Paclitaxel-hyaluronic acid conjugates for treatment of non-muscular invasive bladder cancer

Abstract

The present application discloses a paclitaxel-hyaluronic acid conjugate for use in the treatment of non-muscular invasive bladder cancer, and describes a pharmaceutical composition consisting essentially of a paclitaxel prodrug in combination with a pharmacologically acceptable diluent / excipient for use in the treatment of non-muscular invasive bladder cancer (NMIBC) by intravesical instillation, the treatment is continued for 12 or 6 weeks consecutively according to a single dose of 600 mg of the prodrug per week, or two doses equal to a total of 1200 mg per week. The paclitaxel prodrug used is prepared according to an indirect synthesis method between hyaluronic acid (HA) and molecules of paclitaxel by introducing a spacer (4-bromobutyric acid) between hyaluronic acid and a chemotherapeutic drug.

Description

[0001] This application is a divisional application of a patent application with application number 201980064603.9, application date October 23, 2019, and invention name “Paclitaxel-hyaluronic acid conjugate for the treatment of non-muscle invasive bladder cancer”. Technical Field

[0002] The invention relates to the field of medicine, and in particular to a paclitaxel-hyaluronic acid conjugate for treating bladder tumors. Background Art

[0003] Bladder malignancies are usually formed from its epithelial tissue and are therefore carcinomas. Only in rare cases is the origin of bladder cancer different and therefore it belongs to the category of melanoma, lymphoma or sarcoma. Most bladder tumors are transitional (or urothelial) carcinomas because they originate from transitional epithelium. Squamous cell urothelial carcinomas and glandular carcinomas are much rarer.

[0004] Tumors that invade the detrusor muscle are called muscle-invasive bladder cancer (MIBC) because of its tendency to metastasize by spreading to lymph nodes or other organs, however, approximately 75-85% of newly diagnosed patients have non-muscle-invasive bladder cancer (NMIBC), which is classified as:

[0005] -Ta, papillary epithelial carcinoma confined to the mucosal surface (about 70% of NMIBC);

[0006] -T1, papillary epithelial carcinoma that penetrates the mucosa (about 20% of NMIBC);

[0007] -CIS (epithelial carcinoma in situ), a flat tumor confined to the mucosa, usually multifocal (about 10% of NMIBC), highly anaplastic, considered a precursor of muscle-invasive epithelial carcinoma.

[0008] The most common symptom of bladder cancer is hematuria (blood in the urine), which is macroscopic hematuria or visible hematuria to the naked eye in 78.3% of patients. Suspicion of epithelial cancer may also be seen in patients with nonspecific symptoms affecting the lower urinary tract, which is related to the frequency of their dysuria (difficulty in passing urine) and an increase in urinary irritation. These symptoms are more frequent in patients with CIS regarding papillary tumors, and in all cases they suggest the need for urological evaluation. The lack of specific tumor markers and the variability in the appearance of hematuria are the main reasons for underestimation of this tumor. Diagnostic confirmation is obtained using histological examination of transurethral biopsy.

[0009] The standard of care for bladder cancer is transurethral resection of bladder tumor (TURBT). The following treatments may be performed after endoscopic surgery:

[0010] - For NMIBC: Intravesical instillation of chemotherapy drugs (such as, for example, mitomycin C) or immunotherapy (such as Bacillus Calmette-Guérin (BCG)). Treatment with BCG is currently the best therapy for epithelial carcinoma in situ. The aim of these instillations is to prevent recurrences, which occur at a frequency of 30-60% and require patient monitoring for at least 5 years.

[0011] -For MIBC: Cystectomy and radiation therapy, usually combined with chemotherapy.

[0012] Radical cystectomy is a surgical procedure that involves removing the bladder and possibly other pelvic organs.

[0013] The risk classification for disease recurrence and progression obtained from histological examination allows the opportunity for adjuvant therapy as defined below:

[0014] - Patients at low risk of recurrence underwent TURBT to remove all visible lesions, after which (within the first few hours after surgery) they received a single dose of perioperative intravesical chemotherapy;

[0015] - Patients at intermediate risk of recurrence and low risk of progression undergo perioperative administration of a single dose of intravesical chemotherapy followed by adjuvant therapy based on intravesical chemotherapy or immunotherapy instillations (BCG);

[0016] - Patients at high risk of progression (especially those with CIS) always undergo adjuvant intravesical therapy with BCG, but a high percentage of patients acquire resistance to this treatment. For patients who are unresponsive or refractory to BCG, the only remaining treatment option is therefore radical cystectomy with simultaneous urothelial derivation, otherwise the epithelial carcinoma evolves towards an invasive form.

