Rare & Genetic · Clinical trials
Haemophilia A Clinical Trials
Approved therapies, the pivotal-trial endpoints they were judged on, the magnitude of benefit — and the drugs that failed their endpoints, and why.
Indication overview
About haemophilia a — and why its trials are hard
Haemophilia A is an X-linked recessive bleeding disorder caused by deficiency or dysfunction of clotting factor VIII, resulting in spontaneous and trauma-related bleeding, especially into joints and muscles. Severity tracks with residual factor activity (severe <1%, moderate 1-5%, mild 5-40%). Standard care historically relied on intravenous factor VIII replacement, both plasma-derived and recombinant, given on-demand or prophylactically, with extended half-life products reducing infusion frequency. A major limitation is the development of neutralising inhibitors. The bispecific antibody emicizumab (Hemlibra), which bridges activated factor IX and factor X to mimic factor VIII cofactor activity, transformed prophylaxis with subcutaneous dosing effective in patients with and without inhibitors. Efanesoctocog alfa (Altuvoiio) provides high sustained factor VIII activity with once-weekly dosing. Gene therapy valoctocogene roxaparvovec (Roctavian) delivers an AAV5-borne factor VIII transgene for durable endogenous production. The annualised bleeding rate (ABR) is the central efficacy endpoint. Emerging rebalancing agents targeting antithrombin and TFPI further broaden non-factor options for prophylaxis.
Approved therapies & pivotal evidence
What's been approved — and by how much it moved the endpoint
| Drug (brand) | Approved | Setting | Pivotal trial | Primary endpoint | Magnitude of benefit |
|---|---|---|---|---|---|
| Emicizumab (Hemlibra) | 2017 | Routine prophylaxis in haemophilia A; initially inhibitor patients, later expanded to non-inhibitor | HAVEN 1 / HAVEN 3 (NEJM) | Annualised bleeding rate (treated bleeds) vs no prophylaxis / prior factor prophylaxis | HAVEN 1: 87% reduction in treated ABR vs no prophylaxis in inhibitor patients |
| Efanesoctocog alfa (Altuvoiio) | 2023 | Prophylaxis and on-demand treatment in adults and children with haemophilia A | XTEND-1 (phase 3, NEJM 2023) | Annualised bleeding rate on once-weekly prophylaxis | Median ABR 0; mean ABR ~0.7; provided high, sustained FVIII activity across the week |
| Valoctocogene roxaparvovec (Roctavian) | 2023 | One-time gene therapy for adults with severe haemophilia A without anti-AAV5 antibodies/inhibitors | GENEr8-1 (phase 3, NEJM 2022) | Change in annualised bleeding rate and FVIII activity after infusion | Treated ABR fell ~52% from baseline; large reductions in FVIII use following a single infusion |
Where trials have failed
Drugs that missed their endpoint — and what contributed
The most instructive lessons in haemophilia a development come from programmes that failed the endpoint that mattered.
| Drug / trial | Endpoint outcome | What contributed |
|---|---|---|
| SPK-8011 (Spark Therapeutics AAV FVIII gene therapy) — Phase 1/2 haemophilia A gene therapy | Program setbacks; some participants lost factor VIII expression and the candidate did not advance to routine approval | AAV capsid immune responses/transaminase elevations required immunosuppression, and variable or declining transgene expression limited durability |
Choosing the right endpoint
Primary endpoints that matter in haemophilia a trials
- Annualised bleeding rate (ABR) — Number of treated/all bleeds per year; the primary efficacy endpoint across factor, non-factor and gene-therapy trials
- Factor VIII activity — Circulating FVIII level (one-stage or chromogenic assay); key pharmacodynamic endpoint especially for gene therapy durability
- Inhibitor development — Emergence of neutralising anti-FVIII antibodies; a major safety/efficacy outcome influencing therapy choice
- Factor consumption — Reduction in exogenous FVIII infusions or units used, reflecting real-world treatment burden
How iNGENū runs haemophilia a trials
Physician-led design, built for FDA submission
Endpoint & biomarker strategy
Board-certified specialists design endpoints and patient selection aligned to current FDA guidance for this indication.
FDA-ready data
Built to ICH-GCP and 21 CFR 312.120, with direct FDA submission — data accepted by the FDA, EMA and MHRA.
Faster, lower-cost delivery
~4-week ethics via the TGA CTN scheme, up to 43.5% R&D rebate, and 80–90% below US CRO cost.
Request a fixed-milestone proposal and a tailored endpoint & feasibility summary for this indication.
Frequently asked questions
Haemophilia A clinical trials — FAQs
How is emicizumab different from factor VIII?
Is gene therapy a cure for haemophilia A?
What is the annualised bleeding rate?
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