kg level). In certain embodiments, the subject is escalated to the next dosing level after 1) having been administered at least four weekly doses at a given level; and 2) having not experienced an IRR that required a dose reduction at the given dose level. In certain embodiments, the subject is escalated to the next dosing level after 1) having been administered at least four consecutive weekly doses at a given level; and 2) having not experienced an IRR that required a dose reduction at the given dose level.

[0028] In certain embodiments, the subject is administered about 3 mg / kg QW for about 4 weeks to about 10 weeks. In certain embodiments, the subject is administered about 3 mg / kg QW for about 4 weeks to about 8 weeks. In certain embodiments, the subject is administeredDNL-016-14-WO - 02900.064WO1

[0029] about 3 mg / kg QW for about 4 weeks. In certain embodiments, the subject is administered about 3 mg / kg QW for about 5 weeks. In certain embodiments, the subject is administered about 3 mg / kg QW for about 6 weeks. In certain embodiments, the subject is administered about 3 mg / kg QW for about 7 weeks. In certain embodiments, the subject is administered about 3 mg / kg QW for about 8 weeks. In certain embodiments, the specified number of weeks are consecutive (e.g., a subject has not missed a dosing week and / or has not experienced a dose reduction).

[0030] In certain embodiments, the subject is administered about 7.5 mg / kg QW for about 4 weeks to about 10 weeks. In certain embodiments, the subject is administered about 7.5 mg / kg QW for about 4 weeks to about 8 weeks. In certain embodiments, the subject is administered about 7.5 mg / kg QW for about 4 weeks. In certain embodiments, the subject is administered about 7.5 mg / kg QW for about 5 weeks. In certain embodiments, the subject is administered about 7.5 mg / kg QW for about 6 weeks. In certain embodiments, the subject is administered about 7.5 mg / kg QW for about 7 weeks. In certain embodiments, the subject is administered about 7.5 mg / kg QW for about 8 weeks. In certain embodiments, the specified number of weeks are consecutive (e.g., a subject has not missed a dosing week and / or has not experienced a dose reduction).

[0031] As described herein, tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), is administered intravenously. Intravenous administration of tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), by infusion may be, e.g., over a period of at least about 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 8 hours, 8.5 hours, or 10 hours. In some embodiments, tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), is administered intravenously over a period of time that does not exceed 8 hours (e.g., less than about 8 hours). In some embodiments, tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), is administered intravenously over a period of from about 20 minutes to 6 hours, or from about 30 minutes to 5 hours. In some embodiments, the tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), is administered intravenously over a period of from about 3 hours to 6 hours. In some embodiments, tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), is administered intravenously over a period of from about 3 hours to 5 hours. In some embodiments, the tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), is administeredDNL-016-14-WO - 02900.064WO1

[0032] intravenously over a period of from about 3 hours to 4.5 hours. In some embodiments, the tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), is administered intravenously over a period of about 3 hours. In some embodiments, the tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), is administered intravenously over a period of about 4.5 hours. In some embodiments, the tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), is administered intravenously over a period of about 4 hours. In some embodiments, the tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), is administered intravenously over a period of about 3 hours.

[0033] In certain embodiments, intravenous administration of tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), by infusion may be according to an infusion schedule (e.g., that is based on total infusion volume), wherein the rate of infusion may vary over the delivery period. In certain embodiments, the infusion rate is increased every hour based on patient tolerance. In certain embodiments, the total infusion volume is 25 mL and tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), is administered according to the following infusion schedule: infuse for the first hour at about 2.5 mL / hour, infuse for the second hour at about 5 mL / hour, and then infuse at about 10 mL / hour from the third hour until completion of infusion. In certain embodiments, the total infusion volume is 50 mL and tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), is administered according to the following infusion schedule: infuse for the first hour at about 5 mL / hour, infuse for the second hour at about 10 mL / hour, and then infuse at about 20 mL / hour from the third hour until completion of infusion. In certain embodiments, the total infusion volume is 100 mL and tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), is administered according to the following infusion schedule: infuse for the first hour at about 10 mL / hour, infuse for the second hour at about 20 mL / hour, and then infuse at about 40 mL / hour from the third hour until completion of infusion. In certain embodiments, the total infusion volume is 250 mL and tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), is administered according to the following infusion schedule: infuse for the first hour at about 25 mL / hour, infuse for the second hour at about 50 mL / hour, and then infuse at about 100 mL / hour from the third hour until completion of infusion.

[0034] In certain embodiments, the treatment regimen further comprises administering to the subject one or more therapeutic agents useful for treating an infusion related reaction (IRR), e.g., a hypersensitivity reaction. Such therapeutic agents include, but are not limited to, anDNL-016-14-WO - 02900.064WO1

[0035] antihistamine, an antipyretic (e.g., an NSAID or acetaminophen), a steroid (e.g., a corticosteroid, such a glucocorticoid), and combinations thereof. The administration of such therapeutic agents, or combinations thereof, is also referred to herein as “premedication” and encompasses the administration of said agents prior to, concurrent with, or after the administration of a tividenofusp alfa dose.

[0036] Accordingly, in certain embodiments, the one or more therapeutic agents are selected from the group consisting of: an antihistamine, an antipyretic (e.g., an NSAID or acetaminophen), a steroid (e.g., a corticosteroid), and combinations thereof. In certain embodiments, the one or more therapeutic agents comprise an NSAID or acetaminophen. In certain embodiments, the one or more therapeutic agents comprise diphenhydramine. In certain embodiments, the one or more therapeutic agents comprise epinephrine. In certain embodiments, the one or more therapeutic agents comprise a combination of at least one antipyretic and at least one antihistamine. In certain embodiments, the one or more therapeutic agents comprise a combination of an NSAID or acetaminophen and at least one antihistamine. In certain embodiments, the one or more therapeutic agents comprise a combination of an NSAID or acetaminophen and diphenhydramine. In certain embodiments, the one or more therapeutic agents comprise a combination of an NSAID or acetaminophen, diphenhydramine, and epinephrine.

[0037] When a combination of two or more therapeutic agents that are useful for treating an IRR are administered, they can be formulated separately or in a single composition. When the agents are formulated separately, they can be administered at essentially the same time, i.e., concurrently, or at separately staggered times, i.e., sequentially.

[0038] In certain embodiments, the one or more agents are administered prior to the administration of a tividenofusp alfa dose (e.g., prior to the administration of a dose of a composition comprising tividenofusp alfa), co-administered with a tividenofusp alfa dose (e.g., co-administered with a dose of a composition comprising tividenofusp alfa), and / or administered after a tividenofusp alfa dose (e.g., administered after a dose of a composition comprising tividenofusp alfa). In certain embodiments, the one or more agents are administered prior to the administration of a tividenofusp alfa dose (e.g., prior to an initial dose of tividenofusp alfa). For example, in certain embodiments, the one or more agents are administered up to about 24 hours prior to the administration of a tividenofusp alfa dose. In certain embodiments, the one or more agents are administered up to about 12 hours prior to the administration of a tividenofusp alfaDNL-016-14-WO - 02900.064WO1

[0039] dose. In certain embodiments, the one or more agents are administered up to about 4 hours prior to the administration of a tividenofusp alfa dose. In certain embodiments, the one or more agents are administered up to about 2 hours prior to the administration of a tividenofusp alfa dose. In certain embodiments, the one or more agents are administered about 30 minutes prior to the administration of a tividenofusp alfa dose. In certain embodiments, the one or more therapeutic agents are co-administered with a tividenofusp alfa dose. For example, co-administration may involve interrupting the infusion of tividenofusp alfa and administering one or more therapeutic agents that are useful for treating an IRR prior to continuing the infusion. In certain embodiments, the one or more therapeutic agents are administered concurrently with administration (e.g., infusion) of a tividenofusp alfa dose. In certain embodiments, the one or more therapeutic agents are administered about 3, 4 or 5 hours after initiation of the administration (e.g., infusion) of a tividenofusp alfa dose. In certain embodiments, the one or more therapeutic agents are administered after a tividenofusp alfa dose. For example, in certain embodiments, the one or more therapeutic agents are administered up to about 48 hours after the administration of a tividenofusp alfa dose. In certain embodiments, the one or more therapeutic agents are administered up to about 24 hours after the administration of a tividenofusp alfa dose. In certain embodiments, the one or more agents are administered prior to the administration of a tividenofusp alfa dose and co-administered with a tividenofusp alfa dose. For example, in certain embodiments, the one or more agents are administered about 30 minutes prior to the administration of a tividenofusp alfa dose and about 4 hours after the administration of the tividenofusp alfa dose is initiated. In certain embodiments, the one or more agents are administered prior to the administration of a tividenofusp alfa dose and administered after a tividenofusp alfa dose. In certain embodiments, the one or more agents are co-administered with a tividenofusp alfa dose and administered after a tividenofusp alfa dose. In certain embodiments, the one or more agents are administered prior to the administration of a tividenofusp alfa dose, co-administered with a tividenofusp alfa dose, and administered after a tividenofusp alfa dose.

[0040] In certain embodiments, the dosing regimen reduces the subject’s risk of experiencing an IRR (e.g., a hypersensitivity reaction). In certain embodiments, the dosing regimen reduces the subject’s risk of experiencing a mild or moderate infusion reaction (e.g., a fever). In certain embodiments, the dosing regimen reduces the subject’s risk of experiencing a severe infusion reaction, such as anaphylaxis (e.g., anaphylaxis that meets the Sampson criteria (Sampson, etDNL-016-14-WO - 02900.064WO1

[0041] al., J Allergy Clin Immunol. 2006;117:391-397)). In certain embodiments, the dosing regimen reduces the subject’s risk of a dose reduction resulting from an IRR.

[0042] In certain embodiments, the treatment regimen further comprises administering to the subject an iron supplement.

[0043] In certain embodiments, a method described herein may further comprise obtaining a urine and / or serum sample from the subject prior to the administration of the first dose of tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition) (i.e., a baseline sample). In certain embodiments, a method described herein may further comprise obtaining a urine and / or serum sample from the subject after the administration of one or more tividenofusp alfa doses (e.g., one or more doses of a composition comprising tividenofusp alfa). In certain embodiments, a method described herein may further comprise measuring the levels of one or more glycosaminoglycans (GAGs) in the sample(s) (e.g., heparan sulfate (HS), dermatan sulfate (DS) and / or total GAG levels). In certain embodiments, a method described herein results in the reduction in the urine or serum levels of one or more GAGs as compared to corresponding levels in a control sample. In certain embodiments, a method described herein results in the reduction in the urine or serum levels of one or more GAGs as compared to corresponding levels in a baseline sample obtained from the subject prior to initiating treatment with tividenofusp alfa. In certain embodiments, a method described herein results in the normalization of urine or serum levels of one or more GAGs. For example, in certain embodiments, a method described herein results in the urine or serum levels of one or more GAGs to reduce to a level observed in a corresponding sample from a control subject (e.g., a healthy subject or subject that does not have Hunter syndrome). Methods for quantifying GAG levels (e.g., HS and / or DS levels) are known in the art, including by mass spectrometry (MS) (e.g., liquid chromatography-MS) (see, e.g., Pan et al. 2018. Bioanalysis 10(11):825-838; and Wang etal. 2018. Biomedical Chromatography 32:e4294 (12 pages)).

