Treatment of intracranial hemorrhage

Abstract

The present disclosure relates to compositions and methods useful for improving the hemostatic efficacy in a patient having suffered from intracranial hemorrhage while undergoing an anticoagulation treatment with a factor Xa (FXa) inhibitor. In some embodiments, the patient is selected if the patient exhibits high hematoma growth rate and / or high diastolic blood pressure.

Description

TREATMENT OF INTRACRANIAL HEMORRHAGECROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S Provisional Application Number 63 / 589.271, filed on October 10. 2023, U.S. Provisional Application Number 63 / 597,881, filed on November 10, 2023, U.S. Provisional Application Number 63 / 650,850, filed on May 22, 2024. and U.S. Provisional Application Number 63 / 688.784, filed on August 29, 2024, which are incorporated by reference herein in their entirety.BACKGROUND

[0002] Factor Xa inhibitors, e.g., apixaban, rivaroxaban, edoxaban, betrixaban, and enoxaparin, have a positive benefit-risk profile for treatment and prevention of thrombotic events but may cause or worsen acute major bleeding with substantial morbidity and mortality. Factor Xa inhibitor-associated acute major bleeding episodes may be difficult to treat for lack of a specific reversal agent.

[0003] Andexanet alfa (coagulation factor Xa [recombinant] inactivated-zhzo) is a modified recombinant inactive form of factor Xa designed specifically to bind and sequester factor Xa inhibitor molecules, thereby rapidly reducing anti-factor Xa activity, a measure of the anticoagulant effect of factor Xa inhibitors. In healthy subjects receiving either apixaban or rivaroxaban, andexanet rapidly reduced both unbound fraction of factor Xa inhibitor and antifactor Xa activity, with minimal adverse effects.SUMMARY

[0004] The present disclosure relates to compositions and methods useful for improving the hemostatic efficacy in a patient having suffered from intracranial hemorrhage while undergoing an anticoagulation treatment with a factor Xa (FXa) inhibitor.

[0005] One embodiment of the present disclosure provides a method for improving hemostatic efficacy in a patient having suffered from intracranial hemorrhage while undergoing an anticoagulation treatment with a factor Xa (FXa) inhibitor, comprising administering to the patient a FXa derivative that has a deletion of at least 50% of amino acid residues 6-39 of the light chain and a modification at the active site on the heavy chain.wherein the FXa derivative has reduced catalytic activity as compared to the wild-type FXa protein, and is capable of binding to the factor Xa inhibitor.

[0006] In some embodiments, the factor Xa inhibitor is a direct factor Xa inhibitor, such as apixaban and rivaroxaban.

[0007] In some embodiments, the administration is carried out within 6 hours following onset of a symptom of intracranial hemorrhage, or preferably the administration is carried out within 3 hours following onset of a symptom of intracranial hemorrhage.

[0008] In some embodiments, the administration is carried out within 15 hours following the patient taking the FXa inhibitor. In some embodiments, the administration comprises a bolus injection of the FXa derivative. In some embodiments, the bolus injection comprises 300-500 mg of the FXa derivative, or preferably 350-450 mg of the FXa derivative.

[0009] In some embodiments, the administration further comprises an infusion of the FXa derivative after the bolus injection. In some embodiments, the infusion comprises 400-560 mg of the FXa derivative, or preferably 450-510 mg of the FXa derivative.

[0010] In some embodiments, the anticoagulation treatment comprises 10 mg or less rivaroxaban, 5 mg or less Apixaban, 30 mg or less Edoxaban, or 40 mg or less Enoxaparin. In some embodiments, the anticoagulation treatment comprises 10 mg or less rivaroxaban, or 5 mg or less Apixaban.

[0011] In some embodiments, the patient is at least 75 years old. In some embodiments, the patient has a baseline NIHSS (NIH Stroke Scale / Score) of greater than 9.

[0012] In some embodiments, the FXa derivative is a two-chain protein comprising a light chain comprising the amino acid sequence of SEQ ID NO:3 or a first peptide having at least 85% sequence identity to SEQ ID NO:3, and a heavy chain comprising the amino acid sequence of SEQ ID NO:4 or a second peptide having at least 85% sequence identity to SEQ ID NO:4. In some embodiments, the FXa derivative is andexanet alfa.BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Provided as embodiments of this disclosure are drawings which illustrate by exemplification only, and not limitation, wherein:

[0014] FIG. 1 shows reduction in median anti-FXa activity from baseline to nadir at 2 hours. Median values along with QI (low bars) and Q3 (upper bar) are indicated in the plot. The summaries are based on non-missing values at baseline, 1 hour, and 2 hours post randomization. Participants with missing baseline value in anti-FXa activity were excluded from the analysis. P value was derived per SAP. ANCOVA on the ranked percent change to nadir adjusted for covariates of time from symptom onset to the baseline imaging scan (< 180 minutes versus > 180 minutes) and baseline anti-FXa activity were used to compare andexanet and UC based on a multiple imputation scheme for missing values at 1 and 2 hours post randomization. The imputation process was run 100 times leading to a set of generated 100 p-values, final p-value was obtained by the median p-value rule.

[0015] FIG. 2 presents a Forest plot showing selected sub-groups for hemostatic efficacy. Abbreviations: AF = atrial fibrillation, CI = confidence interval, FXa= factor Xa inhibitor, NIHSS = National Institutes of health Stroke Scale, MI = myocardial infarction, PCC = prothrombin complex concentrate. For the subgroup analysis, the increase with andexanet per 100 patients, 95% CI are from Cochran-Mantel Haenszel (CMH) test stratified by time from symptom onset to baseline imaging scan (<180 minutes vs. > 180 minutes). P values for interaction are obtained using logistic regression with covariates being treatment, group variable, treatment and group interaction, and time from symptom onset to baseline imaging scan (<180 minutes vs. >180 minutes). 3: indicates exploratory sub-group. 4. **Does not include 139 patients randomized before amendment 1.

[0016] FIG. 3 presents a Forest plot showing selected sub-groups for thrombotic events. Abbreviations: AF = atrial fibrillation. CI = confidence interval, FXa= factor Xa inhibitor. NIHSS = National Institutes of health Stroke Scale, MI = myocardial infarction, PCC = prothrombin complex concentrate. The increased risk with andexanet per 100 patients in thrombotic event was estimated from the proportion difference, and the 95% CI is the Wald CI. If the total number of events in both arms are less than 5, then increase risk with 95% CI is not be reported. 3. P values for interaction are obtained using logistic regression with covariates being treatment, group variable, treatment and group interaction. 4: * Indi cates exploratory sub-group. 5. **does not include 139 patients randomized before amendment 1.

[0017] FIG. 4 is a line plot of anti-FXa activity by treatment in patients overall. Time course of anti-FXa activity is shown as mean and SE at each time. The patients with enoxaparin asthe prior FXa inhibitor are excluded due to their unconvertible unit of anti FXa activity . FXa, activated factor X; ITT, intent to treat; SE, standard error.

[0018] FIG. 5A-C are line plots of anti-FXa activity by treatment in patients taking apixaban (A), rivaroxaban (B), and edoxaban (C). Time course of anti-FXa activity is shown as mean and SE at each time.

[0019] FIG. 6A shows likelihood of hematoma expansion (>12.5 rnL or >35%) according to baseline hematoma volume (mL) and treatment group. Variables in the model: treatment, baseline hematoma volume.

[0020] FIG. 6B shows likelihood of hematoma expansion (>12.5 mL or >35%) according to time from symptom onset to treatment (hours) and treatment group. Variables in the model: treatment, time from symptom onset to treatment.

[0021] FIG. 6C shows likelihood of hematoma expansion (>12.5 rnL or >35%) according to baseline anti-FXa levels (ng / mL) and treatment group. Variables in the model: treatment, baseline anti-fXa level.

[0022] FIG. 6D shows likelihood of hematoma expansion (>12.5 mL or >35%) according to pre-scan hematoma growth rate (mL / hour) and treatment group. Variables in the model: treatment, pre-scan hematoma growth rate.

[0023] FIG. 6E shows likelihood of hematoma expansion (>12.5 mL or >35%) according to diastolic blood pressure (mm Hg) and treatment group. Variables in the model: treatment, baseline diastolic blood pressure.

[0024] FIG. 7 illustrates a proposed “11 to 1 rule’?for individualized andexanet treatment decisions in patients with acute FXa inhibitor-associated ICH. Abbreviations: HE, hematoma expansion; hr, hour; ICH, intracerebral hemorrhage; MI, myocardial infarction; NNH, number needed to harm; NNT. number needed to treat; TE, thrombotic event.DETAILED DESCRIPTIONI. Definitions

[0025] All numerical designations, e.g., pH, temperature, time, concentration, and molecular weight, including ranges, are approximations which are varied ( + ) or ( - ) by increments of0.1. It is to be understood, although not always explicitly stated that all numerical designations are preceded by the term “about”. It also is to be understood, although not always explicitly stated, that the reagents described herein are merely exemplary and that equivalents of such are known in the art.

[0026] A “composition” is intended to mean a combination of active agent and another compound or composition, inert (for example, a detectable agent or label) or active.

