June 2 (Reuters) - GSK's multiple myeloma drug Blenrep nearly halved the risk of disease progression or death compared to standard-of-care treatments for the incurable blood cancer, according to data from a late-stage study presented at a medical meeting on Sunday.

In the trial of 302 patients with relapsed or difficult-to-treat multiple myeloma, 71% of those who received Blenrep in combination with the steroid dexamethasone and pomalidomide were alive without their disease worsening at the end of a year.

That compared with progression-free survival (PFS) of 51% of those who were treated with pomalidomide, dexamethasone and bortezomib. Pomalidomide is a generic version of Bristol Myers Squibb's Pomalyst, while bortezomib is the generic of Takeda Pharmaceuticals' Velcade.

"The ability to be able to offer a drug like Blenrep potentially that is administered on an outpatient basis, does not require hospitalization, can be available in a community setting and is not restricted by manufacturing challenges, like cell therapies, is really important," GSK oncology executive Hesham Abdullah said in an interview.

Detailed data from the trial was presented at the American Society of Clinical Oncology meeting in Chicago on Sunday.

Blenrep has had setbacks over the last couple of years, including being pulled from the lucrative U.S. market in 2022 after it failed to show superiority over an existing treatment in a separate late-stage study.

The top-line data from this trial released in March showing it had met the main goal of significantly improving PFS over a current standard treatment regimen appeared to signal a comeback for the drug.

More than half of the Blenrep patients were alive without disease progression after a median follow-up of 21.8 months compared with 12.7 months PFS for the standard of care, the company said.

"The PFS benefit seen in the trial shows the potential of the Blenrep combo, if approved, to redefine the treatment of multiple myeloma for these patients," GSK said in a statement.

The British drugmaker plans to file marketing applications with global regulators in the second half of 2024.

Treatments for multiple myeloma include Johnson & Johnson's Darzalex and other generic cancer drugs. The U.S. FDA in April approved two cell therapies - J&J's Carvykti, and Bristol Myers' Abecma - as earlier lines of treatment in less severe multiple myeloma.

Eye-related side effects led to a 9% treatment discontinuation rate from the study but were generally reversible and manageable through dose modifications, GSK said.

Multiple myeloma, the world's second-most common blood cancer, starts in plasma cells in bone marrow and ultimately disrupts production of normal blood cells.

Roughly 35,780 new multiple myeloma cases are likely to be diagnosed, with 12,540 deaths expected to occur in the United States this year, according to the American Cancer Society. (Reporting by Pratik Jain in Bengaluru; Editing by Bill Berkrot)