[0044] Anemia has been reported in subjects treated with tividenofusp alfa. Accordingly, a method described herein may further comprise steps for obtaining blood sample(s) from the subject and testing hemoglobin levels. For example, in certain embodiments, a method described herein may further comprise obtaining a blood sample from the subject prior to the administration of the first dose of tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition) (i.e., a baseline sample). In certain embodiments, a method described herein may further comprise obtaining a blood sample from the subject after theDNL-016-14-WO - 02900.064WO1

[0045] administration of one or more tividenofusp alfa doses (e.g., one or more doses of a composition comprising tividenofusp alfa). In certain embodiments, a method described herein may further comprise obtaining a blood sample from the subject 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 18 months or more after initiation of tividenofusp alfa. In certain embodiments, a method described herein may further comprise obtaining a blood sample from the subject 3 months after initiation of tividenofusp alfa, and optionally, periodically thereafter as clinically indicated. In certain embodiments, a method described herein may further comprise measuring hemoglobin levels in the sample(s). In certain embodiments, a method described herein results in the reduction in hemoglobin levels in the blood of the subject as compared to corresponding levels in a control sample (e.g., as compared to corresponding levels in a baseline sample obtained from the subject prior to initiating treatment with tividenofusp alfa). Accordingly, as noted above, in certain embodiments, the subject may be further administered an iron supplement. Methods for quantifying hemoglobin levels are known in the art.

[0046] In certain embodiments, tividenofusp alfa is comprised in a pharmaceutical composition that further comprises a pharmaceutically acceptable excipient. In certain embodiments, the pharmaceutical composition can include at least one of (a) a buffer; and (b) an isotonicity agent, such as a salt. In certain embodiments, the pharmaceutical composition further comprises one or more additional components such as, e.g., a surfactant; and / or one or more stabilizers.

[0047] Exemplary pharmaceutical compositions for the formulation of tividenofusp alfa are also described in WO 2020 / 206320 (see, ETV:IDS 35.23.2). In certain embodiments, tividenofusp alfa is comprised in a pharmaceutical composition as described in Example 1 or Example 2.

[0048] In certain embodiments, tividenofusp alfa may be provided as a lyophilized product and a reconstituted tividenofusp alfa solution may be prepared as described herein (see, e.g., Example 2). In certain embodiments, a tividenofusp alfa lyophilized product may be reconstituted in about 5.2 mL of sterile water to provide a reconstituted tividenofusp alfa solution that contains tividenofusp alfa at a concentration of about 30 mg / mL. In certain embodiments, the reconstituted tividenofusp alfa solution is diluted to prepare a solution suitable for infusion, e.g., using a method described herein, such as in Example 2. In certain embodiments, the reconstituted tividenofusp alfa solution is diluted in 0.9% sodium chloride to provide a diluted tividenofusp alfa solution having a final concentration of from about 0.6 mg / mL to about 15 mg / mL. In certain embodiments, the diluted tividenofusp alfa solution has a total volume of about 25 mL (i.e., the infusion volume). In certain embodiments, the dilutedDNL-016-14-WO - 02900.064WO1

[0049] tividenofusp alfa solution has a total volume of about 50 mL. In certain embodiments, the diluted tividenofusp alfa solution has a total volume of about 100 mL. In certain embodiments, the diluted tividenofusp alfa solution has a total volume of about 250 mL.

[0050] Accordingly, certain embodiments provide a method of preparing a diluted tividenofusp alfa solution suitable for intravenous infusion, the method comprising reconstituting a tividenofusp alfa lyophilized product in about 5.2 mL of sterile water to provide a reconstituted tividenofusp alfa solution that contains tividenofusp alfa at a concentration of about 30 mg / mL; and diluting the reconstituted tividenofusp alfa solution in 0.9% sodium chloride to provide the diluted tividenofusp alfa solution, which has a final concentration of from about 0.6 mg / mL to about 15 mg / mL. In certain embodiments, the method further comprises administering the diluted tividenofusp alfa solution to a subject in need thereof. As such, certain embodiments also provide a method of method of administering tividenofusp alfa to a subject in need thereof, comprising reconstituting a tividenofusp alfa lyophilized product in about 5.2 mL of sterile water to provide a reconstituted tividenofusp alfa solution that contains tividenofusp alfa at a concentration of about 30 mg / mL; diluting the reconstituted tividenofusp alfa solution in 0.9% sodium chloride to provide a diluted tividenofusp alfa solution having a final concentration of from about 0.6 mg / mL to about 15 mg / mL; and administering the diluted tividenofusp alfa solution by intravenous infusion to the subject. In certain embodiments, the diluted tividenofusp alfa solution is administered to the subject according to an infusion schedule described herein (e.g., wherein the selected schedule is based on total infusion volume; see, e.g., Table 3). For example, in certain embodiments, the diluted tividenofusp alfa solution is administered to the subject according to one of the following infusion schedules: (a) for a total infusion volume of about 25 mL, infuse for the first hour at about 2.5 mL / hour, infuse for the second hour at about 5 mL / hour, and then infuse at about 10 mL / hour from the third hour until completion of infusion; or (b) for a total infusion volume of about 50 mL, infuse for the first hour at about 5 mL / hour, infuse for the second hour at about 10 mL / hour, and then infuse at about 20 mL / hour from the third hour until completion of infusion; or (c) for a total infusion volume of about 100 mL, infuse for the first hour at about 10 mL / hour, infuse for the second hour at about 20 mL / hour, and then infuse at about 40 mL / hour from the third hour until completion of infusion; or (d) for a total infusion volume of about 250 mL, infuse for the first hour at about 25 mL / hour, infuse for the second hour at about 50 mL / hour, and then infuse at about 100 mL / hour from the third hour until completion of infusion. In certain embodiments, the infusion rate is increased every hourDNL-016-14-WO - 02900.064WO1

[0051] based on patient tolerance. In certain embodiments, intravenous administration of tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), by infusion may be over a period of time described herein. For example, in certain embodiments, the total infusion duration does not exceed 8 hours. In certain embodiments, the total infusion duration is about 4 hours. In certain embodiments, the total infusion duration is about 3 hours.

[0052] Adverse Events

[0053] As described herein, subjects administered tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), may experience an adverse event, such as an infusion related / associated reaction (e.g., a hypersensitivity reaction). Hypersensitivity (also referred to as “hypersensitivity reaction”) is often used to describe a number of conditions related to an exaggerated response of the body to a foreign agent; such conditions include, e.g., allergic reactions of all types. In addition to medication options described herein, such reactions (i.e., an infusion related / associated reaction, including, e.g., hypersensitivity) may also be treated by 1) stopping the infusion treatment and / or reducing the infusion rate of the treatment by at least about 50% from the subject’s current infusion rate; and 2) subsequently titrating to an infusion rate (e.g., gradually increasing, in a step-wise manner, to a target infusion rate) as tolerated by the subject. For example, certain embodiments provide a method of treating an infusion-associated reaction in a subject receiving a tividenofusp alfa infusion according to an infusion schedule, the method comprising 1) stopping the tividenofusp alfa infusion and / or reducing the tividenofusp alfa infusion rate by at least about 50% from the subject’s current infusion rate (i.e., in the subject experiencing an IAR); and 2) subsequently restarting the administration of the tividenofusp alfa infusion and / or increasing, in a step-wise manner, to a tividenofusp alfa infusion rate as tolerated by the subject. In certain embodiments of step 2), the tividenofusp alfa infusion rate is increased to the rate of infusion the subject had been receiving prior to the implementation of step 1). In certain embodiments, the infusion rate is increased every hour based on patient tolerance. In certain embodiments, the method further comprises 3) continuing the administration of the tividenofusp alfa infusion by resuming the infusion schedule. In certain embodiments, the infusion rate follows an infusion rate schedule as described herein (e.g., Table 3). For example, in certain embodiments, the total infusion volume is 25 mL and tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), is administered according to the following infusion schedule: infuse for the first hour at about 2.5 mL / hour,DNL-016-14-WO - 02900.064WO1

[0054] infuse for the second hour at about 5 mL / hour, and then infuse at about 10 mL / hour from the third hour until completion of infusion. In certain embodiments, the total infusion volume is 50 mL and tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), is administered according to the following infusion schedule: infuse for the first hour at about 5 mL / hour, infuse for the second hour at about 10 mL / hour, and then infuse at about 20 mL / hour from the third hour until completion of infusion. In certain embodiments, the total infusion volume is 100 mL and tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), is administered according to the following infusion schedule: infuse for the first hour at about 10 mL / hour, infuse for the second hour at about 20 mL / hour, and then infuse at about 40 mL / hour from the third hour until completion of infusion. In certain embodiments, the total infusion volume is 250 mL and tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), is administered according to the following infusion schedule: infuse for the first hour at about 25 mL / hour, infuse for the second hour at about 50 mL / hour, and then infuse at about 100 mL / hour from the third hour until completion of infusion. In a particular example, if step 1) of the method is implemented during the second hour of any of the foregoing embodiments, the tividenofusp alfa infusion rate is increased to the stated rate of the second hour as quickly as tolerated by the patient before continuing to the final (e.g., third hour) infusion rate until completion of infusion. In a further example, if step 1) of the method is implemented during the third hour or later of any of the foregoing embodiments, the tividenofusp alfa infusion rate is increased to the stated rate of the third hour as quickly as tolerated by the patient and continues at the stated rate until completion of infusion. In certain embodiments, the method further comprises administering to the subject one or more therapeutic agents as described herein that are useful for treating an IRR.

[0055] Subjects

[0056] The term “subject,” “individual,” “patient,” and “participant,” as used interchangeably herein, refers to a human subject.

[0057] In certain embodiments, the subject is a male subject.

[0058] In certain embodiments, the subject is a human male subject.

