GSK, attempting to stage Blenrep comeback, bids adieu to combo studies with SpringWorks' Ogsiveo

Despite the recent approval of SpringWorks Therapeutics’ Ogsiveo, GSK is calling it quits on prior plans to wed the Pfizer spinout’s drug with its withdrawn cancer med Blenrep.

SpringWorks on Thursday received a notice of termination on the partners’ amended collaboration and licensing deal, which was struck on Sept. 6, 2022, according to a Friday securities filing.

Under the updated pact, GSK and SpringWorks were working together to develop and potentially market combinations of Blenrep (belantamab mafodotin-blmf) and Ogsiveo (nirogacestat) in multiple myeloma and other BCMA-expressing cancers.

As part of the collaboration, GSK made a $75 million equity investment in SpringWorks back in 2022. SpringWorks, for its part, was in line to receive up to $550 million in potential development and commercial milestones.

The 2022 deal was a retooled version of a clinical trial collaboration between the companies first set up in the summer of 2019.

“We can confirm that we have provided notice to terminate our agreement with SpringWorks Therapeutics and will end all development of belantamab mafodotin in combination with nirogacestat,” a GSK spokesperson said over email.

The termination will go into effect after 180 days, at which point GSK will work with SpringWorks on “appropriate steps to wind down existing combination study activities,” the spokesperson added.

GSK is stepping away from the collaboration as it works to make sure it’s “investing in the right combination approaches” in multiple myeloma, the spokesperson explained. The move will not affect most of Blenrep’s DREAMM development program, which is exploring the use of the antibody-drug conjugate (ADC) in earlier lines of therapy—including as a potential first-line treatment for multiple myeloma—in combination with other innovative cancer meds and standard-of-care treatments.

Still, the phase 1/2 platform trial DREAMM-5—which is testing Ogsiveo and other anti-cancer agents in combination with Blenrep in relapsed or refractory or refractory multiple myeloma—“will close,” GSK’s spokesperson noted. GSK will not enroll any new patients and does not plan to initiate any new trials with Ogsiveo, she explained.

In its securities filing from last week, SpringWorks said that it “expects GSK will continue” ongoing clinical trials established under the partnership until completion, singling out a 27-patient study combining Ogsiveo with low-dose Blenrep in multiple myeloma. SpringWorks said it would continue to support follow-through on such trials with drug product supply and future publication efforts around generated data.

SpringWorks added that it does not owe any payments or expect to incur other wind-down costs in connection with the terminated deal.

While SpringWorks’ GSK deal is winding down, the company’s drug, Ogsiveo, is just beginning to enjoy its commercial run after securing an FDA nod to treat desmoid tumors in November. Ogsiveo is both SpringWorks' first commercial product and the first drug specifically approved for desmoid tumors, which are marked by noncancerous soft tissue growths that often cause severe pain and disfigurement.

In the first quarter of 2024, Ogsiveo generated $21 million, according to a recent SpringWorks release.

Meanwhile, GSK finds itself in a curious position with Blenrep.

Back in November 2022, GSK pulled Blenrep from the U.S. market a little more than two weeks after the ADC had failed to top a pairing of Bristol Myers Squibb’s Pomalyst and dexamethasone in relapsed or refractory multiple myeloma after at least two prior lines of therapy.

Still, GSK has kept an eye on a potential Blenrep revival in the U.S. In February, the company laid out detailed results from its phase 3 DREAMM-7 trial showing that Blenrep plus Takeda’s Velcade and the steroid dexamethasone significantly cut the risk of progression or death by 59% versus Johnson & Johnson’s Darzalex and dexamethasone in multiple myeloma patients who’d tried at least one prior therapy.

In March, GSK said a combination of Blenrep and BMS’ Pomalyst plus dexamethasone (PomDex) “significantly” beat standard-of-care Velcade and PomDex on progression-free survival in the late-stage DREAMM-8 trial. The Blenrep combo also yielded a positive overall survival trend versus the control at the time of GSK’s analysis, the company added.

GSK is “encouraged” by the recent head-to-head Blenrep combo results and believes, if approved, the Blenrep-based cancer cocktails could “redefine the treatment of relapsed or refractory multiple myeloma,” GSK’s spokesperson said at the time.