Japan follows UK in GSK's comeback tour for Blenrep

The revitalisation of GSK's blood cancer therapy Blenrep has continued with a second regulatory approval, in Japan, as a treatment for multiple myeloma.

The Ministry of Health, Labour and Welfare (MHLW) has cleared the BCMA-targeting antibody-drug conjugate (ADC) as a second-line therapy for adults with relapsed or refractory multiple myeloma, the same indication as the drug's recent UK approval, while regulatory reviews continue in other markets including the US, EU, and China.

Blenrep (belantamab mafodotin) was given accelerated approval as a fourth-line or later treatment in 2020, but was taken off the market two years later after a confirmatory study failed to show an improvement in progression-free survival (PFS) or overall survival (OS) when used as a third-line or later treatment.

That led to the drug, which had been held up by GSK as a future blockbuster, being pretty much written off, but bounced back when data from the DREAMM-8 and DREAMM-7 studies showed improvements in PFS and OS.

The data set up a new round of regulatory filings as a combination regimen with Takeda's Velcade (bortezomib) plus dexamethasone (BVd) and Bristol-Myers Squibb's Pomalyst (pomalidomide) plus dexamethasone (BPd), two standard second-line therapies for multiple myeloma.

In DREAMM-7, Blenrep plus BVd reduced PFS by 59% compared to Genmab and Johnson & Johnson's anti-CD37 therapy Darzalex (daratumumab) plus BVD, while OS was 42% improved. In DREAMM-8, Blenrep plus BPd cut PFS by 48% compared to the combination of Velcade plus BPd.

As the only anti-BCMA (B-cell maturation antigen) ADC in multiple myeloma, GSK hopes the drug will present an attractive alternative to cell therapies like Johnson & Johnson's Carvykti (ciltacabtagene autoleucel) and Bristol-Myers Squibb's Abecma (idecabtagene vicleucel), both of which require expensive and elaborate infrastructure that characterises CAR-T therapies.

"Blenrep combinations have the potential to redefine treatment outcomes based on superior efficacy shown in two phase 3 trials, with the added advantage of in-office administration in both academic and community treatment settings," said GSK's global head of oncology R&D, Hesham Abdullah.

The BCMA market has changed since it was withdrawn from most markets around the world, however. Blenrep was the first drug in the class to be launched, but could see competition from BCMAxCD3 bispecifics like Johnson & Johnson's Tecvayli (teclistamab) and Pfizer's Elrexfio (elranatamab). These are currently approved as fifth-line or later multiple myeloma therapies, but are in trials looking at earlier-line use.

GSK has said it expects Blenrep to achieve peak annual sales of around £3 billion (nearly $4 billion). It also plans to continue working on Blenrep's comeback with the DREAMM-10 study in newly diagnosed, transplant-ineligible multiple myeloma patients.