[0059] In certain embodiments, the subject is from about 1 month to 30 years of age. In certain embodiments, the subject is from about 6 months to 30 years of age. In certain embodiments, the subject is from about 1 to 30 years of age. In certain embodiments, the subject is from aboutDNL-016-14-WO - 02900.064WO1

[0060] 1 to 25 years of age. In certain embodiments, the subject is from about 1 to 18 years of age. In certain embodiments, the subject is from about 2 to 18 years of age. In certain embodiments, the subject is from about 2 to 15 years of age. In certain embodiments, the subject is from about 2 to 10 years of age. In certain embodiments, the subject is from about 5 to 10 years of age. In certain embodiments, the subject is 18 years of age or less. In certain embodiments, the subject is less than 18 years of age. In certain embodiments, the subject is less than 4 years of age. In certain embodiments, the subject is less than 2 years of age. In certain embodiments, the subject is less than 1 year of age. In certain embodiments, the subject is more than 1 year of age. In certain embodiments, the subject is about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 or 18 years of age.

[0061] In certain embodiments, the subject has a weight of > 5 kg. In certain embodiments, the subject has a weight of > 5 kg. In certain embodiments, the subject has a weight of > 9 kg. In certain embodiments, the subject has a weight of > 15 kg. In certain embodiments, the subject has a weight of > 19 kg. In certain embodiments, the subject has a weight of > 23 kg. In certain embodiments, the subject has a weight of > 27 kg. In certain embodiments, the subject has a weight of > 32 kg. In certain embodiments, the subject has a weight of > 36 kg. In certain embodiments, the subject has a weight of > 41 kg. In certain embodiments, the subject has a weight of > 45 kg. In certain embodiments, the subject has a weight of > 50 kg.

[0062] In certain embodiments, the subject has neuronopathic Hunter syndrome, also referred to as neuronopathic MPSII (nMPSII). In certain embodiments, the subject has non-neuronopathic Hunter syndrome. In certain embodiments, the subject has Hunter syndrome with an unknown neuronopathic phenotype.

[0063] In certain embodiments, the subject has a documented mutation in the IDS gene. In certain embodiments, the subject has been diagnosed as having reduced IDS enzyme activity. In certain embodiments, subject has been diagnosed with Hunter syndrome based on reduced IDS enzyme activity and a documented mutation in the IDS gene. In certain embodiments, the subject has a same genetic mutation in the IDS gene as a blood relative with confirmed neuronopathic Hunter Syndrome / nMPS II. In certain embodiments, the subject has neuronopathic Hunter syndrome / nMPS II or has a same genetic mutation in the IDS gene as a blood relative with confirmed neuronopathic Hunter Syndrome / nMPS II.

[0064] In certain embodiments, the subject had previously received idursulfase enzyme replacement therapy (e.g., for more than 4 months, more than 6 months, more than 1 year, moreDNL-016-14-WO - 02900.064WO1

[0065] than 18 months, more than 2 years, or longer) and then switched to the administration of tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), (e.g., without a washout period (i.e., switched from weekly intravenous idursulfase administration to weekly intravenous tividenofusp alfa administration without treatment interruption)).

[0066] In certain embodiments, the subject had pre-existing AD As against IDS prior to administration of tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition). In certain embodiments, the subject’s pre-existing titer of AD As against IDS is greater than 1:100, 1:150, 1:200, 1:300, 1:400, 1:500, 1:1,000, 1:5,000, 1:10,000, 1:25,000, 1:50,000, 1:75,000, 1:100,000, 1:250,000, 1:500,000, 1:1,000,000, 1:2,000,000, 1:3,000,000, 1:4,000,000, 1:5,000,000, 1:10,000,000 or more. In certain embodiments, the subject’s preexisting titer of AD As against IDS ranges from 1 :63 to greater than 1:11 million. In certain embodiments, the subject’s pre-existing titer of AD As against IDS ranges from 1:189 to greater than 1:11 million. In certain embodiments, the subject’s pre-existing titer of AD As against IDS is greater than 1 : 1 million. In certain embodiments, the subject’s pre-existing titer of AD As against IDS is greater than 1:10 million. In certain embodiments, the subject’s pre-existing titer of AD As against IDS is greater than 1:11 million.

[0067] In certain embodiments, the subject has a cognitive deficit.

[0068] In certain embodiments, the subject has a behavioral deficit.

[0069] In certain embodiments, the subject has a deficit in their physical abilities.

[0070] In certain embodiments, a deficit in the subject is determined by comparing a baseline level in the subject prior to treatment with tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), to a healthy subject or a subject that does not have Hunter syndrome.

[0071] Kits

[0072] In certain aspects, kits comprising tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), and instructional materials containing directions (i.e., dosing regimens / protocols) for practicing a method as described herein are provided. In certain embodiments, a kit for use in a method as described herein for treating Hunter syndrome comprising a tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), is provided and instructional materials containing directions (i.e., dosing regimens / protocols) for practicing a method as described herein are provided.DNL-016-14-WO - 02900.064WO1

[0073] In certain embodiments, the instructions include directions for administering a tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), based on a dosing regimen as described herein. In certain embodiments, the instructions further include directions for preparing a diluted tividenofusp alfa solution suitable for intravenous infusion. For example, the instructions may include instructions for reconstituting a tividenofusp alfa lyophilized product and for further diluting the reconstituted solution (see, e.g., Example 2). While the instructional materials typically comprise written or printed materials, they are not limited to such. Any medium capable of storing such instructions and communicating them to an end user is contemplated by this disclosure. Such media include, but are not limited to, electronic storage media (e.g., magnetic discs, tapes, cartridges, chips), optical media (e.g., CD-ROM), and the like. Such media may include addresses to internet sites that provide such instructional materials.

[0074] Certain embodiments also provide one or more containers (e.g., vials) comprising a tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), wherein the one or more containers comprise an amount of tividenofusp alfa suitable for preparing one or more doses in a dosing regimen described herein. Certain embodiments also provide a kit comprising one or more containers (e.g., vials) comprising a tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), and instructions for initiating treatment with tividenofusp alfa according to a dosing regimen described herein, wherein the one or more containers comprise an amount of tividenofusp alfa suitable for preparing one or more doses in the dosing regimen. In certain embodiments, tividenofusp alfa is provided in a single-dose vial in the amount of 150 mg lyophilized powder for reconstitution and further dilution (see, Example 2).

[0075] Certain embodiments provide a kit for treatment of Hunter syndrome in a subject in need thereof, the kit comprising a pharmaceutically acceptable dosage form comprising tividenofusp alfa configured for intravenous administration at a dose of 3 mg / kg to 15 mg / kg, and instructions for administering the pharmaceutically acceptable dosage form at about 3 mg / kg QW for at least about 4 weeks, followed by about 7.5 mg / kg QW for at least about 4 weeks, and followed by about 15 mg / kg QW, wherein the dose is mg of tividenofusp alfa per kg of body weight. In certain embodiments, the instructions further comprise instructions to treat an infusion-associated reaction (IAR) in the subject receiving the pharmaceutically acceptable dosage form, wherein the subject is receiving the pharmaceutically acceptable dosage form according to an infusion schedule, the instructions to treat the IAR comprising: 1) stopping theDNL-016-14-WO - 02900.064WO1

[0076] infusion and / or reducing the infusion rate by at least 50% from the subject’s current rate of infusion; and 2) subsequently, restarting the administration of the infusion if needed and increasing the infusion rate, in a step-wise manner, to the rate of infusion the subject had been receiving prior to the implementation of step 1); and 3) continuing the administration of the infusion by resuming the infusion schedule, wherein the infusion schedule is as follows: (a) For a total infusion volume of about 25 mL, infuse for the first hour at about 2.5 mL / hour, infuse for the second hour at about 5 mL / hour, and then infuse at about 10 mL / hour from the third hour until completion of infusion; or (b) For a total infusion volume of about 50 mL, infuse for the first hour at about 5 mL / hour, infuse for the second hour at about 10 mL / hour, and then infuse at about 20 mL / hour from the third hour until completion of infusion; or (c) For a total infusion volume of about 100 mL, infuse for the first hour at about 10 mL / hour, infuse for the second hour at about 20 mL / hour, and then infuse at about 40 mL / hour from the third hour until completion of infusion; or (d) For a total infusion volume of about 250 mL, infuse for the first hour at about 25 mL / hour, infuse for the second hour at about 50 mL / hour, and then infuse at about 100 mL / hour from the third hour until completion of infusion.

[0077] Certain embodiments also provide the use of tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), in the preparation of a kit for conducting a Hunter syndrome treatment method, wherein the method comprises administering the tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), to a subject in need thereof according to a dosing regimen described herein. In certain embodiments, tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), is administered according to an infusion schedule described herein (see, e.g., Table 3).

[0078] Certain embodiments provide the use of tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), in the manufacture of a kit for treating Hunter syndrome (MPS II) in a subject in need thereof, wherein the kit comprises one or more containers comprising tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), and optionally, instructions for administration, and wherein tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), is administered to the subject according to a dosing regimen described herein. For example, the instructions for administration can include a dosing regimen as described in Table A or Table 1. In certain embodiments, tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), is administered according to anDNL-016-14-WO - 02900.064WO1

[0079] infusion schedule described herein. For example, the instructions for administration can include an infusion schedule as described in Table 3.

[0080] Certain Definitions

[0081] As used herein, the singular forms “a,” “an,” and “the” include plural referents unless the content clearly dictates otherwise.

[0082] The term “subject,” “individual,” “patient,” and “participant,” as used interchangeably herein, refer to a human subject. In some embodiments, the human is a patient in need of treatment for Hunter syndrome. In some embodiments, the patient has one or more signs or symptoms of Hunter syndrome.

[0083] As used herein, the term “tividenofusp alfa” refers to an enzyme replacement therapy that is designed to cross the BBB and is for treating both the peripheral and CNS manifestations of Hunter syndrome. A description of tividenofusp alfa, including sequence and structure information, is provided in “Recommended INN: List 90”, WHO Drug Information, Vol. 37, No. 3, 868-870 (2023), which is incorporated by reference herein in its entirety for all purposes (see, also CAS Registry No. 2641020-57-5, which is incorporated by reference herein in its entirety for all purposes). As described in the tividenofusp alfa INN listing, the protein may undergo a variety of post-translational modifications (PTMs), including but not limited to, C-terminal lysine clipping in the protein and a cysteine to formylglycine modification in the IDS portion of the protein. A certain level of protein heterogeneity is inherent in the recombinant protein production process, and as such, the PTM profile between individual protein molecules may vary, wherein the incidence of a given PTM may be independent of the incidence of other PTMs. Accordingly, the term “tividenofusp alfa” encompasses protein molecules with varying PTM profiles, and as such, a composition comprising tividenofusp alfa may comprise a mixture of tividenofusp alfa protein molecules that have varying PTM profiles.

