Marstacimab 150mg/1ml solution for injection pre-filled disposable devices

In the past year, the European Medicines Agency (EMA), the Food and Drug Administration (FDA) and the Medicines and Healthcare Products Regulatory Agency (MHRA) authorised 53 novel drugs. While the 2024 harvest is not as rich as in 2023, when 70 new chemical entities were approved, the number of 'orphan' drug authorisations in 2024 (21) is similar to that of 2023 (24), illustrating the dynamic development of therapeutics in areas of unmet need. The 2024 approvals of novel protein therapeutics (15) and advanced therapy medicinal products (ATMPs, 6) indicate a sustained trend also noticeable in the 2023 new drugs reviewed in this journal last year (16 and 11, respectively). Clearly, the most striking characteristic of the 2024 drug yield is the creative pharmacological design, which allows these medicines to employ a novel approach to target a disease. Some notable examples are the first drug successfully using a 'dock-and-block' mechanism of inhibition (zenocutuzumab), the first approved drug for schizophrenia designed as an agonist of M1/M4 muscarinic receptors (xanomeline), the first biparatopic antibody (zanidatamab), binding two distinct epitopes of the same molecule, the first haemophilia therapy that instead of relying on external supplementation of clotting factors, restores Factor Xa activity by inhibiting TFPI (marstacimab), or the first ever authorised direct telomerase inhibitor (imetelstat) that reprogrammes the oncogenic drive of tumour cells. In addition, an impressive percentage of novel drugs were first in class (28 out of 53 or 53% of the total) and a substantial number can be considered disease agnostic, indicating the possibility of future approved extensions of their use for additional indications. The 2024 harvest demonstrates the therapeutic potential of innovative pharmacological design, which allows the effective targeting of intractable disorders and addresses crucial, unmet therapeutic needs.

Abstract licence: CC BY

Hemostasis and thrombosis reflect a delicate balance, regulated by the interplay between procoagulant and anticoagulant mechanisms. Hemophilia is traditionally viewed as a bleeding disorder, but emerging evidence highlights the paradoxical risks of thrombosis in hemophilia patients. We explore the landscape of hemophilia management, emphasizing challenges of balancing hemostasis in the context of aging, novel non-factor replacement therapies (NRTs), and comorbidity-driven thrombotic complications. Therapeutic approaches, including innovative NRTs, such as emicizumab, or rebalancing agents (e.g., concizumab, marstacimab, fitusiran), offer promising advancements in bleeding prophylaxis but may increase thrombotic risks. Conversely, novel anticoagulants, such as FXI inhibitors, offer potential thrombosis protection with minimal bleeding risk. Our review examines the impact of aging-related comorbidities, including cardiovascular disease, atrial fibrillation, HIV-associated complications, and acute coronary syndromes, on thrombotic risk in hemophilia patients. Evidence-based strategies for balancing hemostasis and thrombosis are outlined alongside experimental models, thrombin generation assays, and advancements in rebalancing coagulation through natural anticoagulant modulation. FXI inhibition emerges as a paradigm shift in thrombosis management, offering reduced bleeding risks while preserving vascular health. Finally, this review highlights the need for global laboratory assays to personalize treatments, emphasizing strategies to optimize safety and efficacy, particularly as hemophilia patients live longer with complex comorbidity profiles.

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Abstract Marstacimab targets the tissue factor pathway inhibitor to rebalance hemostasis. Previous phase 1 and 2 trials established marstacimab safety and efficacy in adults with severe hemophilia A (HA) or B (HB). BASIS is an open-label, marstacimab phase 3 trial in males aged 12 to 74 years with severe HA (factor VIII <1%) or moderately severe to severe HB (factor IX ≤2%). Participants without inhibitors received on-demand (OD) or routine prophylaxis (RP) therapy during a 6-month observational phase (OP) before receiving once-weekly subcutaneous 150 mg marstacimab during a 12-month active treatment phase (ATP). Primary end points were annualized bleeding rate (ABR) for treated bleeds vs previous OD or RP during the OP, and safety. Of 128 participants enrolled in the OP, 116 received marstacimab in the ATP. In the OD group (n = 33), mean ABR decreased from 39.86 (95% confidence interval [CI], 33.05-48.07) in the OP to 3.20 (95% CI, 2.10-4.88) in the ATP, demonstrating superiority of marstacimab (estimated ABR ratio, 0.080 [95% CI, 0.057-0.113]; P < .0001). In the RP group (n = 83), mean ABR decreased from 7.90 (95% CI, 5.14-10.66) in the OP to 5.09 (95% CI, 3.40-6.78) in the ATP, demonstrating noninferiority and superiority of marstacimab (estimated ABR difference, –2.81 [95% CI, –5.42 to –0.20]; P = .0349). There were no deaths or thromboembolic events. Weekly subcutaneous marstacimab reduced ABR vs OD or RP therapy in the OP in individuals with severe HA or moderately severe to severe HB without inhibitors. Marstacimab was safe and well tolerated with no unanticipated side effects. This trial was registered at www.clinicaltrials.gov as #NCT03938792.