[0017] BCG is a poorly tolerated drug that can produce different side effects such as prostatitis, orchitis, arthritis and rarely urethral obstruction. A patient who does not respond to BCG is one who does not benefit from the therapy, he / she usually belongs to the group of patients who have been previously treated with BCG but then no longer respond to the same therapy, while patients who are defined as refractory are those for whom the toxic effects of the drug far outweigh the benefits.

[0018] The treatment of bladder cancer is one of the most expensive treatments due to the high recurrence rate and therefore requires an intensive surveillance strategy with regular examinations (cystoscopy, blood and urine tests).

[0019] In particular, the management of non-muscle-invasive tumors (NMIBC) is more expensive than that of invasive tumors (MIBC), especially due to the high rate of local recurrence, and involves repeated resection interventions and controlled trials in addition to cycles of intravesical instillation of chemotherapeutic or immunotherapeutic drugs; finally, it should be noted that in case of CIS that does not respond to treatment with BCG, the only remaining treatment option is radical cystectomy, a very invasive intervention with an important impact on the patient's quality of life.

[0020] In Italy, the annual costs for the management of this disease represent 7% of the total health expenditure, since bladder cancer is the fifth cancer in the Western world by incidence and the second among urinary tract tumors, after prostate epithelial cancer.

[0021] Paclitaxel It is an antitumor agent (Huizing MT et al., Cancer Inv., 1995, 13: 381-404), which exerts its antiproliferative effect by acting on the microtubule organization of the cell cytoskeleton system, preventing normal tissue regeneration during mitosis (Manfredi JJ et al., J Cell Biol, 1982, 94: 688-696).

[0022] The main therapeutic indications for paclitaxel are the treatment of advanced breast cancer, lung cancer, ovarian cancer resistant to standard chemotherapy, bladder cancer, prostate cancer and endometrial cancer. Due to its high lipophilicity, the administration of this chemotherapeutic drug poses many problems, but due to its efficacy, it is certainly a candidate for local treatment of bladder cancer; however, the high concentrations of drug used for bladder instillation cause paclitaxel to penetrate the bladder epithelium, resulting in significant systemic, toxic absorption of the drug.

[0023] The solubilizing solvent currently used for paclitaxel administration in normal clinical protocols is Cremophor EL, but it causes a variety of hypersensitivity phenomena.

[0024] In recent years, in order to overcome the problems caused by the formulation of paclitaxel in polyoxyethylene ether (35) castor oil, many experimental attempts have been made to both make paclitaxel soluble in water and to define new methods of administration. For example, attempts have been made to encapsulate the above anticancer agents in microspheres, liposomes and nanocapsules composed of polymer walls formed from biodegradable copolymers (such as polylactic acid or polyphosphate) and non-biodegradable copolymers (such as ethylene-vinyl acetate).

[0025] Attempts have also been made to prepare micelles by coprecipitating paclitaxel with phosphatidylcholine / bile salts in organic solvents (Nuijen B et al., Researchal New Drugs, 2001, 19: 143-153).

[0026] Various attempts were made to solubilize the above drugs with cyclodextrins, but the new formulations did not give the desired results (Nuijen B et al., Researchal New Drugs, 2001, 19: 143-153).

[0027] It is also known to use PEG (polyethylene glycol) for derivatizing the above mentioned chemotherapeutic drugs by esterification thereof, however this new molecule proves to have very high water solubility but limited stability.

[0028] Finally, a paclitaxel delivery system was developed by conjugating paclitaxel to serum albumin (HSA): the paclitaxel-HSA conjugate was found to be extremely water-soluble and capable of carrying up to 30 molecules of chemotherapeutic drugs, but in vitro experiments showed lower antitumor efficacy compared with paclitaxel itself (Nuijen B et al., Researchal New Drugs, 2001, 19: 143-153).

[0029] A conjugate of paclitaxel with hyaluronic acid (HA) derivatized with a hydrazide molecule bound to the carboxyl group of HA via an amide bond has also been recently synthesized (Luo Y et al., Biomacromolecules. 2000, 1(2): 208-218).

