Be Bio bins hemophilia B cell therapy trial—the biotech’s lead program

Be Bio Terminates Lead Hemophilia B Cell Therapy Trial

Be Biopharma has terminated its early-stage Phase 1/2 BeCoMe-9 study for BE-101, an autologous B cell therapy targeting hemophilia B. The decision, affecting a trial that had enrolled five of 24 expected patients, was attributed to a "strategic business decision" rather than safety concerns. This move underscores broader challenges in the hemophilia gene and cell therapy market, following similar product withdrawals by Pfizer (Beqvez) and BioMarin (Roctavian) due to limited patient interest and slow commercial uptake.

• BE-101 is an autologous cell therapy designed to modify a patient's own cells ex vivo to predictably and consistently produce clotting factor IX (FIX), addressing the genetic deficiency in hemophilia B. The terminated Phase 1/2 BeCoMe-9 study was Be Bio's lead program, and the company currently has no other listed trials for BE-101, though a preclinical asset, BE-102, is planned for hypophosphatasia.
• The decision to discontinue the BeCoMe-9 study was explicitly stated as a "strategic business decision" according to a federal clinical trials database, and importantly, was not linked to any safety concerns. This indicates a commercial or strategic re-evaluation rather than issues with the therapy's safety profile during its early-stage development.
• Be Bio's termination follows a pattern of setbacks in the hemophilia gene and cell therapy sector. Pfizer previously ceased funding for its hemophilia B gene therapy, Beqvez, globally due to limited patient and physician interest. Similarly, BioMarin withdrew its hemophilia A gene therapy, Roctavian, from the market after struggling with slow uptake, generating only $26 million in 2024 and $36 million in 2025.

Navigating the Hurdles: Why Hemophilia Gene Therapies Struggle

Despite meaningful advances in recombinant protein therapies and extended half-life (EHL) formulations, Hemophilia B treatment remains constrained by immunological, pharmacological, and systemic barriers. Current modalities fall short of delivering durable, universally accessible correction of factor IX (FIX) deficiency. The following challenges collectively underscore why the field continues to pursue transformative alternatives such as gene therapy and non-factor approaches.

• Inhibitor formation and immune complications: FIX inhibitor development represents the most serious complication of replacement therapy, with severe allergic and anaphylactic reactions occurring in up to 60% of patients with inhibitors — reactions that often herald antibody formation and preclude effective immune tolerance induction (ITI). Unlike Hemophilia A, low inhibitor incidence in Hemophilia B limits the comparative data available to guide evidence-based prevention and eradication strategies.

• Durability and efficacy limitations across therapy classes: Both conventional and novel approaches — including recombinant proteins, EHL products, bispecific antibodies, and rebalancing therapies — struggle to achieve permanent therapeutic effect. Short duration of activity and neutralizing antibody production remain persistent limitations across modalities.

• Pharmacokinetic complexity and monitoring inaccuracies: Inter-individual variability in FIX pharmacokinetics, compounded by disease rarity, has hampered identification of optimal treatment regimens. Assay-related challenges further complicate monitoring, as different aPTT reagents demonstrate variable accuracy when measuring distinct FIX molecules — particularly EHL recombinant FIX products.

• Gene therapy-specific barriers: Early AAV-based clinical trials demonstrated either transient or subtherapeutic FIX expression, attributable to suboptimal vector design and inadvertent immune responses triggering hepatic inflammation. Ongoing challenges include transient liver toxicity, the need for immunosuppression at high vector doses, high prevalence of pre-existing anti-capsid immunity, and elevation of liver transaminases associated with loss of FIX transgene expression in some patients.

• Cost and access disparities: Prophylactic treatment in severe Hemophilia B is clinically effective but significantly limited by cost. Globally, approximately 70% of patients cannot access critical therapies, with advanced modalities remaining largely unavailable in low-resource settings — a gap that new gene and cell-based therapies have yet to bridge.

The Enduring Need for Innovation in Hemophilia B Care

Despite meaningful therapeutic advances — including FDA-approved gene therapies and novel non-factor agents — significant gaps persist in the care of Hemophilia B (HB) patients across clinical, economic, and geographic dimensions. These unmet needs span from treatment durability and inhibitor management to systemic access disparities that leave a substantial proportion of the global patient population without adequate disease control.