[0027] “Factor Xa” or “FXa” or “FXa protein” is a serine protease in the blood coagulation pathway, which is produced from the inactive factor X (fX). The nucleotide sequence coding human factor X (“IX”) can be found in GenBank with accession number “NM_000504.” Upon catalytic cleavage of the first 52 residues of the heavy chain, IX is activated to FXa (SEQ ID NO. 1, Table 1). FXa contains a light chain and a heavy chain (as shown in Table 1). The first 45 amino acid residues (residues 1-45 of SEQ ID NO. 1) of the light chain is called the Gia domain because it contains 11 post-translationally modified y-carboxyglutamic acid residues (Gia). It also contains a short (6 amino acid residues) aromatic stack sequence (residues 40-45 of SEQ ID NO. 1). Chymotry psin digestion selectively removes the 1-44 residues resulting in Gla-domainless FXa. The serine protease catalytic domain of FXa is located on the C-terminal heavy chain. The heavy chain of FXa is highly homologous to other serine proteases such as thrombin, trypsin, and activated protein C.

[0028] “Native FXa” or “wild-type FXa” refers to the FXa naturally present in plasma or being isolated in its original, unmodified form, which possesses the biological activity of activating prothrombin therefore promoting formation of blood clot. The term includes naturally occurring polypeptides isolated from tissue samples as well as recombinantly produced FXa. “Active FXa” refers to FXa having the biological activity of activating prothrombin. “Active FXa” may be a native FXa or modified FXa that retains procoagulant activity.

[0029] As used herein, “FXa derivatives” refer to modified FXa proteins that have a modification or substantial deletion (e.g, deletion of at least 50%, 60%, 70%, 80%, or 90% of the amino acid residues 6-39 of the light chain) of the Gla-domain and a modification to the active site such that the FXa derivatives, as compared to the wild-ty pe protein, have reduced ability in assembling into the prothrombinase complex and reduced or no catalytic activities. Still, similar to the wild-type protein, the FXa derivatives can bind and / orsubstantially neutralize FXa inhibitors. Examples of FXa derivatives are provided in W02009 / 042962 and WO2010 / 117729. and biological equivalents thereof.

[0030] The term “active site” refers to the part of an enzy me or antibody where a chemical reaction occurs. A “modified active site” is an active site that has been modified structurally to provide the active site with increased or decreased chemical reactivity or specificity.Examples of active sites include, but are not limited to, the catalytic domain of human factor X comprising the 235-488 amino acid residues, and the catalytic domain of human factor Xa comprising the 195-448 amino acid residues. Examples of modified active site include, but are not limited to, the catalytic domain of human factor Xa comprising 195-448 amino acid residues in SEQ ID NOS. 2 with at least one amino acid substitution at position Arg306. Glu310, Arg347, Lys351, Lys414, or Arg424.

[0031] An example of a FXa derivative is a “Gla-domainless FXa” or “des-Gla FXa” that refers to FXa or a FXa derivative that does not have a Gla-domain and encompasses FXa derivatives bearing other modification(s) in addition to the removal of the Gla-domain. Examples of Gla-domainless FXa in this invention include, but are not limited to, FXa derivative lacking all or part of the 1-39 (or 6-39) amino acid residues of SEQ ID NO. 1.

[0032] Another example of a FXa derivative is a “Gla-deficient FXa” that refers to FXa or a FXa derivative with reduced number of free side chain v-carboxyl groups in its Gla-domain. Like Gla-domainless FXa, Gla-deficient FXa can also bear other modifications. Gla- deficient FXa includes uncarboxylated, undercarboxylated and decarboxylated FXa.“Uncarboxyl ated FXa” or “decarboxylated FXa” refers to FXa derivatives that do not have the y-carboxy groups of the y-carboxyglutamic acid residues of the Gia domain, such as FXa having all of its Gia domain y-carboxyglutamic acid replaced by different amino acids, or FXa having all of its side chain y-carboxyl removed or masked by means such as amination, esterification, etc. For recombinantly expressed protein, uncarboxylated FXa is, sometimes, also called non-carboxylated FXa. “Undercarboxylated FXa” refers to FXa derivatives having reduced number of y-carboxy groups in the Gia domain as compared with wild-type FXa, such as FXa having one or more but not all of its Gia domain y-carboxyglutamic acids replaced by one or more different amino acids, or FXa having at least one but not all of its side chain y-carboxyl removed or masked by means such as amination and esterification, etc.

[0033] In some embodiments, the FXa derivatives have a deletion of at least amino acid residues 6-39 of the light chain of the wild-type FXa (see light chain in SEQ ID NO: 1). In some embodiments, the FXa derivatives also have a deletion of the EGF1 domain (amino acids 46-84) and / or the EGF2 domain (amino acids 85-128 of the light chain). In some embodiments, the light chain of the FXa derivative includes at least amino acids 129-139 of the wild-type light chain (or 95-105 of SEQ ID NO:3).

[0034] SEQ ID NO: 2 (Table 2), which is also referred to as “andexanet alfa” or simply “andexanef ’, contains two mutations relative to the wild-type FXa’'. The first mutation is the deletion of amino acid residues 6-39 in the Gla-domain of fX. The second mutation is mutation of active site residue S379 to an Ala residue. This amino acid substitution corresponds to amino acid 296 of SEQ ID NOS: 1, respectively. Andexanet includes two chains, referred to as SEQ ID NO:3 (light chain) and 4 (heavy chain), respectively.

[0035] FXa derivatives also encompass those that contain mutations, post-translational modifications, and / or changes to the protein during the manufacturing process. For instance, in another aspect, the FXa derivatives, with or without the Ser379 modification, may contain modifications on the His (to Ala) and / or Asp (to Ala / Asn) residues in the catalytic triad, and a deleted or modified Gia domain. These modifications provide FXa derivatives with reduced enzymatic activity but not competing with FXa in assembling into the prothrombinase complex.

[0036] In some embodiments, the FXa derivative has a heavy chain that has one or two O- linked glycosylation. In some embodiments, the heavy chain may have a C-terminal truncation of an amino acid residue, or up to 13, 14 or 15 amino acid residues. In some embodiments, the light chain may have an N-terminal truncation.

[0037] The present disclosure provides a variety of biological equivalents of the disclosed sequences of the FXa derivatives, or alternatively polypeptides having certain sequence identity to these FXa derivatives. In one aspect, such biological equivalents retain the structural characteristics of these FXa derivatives, that is, a modified active site or heavy chain and a deleted or modified Gia domain. In another aspect, such biological equivalents retain the functional features of these FXa derivatives, that is, not competing with FXa in assembling into the prothrombinase complex and having reduced catalytic activities. Inanother aspect, such biological equivalents can bind and / or substantially neutralize FXa inhibitors.Table 1. Polypeptide sequence of activated human factor X, FXa (SEQ ID NO: 1)Table 2. Polypeptide sequence of andexanet (SEQ ID NO: 2)

[0038] The term “factor Xa inhibitors’" or “inhibitors of factor Xa” refer to compounds that can inhibit, either directly or indirectly, the coagulation factor Xa’s activity of catalyzing conversion of prothrombin to thrombin in vitro and / or in vivo.

[0039] “Direct factor Xa inhibitors” or “direct FXa inhibitors” bind to the FXa directly and non-limiting examples include apixaban, rivaroxaban, edoxaban, betrixaban, NAP-5, rNAPc2, tissue factor pathway inhibitor, DX- DX-9065a (as described in, e.g, Herbert, J.M., et al, J Pharmacol Exp Ther. 1996 276(3): 1030-8), YM-60828 (as described in, e.g, Taniuchi, Y.. et al, Thromb Haemost. 1998 79(3):543-8), YM-150 (as described in, e.g, Eriksson. B.l. et. al, Blood 2005; 106(11), Abstract 1865). TAK-442, PD-348292 (as described in, e.g.. Pipeline Insight: Antithrombotics - Reaching the Untreated Prophylaxis Market, 2007), otamixaban, LY517717 (as described in, e.g, Agnelli, G., et al, J. Thromb. Haemost. 2007 5(4):746-53), GSK913893, razaxaban, or a pharmaceutically acceptable salt thereof, and combinations thereof.

[0040] “Indirect factor Xa inhibitors” or “indirect FXa inhibitors” inhibit the FXa activity via one or more other factors. Non-limiting examples of indirect factor Xa inhibitors includeenoxaparin, fondaparinux, idraparinux, biotinylated idraparinux, fragmin, tinzaparin, low molecular weight heparin (“LMW1T), and combinations thereof.

[0041] In one embodiment, the factor Xa inhibitor is selected from apixaban, rivaroxaban, edoxaban, betrixaban, enoxaparin and combinations thereof.II. Improvement of Hemostatic Efficacy in Patients of Acute Intracerebral Hemorrhage

[0042] Anticoagulants serve a need in the marketplace in treatment or prevention of undesired thrombosis in patients with a tendency to form blood clots, such as, for example, those patients having clotting disorders, confined to periods of immobility or undergoing medical surgeries. One of the major limitations of anticoagulant therapy, however, is the bleeding risk associated with the treatments, and limitations on the ability- to rapidly reverse the anticoagulant activity in case of overdosing or if an urgent surgical procedure is required.

