GSK's Blenrep Makes Promising Comeback in Multiple Myeloma Treatment

GSK's antibody-drug conjugate Blenrep (belantamab mafodotin) is poised for a potential return to the U.S. market, with new data strengthening its case for treatment of relapsed or refractory multiple myeloma (RRMM). The pharmaceutical giant presented compelling progression-free survival (PFS) results at the European Hematology Association (EHA) 2025 Congress, setting the stage for a crucial FDA decision expected in July.

DREAMM-8 Study Demonstrates Significant PFS Improvement

The DREAMM-8 study, focusing on RRMM patients who had received at least one prior line of therapy, revealed impressive efficacy for Blenrep when combined with Bristol Myers Squibb's Pomalyst (pomalidomide) and dexamethasone (PomDex). Patients treated with this combination achieved a median PFS of 32.6 months, compared to 12.5 months for those receiving Takeda's Velcade (bortezomib) with PomDex.

After 18 months of treatment, the estimated PFS rate stood at 63% for the Blenrep arm versus 41% for the comparator group. These results build upon earlier data presented at the 2024 American Society of Clinical Oncology (ASCO) annual meeting, where Blenrep was shown to reduce the risk of disease progression or death by 48% compared to the Velcade-based regimen.

Consistent Efficacy Across Multiple Studies

The DREAMM-8 findings align with results from the previously reported DREAMM-7 study, which compared Blenrep to Johnson & Johnson's Darzalex (daratumumab). In DREAMM-7, Blenrep demonstrated a median PFS of 36.6 months, surpassing Darzalex's 13.4 months when both were combined with Velcade and dexamethasone.

Dr. Hesham Abdullah, GSK's global head of oncology R&D, emphasized the consistency of Blenrep's strong PFS results across different combinations. The DREAMM-7 study also showed a significant overall survival benefit, with Blenrep reducing the risk of death by 42% compared to the Darzalex-based regimen and achieving a three-year survival rate of 74%.

Regulatory Landscape and Market Implications

Blenrep's impressive performance has already led to regulatory approvals for both its Velcade and Pomalyst combinations in the UK, Japan, and Europe. The FDA is set to decide on these combinations by July 23, 2025. A U.S. approval would mark a significant turnaround for Blenrep, which was voluntarily withdrawn from the market in 2022 following disappointing results in its confirmatory DREAMM-3 study.

If approved, Blenrep will face competition from established therapies like J&J and Legend Biotech's CAR-T therapy Carvykti, as well as Bristol Myers Squibb's Abecma and newer bispecific antibodies. However, GSK believes Blenrep's accessibility and outpatient administration potential could give it an edge, particularly in community settings where approximately 70% of multiple myeloma patients receive treatment.

Despite carrying a boxed warning for ocular toxicity, GSK maintains that it has developed an appropriate management plan for these side effects. The company projects peak annual sales for Blenrep to exceed £3 billion (approximately $4 billion), contributing to GSK's ambitious 2031 sales target of over £40 billion.