• Inhibitor development and joint disease burden: Inhibitor incidence of 6.1% has been documented in Chinese HB cohorts, with neutralizing antibody prevalence ranging from 5–20% across the Asian region. Concurrently, 71.4% of HB patients in these populations reported a history of joint hemorrhage, with 64.4% of those developing target joints — underscoring the inadequacy of current prophylactic strategies in preventing long-term musculoskeletal deterioration.

• Diagnostic and treatment delays in underserved regions: In central and western China, 34.6% of HB patients experienced diagnostic delay and 38.5% encountered treatment delay. Globally, approximately 70% of patients remain unable to access critical therapies, with under-diagnosis compounded by limited registry infrastructure, geographic barriers, and patients' reluctance toward intravenous administration regimens.

• Lack of subcutaneous prophylaxis options for HB: Unlike Hemophilia A, Hemophilia B patients have historically lacked subcutaneous (SC) prophylaxis alternatives. The approval of marstacimab (Hympavzi) — an anti-TFPI IgG1 monoclonal antibody with once-weekly SC dosing — begins to address this gap, having demonstrated a 91.6% reduction in annualized bleed rates versus episodic treatment in the Phase 3 BASIS trial.

• Durability and long-term safety of gene therapy: While etranacogene dezaparvovec and fidanacogene elaparvovec represent landmark approvals, long-term durability of FIX transgene expression, potential declines in factor levels over time, and immune responses to AAV capsid vectors remain unresolved. High treatment costs and the absence of established innovative reimbursement models further constrain real-world adoption, particularly in resource-limited healthcare systems.

• Carrier identification and genetic diagnostic gaps: 84.0% of HB mothers were genetically confirmed as carriers in recent Chinese cohort data, with 27.7% exhibiting clotting factor levels below 0.40 IU/mL — placing them at bleeding risk themselves. Genetic testing infrastructure remains limited to select centers, and patient unwillingness to participate further impedes comprehensive carrier identification programs.

• Economic burden and healthcare access inequality: Single-hospitalization costs for HB patients reached a median of ¥11,060 CNY, with costs approximately doubling in the presence of inhibitors. In European contexts, annual per-patient costs for extended half-life FIX products range from €224,407 to €368,587 depending on the agent and country, while factor IX carries extremely high annual costs in the US — reinforcing the need for cost-effective therapeutic pathways and equitable access frameworks globally.

Hemophilia Gene Therapy: A Market Recalibration

The recent decision by Be Biopharma to halt its early-stage hemophilia B gene therapy program, BE-101, underscores a critical juncture for the broader gene therapy landscape in rare bleeding disorders. While gene therapy holds immense promise for a one-time treatment that can significantly reduce bleeding episodes and improve quality of life by enabling endogenous clotting factor production, the path to widespread adoption is fraught with complexities.

This withdrawal, following similar market challenges faced by other approved hemophilia gene therapies, highlights that the hurdles extend beyond just clinical efficacy. Several factors contribute to this challenging environment:

• Patient Eligibility and Hesitancy: A substantial proportion of patients may be ineligible for AAV-based gene therapies due to pre-existing neutralizing antibodies, as studies indicate high screening failure rates. Furthermore, the hemophilia community's historical experience with devastating treatment-related infections fosters a cautious approach to new therapies, necessitating a robust, informed, and shared decision-making process.

• Durability and Safety Profile: While approved therapies like fidanacogene elaparvovec for hemophilia B have shown sustained factor IX activity and reduced bleeding over several years, concerns persist regarding the long-term durability of factor expression, particularly for factor VIII therapies, and the potential for immune-mediated adverse events like liver toxicity. Lifelong monitoring is essential to track these outcomes.

• Economic and Access Barriers: The high upfront costs of gene therapies present significant challenges for payers. Real-world data suggest extended payback periods for these treatments, creating budget uncertainties for healthcare systems. This necessitates innovative payment models, such as value-based contracts, to share risk between manufacturers and payers and facilitate patient access.

For companies navigating this space, the strategic imperative is clear: future gene therapy development must not only demonstrate compelling clinical benefits but also address these real-world challenges head-on. This includes refining patient selection, generating robust long-term safety and durability data, and collaborating with payers to establish sustainable reimbursement pathways. The market is demanding a more holistic value proposition, moving beyond the initial 'cure' narrative to encompass the entire patient and payer journey.