[0043] One embodiment of the present disclosure provides a method for reducing anti-FXa activity and / or improving the rate of hemostatic efficacy in a patient that had acute intracranial hemorrhage (ICH).

[0044] Patients with acute ICH on factor Xa (FXa) inhibitors have a high risk of hematoma expansion and poor outcome. Andexanet binds FXa inhibitors and rapidly reverses anticoagulation. Patients with acute ICH on a FXa inhibitor, within 6 hours of symptom onset, were treated with andexanet or usual care as control. Hemostatic efficacy required <35% hematoma expansion, <7 point change in National Institutes of Health Stroke Scale and no rescue therapy.

[0045] As shown in Example 1, a clinical trial enrolled 530 patients; 87% had atrial fibrillation. Most usual care patients (86%) received prothrombin complex concentrate. Effective hemostasis occurred in 63.9% of patients on andexanet and in 52.4% receiving usual care, an increase with andexanet per 100 patients treated of 11.0 (p=0.009). Reduction in median anti-FXa activity was 94.4% with andexanet and 23.5% with usual care (p<0.001). Thrombotic events occurred in 10.3% patients receiving andexanet and in 5.6% receiving usual care, an increase with andexanet per 100 patients of 4.6 (p=0.048).

[0046] The clinical trial results, therefore, demonstrate that andexanet rapidly reduces anti- FXa activity, reduces hematoma expansion and increases hemostatic efficacy in patients with acute ICH. In particular, when the anti-FXa inhibitor was a direct inhibitor, such as apixaban and rivaroxaban, andexanet was significantly more efficient in reducing its activity as compared to the usual care (Example 2). Andexanet, therefore, can be suitably used for patients on FXa inhibitors with acute ICH.

[0047] It has also been observed that higher hematoma expansion (HE) correlated with higher hematoma grow th rate (which is a composite of time from symptom onset to baseline scan and baseline hematoma volume) and higher diastolic blood pressure (Example 3). Patients predicted to have higher HE would be more likely benefit from andexanet treatment.

[0048] In accordance with one embodiment of the present disclosure, therefore, provided is a method for assessing the hemostatic efficacy in a patient having suffered from intracranial hemorrhage while undergoing an anticoagulation treatment with a factor Xa (FXa) inhibitor. In some embodiments, the method entails administering to the patient a FXa derivative of the present disclosure, obtaining a blood sample from the patient following the administration and measuring an anti-FXa activity in the sample. The anti-FXa activity can be used to predict the hemostatic efficacy in the patient. In some embodiments, the FXa inhibitor is a direct FXa inhibitor. In some embodiments, the FXa inhibitor is apixaban. In some embodiments, the FXa inhibitor is rivaroxaban.

[0049] “Intracranial hemorrhage or ICH, refers to bleeding within the skull or brain. Intracranial hemorrhage is a serious medical emergency because the buildup of blood within the skull can lead to increases in intracranial pressure, which can crush delicate brain tissue or limit its blood supply. Severe increases in intracranial pressure (ICP) can cause brain herniation, in which parts of the brain are squeezed past structures in the skull. Intracranial bleeding occurs when a blood vessel within the skull is ruptured or leaks. It can result from physical trauma or nontraumatic causes. Anticoagulant therapy, as well as disorders with blood clotting can heighten the risk that an intracranial hemorrhage will occur.

[0050] In some embodiments, the patient has suffered from intracranial hemorrhage. In some embodiments, the patient has suffered from a subtype of intracranial hemorrhage, such as intra-axial bleed or hemorrhage (cerebral hemorrhage), extra-axial bleed (including epiduralhemorrhage, subdural hemorrhage, and subarachnoid hemorrhage), epidural hematoma, subdural hematoma, or subarachnoid hemorrhage.

[0051] “Intra-axial hemorrhage” is bleeding within the brain itself, or cerebral hemorrhage. This subtype includes intraparenchymal hemorrhage, or bleeding within the brain tissue, and intraventricular hemorrhage, bleeding within the brain's ventricles (particularly of premature infants). Intra-axial hemorrhages are more dangerous and harder to treat than extra-axial bleeds.

[0052] “Extra-axial hemorrhage” refers to bleeding that occurs within the skull but outside of the brain tissue. Examples of extra-axial hemorrhage include epidural hemorrhage, subdural hemorrhage, and subarachnoid hemorrhage.

[0053] “Epidural hemorrhage” (extradural hemorrhage) which occurs between the dura mater (the outermost meninx) and the skull, is caused by trauma. It may result from laceration of an artery, most commonly the middle meningeal artery. This is a dangerous type of injury because the bleed is from a high-pressure system and deadly increases in intracranial pressure can result rapidly. However, it is the least common type of meningeal bleeding and is seen in 1% to 3% cases of head injury.

[0054] “Subdural hemorrhage” results from tearing of the bridging veins in the subdural space between the dura and arachnoid mater.

[0055] “Subarachnoid hemorrhage,” which occurs between the arachnoid and pia meningeal layers, like intraparenchymal hemorrhage, can result either from trauma or from ruptures of aneurysms or arteriovenous malformations. Blood is seen layering into the brain along sulci and fissures, or filling subarachnoid cisterns (most often the chiasmatic cistern because of the presence of the anterior cerebral arteries of the circle of Willis and their branchpoints within that space). The classic presentation of subarachnoid hemorrhage is the sudden onset of a severe headache (a thunderclap headache). This can be a dangerous entity, and requires emergent neurosurgical evaluation, and sometimes urgent intervention.

[0056] “Epidural hematoma” (EDH) is a rapidly accumulating hematoma between the dura mater and the cranium. These patients have a history7of head trauma w ith loss of consciousness, then a lucid period, followed by loss of consciousness. Clinical onset occurs over minutes to hours. Many of these injuries are associated with lacerations of the middlemeningeal artery. A ‘‘lenticular ’ or convex, lens-shaped extracerebral hemorrhage that does not cross suture lines will likely be visible on a CT scan of the head.

[0057] “Subdural hematoma” occurs when there is tearing of the bridging vein between the cerebral cortex and a draining venous sinus. At times they may be caused by arterial lacerations on the brain surface. Acute subdural hematomas are usually associated with cerebral cortex injury as well and hence the prognosis is not as good as extra dural hematomas. Clinical features depend on the site of injury and severity of injury. Patients may have a history of loss of consciousness but they recover and do not relapse. Clinical onset occurs over hours. A crescent shaped hemorrhage compressing the brain that does cross suture lines will be noted on CT of the head. Craniotomy and surgical evacuation is required if there is significant pressure effect on the brain. Complications include focal neurologic deficits depending on the site of hematoma and brain injury', increased intracranial pressure leading to herniation of brain and ischemia due to reduced blood supply and seizures.

[0058] A “subarachnoid hemorrhage” is bleeding into the subarachnoid space — the area between the arachnoid membrane and the pia mater surrounding the brain. Besides from head injury', it may occur spontaneously, usually from a ruptured cerebral aneury sm. Symptoms of SAH include a severe headache with a rapid onset (thunderclap headache), vomiting, confusion or a lowered level of consciousness, and sometimes seizures. The diagnosis is generally' confirmed with a CT scan of the head, or occasionally by7lumbar puncture. Treatment is by prompt neurosurgery' or radiologically guided interventions with medications and other treatments to help prevent recurrence of the bleeding and complications.

[0059] The FXa derivative may be administered via either intravenous administration by bolus or a combination of bolus and infusion or by subcutaneous administration. In certain embodiments, about 10 to about 20% of the formulation is administered as a bolus and the remaining formulation is infused over a period until bleeding has substantially ceased. It is contemplated that the infusion can be administered for about 6 hours, or about 6 to about 12 hours, or about 12 to about 24 hours or 48 hours.

[0060] In some embodiments, the FXa derivative is administered as an intravenous (IV) bolus, with a target rate of about 30 mg / min, followed by continuous infusion for up to 120 minutes. In some embodiments, the initial IV bolus includes about 300-500 mg of the FXa derivative. In some embodiments, the initial IV bolus includes about 350-450 mg of the FXaderivative. In some embodiments, the initial IV bolus includes about 380-420 mg of the FXa derivative. In some embodiments, the initial IV bolus includes about 400 mg of the FXa derivative.

[0061] In some embodiments, the initial IV bolus includes about 700-900 mg of the FXa derivative. In some embodiments, the initial IV bolus includes about 750-850 mg of the FXa derivative. In some embodiments, the initial IV bolus includes about 800 mg of the FXa derivative.

[0062] In some embodiments, the follow-on IV infusion administers about 4 mg / min for 120 minutes. In some embodiments, the follow-on IV infusion administers about 8 mg / min for 120 minutes.

[0063] One embodiment provides a method for improving hemostatic efficacy in a patient having suffered from intracranial hemorrhage while undergoing an anticoagulation treatment with a factor Xa (FXa) inhibitor, comprising administering to the patient a FXa derivative that has a deletion of at least 50% of amino acid residues 6-39 of the light chain and a modification at the active site on the heavy chain, wherein the FXa derivative has reduced catalytic activity as compared to the wild-type FXa protein, and is capable of binding to the factor Xa inhibitor.

[0064] In some embodiments, the administration is carried out within 6 hours following onset of a symptom of intracranial hemorrhage, or preferably the administration is carried out within 3 hours following onset of a symptom of intracranial hemorrhage.