Abstract licence: CC BY-NC-ND

SummaryMarstacimab, an investigational human monoclonal antibody targeting tissue factor pathway inhibitor, demonstrated safety and efficacy in preventing bleeding episodes in patients with haemophilia. This multicentre, open‐label study investigated safety, tolerability, and efficacy of long‐term weekly prophylactic marstacimab treatment in participants with severe haemophilia A and B, with or without inhibitors. Adult participants were enrolled from a previous phase Ib/II study or de novo and assigned to one of two subcutaneous (SC) marstacimab doses: once‐weekly 300 mg or a 300‐mg loading dose followed by once‐weekly 150‐mg doses, for up to 365 days. Study end‐points included safety assessments and annualised bleeding rates (ABRs). Of 20 enrolled participants, 18 completed the study. Overall, 70% of participants had treatment‐emergent adverse events, including injection site reactions, injection site haematoma, and haemarthrosis. No treatment‐related serious adverse events or thrombotic events occurred. Across all dose cohorts, mean and median on‐study ABRs ranged from 0 to 3.6 and 0 to 2.5 bleeding episodes/participant/year respectively, demonstrating comparable efficacy to that observed in the short‐term parent study. No treatment‐induced anti‐drug antibodies were detected. Once‐weekly SC marstacimab prophylaxis was well tolerated, with an acceptable safety profile, and maintained long‐term efficacy up to 365 days. (Clinicaltrials.gov identifier, NCT03363321).

Abstract licence: CC BY-NC 4.0

Abstract Marstacimab, a monoclonal antibody that inhibits tissue factor pathway inhibitor, is approved for prophylactic use in individuals with hemophilia A or B without inhibitors. We present efficacy and safety for individuals with inhibitors. The open-label, single-arm, phase 3 study evaluated once-weekly subcutaneous flat-dose marstacimab in males aged 12 to <75 years with severe hemophilia A or moderately severe to severe hemophilia B. Participants with inhibitors received bypassing agents (on-demand or routine prophylaxis) during a 6-month observational phase (OP) before entering a 12-month active treatment phase (ATP) with marstacimab. Primary end points were annualized bleeding rate (ABR) of treated bleeds and safety. Of 60 participants with inhibitors in the OP, 51 entered the ATP and received marstacimab. In the on-demand group (n = 48), mean estimated ABR declined from 19.78 (95% confidence interval [CI], 16.12-24.27) in the OP to 1.39 (95% CI, 0.85-2.29) during the ATP (ABR ratio, 0.07 [95% CI, 0.042-0.118]; 2-sided P< .0001). Results were consistent by hemophilia type (ABR ratio, 0.05 [hemophilia A, n = 40]; 0.13 [hemophilia B, n = 8]). Participants reported significant improvements in health-related quality of life. Adverse events were common but mostly mild; 1 treatment-related grade 3 skin rash led to discontinuation. Antidrug antibodies were detected in 19.6% of participants, with no apparent effect on efficacy or safety. In participants with inhibitors, marstacimab was associated with reduced bleeding rates and an acceptable safety profile, with no thromboembolic events. Marstacimab may be a viable treatment option for people with hemophilia A or B with inhibitors. This trial was registered at www.clinicaltrials.gov as #NCT03938792. ClinicalTrials.gov identifier: NCT03938792.

Abstract licence: CC BY-NC-ND

SummaryA phase 1b/2, three‐month study of marstacimab, a human monoclonal antibody targeting tissue factor pathway inhibitor (TFPI), was conducted in participants with haemophilia A or B, with or without inhibitors. Participants assigned to four cohorts received escalating weekly doses based on inhibitor status (without inhibitors: 300 mg, a single 300‐mg loading dose with subsequent 150‐mg doses, or 450 mg; with inhibitors: 300 mg). Safety outcomes were treatment‐emergent adverse events (TEAEs), injection site reactions, clinical and laboratory parameter changes. Efficacy was assessed by annualised bleeding rates (ABRs). Pharmacokinetics and pharmacodynamics (PD) were also evaluated. Among 26 treated participants [haemophilia A without inhibitor, n = 16 (61.5%); haemophilia A with inhibitor, n = 7 (26.9%); haemophilia B, n = 3 (11.5%)], 24 completed the study. Overall, 80.8% experienced TEAEs. ABR during treatment was significantly reduced versus an external on‐demand control group (p < 0.0001) and versus pretreatment ABR (p < 0.0001), with significant reductions observed across all dose cohorts. Marstacimab exposure generally increased in a dose‐related manner, with steady‐state concentration reached by day 57. Changes in pharmacodynamic biomarkers occurred across all dose cohorts. Marstacimab was safe and well tolerated. Clinically meaningful reductions in ABR and treatment‐related changes for all PD biomarkers indicated effective targeting of TFPI. (Clinicaltrials.gov identifier, NCT02974855).

Abstract licence: CC BY-NC 4.0