[0030] The bond between paclitaxel and HA allows the drug to directly reach the surface of the tumor cell membrane, which is characterized by an overexpression of the HA receptor CD44. Thus, paclitaxel conjugated to HA proves to be able to bind specifically to CD44 of tumor cells, allowing it to enter the cell cytoplasm where it is activated due to the hydrolysis of the drug / HA bond. This selective drug transport mechanism is called "targeted" target cells.

[0031] HA is a heteropolysaccharide composed of alternating residues of D-glucuronic acid and N-acetyl-D-glucosamine. It has a molecular weight ranging from 50,000 to 13×10 6 A linear chain polymer of Da (depending on the source from which it is obtained and the method of preparation used). It occurs naturally in the gel surrounding cells, in the basic substance of the connective tissue of vertebrate organisms (it represents one of the main components thereof), in the synovial fluid of the joints, in the vitreous humor and in the umbilical cord. Summary of the invention

[0032] The present invention describes a pharmaceutical composition consisting essentially of a paclitaxel prodrug in combination with a pharmacologically acceptable diluent / excipient for the treatment of non-muscle invasive bladder cancer (NMIBC) by intravesical instillation according to a treatment regimen comprising administering a single dose of 600 mg of the prodrug per week, or two doses per week equal to a total of 1200 mg, for a duration of treatment of 12 weeks or 6 weeks.

[0033] The used paclitaxel prodrug was prepared according to an indirect synthesis method between the molecules of hyaluronic acid (HA) and paclitaxel by introducing a spacer (4-bromobutyric acid) between HA and the chemotherapeutic drug.

[0034] The present invention proposes to overcome the disadvantages of the above-mentioned prior art and relates to a pharmaceutical composition consisting essentially of a paclitaxel prodrug in association with a pharmacologically acceptable diluent / excipient for the treatment of non-invasive bladder cancer by intravesical instillation according to a treatment regimen comprising the administration of a single dose of 600 mg of said prodrug per week, or two doses per week equal to a total of 1200 mg, for a treatment duration of 12 weeks (in the case of 600 mg as a single dose) or 6 weeks (in the case of 1200 mg as two doses).

[0035] The paclitaxel prodrug used in the above-mentioned treatment regimen is prepared according to an indirect synthesis method between the molecules of hyaluronic acid (HA) and paclitaxel, by introducing a spacer (4-bromobutyric acid) between hyaluronic acid and the chemotherapeutic drug. This synthesis is described in EP2045270, which states that conjugation with HA makes paclitaxel soluble: therefore, its administration can occur without the various hypersensitivity phenomena that usually occur during drug use due to the presence of polyoxyethylene ether (35) castor oil EL, which is the solubilizing solvent currently used in the normal clinical regimen for the administration of paclitaxel as a lipid-soluble drug. DETAILED DESCRIPTION

[0036] The present invention relates to a pharmaceutical composition consisting of a paclitaxel prodrug in combination with a pharmacologically acceptable diluent / excipient for the treatment of non-muscle invasive bladder cancer (NMIBC), in particular bladder carcinoma in situ (CIS), by intravesical instillation, and preferably for the treatment of CIS that is unresponsive or refractory to treatment with Bacillus Calmette-Guérin (BCG), wherein the pharmaceutical composition is administered as follows:

[0037] a. a single dose of 600 mg per week for 12 weeks, or

[0038] b. twice weekly doses totaling 1,200 mg of the composition per week for 6 weeks,

[0039] The paclitaxel prodrug is composed of a chemical conjugate between paclitaxel and hyaluronic acid via 4-bromobutyric acid, wherein the HA is indirectly bound to paclitaxel via an ester bond between the carboxyl group of HA and the 4-bromobutyric acid spacer, and the 4-bromobutyric acid spacer is in turn ester-bonded to the hydroxyl group of the C2' carbon of paclitaxel via its carboxyl group, and the degree of derivatization is in the range of 18-21% w / w, preferably equal to 20% w / w.

[0040] The pharmaceutical composition used according to the present invention is preferably used for the treatment of CIS unresponsive or refractory to treatment with BCG, and the paclitaxel-HA prodrug consists of a chemical conjugate between paclitaxel and hyaluronic acid with a degree of derivatization in the range of 18-21% w / w.