[0084] As used herein, the terms “about” and “approximately,” when used to modify an amount specified in a numeric value or range, indicate that the numeric value as well as reasonable deviations from the value known to the skilled person in the art, for example ± 20%, ± 10%, ± 5%, ± 4%, ± 3%, ± 2%, ± 1%, ± 0.5%, ± 0.25% are within the intended meaning of the recited value. For example, a dose of about, e.g., 3 mg / kg of tividenofusp alfa, would include 3 mg / kg, as well as reasonable deviations from 3 mg / kg. Thus, in certain embodiments, a dose of about 3 mg / kg includes, e.g., 3 mg / kg ± 5%, ± 4%, ± 3%, ± 2%, ± 1%, ± 0.5%, or ± 0.25%. InDNL-016-14-WO - 02900.064WO1

[0085] certain embodiments, a dose of about 7.5 mg / kg includes, e.g., 7.5 mg / kg ± 5%, ± 4%, ± 3%, ± 2%, ± 1%, ± 0.5%, or ± 0.25%. In certain embodiments, a dose of about 15 mg / kg includes, e.g., 15 mg / kg ± 5%, ± 4%, ± 3%, ± 2%, ± 1%, ± 0.5%, or ± 0.25%.

[0086] As used herein, the terms “infusion related reaction (IRR)” and “infusion-associated reaction (IAR)” are used interchangeably and refer to an adverse reaction (e.g., a hypersensitivity reaction) to the infusion of a pharmacological or biological substance, which typically develops during or shortly after administration. Mild to moderate infusion reactions are associated with, e.g., chills, fever, mild hypotension, dyspnea and / or rash. Severe reactions are less common and are, amongst other symptoms, associated with, e.g., severe hypotension, anaphylaxis (including, e.g., anaphylaxis based on the Sampson criteria) and / or cardiac dysfunction.

[0087] As used herein, the phrase “sample” or “physiological sample” is meant to refer to a biological sample obtained from a subject that contains an analyte of interest (e.g., a GAG). In certain embodiments, the physiological sample comprises, e.g., CSF, urine, blood, serum, or plasma. In certain embodiments, the sample comprises urine. In certain embodiments, the sample comprises blood, plasma, or serum. In certain embodiments, the sample comprises serum.

[0088] The terms “control” or “control sample” refer to any sample or cohort appropriate to the experiment or detection technique employed. The controls may be positive or negative controls.

[0089] The terms “obtaining a sample from a subject”, “obtained from a subject” and similar phrasing, is used to refer to obtaining the sample directly from the subject, as well as obtaining the sample indirectly from the subject through an intermediary individual e.g., obtaining the sample from a courier who obtained the sample from a nurse who obtained the sample from the subject).

[0090] As described herein, levels of an analyte of interest (e.g., a GAG) may be compared to control or baseline levels. Such a control or baseline level may vary. For example, in certain embodiments, the term “control” may refer to a healthy subject or a subject that does not have Hunter syndrome (or a sample therefrom). Alternatively, the term “control” may refer to a Hunter syndrome patient that was not administered tividenofusp alfa or to the subject prior to treatment (or a sample therefrom). Similarly, a “baseline level” may refer to a level or a range of levels that is measured in, e.g., a healthy individual or in a subject that does not have Hunter syndrome. In certain other embodiments described herein, a “baseline level” may also refer to aDNL-016-14-WO - 02900.064WO1

[0091] level or a range of levels in a Hunter syndrome patient that was not administered tividenofusp alfa or in the subject prior to administration of tividenofusp alfa.

[0092] In certain embodiments, a control value or baseline level may be established using data from a population of control subjects. In some embodiments, the population of subjects is matched to a test subject according to one or more patient characteristics such as age, sex, ethnicity, or other criteria. In some embodiments, the control value is established using the same type of sample from the population of subjects (e.g, a sample comprising serum) as is used for assessing the levels in the test subject.

[0093] The terms “analyte level(s)”, “GAG levels”, “HS levels”, “DS levels”, and “hemoglobin levels” refer to the amount and / or concentration of analyte that is present, either in a subject or in a sample (e.g, a sample obtained from a subject). An analyte level can refer to an absolute amount and / or concentration of analyte that is present, or can refer to a relative amount and / or concentration.

[0094] As used herein, the term “normalized” or “normalization” refers to an analyte of interest having a level that falls within a normal range for the specified analyte, as determined by one or more healthy subjects or subjects that do not have Hunter syndrome. In some embodiments, a normalized level of an analyte is within the 10thto 90thpercentile range from the determined normal range for the analyte.

[0095] The term “pharmaceutically acceptable excipient” refers to a non-active pharmaceutical ingredient that is biologically or pharmacologically compatible for use in humans or animals, such as but not limited to a buffer, carrier, or preservative.

[0096] The term “administer” refers to a method of delivering agents (e.g., tividenofusp alfa or an agent useful for treating an IRR), compounds, or compositions (e.g., a pharmaceutical composition) to the desired site of biological action. These methods include, but are not limited to, oral, topical delivery, parenteral delivery, intravenous delivery, intradermal delivery, intramuscular delivery, or intraperitoneal delivery. In one embodiment, tividenofusp alfa, or a composition thereof (e.g., a pharmaceutical composition), is administered by intravenous infusion.

[0097] As used herein, “treatment” (and grammatical variations thereof such as “treat” or “treating”) refers to clinical intervention to alter the natural course of the individual being treated, and can be performed either for prophylaxis or during the course of clinical pathology. Desirable effects of treatment include, but are not limited to, preventing occurrence orDNL-016-14-WO - 02900.064WO1

[0098] recurrence of disease, alleviation of symptoms, diminishment of any direct or indirect pathological consequences of the disease, decreasing the rate of disease progression, amelioration or palliation of the disease state, and remission or improved prognosis.

[0099] The term “weekly” or “QW” as used herein refers to administration about once a week or once every 7 days, wherein at least two or more weekly doses are administered.

[0100] The term “maintenance dose” refers to a dose that has been deemed to be effective for a given therapeutic (e.g., tividenofusp alfa) in a subject, and is typically considered to be a therapeutically effective dose. The efficacy of the therapeutic can be based upon a desired pharmacodynamic effect (e.g., pharmacokinetic exposure and / or pharmacodynamic effect upon downstream signaling target or substrate). In some embodiments, the term “maintenance dose” refers to a dose of tividenofusp alfa that is able to reduce CSF HS by at least about 70%, 80%, or 90% relative to baseline (e.g., pre-treatment) levels in a subject. In some embodiments, the term “maintenance dose” refers to a dose of tividenofusp alfa that is able to reduce CSF HS to a level that is within a reference range measured from a population of healthy control subjects or a population of subjects who do not have Hunter syndrome (MPS II), i.e. is considered a normal, healthy level or is considered normalized.

[0101] The phrase “effective amount” means an amount of a compound / molecule described herein that (i) treats or prevents the particular disease, condition, or disorder, (ii) attenuates, ameliorates, or eliminates one or more symptoms of the particular disease, condition, or disorder, or (iii) prevents or delays the onset of one or more symptoms of the particular disease, condition, or disorder described herein.

[0102] A “therapeutically effective amount” of a substance / molecule disclosed herein may vary according to factors such as the disease state, age, sex, and weight of the individual, and the ability of the substance / molecule, to elicit a desired response in the individual. A therapeutically effective amount encompasses an amount in which any toxic or detrimental effects of the substance / molecule are outweighed by the therapeutically beneficial effects.

[0103] As used herein, the term “standard-of-care” refers to a therapy approved for the treatment of Hunter syndrome, including idursulfase enzyme replacement therapy (e.g., Elaprase).

[0104] An “iduronate sulfatase,” “iduronate-2-sulfatase,” or “IDS” as used herein refers to iduronate 2-sulfatase (EC 3.1.6.13), which is an enzyme involved in the lysosomal degradation of the glycosaminoglycans heparan sulfate and dermatan sulfate. Deficiency of IDS isDNL-016-14-WO - 02900.064WO1

[0105] associated with Mucopolysaccharidosis II, also known as Hunter syndrome. The structure of human IDS has been well-characterized. An illustrative structure is available under PDB accession code 5FQL. The structure is also described in Nat. Comm. 8:15786 doi:

[0106] 10.1038 / ncomms 15786, 2017.

[0107] The term “amino acid” refers to naturally occurring and synthetic amino acids, as well as amino acid analogs and amino acid mimetics that function in a manner similar to the naturally occurring amino acids.

[0108] The terms “polypeptide” and “peptide” are used interchangeably herein to refer to a polymer of amino acid residues in a single chain. The terms apply to amino acid polymers in which one or more amino acid residue is an artificial chemical mimetic of a corresponding naturally occurring amino acid, as well as to naturally occurring amino acid polymers and non-naturally occurring amino acid polymers. Amino acid polymers may comprise entirely L-amino acids, entirely D-amino acids, or a mixture of L and D amino acids.

[0109] The term “protein” as used herein refers to either a polypeptide or a dimer (z.e., two) or multimer (z.e., three or more) of single chain polypeptides. The single chain polypeptides of a protein may be joined by a covalent bond, e.g., a disulfide bond, or non-covalent interactions.

[0110] The following Examples are intended to be non-limiting.

[0111] EXAMPLE 1 : A Study to Determine the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of tividenofusp alfa in Pediatric Subjects with Hunter Syndrome

[0112] A study was performed to assess the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of tividenofusp alfa, an investigational central nervous system (CNS)-penetrant enzyme replacement therapy (ERT), designed to treat both the peripheral and CNS manifestations of Hunter syndrome (MPS II) (see, Figure 1). The study included a 24-week study period, followed by a safety extension period (80 weeks) and an open label extension (OLE) period (157 weeks) to evaluate the long-term safety and explore the potential clinical efficacy of tividenofusp alfa.

[0113] During the 24-week study period (Part 1), participants were administered tividenofusp alfa at an initial dose of 3, 7.5, or 15 mg / kg, and depending on their cohort assignment, either were maintained on the starting dose or underwent dose escalation to 7.5, 15, or 30 mg / kg (Figure 1). Cohort A received the maximum administered dose of 30 mg / kg QW throughout theDNL-016-14-WO - 02900.064WO1

[0114] safety extension following completion of dose escalation in the 24-week study period, whereas all other cohorts have received or are receiving 15 mg / kg QW in the safety extension (Part 2). All cohorts have been or are maintained on a dose of 15 mg / kg QW in the OLE (Part 3).

[0115] As outlined below, the totality of the data from this ongoing study indicates that dose escalation of tividenofusp alfa may reduce the risk of dose reductions due to IRRs during tividenofusp alfa initiation, thereby facilitating more rapid attainment of the 15 mg / kg dose.

