GSK Strengthens Blenrep’s Case with New Data

Highlights

• Blenrep, GSK’s ADC, achieved a median PFS of 32.6 months in the DREAMM-8 trial, versus 12.5 months for the comparator regimen.
• The DREAMM-7 study also showed a 36.6-month PFS for Blenrep, compared to 13.4 months for Darzalex.
• Blenrep combinations have already received regulatory approval in the U.K., Japan, and Europe.
• FDA decision on Blenrep’s reapproval in the U.S. is expected by July 23, 2025.
• The drug was withdrawn in 2022 after a failed monotherapy trial but is now being pursued as part of combination therapy.
• GSK projects Blenrep could achieve over $4 billion in peak annual sales and contribute significantly to its long-term revenue goals.

Progression-Free Survival Gains in DREAMM-8

GlaxoSmithKline (GSK) has unveiled new data at the 2025 European Hematology Association (EHA) Congress that bolsters the case for its antibody-drug conjugate (ADC), Blenrep (belantamab mafodotin), in the treatment of relapsed or refractory multiple myeloma (RRMM). This marks a significant milestone as the company prepares for the drug’s potential reentry into the U.S. market later this summer.

The latest update from the DREAMM-8 clinical trial demonstrates Blenrep’s ability to significantly prolong progression-free survival (PFS) when combined with Bristol Myers Squibb’s Pomalyst (pomalidomide) and dexamethasone (PomDex). Compared to Takeda’s Velcade-based regimen, the Blenrep combination nearly tripled median PFS — "patients treated with Blenrep and PomDex lived without their disease getting worse for a median of 32.6 months, while those taking the Velcade-based version of the regimen experienced 12.5 months of median PFS."

At 18 months, the estimated PFS rate for the Blenrep combination was 63%, significantly outperforming the 41% observed in the comparator arm.

Consistency Reinforced by DREAMM-7 Study

The new DREAMM-8 results echo findings from the earlier DREAMM-7 trial, in which Blenrep, combined with Velcade and dexamethasone, outperformed Johnson & Johnson’s Darzalex-based regimen. That study reported a median PFS of 36.6 months for Blenrep versus 13.4 months for Darzalex.

GSK’s Head of Oncology R&D, Dr. Hesham Abdullah, emphasized the significance of these outcomes: "In both instances, we’re seeing such great magnitude of effect," he said at the recent American Society of Clinical Oncology (ASCO) annual meeting. He described the emerging data as proof of Blenrep’s consistency across various combinations and its robust ability to extend PFS.

Overall Survival and Regulatory Outlook

Additional support for Blenrep’s efficacy comes from overall survival data in DREAMM-7. As of December, the combination therapy reduced the risk of death by 42% over the Darzalex-based regimen and demonstrated a three-year survival rate of 74%.

These findings have underpinned regulatory approvals in the U.K., Japan, and Europe for Blenrep combinations involving Velcade and Pomalyst. A U.S. FDA decision is anticipated by July 23, which could signal a major comeback for the drug.

Comeback After Withdrawal

Blenrep’s return would mark a significant turnaround after its earlier U.S. market withdrawal. Initially granted accelerated approval in 2020 as a monotherapy for heavily pre-treated RRMM patients, the drug was pulled in 2022 following the DREAMM-3 trial, which failed to meet its confirmatory endpoint.

Despite the setback, GSK has leveraged insights from that failed study to refine its strategy. Dr. Abdullah reflected on the journey: "a process where science and data ultimately prevail." Now repositioned as part of a combination therapy earlier in the treatment sequence, Blenrep is poised for a fresh opportunity in a competitive landscape.

Competitive Landscape and Accessibility

Blenrep reenters a market that has evolved rapidly with the rise of BCMA-targeted therapies. Johnson & Johnson and Legend Biotech’s Carvykti, as well as Bristol Myers Squibb’s Abecma, both CAR-T therapies, present significant competition, particularly in second-line and later-line settings.

However, GSK sees a niche for Blenrep in community-based care. According to Dr. Abdullah, "About 70% of patients are seen in community settings, while the remaining 30% receive treatment at academic sites." He emphasized the drug’s outpatient suitability: "It delivers robust efficacy, has a manageable safety profile, and is going to be available to all patients."

Managing Safety Concerns

While Blenrep has previously drawn FDA attention for its risk of ocular toxicity, GSK maintains that it has implemented a comprehensive management strategy. Dr. Abdullah highlighted the company’s commitment to monitoring visual acuity through patient-reported outcomes and other safety protocols.

He also noted that competing therapies are not without their own safety concerns: "rival medicines in the space each come with certain and unique side effect profiles." GSK believes its targeted approach to managing Blenrep’s known risks strengthens the drug’s overall profile.

Outlook and Financial Projections

GSK anticipates that Blenrep could generate peak annual sales exceeding ￡3 billion (approximately $4 billion USD). The company’s confidence in the drug’s market potential contributed to an upward revision of its 2031 sales target, now forecasted at over ￡40 billion.

With positive clinical data, a strong strategic positioning, and clear regulatory timelines, Blenrep’s pending reentry into the U.S. market may redefine its role in the evolving treatment landscape for multiple myeloma.