[0041] The pharmaceutical composition used according to the present invention is preferably used to treat non-muscle invasive bladder epithelial carcinoma (NMIBC), in particular bladder carcinoma in situ (CIS), and is preferably used to treat CIS that is unresponsive or refractory to treatment with BCG, and the paclitaxel-HA prodrug consists of a chemical conjugate between paclitaxel and hyaluronic acid, with a degree of derivatization equal to 20% weight / weight.

[0042] The pharmaceutical composition for medical use according to the present invention is even more preferably used for the treatment of bladder carcinoma in situ (CIS) which is unresponsive or refractory to treatment with BCG.

[0043] In a preferred embodiment, the pharmaceutical composition used according to the present invention is used for the treatment of bladder carcinoma in situ (CIS) that is unresponsive or refractory to treatment with BCG, wherein the pharmaceutical composition is administered in a single dose of 600 mg per week for 12 weeks of treatment, and the prodrug consists of a chemical conjugate between paclitaxel and HA, wherein the HA has a weight average molecular weight ranging from 160,000 to 230,000 Da, preferably with a degree of derivatization equal to 20% weight / weight.

[0044] In a further preferred embodiment, the pharmaceutical composition for use according to the present invention is used for the treatment of bladder carcinoma in situ (CIS) that is unresponsive or refractory to treatment with BCG, wherein the pharmaceutical composition is administered in a dose twice a week totaling 1,200 mg of the composition per week for 6 weeks of treatment, and wherein the prodrug consists of a chemical conjugate between paclitaxel and HA having a weight average molecular weight ranging from 160,000 to 230,000 Da, preferably with a degree of derivatization equal to 20% w / w.

[0045] In the pharmaceutical composition for use according to the present invention, the paclitaxel prodrug is preferably formulated in sterile isotonic water containing 5% glucose.

[0046] Thus, the present invention relates to a pharmaceutical composition consisting of a paclitaxel prodrug in combination with a pharmacologically acceptable diluent / excipient for use in the treatment of bladder cancer by intravesical instillation, wherein the pharmaceutical composition is administered as follows (i.e. instilled in the bladder):

[0047] · a single dose of 600 mg per week for 12 weeks, or

[0048] Twice weekly doses (i.e., with two intravesical instillations) totaling 1,200 mg of the composition (i.e., 600 mg + 600 mg) per week for 6 weeks,

[0049] The paclitaxel prodrug (hereinafter defined as paclitaxel-HA prodrug or simply prodrug) consists of a chemical conjugate between paclitaxel and hyaluronic acid through 4-bromobutyric acid, with a degree of derivatization in the range of 18%-21% weight / weight (w / w), preferably equal to 20% w / w, wherein the bladder cancer is non-muscle invasive epithelial carcinoma (NMIBC), in particular bladder carcinoma in situ (CIS), and is preferably used to treat CIS that is unresponsive or refractory to treatment with BCG.

[0050] In the present specification, by the degree of derivatization of the above-mentioned prodrug, the applicant intends to define the weight percentage of paclitaxel to the weight of paclitaxel-HA prodrug, thus, 100 mg of said prodrug having a degree of derivatization ranging from 18% to 21% w / w will contain 18 mg, 19 mg, 20 mg or 21 mg of the above-mentioned paclitaxel chemotherapy drug, depending on the degree of derivatization indicated: thus, for further clarification, a 20% w / w degree of derivatization contains 20 mg of paclitaxel per 100 mg of prodrug.

[0051] However, it is obvious to a person skilled in the art that at the end of said industrial synthesis process there can always be small variations in the weight ratios between the molecules and therefore the Applicant subsequently describes and claims a derivative range of the above-mentioned prodrug ranging from 18% to 21% w / w, intending to claim all written percentage values ​​including ±1% : for example, a degree of 20% w / w should therefore be understood as 20% ± 1%.

[0052] The paclitaxel-HA prodrug used in the above treatment regimen is prepared by introducing a 4-bromobutyric acid molecule as a spacer between the acid hyaluronic acid and the above chemotherapy drugs according to the indirect synthesis method between hyaluronic acid and paclitaxel molecules (described in EP2045270), and is summarized as follows:

[0053] - The carboxyl group of the spacer is activated by an activating agent (such as, for example, a carbodiimide) and thus makes it suitable for esterification of the hydroxyl function of the carbon on C2′ of paclitaxel; the bond formed between the spacer and paclitaxel is therefore of the ester type. Subsequently, by direct contact with the TBA (tetrabutylammonium) salt of HA in an anhydrous environment, a nucleophilic substitution of the carboxyl group of HA with the bromine of the spacer (i.e. 4-bromobutyric acid) is obtained. In this way, also in this case, an ester bond is generated between HA and the spacer previously bound to paclitaxel; alternatively, the nucleophilic substitution between the carboxyl group of HA and the bromine of the spacer can occur before the spacer itself is bound to the taxane component.