[0116] RESULTS

[0117] Overall, tividenofusp alfa was generally well tolerated in pediatric participants with MPS II in the study, and the majority of treatment emergent adverse effects (TEAEs), including IRRs, were manageable without dose reductions, and were mild to moderate in severity.

[0118] Specifically, across all periods, 87.2% of participants experienced IRRs, of which most participants (92.7%) had IRRs that were mild or moderate (Figure 2). One participant (2.1%) discontinued the study in part due to a TEAE of IRR (and other adverse events considered not related to the drug). Two participants (4.3%), who remain in the study, experienced serious TEAEs owing to IRRs that resolved. One of these participants experienced a mild IRR and was hospitalized overnight for observation. The other participant experienced a severe IRR at weeks 3 and 4 that met Sampson criteria of anaphylaxis; the IRRs were managed with pre-infusion medications and dose and infusion rate reductions and the participant subsequently dose escalated to 15 mg / kg.

[0119] The majority of participants experienced their first IRR within the first 4 weeks of treatment (Figure 3). IRR frequency in most participants decreased over time and was clinically manageable with standard pre-medications and / or adjustment of infusion time. Over the 24-week study period, 18 of 47 (38.3%) of study participants experienced an IRR leading to temporary dose reductions. The proportion of participants with IRRs leading to dose reductions was highest in Cohort C (8 / 10 [80.0%] participants) and Cohort D (5 / 6 [83.3%] participants), both of which had study participants who were predominantly ERT naive (14 / 16 [87.5%]) and had a starting dose of 15 mg / kg. Tividenofusp alfa infusion appeared to be better tolerated in ERT-exposed participants who started at 3 mg / kg (fewer IRRs and no consecutive dose reductions) than in ERT-exposed participants who started at higher doses.

[0120] Premedications were used frequently over the first 24 weeks across all cohorts.

[0121] Premedications included antihistamines, NSAIDS / acetaminophen, steroids, leukotriene receptorDNL-016-14-WO - 02900.064WO1

[0122] antagonists, and anti emetics. Use of premedications in all categories and across all cohorts increased between Week 2-4 and Week 21-24, with the percentage of patients on each category of premedication relatively stable after Week 5-8. Premedication utilization is likely useful in management of IRRs and may contribute to the reduction in IRRs observed over time.

[0123] The proportion of participants receiving steroid premedication for IRRs was highest in Cohorts C and D (9 / 10 [90%] and 6 / 6 [100%] participants, respectively). In comparison, a lower proportion of participants in Cohorts A and Bl (7 / 13 [53.9%] participants) who were both ERT exposed and underwent dose escalation received steroid premedication. The profile of steroid premedication use, some of which was dependent on investigator discretion, may be related to cohort demographics and baseline characteristics, including prior therapy (gene therapy and HSCT) status, prior ERT status, and age.

[0124] Based on the totality of this study data, a dose escalation scheme for initiation of tividenofusp alfa is proposed, which has a starting dose at 3 mg / kg QW for a minimum of 4 weeks followed by a minimum of 4 weeks at 7.5 mg / kg QW, wherein escalation is based on patient tolerability (see, Table A for exemplary dosing escalation scheme). In the dose escalation scheme, the patient continues each dosage level for at least four weeks before escalating to the next dosage level. For example, once it is demonstrated that patients have tolerated 3 mg / kg QW for a minimum of 4 weeks, dose escalation to 7.5 mg / kg QW may proceed. Similarly, once it is demonstrated that patients have tolerated 7.5 mg / kg QW for a minimum of 4 weeks, dose escalation to 15 mg / kg QW is recommended. Dose escalation for initiating treatment with tividenofusp alfa is proposed independent of prophylactic premedication use for management of IRRs. However, the data collectively suggest that premedications are likely a useful adjunct to dose escalation in the management of ERT for MPS II. Accordingly, in some embodiments, dose escalation from a starting dose of 3 mg / kg as described herein, in addition to premedication use, is used in the initiation of tividenofusp alfa for treatment of MPS II.

[0125] Within the context of dose escalation for initiation of tividenfusp alfa, patient toleration of a given dose means that an IRR may occur but that it is manageable by medications / slowing down the infusion and without a dose reduction. For example, in the event that an IRR is managed by a dose reduction during an administration event, the week count is restarted, and the patient continues on the given dose for at least 4 more weeks before escalating to the next dose level. Medications for management of IRR include, e.g., antihistamines, NSAID / acetaminophen, and / or steroids. Such medications can be administered before, during, or after infusions.DNL-016-14-WO - 02900.064WO1

[0126] Table A. Recommended Dosage for the Tividenofusp Alfa

[0127]

[0128] In conclusion, a dose escalation scheme for initiation of tividenofusp alfa, starting at 3 mg / kg QW for a minimum of 4 weeks, followed by 7.5 mg / kg QW for a minimum of 4 weeks, then increased to 15 mg / kg QW, may be used to reduce the risk of IRRs, reduce the frequency of dose reductions (e.g., due to IRRs), improve tolerability, and allow patients to reach the therapeutic maintenance dose of 15 mg / kg QW in a timely manner.

[0129] METHODS

[0130] Tividenofusp alfa

[0131] Tividenofusp alfa (see, Recommended INN: List 90, WHO Drug Information, Vol. 37, No. 3, 868-870 (2023)) was produced and formulated using methods similar to those described in WO 2020 / 206320 (see, ETV:IDS 35.23.2), which is incorporated in its entirety for all purposes. Tividenofusp alfa was provided as an aqueous solution or a lyophilized powder for reconstitution. For the study, a pharmaceutical composition (whether as provided as an aqueous solution or a reconstituted powder) containing: 30 mg tividenofusp alfa per ml, in 20 mM sodium phosphate, 175 mM sucrose, 50 mM sodium chloride, 10 mM L-methionine,

[0132] 0.06% (w / v) polysorbate 20, pH 6.5, was diluted in 0.9% sodium chloride solution for infusion.

[0133] Study Design

[0134] The study includes Cohorts A-E: subjects with neuronopathic MPS II aged 5 to 10 years (Cohort A); subjects with MPS II, (neuronopathic, non-neuronopathic, or unknown phenotype) 1 to 18 years of age (Cohort B); subjects with neuronopathic MPS II who are younger than 4 years of age and subjects >4 years of age if subject is a blood relative of a subject <4 years of age (Cohort C); subjects with MPS II, either neuronopathic or non-neuronopathic, with preexisting hepatomegaly who have never taken standard-of-care ERT, and 18 years of age or younger (Cohort D); and subjects that have completed the biomarker protocol that are aged 1 to 18 years (Cohort E) (see, Figure 1). The study included an ascending-dose stage in Cohorts A and B toDNL-016-14-WO - 02900.064WO1

[0135] assess the safety, tolerability, PK, and PD of tividenofusp alfa over approximately 24 weeks. In particular, tividenofusp alfa was intravenously administered to the subjects weekly using dose escalation. For Cohort A, the dose escalation of tividenofusp alfa was: 3 mg / kg (“Dose A,” 2 weekly infusions), 7.5 mg / kg (“Dose B,” at least 2 weekly infusions); 15 mg / kg (“Dose C,” at least 4 weekly infusions), and 30 mg / kg (“Dose D,” weekly until completion). Cohort A received the maximum administered dose of 30 mg / kg QW from completion of dose escalation in the 24-week study period and throughout the safety extension (Parts 1 and 2 of the study). Cohort B includes three sub-cohorts with starting doses of 3 mg / kg (Bl), 7.5 mg / kg (B2), and 15 mg / kg (B3). After 24 weeks of dosing, all subjects in Cohort B received weekly doses of 15 mg / kg thereafter (during the safety extension period). The dose administered in Cohorts C, D, and E was 15 mg / kg during the 24-week study period and has been maintained in the safety extension period. All cohorts have been maintained on a dose of 15 mg / kg QW in the OLE (Part 3). During the study, based on emerging data, it was possible to increase the dose to the maximum permitted dose of 30 mg / kg for individual participants.

[0136] Administration of antipyretic and antihistamine premedication was recommended prior to and during infusion with tividenofusp alfa, and participants who had previously received premedication for ERT could continue on the same premedication regimen. If a participant experienced an IRR, the tividenofusp alfa infusion could be slowed or halted. Participants who experienced IRRs could receive additional premedications (e.g., antihistamines, antipyretics, corticosteroids, or other medications) as per the investigator’s discretion for the next infusion.

[0137] Administration of antipyretic and antihistamine premedications (e.g., acetaminophen and diphenhydramine) was recommended prior to starting tividenofusp alfa infusion, and administration of an antipyretic was recommended to be repeated later, even if the participant had never experienced an IRR previously with ERT. If the participant was previously taking premedications for standard-of-care ERT, the same regimen was recommended to be administered prior to tividenofusp alfa infusion. Attempts to gradually wean off premedications were recommended at the discretion of the investigator. In the event of hypersensitivity reactions during the visit, it was recommended to decrease, temporarily stop, or discontinue the infusion rate for that visit, but the total duration of infusion was not to exceed 8 hours, at which time the infusion was stopped, and the amount of administered dose was documented if dosing was incomplete.

[0138] The recommended total duration of tividenofusp alfa infusion was approximately 4.5DNL-016-14-WO - 02900.064WO1

[0139] hours, and the infusion time could be gradually reduced to 3 hours after infusions without any infusion-related adverse events.

[0140] Patients who were on standard of care (idursulfase) enzyme replacement treatment received weekly intravenous doses of tividenofusp alfa on Day 1 of the study after switching from the standard of care therapy. Patients who were treatment naive began weekly intravenous doses of tividenofusp alfa on Day 1 of the study. The study week approximates the number of doses received by the subject, wherein at week “N” of the study a subject has typically received “N-l” weekly doses; however, due to personal circumstances (e.g., illness unrelated to the treatment) a given subject may have missed one or more weekly doses during the specified period.

[0141] Inclusion Criteria

[0142] Study participants must have a confirmed diagnosis of MPS II. Participants enrolled in Cohort A are aged 5-10 years with neuronopathic MPS II. Participants enrolled in Cohort B are 1 to 18 years of age with non-neuronopathic MPS II, neuronopathic MPS II, or unknown phenotype. Participants enrolling in Cohort C are younger than 4 years of age with neuronopathic MPS II and can include participants >4 years of age if participant is a blood relative of a participant <4 years of age. Participants enrolling in Cohort D are 18 years of age or younger with non-neuronopathic MPS II or neuronopathic MPS II with preexisting hepatomegaly who have never taken standard-of-care ERT. Participants enrolling in Cohort E are 1 to 18 years of age. For subjects receiving intravenous iduronate 2-sulfastase (IDS) ERT, they are required to have tolerated a minimum of 4 months of therapy during the period immediately prior to screening.