[0065] In some embodiments, the administration is carried out within 15 hours following the patient taking the FXa inhibitor.

[0066] In some embodiments, the administration comprises a bolus injection of the FXa derivative.

[0067] In some embodiments, the bolus injection comprises 300-500 mg of the FXa derivative, or preferably 350-450 mg of the FXa derivative.

[0068] In some embodiments, the administration further comprises an infusion of the FXa derivative after the bolus injection.

[0069] In some embodiments, the infusion comprises 400-560 mg of the FXa derivative, or preferably 450-510 mg of the FXa derivative.

[0070] In some embodiments, dosing of the FXa derivative is according to the selection criteria in Table 1. The higher dosing regime (e.g., a bolus dose of 800 mg over a period of 30 minutes and a total infusion dose of 960 mg) can be used when the last FXa inhibitor dosing was high (e.g., >10 mg rivaroxaban, >5 mg apixaban, >30 mg edoxaban, or >40 mg enoxaparin) if the FXa derivative is administered within 8 hours following the FXa inhibitor dosing. The higher dosing regime (e.g., a bolus dose of 800 mg over a period of 30 minutes and a total infusion dose of 960 mg) can also be used if the FXa derivative is administered longer than 15 hours following the FXa inhibitor dosing, or if the FXa inhibitor dosing time is unknown.

[0071] By contrast, the lower dosing regime (e.g.. a bolus dose of 400 mg over a period of 15 minutes and a total infusion dose of 480 mg) can be used when the last FXa inhibitor dosing was low (e.g, <10 mg rivaroxaban, <5 mg apixaban, <30 mg edoxaban, or <40 mg enoxaparin) if the FXa derivative is administered within 8 hours following the FXa inhibitor dosing. Such lower dosing regime can be also used when the last FXa inhibitor dosing 8 to 15 hours before the administration of the FXa derivative, for instance.

[0072] In some embodiments, the patient is at least 75 years old.

[0073] In some embodiments, the patient has a baseline NIHSS (NIH Stroke Scale / Score) of greater than 9.

[0074] Also provided, in one embodiment, is a method for selecting a patient to receive a treatment with a factor Xa (FXa) derivative. As shown in Example 3, higher pre-scan hematoma growth rate, which is a composite of time from symptom onset to baseline scan and baseline hematoma volume, and higher diastolic blood pressure can predict hematoma expansion but not thrombotic events in patients with FXa-associated ICH. As summarized in FIG. 7, patients with a > 11 mL / hr pre-scan hematoma growth rate have the highest risk of HE; patients with a 1 to <11 mL / hr pre-scan hematoma growth rate have the intermediate risk of HE; and patients with a <1 mL / hr pre-scan hematoma growth rate have the lowest risk of HE. With respect to diastolic blood pressure, the data show that higher diastolic blood pressure (e.g, > 95 mm Hg) is associated with higher HE risks.

[0075] Accordingly, in one embodiment, the present disclosure provides a method for selecting a patient to receive a treatment with a factor Xa (FXa) derivative, which entails (a) measuring, following symptom onset of intracranial hemorrhage in a patient undergoing an anticoagulation treatment with a FXa inhibitor, a baseline hematoma volume, thereby obtaining a hematoma growth rate that is the baseline hematoma volume divided by the time period from the symptom onset to the measurement; and (b) selecting the patient for receiving a treatment with a FXa derivative when the hematoma growth rate is greater than 1 mL / hr.

[0076] A “hematoma growth rate'’ as used herein refers to the initial hematoma growth rate from onset of an ICH symptom to when the baseline imaging scan is conducted (hence a “pre-scan” hematoma growth rate) or when a FXa derivative treatment is given. It can be calculated by dividing the measured baseline hematoma volume by the time. In some embodiments, the baseline imaging scan or administration of the FXa derivative is conducted within 24 hours following the ICH symptom onset. In some embodiments, the baseline imaging scan or administration of the FXa derivative is conducted within 20, 18, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 hours following the ICH symptom onset. In some embodiments, the baseline imaging scan or administration of the FXa derivative is conducted within 6 hours following the ICH symptom onset. In some embodiments, the baseline imaging scan or administration of the FXa derivative is conducted betw een 2 and 4 hours following the ICH symptom onset.

[0077] In some embodiments, the patient selected for receiving a treatment with a FXa derivative has a hematoma growth rate that is greater than or equal to 11 mL / hr. In some embodiments, the patient selected for receiving a treatment with a FXa derivative has a hematoma growlh rate that is greater than or equal to 2, 3, 4, 5, 6, 7, 8, 9, 10, or 11 mL / hr.

[0078] In some embodiments, the patient selected for receiving a treatment with a FXa derivative has a diastolic blood pressure that is greater than 95 mm Hg. In some embodiments, the patient selected for receiving a treatment with a FXa derivative has a diastolic blood pressure that is greater than 80, 85, 90, 95. 100, 105, 110, 115 or 120 mm Hg.

[0079] Yet another embodiment provides a method for improving hemostatic efficacy in a patient having suffered from intracranial hemorrhage while undergoing an anticoagulation treatment with a factor Xa (FXa) inhibitor, comprising administering to the patient a FXaderivative that has a deletion of at least 50% of amino acid residues 6-39 of the light chain and a modification at the active site on the heavy chain, wherein the FXa derivative has reduced catalytic activity as compared to the wild-type FXa protein, and is capable of binding to the factor Xa inhibitor. In some embodiments, the patient has a hematoma grow th rate, following onset of an intracranial hemorrhage symptom, that is greater than 1 mL / hr. In some embodiments, the patient has a hematoma growth rate that is greater than or equal to 2, 3, 4, 5, 6, 7. 8. 9, 10, or 11 mL / hr. In some embodiments, the patient has a diastolic blood pressure that greater than 80, 85, 90, 95, 100, 105, 110, 115 or 120 mm Hg.

[0080] In some embodiments, the FXa derivative is a two-chain protein comprising a light chain comprising the amino acid sequence of SEQ ID NO:3 or a first peptide having at least 85% sequence identity to SEQ ID NO:3, and a heavy chain comprising the amino acid sequence of SEQ ID NO: 4 or a second peptide having at least 85% sequence identity to SEQ ID NON. In some embodiments, the FXa derivative is andexanet alfa.III. Factor Xa Derivative Compositions

[0081] In various embodiments, a factor Xa derivative is administered to a patient. Accordingly, compositions including the factor Xa derivative are also provided. In some embodiments, the compositions further include a pharmaceutically acceptable carrier. In some embodiments, the FXa derivative is conjugated with a moiety' capable of extending the circulating half-life of the derivative.

[0082] '‘Pharmaceutically acceptable carriers’’ refers to any diluents, excipients, or carriers that may be used in the compositions of the disclosure. Pharmaceutically acceptable carriers include saline, ion exchangers, alumina, aluminum stearate, lecithin, serum proteins, such as human serum albumin, buffer substances, such as phosphates, glycine, sorbic acid, potassium sorbate, partial glyceride mixtures of saturated vegetable fatty acids, water, salts or electrolytes, such as protamine sulfate, disodium hydrogen phosphate, potassium hydrogen phosphate, sodium chloride, zinc salts, colloidal silica, magnesium trisilicate, polyvinyl pyrrolidone, cellulose-based substances, polyethylene glycol, sodium carboxymethylcellulose, polyacrylates, waxes, polyethylene-polyoxypropylene-block polymers, polyethylene glycol and wool fat. Suitable pharmaceutical carriers are described in Remington ’s Pharmaceutical Sciences, Mack Publishing Company, a standard reference text in this field. They are preferably selected with respect to the intended form of administration,that is, oral tablets, capsules, elixirs, syrups and the like, and consistent with conventional pharmaceutical practices.

[0083] The formulations of the disclosure can be manufactured by methods well known in the art such as conventional granulating, mixing, dissolving, encapsulating, lyophilizing, or emulsifying processes, among others. Compositions may be produced in various forms, including granules, precipitates, or particulates, powders, including freeze dried, rotary dried or spray dried powders, amorphous powders, injections, emulsions, elixirs, suspensions or solutions. Formulations may optionally contain stabilizers, pH modifiers, surfactants, bioavailability modifiers and combinations of these.

[0084] In one embodiment, the FXa derivative is lyophilized. Methods for lyophilizing polypeptides are well known in the art. In some embodiments, the FXa derivative is provided in single-use vials, containing 100, 200 or 400 mg of the lyophilized FXa derivative formulated with the inactive ingredients tromethamine (Tris). L-arginine hydrochloride, sucrose (2% w / v), mannitol (5% w / v), and polysorbate 80 (0.01% w / v) at pH 7.8. It can be reconstituted with sterile waler for injection for intravenous (IV) administration.

[0085] Pharmaceutical formulations may also be prepared as liquid suspensions or solutions using a sterile liquid, such as oil, water, alcohol, and combinations thereof. Pharmaceutically suitable surfactants, suspending agents or emulsifying agents, may be added for oral or parenteral administration. Suspensions may include oils, such as peanut oil, sesame oil, cottonseed oil, com oil and olive oil. Suspension preparation may also contain esters of fatty acids, such as ethyl oleate, isopropyl myristate, fatty acid glycerides and acetylated fatty acid glycerides. Suspension formulations may include alcohols, such as ethanol, isopropyl alcohol, hexadecyl alcohol, glycerol and propylene glycol. Ethers, such as poly(ethyleneglycol), petroleum hydrocarbons, such as mineral oil and petrolatum, and water may also be used in suspension formulations.