[0054] In short, the paclitaxel-HA prodrug claimed by the applicant has an ester bond between the carboxyl group of the above polysaccharide and the spacer, which in turn is bonded (again with an ester bond) to the hydroxyl group of the C2' carbon of paclitaxel via its carboxyl group.

[0055] HA used for the synthesis of paclitaxel-HA prodrug can be obtained from any source, for example by extraction from rooster combs (for example, according to EP0138572 or WO2018020458), or by technical means (for example, according to EP2614088 or EP2614087), or preferably by fermentation (for example, according to EP0716688), and has a range of 400 to 3×10 6 Da, especially from 400 to 1×10 6 Da, even more particularly a weight average molecular weight of from 160,000 to 230,000 Da (the weight average molecular weight refers to the weight average molecular weight calculated by the "intrinsic viscosity" method (Terbojevich et al., Carbohydr Res, 1986, 363-377).

[0056] The paclitaxel-HA prodrugs described and claimed by the applicants having a degree of derivatization ranging from 18% to 21% w / w are preferably prepared from fermentation-derived HA having a weight average molecular weight ranging from 160,000 to 230,000 Da; prodrugs having a degree of derivatization of 20% w / w are preferred, again prepared from fermentation-derived HA having a weight average molecular weight ranging from 160,000 to 230,000 Da, so that 600 mg of the above paclitaxel-HA prodrug contains 120 mg of paclitaxel chemotherapy drug.

[0057] Thus, the paclitaxel-HA prodrug claimed by the applicant for use in the treatment of non-muscle invasive bladder cancer has an ester bond between the carboxyl group of HA and a 4-bromobutyric acid spacer, which in turn is ester-bonded to the hydroxyl group of the C2' carbon of paclitaxel via its carboxyl group with a degree of derivatization ranging from 18% to 21% w / w; the prodrug used in the in vivo tests described hereinafter is prepared from fermentation-derived HA having a weight average molecular weight ranging from 160,000 to 230,000 Da and has a degree of derivatization of 20% w / w.

[0058] The described and claimed paclitaxel-HA prodrug is prepared as a pharmaceutical composition together with a pharmacologically acceptable diluent / excipient; the prodrug is preferably prepared in sterile isotonic water containing 5% glucose in order to obtain the composition as a sterile and isotonic aqueous solution consisting essentially of the prodrug itself.

[0059] Example

[0060] Example of preparation of paclitaxel-HA prodrug having a derivatization degree of 20% w / w

[0061] Preparation of HA ester derivatives with paclitaxel (HA used for this synthesis has a weight average molecular weight ranging from 160,000 to 230,000 Da), the degree of esterification of the carboxyl groups being 20% ​​w / w:

[0062] 185.2 mg of 4-bromobutyric acid, 254.6 mg of EDC (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide) and 32.4 mg of DMAP (4-dimethylaminopyridine) are added to 308.7 mg of paclitaxel dissolved in 15 ml of dichloromethane. Water is then added to the solution: the organic phase separated from the aqueous phase (containing bromide residues) is collected, and the aqueous phase is removed. 25 ml of N-heptane is added to the obtained organic solution at 10° C., and crystals of the intermediate product are obtained, which are then separated by filtration and subsequently dried. In this way, 301 mg of a dry intermediate product is obtained. 164 mg of the intermediate is added to a solution of 566 mg of HA-TBA (HA salt with tetrabutylammonium) dissolved in 26 ml of NMP. After reacting at 38° C. for 2 days, 1 ml of saturated sodium bromide is added to the solution. After 1 hour, ethanol is slowly added dropwise. The product obtained is then precipitated in pure ethanol and washed in ethanol-water (8.5 / 1.5), washed again with 100% ethanol and then dried at 40° C. The product is analyzed by HPLC analysis in order to control the actual degree of derivatization and purity of the prodrug prepared.

