On January 29, 2026 AB Science SA (Euronext – FR0010557264 – AB) reported that the United States Patent and Trademark Office (USPTO) issued a Notice of Allowance (NOA) for a patent relating to methods of treating metastatic castrate resistant prostate cancer (mCRPC) with its lead compound masitinib (US 18/040884).

Schedule your 30 min Free 1stOncology Demo!
Discover why more than 1,500 members use 1stOncology™ to excel in:

Early/Late Stage Pipeline Development - Target Scouting - Clinical Biomarkers - Indication Selection & Expansion - BD&L Contacts - Conference Reports - Combinatorial Drug Settings - Companion Diagnostics - Drug Repositioning - First-in-class Analysis - Competitive Analysis - Deals & Licensing

                  Schedule Your 30 min Free Demo!

Delivery of masitinib patent in mCRPC

Once granted, this new US secondary medical use patent will provide intellectual property (IP) protection for masitinib in mCRPC until May 2042. A NOA signifies that the USPTO intends to grant the patent application after completing certain formal procedural steps. The US NOA is issued after an examiner confirms that the patent application meets all patentability requirements.

This new US patent adds to the IP coverage already granted in Europe (EP4175639) [1].

Counterpart patent applications have also been filed in other major international markets.

Masitinib positioning in metastatic prostate cancer after failure to hormone therapy

In metastatic prostate cancer, patients take hormone therapies (i.e., androgen-deprivation therapy) in first line and second line. Then when metastatic cancer advances patients have to be treated by chemotherapy. There is only one chemotherapy registered, docetaxel, and no drug in combination with docetaxel or replacement of docetaxel has improved PFS or OS and has been registered for the last 20 years.

Masitinib is positioned in combination with docetaxel as a treatment of mCRPC patients who are eligible to chemotherapy. That is to say, it is administered directly following the metastatic hormone-sensitive prostate cancer (mHSPC) treatment space.

Masitinib is one of the rare drugs to have generated positive data on progression free survival (PFS) in combination with docetaxel in this population.

Masitinib positioning in mCRPC with low metastatic involvement measured by a biomarker

More specifically, this patent provides protection for masitinib and related compounds for the treatment of mCRPC in a patient subpopulation with low metastatic involvement (as measured by baseline alkaline phosphatase levels).

This patient population is fully consistent with the results of the masitinib study AB12003 [2] and the ongoing clinical development program of masitinib in mCRPC.

As a reminder, the key results from study AB12003 include:

Masitinib (6.0 mg/kg/day) plus docetaxel conferred a significant progression-free survival (PFS) benefit in mCRPC patients with baseline alkaline phosphatase levels (ALP) less than or equal to 250 IU/L; hazard ratio of 0.79 [0.64,0.97] (p=0.0087), corresponding to a 21% reduction in risk of progression relative to control.
Assessment of PFS rates was convergent with this primary outcome, with 12-, 18-, and 24-month PFS rates showing significant improvement in favor of masitinib plus docetaxel relative to the control: 1.6-fold (p=0.0035), 1.9-fold (p=0.0001), and 1.9-fold (p=0.0028), respectively.
A progressively greater masitinib treatment effect was observed for lower baseline ALP levels (i.e., less advanced metastatic disease), with a significant 47% reduced risk of progression in patients with ALP less than or equal to 100 IU/L (hazard ratio=0.53, p=0.002).
The safety profile of masitinib plus docetaxel was acceptable and consistent with the known masitinib profile, with no new safety signals observed.
Unmet medical need in mCRPC

Although localized disease is associated with high survival rates, metastatic prostate cancer still represents an unmet medical need with a 5-years survival rate of approximately 32% [3]. Practically all patients with metastatic disease become resistant to androgen-deprivation therapy.

With 1.5 million new cases and 397,000 deaths worldwide, prostate cancer is the world’s second most frequent cancer and the fifth leading cause of cancer death among men [4]. It is estimated that there are at least 3.5 million men living with prostate cancer in the United States [5] and 2.5 million in Europe [6]. Approximately 2% of all prostate cancer cases are mCRPC [7], and practically all patients with metastatic disease will become resistant to androgen-deprivation therapy. As such, the population with mCRPC eligible to chemotherapy is around 50,000 in the EU and 70,000 in the USA.

(Press release, AB Science, JAN 29, 2026, https://www.ab-science.com/ab-science-receives-notice-of-allowance-for-us-patent-covering-masitinib-in-the-treatment-of-metastatic-castrate-resistant-prostate-cancer/ [SID1234662345])