[0086] The formulations are for administration to a mammal, preferably a human being. Such formulations of the disclosure may be administered in a variety of ways, preferably parenterally.

[0087] The term “parenteral” as used herein includes subcutaneous, intravenous, intramuscular, intra-articular, intra-synovial, intrastemal, intrathecal, intrahepatic, intralesional and intracranial injection or infusion techniques. However, in cases where theFXa inhibitor being neutralized has a long plasma half-life, a continuous infusion or a sustained release formulation may be required to bind to the FXa inhibitor and such free up the active FXa prior to the clearance of the FXa inhibitor from the body. Therefore, in one aspect, the formulation is administered to the subject as a bolus. In another aspect, the formulation is administered by infusion. In another aspect, the formulation is administered by a combination of bolus and infusion.

[0088] Sterile injectable forms of the compositions of this disclosure may be aqueous or oleaginous suspension. These suspensions may be formulated according to techniques known in the art using suitable dispersing or wetting agents and suspending agents. The sterile injectable preparation may also be a sterile injectable solution or suspension in a non-toxic parenterally acceptable diluent or solvent, for example as a solution in 1,3-butanediol. Among the acceptable vehicles and solvents that may be employed are water, Ringer's solution and isotonic sodium chloride solution. In addition, sterile, fixed oils are conventionally employed as a solvent or suspending medium. For this purpose, any bland fixed oil may be employed including synthetic mono- or di-glycerides. Fatty acids, such as oleic acid and its glyceride derivatives are useful in the preparation of injectables, as are natural pharmaceutically-acceptable oils, such as olive oil or castor oil, especially in their polyoxyethylated versions. These oil solutions or suspensions may also contain a long-chain alcohol diluent or dispersant, such as carboxymethyl cellulose or similar dispersing agents w hich are commonly used in the formulation of pharmaceutically acceptable dosage forms including emulsions and suspensions. Other commonly used surfactants, such as Tweens, Spans and other emulsifying agents or bioavailability enhancers which are commonly used in the manufacture of pharmaceutically acceptable solid, liquid, or other dosage forms may also be used for the purposes of formulation. Compositions may be formulated for parenteral administration by injection such as by bolus injection or continuous infusion. A unit dosage form for injection may be in ampoules or in multi-dose containers.

[0089] In addition to dosage forms described above, pharmaceutically acceptable excipients and carriers and dosage forms are generally known to those skilled in the art and are included in the disclosure. It should be understood that a specific dosage and treatment regimen for any particular patient will depend upon a variety of factors, including the activity of the specific FXa derivative employed, the age, body weight, general health, sex and diet, renal and hepatic function of the patient, and the time of administration, rate of excretion, drugcombination judgment of the treating physician or veterinarian and severity' of the particular disease being treated.EXAMPLES

[0090] The disclosure is further understood by reference to the following examples, which are intended to be purely exemplary of the disclosure. The present disclosure is not limited in scope by the exemplified embodiments, which are intended as illustrations of single aspects of the disclosure only. Any methods that are functionally equivalent are within the scope of the disclosure. Various modifications of the disclosure in addition to those described herein will become apparent to those skilled in the art from the foregoing description and accompanying figures. Such modifications fall within the scope of the appended claims.Example 1. Andexanet for Factor Xa Inhibitor-Related Acute Intracerebral Hemorrhage

[0091] This example tested the ability of andexanet alfa (or simply andexanet) to reduce antifactor Xa (FXa) activity and to restore hemostatic efficacy in patients who suffered from acute major bleeding associated with factor Xa inhibitor-based anticoagulant treatments.

[0092] The "usual care’' was used as control. The usual care consisted of any treatment(s) (including no treatment) other than andexanet administered within 3 hours postrandomization that the investigator and / or other treating physicians considered to be appropriate.MethodsTrial Design and Oversight

[0093] Independent ethics committees at each study site approved the protocol. Consent was obtained directly, by proxy or was deferred where approved. The trial was conducted in accordance w ith ethical principles derived from the Declaration of Helsinki and the Council for International Organizations of Medical Sciences International Ethical Guidelines. An independent Data Safety Monitoring Board (DSMB) monitored the trial.

[0094] This study was designed and coordinated by Population Health Research Institute (PHRI), a joint institute of McMaster University and of Hamilton Health Sciences, and was funded by Alexion, AstraZeneca Rare Disease. The study protocol was amended during thecourse of the study. Although the treatment was unblinded at the study sites, members of the steering committee were always blinded to summary statistics and trial results.Patients

[0095] Initially patients with any acute FXa-related intracranial hemorrhage were eligible, but after protocol amendments only patients with an acute ICH as the main bleeding event with an estimated blood volume of >0.5 to <60 mL were eligible; and time from onset of bleeding symptoms to baseline imaging scan needed to be <6 hours. The hemorrhage needed to be observed radiographically within the cerebrum within <2 hours prior to randomization. Patients receiving treatment with a FXa inhibitor were eligible, with last dose <15 hours prior to randomization. Patients were excluded for any of the following: Glasgow Coma Scale score <7 at time of consent, National Institutes of Health Stroke Scale (NIHSS) >35, planned surgery within 12 hours or recent history of thrombotic event.Randomization and Treatments

[0096] Patients were randomized 1 : 1 to andexanet or usual care, stratified (after amendment 1) by intention to use prothrombin complex concentrate (PCC) if randomized to usual care, and by time from symptom onset to baseline imaging scan (<180 vs >180 minutes). The randomization scheme was generated by PHRI. There were 20 patients found before database lock and without unblinding, to have not correctly consented; and their data was removed from the database.

[0097] Patients assigned to the andexanet group received either high-dose or low-dose bolus over 15-30 minutes followed by continuous infusion over 2 hours. The high dose included a bolus dose of 800 mg over a period of 30 minutes and a total infusion dose of 960 mg. The low dose included a bolus dose of 400 mg over a period of 15 minutes and a total infusion dose of 480 mg.

[0098] Dose was based on FXa inhibitor used, and the amount and timing of last dose (Table 1). Usual care was at the discretion of local physicians, but excluded andexanet, and could include PCC.Table 1: Andexanet Dose SelectionEndpoints and Assessments

[0099] The primary efficacy endpoint was effective hemostasis assessed at 12 hours postrandomization. Excellent or good hemostasis was achieved if all of the following occurred: change in hematoma volume of <20% (excellent) or <35% (good) between baseline and 12 hours, increase in NIHSS score of <7 between baseline and 12 hours; and no rescue therapies (e.g., andexanet, PCC or surgery' to decompress the hematoma) received 3 to 12 hours from randomization. The 12-hour NIHSS assessment was done by trained health care professionals blinded to treatment allocation. The secondary’ efficacy endpoint was percent change from baseline to nadir in anti-FXa activity during the first 2 hours post-randomization. The modified Rankin Scale (mRS) at 30 days post-randomization was an exploratory outcome. Safety’ endpoints were assessed at 30 days and included thromboembolic events and death. A blinded endpoint adjudication committee reviewed all potential thrombotic events; and assessments of hemostatic efficacy. Where there were missing brain scans or assessments of NIHSS, the committee assessed whether this lack was due to clinical reasons (such as patient death) or administrative reasons. A blinded core lab reviewed brain imaging to determine the change in hematoma volume.Statistical Analysis

[0100] Based on an assumed hemostatic efficacy rates of 70% and 80% for patients treated with usual care and andexanet. respectively, a total sample size of 900 patients was estimated to be required for 90% power to detect a 10% absolute difference in the rate of effective hemostasis with a 2-sided type I error rate of 5%. The primary efficacy analysis compared the proportion of patients with effective hemostasis between the andexanet and usual care groups using a Cochran-Mantel-Haenszel test stratified by time from symptom onset to baseline imaging scan (<180 vs >180 minutes). The secondary endpoint of percent change in anti-FXaactivity was assessed using analysis of covariance (ANCOVA) on the ranked data, including intended-usual-care agent, time from symptom onset to baseline imaging scan, and baseline anti-FXa activity as covariates. Both the efficacy and safety analyses are based on intention to treat analysis.

[0101] Two analyses of effective hemostasis were planned, when 50% and when 100% of planned patients had been assessed. A hierarchical testing procedure controlled the overall family -wise type I error rate at 5% with a significance level of 0.0310 used at the first analysis. The interim analysis was performed by the unblinded statistician at PHRI and reviewed by the DSMB who made the recommendation whether to stop the trial or not.Results

[0102] The study enrolled 530 patients at 131 sites in 23 countries. The interim analysis of efficacy met its pre-specified criterion for early trial stopping and the DSMB recommended that the trial be stopped. Between the time of database lock for the interim analysis and the time of the stopping recommendation by the DSMB, 78 patients were enrolled for a total of 530 patients. Of the patients randomized to usual care, 230 (86. 1%) received PCC in the first 3 hours after randomization (median dose 3000 IU (QI, Q3 2000, 3500 IU)). The type of PCC used was known in 137 patients (4-factor in 128 (93%), 3-factor in 4 patients (3%) and activated PCC or factor eight bypassing activity (FEIBA) in 5 (4%). For andexanet patients, 199 (75.7%) received the low dose regimen and the remainder the high dose. There were 18 patients in whom hemostatic efficacy was not assessable due to lack of essential data, such as follow up brain scan or NIHSS. These were adjudicated as due only to administrative reasons (no clinical reason found for lack of data) in 10 (7 on andexanet); and due to clinical deterioration (such as death) in 8 (5 on andexanet). Five patients randomized to andexanet did not receive it (2 received PCC); and 4 patients randomized to usual care received andexanet.