[0063] In the clinical trial described below, the applicant demonstrated how treatment by intravesical instillation of 20% of the prodrug (as described above) in patients with CIS that was unresponsive or refractory to BCG caused complete regression of the CIS epithelial carcinoma in 15 of the 20 treated patients, thereby eliminating them from radical cystectomy, which would otherwise be necessary to avoid progression of this epithelial carcinoma towards its metastatic form, in which patients the treatment was administered as a single dose of 600 mg per week for 12 weeks.

[0064] Clinical trials

[0065] Target :

[0066] 1. To evaluate the effectiveness of a pharmaceutical composition consisting essentially of a paclitaxel-HA prodrug administered at a single dose of 600 mg per week for 12 consecutive weeks for the treatment of NMIBC bladder cancer, particularly carcinoma in situ (CIS) that is unresponsive or refractory to BCG, by intravesical intravenous instillation, wherein the prodrug has a degree of derivatization of 20% w / w; this evaluation is performed by cystoscopy of the bladder at the end of treatment and relative biopsy of the bladder mucosa with cytology of its bladder epithelium. "Patients with a complete positive response" (CR) are defined as patients with negative biopsy with cytology and negative relative cystoscopy at the end of 12 instillations, i.e., patients with no or no tumor cells detected throughout the thickness of the mucosa;

[0067] 2. To evaluate the safety and tolerability of treatment with the prodrug by analyzing / recording not only all adverse events occurring during treatment and at the end of treatment, but also evaluating the possible systemic absorption of paclitaxel after administration of the prodrug. To this end, the patients were regularly subjected to hematological analysis as well as urinalysis and medical examinations.

[0068] Preparation of paclitaxel-HA prodrug pharmaceutical composition

[0069] The final drug form was presented as a solution for intravesical instillation consisting of 600 mg of the previously described paclitaxel-HA prodrug prepared in 50 ml of sterile isotonic water containing 2.5 mg of glucose (thus, the prodrug was prepared in 5% glucose).

[0070] The final concentration of the prodrug in the glucose solution was 12 mg / ml.

[0071] treat

[0072] At the end of the trial, 20 patients with CIS that were unresponsive or refractory to BCG were recruited, i.e., those who were candidates for radical cystectomy, because treatment of patients with BCG did not result in any positive response to the immunotherapy. They were treated according to the described and claimed regimen, i.e., by intravesical instillation of a single dose of 600 mg paclitaxel-HA prodrug (described above) per week for 12 weeks. The prodrug-containing glucose solution was slowly injected into the bladder (within 5 minutes) via an intravesical catheter, and the drug's residence time in the bladder was then 120 minutes; during this treatment, the patient was instructed to alternately turn to his right and left sides every 30 minutes to ensure that the composition was completely in contact with the entire inner surface of the bladder.

[0073] Any adverse events were promptly reported to the physician performing the regular check-ups. Blood samples were collected at the start of the trial and at the end of each infusion to assess the systemic absorption of paclitaxel. At the end of the trial, each patient underwent a medical examination with cystoscopy and a bladder mucosal biopsy with cystoepithelial cytology, hematology samples, and urinalysis for final clinical evaluation.

[0074] result

[0075] 1. To evaluate the effectiveness of treatments for CIS that is unresponsive or refractory to BCG :

[0076] 15 out of 20 treated patients were classified as patients with a complete positive response and thus defined as a CR: this result therefore shows how 75% of the treated patients, all potential candidates for radical cystectomy to reduce the risk of tumor transformation from NMIBC to MIBC, were CR, since they were patients who were negative for both endoscopic and biopsy analysis, since they did not have any tumor cells detected at the bladder level after cytological examination of both the mucosa and the bladder epithelium.

[0077] 2. Evaluate the safety and tolerability of treatment with this prodrug :

[0078] Blood analysis of the treated patients to evaluate the possible systemic absorption of paclitaxel did not yield quantifiable drug values; in addition, no adverse events were reported as "serious," nor were there any significant changes in regularly measured hematological and clinical values ​​in the reported patients, whose vital signs did not change.

[0079] This clinical trial clearly demonstrated the efficacy of the invented treatment method objective, as it allowed patients with CIS that was unresponsive or refractory to treatment with BCG to avoid radical cystectomy.