[0143] Exclusion Criteria

[0144] Criteria for exclusion from the study include the following conditions or events: 1) unstable or poorly controlled medical condition(s) or significant medical or psychological comorbidity or comorbidities that may interfere with safe participation in the study or interpretation of study assessments; 2) use of any CNS-targeted MPS II ERT within 3 months before study start for participants aged >5 years, and within 6 months before study start for participants aged <5 years; 3) clinically significant thrombocytopenia, other clinically significant coagulation abnormality, or significant active bleeding, or required treatment with anDNL-016-14-WO - 02900.064WO1

[0145] anticoagulant or more than two antiplatelet agents; 4) contraindication for lumbar punctures; 5) have a clinically significant history of stroke, status epilepticus, head trauma with loss of consciousness, or any CNS disease that is not MPS II related within 1 year of screening; 6) have had a ventriculoperitoneal (VP) shunt placed, or any other brain surgery, or have a clinically significant VP shunt malfunction within 30 days of screening; 7) have any clinically significant CNS trauma or disorder that may interfere with assessment of study endpoints or make participation in the study unsafe, or 8) have clinically significant anemia, defined by an Hb level < 10.0 g / dL, < 6.2 mmol / L, or < 100 g / L.

[0146] Subjects

[0147] Any subjects who were on a standard-of-care (SOC) treatment (e.g., Elaprase, or idursulfase) prior to initiation of treatment with tividenofusp alfa were switched to tividenofusp alfa treatment without a washout period upon enrollment in the study. Anti -drug antibody titer information available for Cohort A indicated that four of the five subjects had anti-drug antibodies (AD As) against IDS at baseline, with titers ranging from 1 : 189 to greater than 1:11 million. Information for Cohorts Bl and B2 indicate that for participants who tested positive for AD As at baseline, titers ranged from 1 : 63 to greater than 1 : 1 million.

[0148] Safety Assessments

[0149] Safety was evaluated using one or more of the following assessments: Frequency and severity of adverse events (AEs), including infusion-related reactions (IRRs), which include allergic reactions and anaphylaxis; Vital sign measurements; Physical examinations, including neurological examinations; Safety laboratory assessments (including hematology, serum clinical chemistry, urinalysis, and coagulation); Urine total GAG concentrations (as measured by colorimetric assay and normalized to creatinine); Characterization of immunogenicity of tividenofusp alfa in serum, as measured by the incidence of anti-drug antibodies (AD As) during the study relative to baseline; and Use of concomitant medications.

[0150] EXAMPLE 2: Administration of tividenofusp alfa in patients with Hunter Syndrome Tividenofusp alfa is indicated for the treatment of Hunter Syndrome (Mucopolysaccharidosis II, MPS II) in patients. Tividenofusp alfa is provided in a single-dose vial in the amount of 150 mg lyophilized powder for reconstitution and further dilution.DNL-016-14-WO - 02900.064WO1

[0151] Tividenofusp alfa (see, Recommended INN: List 90, WHO Drug Information, Vol. 37, No. 3, 868-870 (2023) is a fusion protein consisting of the hydrolytic lysosomal glycosaminoglycan (GAG)-specific enzyme iduronate-2-sulfatase (IDS) fused to the N-terminus of an immunoglobulin G1 (IgGl) Fc (fragment, crystallizable). It is produced by recombinant DNA technology in Chinese Hamster Ovary (CHO) cells. The approximate molecular weight of tividenofusp alfa is 110 kDa.

[0152] Tividenofusp alfa for injection is a sterile, preservative-free, white to off-white lyophilized powder with a cake-like appearance for intravenous infusion after reconstitution and dilution. Each single-dose vial contains 150 mg tividenofusp alfa, and the inactive ingredients dibasic sodium phosphate (5 mg), methionine (7.5 mg), monobasic sodium phosphate (7.7 mg), polysorbate 20 (3 mg), sodium chloride (14.6 mg), and sucrose (300 mg). The pH is 6.5 after reconstitution.

[0153] Dosage and Administration

[0154] Administer tividenofusp alfa under the supervision of a healthcare provider knowledgeable in the management of hypersensitivity reactions including anaphylaxis. Initiate tividenofusp alfa in a healthcare setting with appropriate medical monitoring and support measures, including access to cardiopulmonary resuscitation equipment. Consider pretreatment with antihistamines, antipyretics, and / or corticosteroids. Obtain a baseline hemoglobin value in all patients.

[0155] The recommended starting dosage of tividenofusp alfa is 3 mg / kg administered once weekly via intravenous infusion. To reduce the risk of infusion-associated reactions (IARS), follow the dose escalation regimen in Table 1. Administer each dosage level for at least 4 weeks before escalating to the next dosage level. The recommended maintenance dosage of tividenofusp alfa is 15 mg / kg administered once weekly via intravenous infusion.DNL-016-14-WO - 02900.064WO1

[0156] Table 1: Recommended tividenofusp alfa dosage *

[0157]

[0158] * Do not escalate the dosage level if the current dosage level is not tolerated.

[0159] In the event of a severe hypersensitivity reaction (e.g., anaphylaxis) or a severe infusion-associated reaction (IAR), discontinue tividenofusp alfa and immediately initiate appropriate medical treatment. Consider the risks and benefits of re-administering tividenofusp alfa following a severe reaction. If the decision is made to re-administer tividenofusp alfa, reevaluate pretreatment medications (e.g., antihistamines, antipyretics, and / or corticosteroids), slow the infusion rate, and / or reduce the tividenofusp alfa dose. Monitor patients closely upon re-administration of tividenofusp alfa.

[0160] In the event of a mild to moderate hypersensitivity reaction or a mild to moderate IAR, temporarily hold the infusion and / or reduce the infusion rate by at least 50% from the current rate, then titrate to the recommended infusion rate as tolerated (see Table 3).

[0161] If the dose has been decreased due to an adverse reaction, evaluate when it is appropriate to increase the dose and follow the recommended dose escalation regimen to achieve the maintenance dosage of 15 mg / kg once weekly (Table 1).

[0162] Preparation Instructions

[0163] Prepare tividenofusp alfa using polypropylene syringes and infusion bags (e.g., syringes composed of polyvinylchloride (PVC) or polyolefins (PO) such as polyethylene (PE) and polypropylene (PP); infusion bags composed of PVC or PE; and filter membranes (e.g., filter membranes composed of polyethersulfone (PES). Use aseptic technique during preparation. Reconstitute and dilute tividenofusp alfa in the following manner:DNL-016-14-WO - 02900.064WO1

[0164] Reconstitution Instructions

[0165] 1) Determine the number of tividenofusp alfa vials to be reconstituted based on the patient’s weight in kilograms (kg) and the recommended dosage (Table 1). Round the number of vials up to the next whole number.

[0166] 2) Remove the required number of tividenofusp alfa vials from the refrigerator and set aside for 15 to 30 minutes to allow vials to reach room temperature 20°C to 25°C (68°F to 77°F). Do not use an external heat source.

[0167] 3) Reconstitute each vial with 5.2 mL of Sterile Water for Injection by slowly injecting the diluent onto the inside wall of each vial to avoid foaming. Do not inject forcefully or directly onto the lyophilized powder.

[0168] 4) Gently swirl each vial to completely dissolve the lyophilized powder. Do not invert or shake the vial. Each reconstituted vial will yield a concentration of 30 mg / mL of tividenofusp alfa.

[0169] 5) Visually inspect the reconstituted solution in the vial(s) for particulate matter and discoloration. The solution should be clear to slightly opalescent and colorless to slightly brown / yellow, and free of visible particles. Discard the reconstituted tividenofusp alfa solution if it is discolored, cloudy, or contains visible particulates.

[0170] Dilution Instructions

[0171] Dilute the reconstituted tividenofusp alfa solution, to ensure a final concentration in the range of 0.6 mg / mL to 15 mg / mL, into an infusion bag containing 0.9% Sodium Chloride Injection as follows:

[0172] 1) Determine the appropriate volume of the infusion bag based on the patient weight (see Table 2) and determine the volume of reconstituted tividenofusp alfa solution required for the calculated dose.

[0173] 2) Prepare the infusion bag as follows:

[0174] a. Remove any airspace within the infusion bag.

[0175] b. Withdraw a volume of 0.9% Sodium Chloride Injection from the infusion bag equivalent to the volume of tividenofusp alfa to be added.

[0176] 3) Slowly withdraw the required volume of reconstituted solution from the tividenofusp alfa vial(s). Discard unused portion after each use; do not administer more than one dose from the vial.DNL-016-14-WO - 02900.064WO1

[0177] 4) Slowly inject tividenofusp alfa reconstituted solution into the infusion bag of 0.9% Sodium Chloride Injection. Avoid introducing air into the infusion bag.

[0178] 5) Gently invert the infusion bag to mix the solution. Do not shake.

[0179] Table 2: Recommended Total Infusion Volumes for Tividenofusp Alfa Based on Patient Weight3

[0180]

[0181] aEnsure the final concentration of the diluted TIVIDENOFUSP ALFA solution is 0.6 mg / mL to 15 mg / mL.

[0182] bAt the starting dose level of 3 mg / kg, choose a lower volume.

[0183] cAt the maintenance dose level of 15 mg / kg, choose a higher volume.

[0184] Note: The recommended total infusion volume based on patient weight ensures that the diluted TIVIDENOFUSP ALFA solution is within the acceptable range of 0.6 mg / mL to 15 mg / mL. In combination with the recommended infusion rates based on total infusion volume (Table 3), the recommended total infusion volume ensures that the maximum infusion rate does not exceed Holliday-Segar guidance for pediatric patients.

[0185] After reconstitution, do not shake or freeze the tividenofusp alfa solution. If the reconstituted tividenofusp alfa vials are not diluted immediately, store at controlled room temperature between 20°C to 25°C (68°F to 77°F) for up to 4 hours.

[0186] After dilution, if the diluted tividenofusp alfa solution is not used immediately, store refrigerated at 2°C to 8°C (36°F to 46°F) for up to 24 hours. After removal of the diluted solution from the refrigerator, complete the infusion of the diluted solution within 10 hours. Do not store the diluted solution back into the refrigerator. Discard the diluted solution ifDNL-016-14-WO - 02900.064WO1

[0187] refrigerated more than 24 hours or if the diluted solution cannot be completely infused within 10 hours after removal from the refrigerator. Do not shake or freeze the diluted solution.

[0188] Administration Instructions

[0189] 1) Administer tividenofusp alfa as an intravenous infusion using infusion sets composed of PVC or PE and filter membranes composed of PES.