[0103] Patients enrolled were elderly with a substantial burden of vascular disease including prior stroke in 21.3%, myocardial infarction in 12.3%, pulmonary embolism in 8.5% and venous thrombosis in 8.9% (Table 2) Most patients (87.4%) had a history of atrial fibrillation. Apixaban was the FXa inhibitor most often used (60.4%). The site of bleeding was intracerebral in 91.9% of patients. Bleeding was preceded by trauma in 12.3% of patients. Median presenting hematoma volume was 9.8 ml (QI. Q3 3.7, 24.2) and median baseline NIHSS was 9.0 (QI, Q3 5.0, 16.0). Median time from symptom onset to baseline scan was 2.3 hours (QI, Q3 1.4, 3.8), median time from scan to randomization was 1.1 hours(QI, Q3 0.7, 1.6) and median time from randomization to andexanet treatment was 0.3 hours(QI, Q3 0.2, 0.5).Table 2. Baseline CharacteristicsEfficacy

[0104] Hemostasis was determined to be excellent or good in 168 (63.9%) patients in the andexanet arm and in 140 (52.4%) in the usual care arm, an increase with andexanet of 11.0 (95%CI 2.8,19.3) patients per 100 patients treated (p=0.009) (Table 3). The excess of patients on andexanet with excellent / good hemostatic efficacy fell almost entirely in the excellent category (<20% hematoma expansion). Excluding 10 patients in whom hemostatic efficacy was non-evaluable for administrative reasons, andexanet increased by 12.3 (95%CI 4.0, 20.5) the number of patients per 100 patients treated who had excellent / good hemostasis. Based on hematoma volume change <35%, with andexanet there were 13. 1 (95%CI 5.2, 21.0) more patients per 100 patients. Very large hematoma expansion volume (>12.5 ml), or death within 12 hours, occurred in 29 (11.6%) patients on andexanet and in 48 (19.0%) with usual care, a decrease with andexanet of 7.4 (95%CI 1.2, 13.6) patients per 100 patients treated. The proportion of patients with modified Rankin Score <3 at 30 days was similar for both groups (69 / 246 (28.0%) and 79 / 255 (31.0%) for andexanet and usual care respectively). The change in median FXa activity between baseline and 1- or 2-hour nadir was 94.4% with andexanet and was 23.5% with usual care (pO.OOl) (FIG. 1).Table 3: Efficacy OutcomesThrombotic events and death within 30 days

[0105] By intention to treat, there were 27 (10.3%) patients on andexanet with a thrombotic event compared to 15 (5.6%) patients receiving usual care, an increase with andexanet per 100 patients treated of 4.6 (95%CI 0.1, 9.2; p=0.048) (Table 4). Thrombotic events in the safety population, which assigns patients to the treatment arms based on treatment received, are presented in Table 5. Ischemic stroke occurred in 17 (6.5%) patients on andexanet and in 4 (1.5%) patients receiving usual care, an increase with andexanet per 100 patients treated of 5.0 (95%CI 1.5, 8.8). There was no difference in death which occurred in 73 (27.8%) patients receiving andexanet and in 68 (25.5%) patients receiving usual care.Table 4. Thrombotic events and deaths within 30 daysTable 5: Thrombotic events and Death Within 30 Days (Safety set*)Sub-group analysis

[0106] FIG. 2 shows the forest plot for selected sub-groups for the outcome of hemostatic efficacy. There are no significant treatment interactions suggesting that the improvement in hemostatic efficacy is consistent across the sub-groups. Baseline rates of hemostatic efficacy in the usual care arm varied according to clinical presentation. Patients with symptom onset to randomization time <2 hours and patients with NIHSS >9 had rates of excellent or good hemostasis under 50% with usual care and greater than average increases in excellent or good hemostatic efficacy with andexanet. FIG. 3 shows the forest plot for selected sub-groups forthe outcome of thrombotic events. Due to the paucity of events, interaction p values are not calculated. Patients with prior stroke or myocardial infarction, a group known to be high risk of stroke with atrial fibrillation, may have a higher risk of thrombotic events than average with andexanet.

[0107] This example demonstrated in patients with acute ICH while on a FXa inhibitor, that andexanet, compared to usual care, increased the number of patients with hemostatic efficacy, a measure that combines radiological assessment of hematoma expansion, clinical assessment using the NIHSS and absence of rescue therapy. Hematoma expansion is the most important modifiable risk factor in patients with acute ICH and is known to have an important impact on morbidity and mortality. For example, in the INTERACTl trial data (8), each 1 mL of hematoma growth w as associated with a 5% (95% CI 2%-9%) higher chance of being dead or dependent at 90 days. Hematoma expansion of >12.5 ml is also very strongly correlated with poor clinical outcome in patients with ICH, with an 80% positive predictive value for significant disability or death (8). Thus, the effect of andexanet to increase by 13.1 (95% CI 5.2, 21.0) the number of patients per 100 with hematoma expansion of <35%, and to increase overall hemostatic efficacy by 11.0% (95% CI 2.8, 19.3) is substantial and clinically relevant. Large absolute hematoma expansion (>12.5 mL) was also substantially reduced.

[0108] There was substantial and rapid reduction in anti-FXa activity with andexanet, but only minimal reduction with usual care. The efficacy of andexanet demonstrated in this study is consistent with the mechanism of action of the drug w hich is to rapidly sequester FXa inhibitor molecules to allow normalization of natural hemostatic mechanisms.

[0109] In conclusion, andexanet rapidly reduces anti-FXa activity, reduces hematoma expansion and increases hemostatic efficacy in patients with acute ICH. Andexanet increases thrombotic events, including ischemic stroke. Andexanet should be considered for patents on FXa inhibitors with acute ICH.Example 2. Secondary Endpoint for Efficacy

[0110] This example describes the results of a clinical study expanded from that trial as reported in Example 1 . The primary endpoint, i. e. , effective hemostasis, of the expanded study w as similar to that of Example 1. In this example, the results of the secondary endpoint are provided.[OHl] Overall, andexanet was superior to usual care in reducing anti-FXa activity from baseline to nadir during the first 2 hours post randomization in acute ICH in patients receiving a direct oral FXa inhibitor (Table 6, -94.4% median reduction in the andexanet group, -27.5% median reduction in the usual care group, p < 0.0001).Table 6. Summary of Anti-FXa Activity (ng / mL) by Visit and Treatment by Prior FXa Inhibitor (ITT Set, Primary Efficacy Population)acxThe patients with enoxaparin as the prior FXa inhibitor are excluded due to their unconvertible unit of anti-FXa activity.FXa. activated factor X; IQR, interquartile range; ITT, intent to treat; N, number of patients in treatment group; n, number of patients included in the category: SD, standard deviation.

[0112] The reduction in anti-FXa activity overall for the FXa inhibitors is presented in FIG.4. The reduction in anti-FXa activity for each of the direct oral FXa inhibitors following study treatment is presented in FIG. 5A-C.

[0113] The correlation between anti-FXa activity and the achievement of hemostatic efficacy was also determined. As shown in Table 7, there was a correlation between the hemostatic efficacy and percentage change in anti-FXa activity (odds ratio 0.9988, 95% CI [0.9952, 1.0024], AUC 0.56, 95% CI [0.51, 0.62]).Table 7. Correlation Analysis for Effective Hemostasis with Anti-FXa Activity (ITT Set,Primary Efficacy Population)The odds ratio and 95% CI, AUC and 95% CI are estimated from a logistic regression for effective hemostasis, where (percent) change from baseline to nadir in anti-FXa activity is the independent variable; treatment, baseline anti-FXa activity and time from symptom onset to baseline imaging scan (< 180 minutes vs. > 180 minutes) are adjusted as covariates.

[0114] As shown in Examples 1 and 2, the primary efficacy objective of the clinical studies was met. Andexanet was superior to usual care in achieving effective hemostasis at 12 hours post-randomization in acute ICH in patients receiving a direct oral FXa inhibitor (67.0% ofpatients in the andexanet group, 53.1% of patients in the usual care group, difference 13.4%, 95% CI [4.6%. 22.2%], p = 0.0032).

[0115] The primary endpoint results were consistent across pre-defined subgroups based on demographic and important baseline characteristics.

[0116] The secondary efficacy objective was also met. Andexanet was superior to usual care in reducing anti-FXa activity from baseline to nadir during the first 2 hours post-randomization in acute ICH in patients receiving a direct oral FXa inhibitor.