[0080] For the present patent application, the applicant describes and claims a pharmaceutical composition consisting essentially of the prodrug paclitaxel-HA in combination with a pharmacologically acceptable diluent / excipient for the treatment of non-muscle invasive bladder cancer (NMIBC), in particular carcinoma in situ (CIS) of the bladder, by intravesical instillation, preferably for the treatment of CIS that is unresponsive or refractory to treatment with BCG, wherein the pharmaceutical composition is administered as follows:

[0081] · a single dose of 600 mg per week for 12 weeks, or

[0082] Twice weekly doses totaling 1,200 mg of the composition (i.e. 600 mg + 600 mg) for 6 weeks of treatment,

[0083] wherein the prodrug consists of a chemical conjugate between paclitaxel and HA, HA preferably having a weight average molecular weight ranging from 160,000 to 230,000 Da, wherein the HA is indirectly bound to paclitaxel via an ester bond between the carboxyl group of HA and a 4-bromobutyric acid spacer, the 4-bromobutyric acid spacer in turn being ester-bonded to the hydroxyl group of the C2' carbon of paclitaxel via its carboxyl group, the degree of derivatization being in the range of 18-21% w / w (defined as the percentage of the weight of paclitaxel to the weight of the paclitaxel-HA prodrug), and preferably being equal to 20% w / w.

Claims

1. A pharmaceutical composition consisting essentially of a paclitaxel prodrug in combination with a pharmaceutically acceptable diluent / excipient for use in the treatment of non-muscle invasive bladder cancer (NMIBC), particularly carcinoma in situ (CIS) of the bladder, by intravesical instillation, and preferably for the treatment of CIS that is unresponsive or refractory to treatment with Bacillus Calmette-Guérin (BCG), wherein the pharmaceutical composition is administered as follows: c. A single dose of 600 mg per week for 12 weeks, or d. twice weekly doses of the composition totaling 1,200 mg per week for 6 weeks, The paclitaxel prodrug consists of a conjugate between paclitaxel and hyaluronic acid with the aid of 4-bromobutyric acid, wherein the HA is indirectly bound to paclitaxel via an ester bond between the carboxyl group of HA and the 4-bromobutyric acid spacer, and the 4-bromobutyric acid spacer is in turn bound to the hydroxyl group of the C2' carbon of paclitaxel via its carboxyl group with an ester bond, and the degree of derivatization is in the range of 18-21% w / w, preferably 20% w / w.

2. A pharmaceutical composition according to claim 1 for the treatment of non-muscle invasive bladder cancer (NMIBC), in particular carcinoma in situ (CIS) of the bladder, and preferably for the treatment of CIS that is unresponsive or refractory to treatment with BCG, wherein the paclitaxel-HA prodrug consists of a chemical conjugate between paclitaxel and hyaluronic acid with a degree of derivatization equal to 20% weight / weight.

3. A pharmaceutical composition according to any one of claims 1-2, for use in the treatment of bladder carcinoma in situ (CIS) that is unresponsive or refractory to treatment with BCG.

4. The pharmaceutical composition according to any one of claims 1 to 3, wherein the pharmaceutical composition is administered as a single dose of 600 mg per week for 12 weeks of treatment.

5. The pharmaceutical composition according to any one of claims 1 to 3, wherein the pharmaceutical composition is administered at a dose twice a week totaling 1,200 mg of the composition per week for 6 weeks of treatment.

6. A pharmaceutical composition according to claim 4 for the treatment of bladder carcinoma in situ (CIS) that is unresponsive or refractory to treatment with BCG, wherein the prodrug consists of a chemical conjugate between paclitaxel and HA having a weight average molecular weight ranging from 160,000 to 230,000 Da.

7. Pharmaceutical composition for use according to claim 6, wherein the paclitaxel-HA prodrug consists of a chemical conjugate between paclitaxel and hyaluronic acid, with a degree of derivatization equal to 20% weight / weight.

8. A pharmaceutical composition for use according to claim 5 for the treatment of bladder carcinoma in situ (CIS) unresponsive or refractory to treatment with BCG, wherein the prodrug consists of a chemical conjugate between paclitaxel and HA having a weight average molecular weight ranging from 160,000 to 230,000 Da.

9. Pharmaceutical composition for use according to claim 6, wherein the paclitaxel-HA prodrug consists of a chemical conjugate between paclitaxel and hyaluronic acid, with a degree of derivatization equal to 20% weight / weight.

10. A pharmaceutical composition according to any one of the preceding claims, wherein the paclitaxel prodrug is formulated in sterile isotonic water containing 5% glucose.