[0190] 2) If the diluted solution was refrigerated, allow solution to equilibrate to room temperature prior to infusion.

[0191] 3) Use a dedicated infusion line equipped with a sterile, non-pyrogenic, low proteinbinding, 0.2 micron, in-line filter to administer tividenofusp alfa.

[0192] 4) Infuse tividenofusp alfa over approximately 4 hours per the recommended infusion rates in Table 3. Increase the initial infusion rate to the subsequent infusion rate every hour based on patient tolerance. Total infusion time should not exceed 8 hours.

[0193] 5) In the absence of hypersensitivity reactions and IARS, tividenofusp alfa infusion rate can be gradually increased to complete the infusion in a minimum infusion duration of 3 hours based on patient tolerance.

[0194] Table 3: Tividenofusp alfa Infusion Rate Based on Total Infusion Volume

[0195]

[0196] 6) At the end of the infusion, flush the infusion line with 0.9% Sodium Chloride Injection using the final infusion rate that was used to administer tividenofusp alfa.

[0197] 7) Do not infuse tividenofusp alfa in the same intravenous infusion line with other products.DNL-016-14-WO - 02900.064WO1

[0198] If a patient reaches and tolerates the maintenance tividenofusp alfa dosage, the patient may receive home infusion under the supervision of a healthcare provider. The decision to have patients move to home infusion should be made after evaluation and recommendation by a healthcare provider. In case of a missed dose or an IAR, contact a healthcare provider.

[0199] If a tividenofusp alfa dose is missed, skip the missed dose. Do not double a dose to compensate for a missed dose. Restart tividenofusp alfa treatment as soon as possible, maintaining the one-week interval between infusions thereafter. Resume dosing at the last administered dosage following the recommended infusion.

[0200] Hypersensitivity Reactions Including Anaphylaxis

[0201] Life-threatening hypersensitivity reactions, including anaphylaxis, have been reported in patients treated with enzyme replacement therapies (ERTs) including tividenofusp alfa.

[0202] Symptoms of anaphylaxis that have occurred with tividenofusp alfa have included tachycardia, hypotension, wheezing, vomiting, hives, and lip and tongue swelling. Anaphylaxis has occurred during the early course of ERT and after extended duration of therapy.

[0203] Administer tividenofusp alfa under the supervision of a healthcare provider knowledgeable in the management of hypersensitivity reactions including anaphylaxis. Initiate tividenofusp alfa in a healthcare setting with appropriate medical monitoring and support measures including access to cardiopulmonary resuscitation equipment.

[0204] Prior to tividenofusp alfa administration, consider pretreatment with antihistamines, antipyretics, and / or corticosteroids.

[0205] • If a severe hypersensitivity reaction (including anaphylaxis) occurs, discontinue tividenofusp alfa and immediately initiate appropriate medical treatment, including use of epinephrine. Consider the risks and benefits of re-administering tividenofusp alfa following a severe hypersensitivity reaction (including anaphylaxis). If the decision is made to re-administer tividenofusp alfa, re-evaluate pretreatment medications, consider slowing the infusion rate, and / or reducing the tividenofusp alfa dose. Monitor patients closely upon re-administration of tividenofusp alfa.

[0206] • Inform patients of the symptoms of life-threatening hypersensitivity reactions, including anaphylaxis, and to seek immediate medical care should symptoms occur.DNL-016-14-WO - 02900.064WO1

[0207] • If a mild or moderate hypersensitivity reaction occurs, consider temporarily holding the infusion, slowing the infusion rate, and / or reducing the tividenofusp alfa dose for the subsequent visit. Re-evaluate the pretreatment medication regimen.

[0208] If the tividenofusp alfa dose has been decreased due to an adverse reaction, evaluate when it is appropriate to increase the dose and follow the recommended dose escalation regimen to achieve the recommended maintenance dosage of 15 mg / kg once weekly (see, e.g., Table 1).

[0209] Infusion-Associated Reactions

[0210] Infusion-associated reactions (IARS) have been reported in patients treated with tividenofusp alfa. IARs are defined as adverse reactions occurring during or within 24 hours of the infusion. Symptoms of IARs observed with tividenofusp alfa can include (but are not limited to) chills, angioedema, hypotension, tachycardia, urticaria, vomiting, wheezing, pyrexia, flushing, erythema, rash, cough, diarrhea, abdominal pain, retching, headache, irritability, and papules. IARs have been reported more frequently in ERT-naive patients compared to ERT-experienced patients. Cases of infusion-associated reactions occurring two hours or more after completion of the infusion have occurred with tividenofusp alfa.

[0211] Prior to tividenofusp alfa administration, consider pretreatment with antihistamines, antipyretics, and / or corticosteroids to reduce the risk of IARs. IARs may still occur in patients after receiving pretreatment. Onset of IARs was most common during the first 8 weeks of treatment with a median time to onset of approximately 2 weeks for the first IAR; IARs declined in frequency with continued use of tividenofusp alfa. IARs may still occur despite extended duration of tividenofusp alfa treatment. Appropriate medical monitoring and support measures, including cardiopulmonary resuscitation equipment, should be readily available during tividenofusp alfa administration.

[0212] • If a severe IAR occurs, discontinue tividenofusp alfa and immediately initiate appropriate medical treatment. Consider the risks and benefits of re-administering tividenofusp alfa following a severe IAR. If the decision is made to re-administer tividenofusp alfa, re-evaluate pretreatment medications, slow the infusion rate, and / or reduce the tividenofusp alfa dose. Monitor patients closely upon re-administration of tividenofusp alfa.

[0213] • If a mild or moderate IAR occurs, temporarily hold the infusion, and / or reduce the infusion rate by at least 50% from the current rate, then titrate up to the recommended infusion rate as tolerated.DNL-016-14-WO - 02900.064WO1

[0214] If the tividenofusp alfa dose has been decreased due to an adverse reaction, evaluate when it is appropriate to increase the dose and follow the recommended dose escalation regimen to achieve the maintenance dosage of 15 mg / kg once weekly (see, e.g., Table 1).

[0215] Patients with Hunter syndrome may have compromised cardiac and respiratory function which may predispose them to a higher risk of severe complications from IARS. Closely monitor patients with compromised cardiac and respiratory function following tividenofusp alfa administration.

[0216] Anemia

[0217] Anemia has been reported in patients treated with tividenofusp alfa.

[0218] The incidence of anemia after initiation of tividenofusp alfa was higher in patients with pre-existing anemia compared to those without pre-existing anemia. Reductions in hemoglobin levels were generally observed by Week 13, though the occurrence was observed up to one year in some patients. Overall, the incidence and severity of anemia decreased over time, with the majority of patients recovered by Week 24. Anemia did not result in treatment discontinuation; management may include supplementation with iron.

[0219] Obtain hemoglobin levels prior to initiating tividenofusp alfa, at three months after initiation, and periodically thereafter as clinically indicated. Administer appropriate supportive measures for anemia based on clinical judgment.

[0220] All publications, patents, and patent documents are incorporated by reference herein, as though individually incorporated by reference. The present disclosure has been described with reference to various specific and preferred embodiments and techniques. However, it should be understood that many variations and modifications may be made while remaining within the spirit and scope of the invention.

Claims

DNL-016-14-WO - 02900.064W01CLAIMSWhat is claimed is:

1. A method of treating Hunter syndrome in a subject in need thereof, comprising administering tividenofusp alfa by intravenous infusion to the subject according to a dosing regimen, wherein the dosing regimen of tividenofusp alfa (mg / kg of body weight) to be administered comprises: about 3 mg / kg QW for at least about 4 weeks, which is followed by about 7.5 mg / kg QW for at least about 4 weeks, and which is followed by about 15 mg / kg QW.

2. The method of claim 1, wherein the subject is dose escalated based on treatment tolerability.

3. The method of claim 1 or 2, wherein the subject is administered about 3 mg / kg QW for about 4 weeks to about 10 weeks.

4. The method of claim 1 or 2, wherein the subject is administered about 3 mg / kg QW for about 4 weeks to about 8 weeks.

5. The method of claim 1 or 2, wherein the subject is administered about 3 mg / kg QW for about 4 weeks.

6. The method of any one of claims 1-5, wherein the subject is administered about 7.5 mg / kg QW for about 4 weeks to about 10 weeks.

7. The method of any one of claims 1-5, wherein the subject is administered about 7.5 mg / kg QW for about 4 weeks to about 8 weeks.

8. The method of any one of claims 1-5, wherein the subject is administered about 7.5 mg / kg QW for about 4 weeks.

9. The method of any one of claims 1-8, wherein the treatment regimen further comprisesDNL-016-14-WO - 02900.064W01administering to the subject one or more therapeutic agents useful for treating an infusion related reaction (IRR).

10. The method of claim 9, wherein the one or more therapeutic agents are selected from the group consisting of: an antihistamine, an antipyretic, a steroid (e.g., a corticosteroid), and combinations thereof.

11. The method of claim 10, wherein the one or more therapeutic agents comprise a combination of an NS AID or acetaminophen and diphenhydramine.

12. The method of any one of claims 9-11, wherein the one or more agents are administered prior to the administration of a tividenofusp alfa dose, co-administered with a tividenofusp alfa dose, and / or administered after a tividenofusp alfa dose.

13. The method of claim 12, wherein the one or more agents are administered prior to the administration of a tividenofusp alfa dose.

14. The method of claim 12 or 13, wherein the one or more agents are co-administered with the administration of a tividenofusp alfa dose.

15. The method of any one of claims 1-14, wherein the treatment regimen further comprises administering to the subject an iron supplement.

16. The method of any one of claims 1-15, further comprising obtaining a urine and / or serum sample from the subject prior to the administration of the first dose of tividenofusp alfa (i.e., a baseline sample).

17. The method of any one of claims 1-16, further comprising obtaining a urine and / or serum sample from the subject after the administration of one or more tividenofusp alfa doses.

18. The method of claim 16 or 17, further comprising measuring the levels of one or more glycosaminoglycans (GAGs) in the sample(s) (e.g., heparan sulfate (HS), dermatan sulfate (DS)DNL-016-14-WO - 02900.064W01and / or total GAG levels).

19. The method of any one of claims 1-18, further comprising obtaining a blood sample from the subject prior to the administration of the first dose of tividenofusp alfa (i.e., a baseline sample).

20. The method of any one of claims 1-19, further comprising obtaining a blood sample from the subject after the administration of one or more tividenofusp alfa doses.

21. The method of claim 19 or 20, further comprising measuring hemoglobin levels in the blood sample(s).

22. The method of any one of claims 1-21, wherein the dosing regimen reduces the subject’s risk of a dose reduction resulting from an infusion-related reaction (IRR).