[0117] There was a relationship between hemostatic efficacy and percentage change in anti- FXa activity. The results of the sensitivity analyses, including the analyses of the extended population, were consistent with the results of the primary efficacy analyses.Example 3. Predictors of Hematoma Expansion and Response to Andexanet Alfa in Patients with Intracerebral Hemorrhage

[0118] This example describes secondary analyses derived from the clinical trial reported in Examples 1 and 2. These secondary analysis support methods of treatment aimed at identifying FXa inhibitor-associated intracerebral hemorrhage (ICH) patients at greater risks for hematoma expansion (HE) and more likely to benefit from treatment with andexanet.

[0119] Treatment with factor Xa (FXa) inhibitors is associated with a high risk of hematoma expansion in patients who experience ICH. Final hematoma volume is a major determinant of the extent of primary and secondary injury' following ICH. By extension, hematoma expansion is a significant predictor of poor outcome in patients with acute ICH. It is estimated that for each mL and 10% increase in baseline hematoma volume, patients are 6% and 16% more likely, respectively, to shift one point towards greater disability or death on the modified Rankin Scale (mRS) at 90 days. Reducing hematoma growth is thus an important mechanistic target to improve clinical outcomes in treatment trials of patients with acute ICH.

[0120] Andexanet rapidly reverses the anticoagulant effects of FXa inhibitors, and increases hemostatic efficacy. However, this benefit may be partially offset by increased thrombotic events in patients receiving andexanet, underscoring the importance of patient selection for optimal treatment outcomes.Methods:Study Participants

[0121] Patients enrolled into the trial with qualifying ICH (excluding patients with subdural, epidural or subarachnoid hemorrhages) and who had interpretable baseline and subsequent 12-hour brain imaging were eligible for these secondary analyses. This study followed the Consolidated Standards of Reporting Trials (CONSORT) reporting guideline.Baseline characteristics

[0122] Baseline demographics, medical history, medication use, stroke severity and hematoma characteristics were collected at study entry. Pre-scan hematoma growth rate (mL / hour) was calculated as the baseline hematoma volume divided by time from symptom onset to the baseline scan.Outcomes

[0123] For this analysis, hematoma expansion is defined as an increase in hematoma volume of >12.5 mL or >35% between brain imaging obtained at baseline and 12 hours following randomization. These thresholds were selected due to their strong association with poor outcome on the modified Rankin Scale (mRS) score at 90 days in patients with acute ICH. The safety outcome was thrombotic events within 30 days. An endpoint adjudication committee masked to treatment assignment reviewed all potential thrombotic events.Volumetric analysis of the hemorrhage using Quantomo software (Cybertrials, Inc, Calgary7, Canada) was performed at a dedicated imaging core lab by trained physicians masked to treatment assignment to determine the change in hematoma volume.Statistical analysis

[0124] Baseline characteristics were summarized and compared between the two groups defined by participants with and without hematoma expansion. Continuous variables were summarized as mean±SD or median (interquartile range [IQR]) and compared between groups by using either t test for the means or Wilcoxon rank sum tests for the medians. Categorical variables were reported as counts (percentages) and compared between groups by Pearson chi-squared test. Missing values in time from symptom onset to treatment were imputed with the median value of this variable in the corresponding treatment arm.

[0125] Multivariate logistic regression was performed using the dichotomized hematoma expansion as the outcome and risk factors identified from the baseline univariate analysis (p value <0. 10), along with treatment arm as independent variables. Odds ratios (OR) and 95% confidence intervals (CI) obtained from the logistic regressions were used to assess the association between the risk factors and the outcome of hematoma expansion. Due to the fact that the indication for high dose andexanet is highly correlated with baseline anti-FXa levels, only baseline anti-FXa level but not high dose andexanet indication variable was included in the model to avoid co-linearity. Furthermore, the anti-FXa level has greater biological plausibility7for causal relationship with hematoma expansion. Moreover, to avoid co-linearity between pre-scan hematoma growth rate (mL / hour) and baseline ICH volume (mL) or time from symptom onset to treatment (hour), these variables were separately considered in two different regression models. The final models were subsequently applied to the safety outcome of thrombotic events within 30 days.

[0126] For continuous variables that were identified to be significantly associated with hematoma expansion in the above regression model, the difference in the proportion of participants with hematoma expansion between the andexanet and usual care groups across the quartiles of these variables along with the 95% confidence intervals were estimated using Wald confidence limit method.

[0127] Predicted probability of hematoma expansion stratified by treatment arm at various levels of each independent variables were estimated from fitting each of the corresponding logistic regression model, in which two independent variables were included: the treatment variable and the investigated variable.

[0128] P-values are two-sided. Statistical significance was accepted at the .05 level. Statistical analyses were performed using SAS software (release 9.4).Results:

[0129] Of 530 patients enrolled between 2019 and 2023, 459 had baseline ICH or IVH and adequate baseline and follow-up imaging and were included in these analyses. The mean (±standard deviation, SD) age was 79.1 (±8.3) years and 46.2% (n=212) were female. The majority' of patients (99. 1%) had an intraparenchymal hemorrhage, only 4 had primary intraventricular hemorrhage (0.9%), and in 30 (6.5%) cases the ICH was preceded by trauma. The median (interquartile range, IQR) baseline hematoma volume was 9.2 (3.5, 22.4) mL andNIHSS score was 9.0 (IQR 5.0, 16.0). The median (IQR) time from symptom onset to baseline scan was 2.3 (IQR 1.4, 3.8) hours and median time from symptom onset to treatment was 4.0 (IQR 3.2, 5.5) hours. Most patients assigned to the usual care group (86.4%) received PCC.

[0130] In univariate analysis, higher baseline National Institutes of Health Stroke Scale (NIHSS) score, anti-FXa level, hematoma volume, and pre-scan hematoma growth rate were associated with hematoma expansion (Table 8). Patients with hematoma expansion additionally had higher baseline diastolic blood pressure, shorter time from symptom onset to treatment and greater likelihood to be eligible for high dose andexanet.Table 8. Baseline Characteristics stratified between patients with and without hematoma expansion (>12.5 ml or >35%) at 12 hoursAbbreviations: AF, atrial fibrillation: DBP, diastolic blood pressure; GCS, Glasgow Coma Scale; MI, myocardial infarction; NIHSS, National Institutes of Health Stroke Scale; QI, first quartile; Q3, third quartile; SBP, systolic blood pressure; SD, standard deviation.*: Time from symptom onset to treatment was assessed only in patients who received andexanet or PCC (n=426) and excludes patients in tire usual-care group who did not receive PCC (n=33).

[0131] In the first multivariable regression model (Table 9. model 1), shorter symptom onset to treatment time (OR per 1-hour increase 0.73. 95% Cl 0.63-0.85, p<0.001). larger baseline hematoma volume (OR per 10 mL 1.11, 95% CI 1.01-1.23, p=0.04), and higher diastolic blood pressure (OR per 10 mm Hg 1.15 (1.02-1.29, p=0.02) were independently associated with hematoma expansion. In the second model, pre-scan hematoma growth rate (OR per mL / hour 1.03, 95% CI 1.01-1.04, p<0.001) and diastolic blood pressure (OR per 10 mm Hg 1.18, 95% CI 1.05-1.33, p<0.01) were associated with hematoma expansion.Table 9. Multivariable models for risk of hematoma expansion (>12.5 ml or >35%) at 12 hours

[0132] The effect of andexanet alfa vs. usual care on hematoma expansion was constant across the range of hematoma volumes, time to treatment and hematoma growth rates (FIG. 6A-E)

[0133] The rate of hematoma expansion in the usual care arm increased from 27.9% to 53.6% between participants within the 1st(<3.5 mL) and 4th(>22.4 mL) quartiles of baseline ICH volume. Corresponding rates of hematoma expansion between the lowest and highest quartiles were 48.8% (<3.3 hours) and 24.6% (>5.4 hours), respectively, for time from symptom onset to treatment, 20.0% (<1.2 mL / hour) and 59.3% (>11.4 mL / hour) for pre-scan hematoma growth rate, and 29.5% (<73.0 mm Hg) and 51.8%, (>95.0 mm Hg) for baseline diastolic blood pressure (Table 10). The number needed to treat (NNT) with andexanet to prevent hematoma expansion in this total sample of participants was 7. In patients within the highest risk quartiles of baseline hematoma volume (>22.4 mL), time from symptom onset to treatment (<3.3 hours), pre-scan hematoma growth rate (>11.4 mL / hour). and diastolic blood pressure (>95 mm Hg), the NNTs were 4, 7, 4, and 6 respectively (Table 10). Baseline hematoma volume, time from symptom onset to treatment, diastolic blood pressure, or prescan hematoma growth rate were not predictive of thrombotic events (Table 11). The number needed to harm (NNH) for an excess thrombotic event with andexanet alfa compared with usual care was ~26 (increase with andexanet per 100 patients treated 3.9 [95% confidence interval -1.2, 8.9]) in this sample of patients with ICH.Table 10. Rates of hematoma expansion ( 12.5 ml or £35%) at 12 hours according stratified according to independent predictors of hematoma expansion and treatment groupAbbreviations: CI, confidence interval; QI, first quartile; Q3, third quartileThe increase with andexanet per 100 patients is estimated from the proportion difference and the 95% Cis are Wald Cis.If the total number of events is less than 5, then proportion difference and 95% Cis are not given.Missing values (n=33) for time from symptom onset to treatment are imputed using the median in the corresponding armTable 11. Multivariable models for risk of thrombotic events within 30 days*: Missing values (n=33) for time from symptom onset to treatment are imputed using tire median in the corresponding arm in the ICrH populationNumber of thrombotic events within 30 days: 37

[0134] This example shows that there are three primary factors that independently predict the risk of hematoma expansion. These are a higher baseline hematoma volume, shorter duration from symptom onset to treatment (or scan), and higher baseline diastolic blood pressure. Two of these, volume and time, can be combined in the metric of pre-scan hematoma growth rate. It has also shown that the treatment effect of andexanet in preventing hematoma expansion is highly consistent with similar relative treatment effects observed in patients predicted to be low risk or high risk of expansion. As there exists urgency to restore normal coagulation in patients with FXa inhibitor-associated acute ICH, these variables can be used to rapidly triage benefit risk (FIG. 7).

