GSK's Pulled Myeloma Drug Outperforms J&J's Darzalex in Key Trial

A multiple myeloma drug withdrawn from the market by GSK has now demonstrated positive results in a pivotal trial, surpassing a rival product by Johnson & Johnson. These findings lay the groundwork for a potential comeback for this cancer therapy,

Med City News reported that based on Preliminary Phase 3 results unveiled on Monday, GSK's Blenrep achieved the primary goal by showing superior progression-free survival when compared to J&J's daratumumab, commonly known as Darzalex, in patients with blood cancer multiple myeloma.

Additionally, the interim efficacy analysis revealed "strong and clinically meaningful" overall survival results, further validating the potential of this treatment. The trial will continue to assess this endpoint, according to Nasdaq.

Darzalex's Significance and Blenrep's Mechanism

Darzalex, an antibody drug, is approved for treating multiple myeloma patients who have undergone at least one prior line of therapy. It is considered the standard of care treatment and is J&J's top cancer product, generating $7.9 billion in sales in 2022. By targeting B-cell maturation antigen (BCMA), a protein found abundantly on multiple myeloma cells, Darzalex has gained regulatory approvals and played a critical role in patients' treatment journeys.

Blenrep, an antibody-drug conjugate (ADC) developed by GSK, combines a targeting antibody with a toxic drug payload. Specifically designed to focus on BCMA, this therapy has demonstrated efficacy as a fifth-line treatment for multiple myeloma, making it the first BCMA-targeting therapy to gain accelerated FDA approval. While other BCMA-targeting drugs, including two from J&J, have also received regulatory approval, Blenrep stands out as an innovative treatment option.

A Bumpy Journey for Blenrep

Last year, GSK faced a setback when Blenrep failed to meet the confirmatory clinical trial requirements for its initial FDA approval. The trial aimed to measure progression-free survival against Pomalyst, Bristol Myers Squibb's approved multiple myeloma drug. Following this setback, the FDA requested GSK to withdraw Blenrep from the U.S. market. However, GSK continued its clinical testing of the therapy, determined to explore its potential further.

The latest results stem from a Phase 3 trial that evaluated Blenrep alongside bortezomib and dexamethasone, forming the abbreviated treatment regimen known as BorDex. This open-label study enrolled patients with advanced cases of multiple myeloma who had undergone at least one prior line of therapy.

Randomly assigning 494 patients to receive either Blenrep and BorDex or Darzalex and BorDex, the trial aimed to measure multiple endpoints, including progression-free survival and overall survival. Additional goals included assessing the duration of response and minimal residual disease.

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