23. The method of any one of claims 1-22, wherein a tividenofusp alfa dose is administered intravenously over a period of less than about 8 hours.

24. The method of any one of claims 1-22, wherein a tividenofusp alfa dose is administered intravenously over a period of from about 3 hours to 4.5 hours.

25. The method of claim 24, wherein a tividenofusp alfa dose is administered intravenously over a period of about 4 hours.

26. The method of any one of claims 1-25, wherein the subject has a weight of > 5 kg.

27. The method of any one of claims 1-26, wherein the subject had previously received idursulfase enzyme replacement therapy and switched to the administration of tividenofusp alfa.

28. The method of any one of claims 1-27, wherein the subject had pre-existing anti-drug antibodies against iduronate 2-sulfatase (IDS) prior to administration of tividenofusp alfa.DNL-016-14-WO - 02900.064W0129. The method of any one of claims 1-28, wherein the tividenofusp alfa is comprised in a pharmaceutical composition that further comprises a pharmaceutically acceptable excipient.

30. Tividenofusp alfa for use in a method of treating Hunter syndrome, the method comprising administering tividenofusp alfa by intravenous infusion to a subject in need thereof according to a dosing regimen, wherein the dosing regimen of tividenofusp alfa (mg / kg of body weight) to be administered comprises: about 3 mg / kg QW for at least about 4 weeks, which is followed by about 7.5 mg / kg QW for at least about 4 weeks, and which is followed by about 15 mg / kg QW.

31. The use of tividenofusp alfa in the preparation of a medicament for the treatment of Hunter syndrome by administering the medicament by intravenous infusion to a subject in need thereof according to a dosing regimen, wherein the dosing regimen of the medicament to be administered comprises: about 3 mg / kg QW for at least about 4 weeks, which is followed by about 7.5 mg / kg QW for at least about 4 weeks, and which is followed by about 15 mg / kg QW, wherein the dose is mg of tividenofusp alfa per kg of body weight.

32. A method of administering tividenofusp alfa to a subject in need thereof, comprising reconstituting a tividenofusp alfa lyophilized product in 5.2 mL of sterile water to provide a reconstituted tividenofusp alfa solution that contains tividenofusp alfa at a concentration of about 30 mg / mL; diluting the reconstituted tividenofusp alfa solution in 0.9% sodium chloride to provide a diluted tividenofusp alfa solution having a final concentration of from about 0.6 mg / mL to about 15 mg / mL; and administering the diluted tividenofusp alfa solution by intravenous infusion to the subject.

33. The method of claim 32, wherein the diluted tividenofusp alfa solution is administered to the subject according to one of the following infusion schedules:(a) for a total infusion volume of about 25 mL, infuse for the first hour at about 2.5 mL / hour, infuse for the second hour at about 5 mL / hour, and then infuse at about 10 mL / hour from the third hour until completion of infusion; orDNL-016-14-WO - 02900.064W01(b) for a total infusion volume of about 50 mL, infuse for the first hour at about5 mL / hour, infuse for the second hour at about 10 mL / hour, and then infuse at about 20 mL / hour from the third hour until completion of infusion; or(c) for a total infusion volume of about 100 mL, infuse for the first hour at about 10 mL / hour, infuse for the second hour at about 20 mL / hour, and then infuse at about 40 mL / hour from the third hour until completion of infusion; or(d) for a total infusion volume of about 250 mL, infuse for the first hour at about 25 mL / hour, infuse for the second hour at about 50 mL / hour, and then infuse at about 100 mL / hour from the third hour until completion of infusion.

34. The method of claim 32 or 33, wherein the infusion rate is increased every hour based on patient tolerance.

35. The method of any one of claims 32 to 34, wherein the total infusion duration does not exceed 8 hours.

36. The method of any one of claims 32 to 35, wherein the total infusion duration is about 4 hours.

37. The method of any one of claims 32 to 35, wherein the total infusion duration is about 3 hours.

38. Tividenofusp alfa for use in a method of administration to a subject in need thereof, the method comprising reconstituting a tividenofusp alfa lyophilized product in 5.2 mL of sterile water to provide a reconstituted tividenofusp alfa solution that contains tividenofusp alfa at a concentration of about 30 mg / mL; diluting the reconstituted tividenofusp alfa solution in 0.9% sodium chloride to provide a diluted tividenofusp alfa solution having a final concentration of from about 0.6 mg / mL to about 15 mg / mL; and administering the diluted tividenofusp alfa solution by intravenous infusion to the subject.

39. The tividenofusp alfa for use according to claim 38, wherein the diluted tividenofusp alfa solution is administered to the subject according to one of the following infusion schedules:DNL-016-14-WO - 02900.064W01(a) for a total infusion volume of about 25 mL, infuse for the first hour at about 2.5 mL / hour, infuse for the second hour at about 5 mL / hour, and then infuse at about 10 mL / hour from the third hour until completion of infusion; or(b) for a total infusion volume of about 50 mL, infuse for the first hour at about5 mL / hour, infuse for the second hour at about 10 mL / hour, and then infuse at about 20 mL / hour from the third hour until completion of infusion; or(c) for a total infusion volume of about 100 mL, infuse for the first hour at about 10 mL / hour, infuse for the second hour at about 20 mL / hour, and then infuse at about 40 mL / hour from the third hour until completion of infusion; or(d) for a total infusion volume of about 250 mL, infuse for the first hour at about 25 mL / hour, infuse for the second hour at about 50 mL / hour, and then infuse at about 100 mL / hour from the third hour until completion of infusion.

40. The use of tividenofusp alfa in the preparation of a medicament for the administration of the medicament by intravenous infusion to a subject in need thereof, wherein the medicament is prepared by reconstituting a tividenofusp alfa lyophilized product in 5.2 mL of sterile water to provide a reconstituted tividenofusp alfa solution that contains tividenofusp alfa at a concentration of about 30 mg / mL; diluting the reconstituted tividenofusp alfa solution in 0.9% sodium chloride to provide the medicament having a final concentration of from about 0.6 mg / mL to about 15 mg / mL.

41. The use of claim 40, wherein the administration of the medicament by intravenous infusion is according to one of the following infusion schedules:(a) for a total infusion volume of about 25 mL, infuse for the first hour at about 2.5 mL / hour, infuse for the second hour at about 5 mL / hour, and then infuse at about 10 mL / hour from the third hour until completion of infusion; or(b) for a total infusion volume of about 50 mL, infuse for the first hour at about5 mL / hour, infuse for the second hour at about 10 mL / hour, and then infuse at about 20 mL / hour from the third hour until completion of infusion; or(c) for a total infusion volume of about 100 mL, infuse for the first hour at about 10 mL / hour, infuse for the second hour at about 20 mL / hour, and then infuse at about 40 mL / hour from the third hour until completion of infusion; orDNL-016-14-WO - 02900.064W01(d) for a total infusion volume of about 250 mL, infuse for the first hour at about 25 mL / hour, infuse for the second hour at about 50 mL / hour, and then infuse at about 100 mL / hour from the third hour until completion of infusion.

42. A method of treating an infusion-associated reaction (IAR) in a subject receiving a tividenofusp alfa infusion according to an infusion schedule, the method comprising 1) stopping the tividenofusp alfa infusion and / or reducing the tividenofusp alfa infusion rate by at least 50% from the subject’s current rate of infusion; 2) subsequently, restarting the administration of the tividenofusp alfa infusion if needed and increasing the infusion rate, in a step-wise manner, to the rate of infusion the subject had been receiving prior to the implementation of step 1); and 3) continuing the administration of the tividenofusp alfa infusion by resuming the infusion schedule, wherein the infusion schedule is as follows:(a) For a total infusion volume of about 25 mL, infuse for the first hour at about 2.5 mL / hour, infuse for the second hour at about 5 mL / hour, and then infuse at about 10 mL / hour from the third hour until completion of infusion; or(b) For a total infusion volume of about 50 mL, infuse for the first hour at about 5 mL / hour, infuse for the second hour at about 10 mL / hour, and then infuse at about 20 mL / hour from the third hour until completion of infusion; or(c) For a total infusion volume of about 100 mL, infuse for the first hour at about 10 mL / hour, infuse for the second hour at about 20 mL / hour, and then infuse at about 40 mL / hour from the third hour until completion of infusion; or(d) For a total infusion volume of about 250 mL, infuse for the first hour at about 25 mL / hour, infuse for the second hour at about 50 mL / hour, and then infuse at about 100 mL / hour from the third hour until completion of infusion.

43. The method of claim 42, wherein the IAR is a hypersensitivity reaction.

44. A kit for treatment of Hunter syndrome in a subject in need thereof, the kit comprising a pharmaceutically acceptable dosage form comprising tividenofusp alfa configured for intravenous administration at a dose of 3 mg / kg to 15 mg / kg, and instructions for administering the pharmaceutically acceptable dosage form at about 3 mg / kg QW for at least about 4 weeks, followed by about 7.5 mg / kg QW for at least about 4 weeks, and followed by about 15 mg / kgDNL-016-14-WO - 02900.064W01QW, wherein the dose is mg of tividenofusp alfa per kg of body weight.

45. The kit of claim 44, wherein the instructions further comprise instructions to treat an infusion-associated reaction (IAR) in the subject receiving the pharmaceutically acceptable dosage form, wherein the subject is receiving the pharmaceutically acceptable dosage form according to an infusion schedule, the instructions to treat the IAR comprising: 1) stopping the infusion and / or reducing the infusion rate by at least 50% from the subject’s current rate of infusion; and 2) subsequently, restarting the administration of the infusion if needed and increasing the infusion rate, in a step-wise manner, to the rate of infusion the subject had been receiving prior to the implementation of step 1); and 3) continuing the administration of the infusion by resuming the infusion schedule, wherein the infusion schedule is as follows:(a) For a total infusion volume of about 25 mL, infuse for the first hour at about 2.5 mL / hour, infuse for the second hour at about 5 mL / hour, and then infuse at about 10 mL / hour from the third hour until completion of infusion; or(b) For a total infusion volume of about 50 mL, infuse for the first hour at about 5 mL / hour, infuse for the second hour at about 10 mL / hour, and then infuse at about 20 mL / hour from the third hour until completion of infusion; or(c) For a total infusion volume of about 100 mL, infuse for the first hour at about 10 mL / hour, infuse for the second hour at about 20 mL / hour, and then infuse at about 40 mL / hour from the third hour until completion of infusion; or(d) For a total infusion volume of about 250 mL, infuse for the first hour at about 25 mL / hour, infuse for the second hour at about 50 mL / hour, and then infuse at about 100 mL / hour from the third hour until completion of infusion.

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