[0135] In FIG. 7, pre-scan hematoma growth rate quartiles 2 and 3 from Table 10 were combined for the intermediate category. The absolute risk of thrombotic events with andexanet compared to usual care was greater in patients with a prior history of ischemic stroke or myocardial infarction (10.1% with andexanet vs. 8.1% with usual care; adjusted difference per 100 patients treated [2.0, 95% confidence interval -4.3, 8.3; NNH: 50) compared to those without (10.8% vs. 2.7%; adjusted difference per 100 patients treated 8.1, 95% confidence interval -0.3, 16.5; NNH: 12). The small total number of thrombotic events negates further stratification of NNH by pre-scan hematoma growth rate, but there was no association betw een pre-scan hematoma growth rate and risk of thrombotic events observed.Elevated blood pressure additionally increases the risk of hematoma expansion and should be considered in individualized treatment decisions.

[0136] Absolute risk reductions (ARR) in hematoma expansion and corresponding NNT were robust across all quartiles of these variables (NNT mainly <10), with the greatest ARR being observed in patients within highest quartiles of baseline hematoma volume (>22.4 mL) and pre-scan hematoma growth rate (>11.4 mL / hour), where the NNT to prevent hematoma expansion was 4.

[0137] These data indicate that the benefit risk ratio of andexanet treatment can be optimized through patient selection. Rates of hematoma expansion with usual care were roughly 50% in patients within the highest quartiles of baseline hematoma volume and diastolic blood pressure, and those within the lowest quartile of time from symptom onset to treatment. The rate of hematoma expansion was greatest and nearing 60% (59.3%) in patients within the highest quartile of pre-scan hematoma growth rate. Notably, the rate of hematoma expansion with usual care remained clinically significant (ranging between 20-30%) and NNT to reduce hematoma expansion robust (less than 10) even in patients within the low est risk quartiles of these variables and none of these variables were associated with thrombotic events. Thus, by selecting patients at higher risk of hematoma expansion through these variables, and in particular hematoma growth rate, treatment effects for hematoma expansion can be maximized w hile maintaining the same level of thrombotic risk.

[0138] On the basis of these analyses, a simple model that uses hematoma growth rate, diastolic blood pressure and prior history of arterial thrombotic events could be used for individualized treatment decisions to select patients with optimized benefit risk (FIG. 7). When balancing the NNT for reducing hematoma expansion and NNH for thrombotic events, the estimates favor andexanet treatment over usual care in patients presenting with FXa inhibitor-associated ICH who fulfil the trial eligibility, except for patients with prior arterial thrombotic events who present with low-to-intermediate hematoma growth rates (< 11 mL / hr; FIG. 7)

[0139] These findings highlighting the importance of blood pressure as a predictor of expansion in FXa inhibitor-associated ICH further support the importance of bundles of care in patients with acute ICH that prioritize timely normalization of coagulation and lowering of blood pressure, amongst other acute interventions.

[0140] To conclude, higher hematoma growth rate, a composite of time from symptom onset to baseline scan and baseline hematoma volume, and higher diastolic blood pressure predict hematoma expansion but not thrombotic events in patients with FXa-associated ICH. The benefit of andexanet is robust across the range of these variables and may be further amplified by patient selection using these metrics.

[0141] The contents of the articles, patents, and patent applications, and all other documents and electronically available information mentioned or cited herein, are hereby incorporated by reference in their entirety to the same extent as if each individual publication was specifically and individually indicated to be incorporated by reference.

[0142] Applicants reserve the right to physically incorporate into this application any and all materials and information from any such articles, patents, patent applications, or other physical and electronic documents.

[0143] The disclosure has been described broadly and generically herein. Each of the narrower species and subgeneric groupings falling within the generic disclosure also form part of the disclosure. This includes the generic description of the disclosure with a proviso or negative limitation removing any subject matter from the genus, regardless of whether or not the excised material is specifically recited herein. Other embodiments are within the following claims. In addition, where features or aspects of the disclosure are described in terms of Markush groups, those skilled in the art will recognize that the disclosure is also thereby described in terms of any individual member or subgroup of members of the Markush group.

Claims

CLAIMS:

1. A method for improving hemostatic efficacy in a patient having suffered from intracranial hemorrhage while undergoing an anticoagulation treatment with a factor Xa (FXa) inhibitor, comprising administering to the patient a FXa derivative that has a deletion of at least 50% of amino acid residues 6-39 of the light chain and a modification at the active site on the heavy chain, wherein the FXa derivative has reduced catalytic activity as compared to the wildtype FXa protein, and is capable of binding to the factor Xa inhibitor.

2. The method of claim 1, wherein the administration is carried out within 6 hours following onset of a symptom of intracranial hemorrhage, or preferably the administration is carried out within 3 hours following onset of a symptom of intracranial hemorrhage.

3. The method of claim 1 or 2, wherein the administration is carried out within 15 hours following the patient taking the FXa inhibitor.

4. The method of any preceding claim, wherein the administration comprises a bolus injection of the FXa derivative.

5. The method of claim 4, wherein the bolus injection comprises 300-500 mg of the FXa derivative, or preferably 350-450 mg of the FXa derivative.

6. The method of claim 4 or 5, wherein the administration further comprises an infusion of the FXa derivative after the bolus injection.

7. The method of claim 6, wherein the infusion comprises 400-560 mg of the FXa derivative, or preferably 450-510 mg of the FXa derivative.

8. The method of claim 7, wherein the anti coagulation treatment comprises 10 mg or less rivaroxaban, 5 mg or less Apixaban, 30 mg or less Edoxaban, or 40 mg or less Enoxaparin.

9. The method of claim 7 , wherein the anti coagul tion treatment comprises 10 mg or less rivaroxaban, or 5 mg or less Apixaban.

10. The method of any preceding claim, wherein the patient is at least 75 years old.

11. The method of any preceding claim, wherein the patient has a baseline NIHSS (NIH Stroke Scale / Score) of greater than 9.

12. The method of any preceding claim, wherein the patient has a hematoma growth rate, following onset of a symptom of intracranial hemorrhage, that is greater than 1 mL / hr.

13. The method of claim 12, wherein the hematoma growth rate is measured from the onset of the symptom of the intracranial hemorrhage to time of baseline imaging or administration of the FXa derivative.

14. The method of claim 12 or 13, wherein the time of baseline imaging or administration of the FXa derivative is within 6 hours following the onset of the symptom of the intracranial hemorrhage, or within 5 hours, 4 hours, or 3 hours following the onset of the symptom of the intracranial hemorrhage.

15. The method of any one of claims 12-14, wherein the patient has a hematoma growth rate that is greater than or equal to 11 mL / hr.

16. The method of any preceding claim, wherein the patient has a diastolic blood pressure greater than 95 mm Hg.

17. A method for selecting a patient to receive a treatment with a factor Xa (FXa) derivative, comprising:(a) measuring, following onset of a symptom of an intracranial hemorrhage in a patient undergoing an anti coagulation treatment with a FXa inhibitor, a baseline hematoma volume, thereby obtaining a hematoma growth rate that is the baseline hematoma volume divided by the time period from the onset of the symptom to the measurement; and(b) selecting the patient for receiving a treatment with a FXa derivative when the hematoma growth rate is greater than 1 mL / hr, wherein the FXa derivative has a deletion of at least 50% of amino acid residues 6-39 of the light chain and a modification at the active site on the heavy chain, and wherein the FXa derivative has reduced catalytic activity as compared to the wild-type FXa protein, and is capable of binding to the factor Xa inhibitor.

18. The method of claim 17, further comprising administering to the selected patient the FXa derivative.

19. The method of any preceding claim, wherein the FXa derivative is a two-chain protein comprising a light chain comprising the amino acid sequence of SEQ ID NO:3 or a first peptide having at least 85% sequence identity to SEQ ID NO:3, and a heavy chain comprising the amino acid sequence of SEQ ID NO:4 or a second peptide having at least 85% sequence identity to SEQ ID NO:4.

20. The method of claim 19, wherein the FXa derivative is andexanet alfa.

21. The method of any preceding claim, wherein the patient is selected for receiving the treatment with the FXa derivative when the hematoma growth rate is greater than 11 mL / hr.

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