Just three weeks after Bristol-Myers Squibb shareholders gave a thumbs-up to the company’s $74 billion acquisition of Celgene, the acquired company has rolled out fresh data on one of the pipeline assets used to justify the deal: bb2121, its CAR-T treatment for multiple myeloma.
Celgene and its development partner, Bluebird Bio, released interim data from a phase 1 study of bb2121 Thursday, with the study’s senior author declaring “deep and durable responses” to the engineered cell therapy. Of the first 33 patients who were treated in the trial, 15 experienced full responses and nine had partial responses, the companies said. The study was published in The New England Journal of Medicine.
Still, the results do raise some doubts about just how durable the response will be to the cell therapy. Six of the 15 patients who experienced complete responses ended up relapsing. The median progression-free survival among all the patients was about a year.
Celgene’s CAR-T for multiple myeloma is already being tested in a pivotal trial, with an FDA decision expected in the second half of 2020. But because of its status as one of the crown jewels in the BMS deal, investors are likely to latch onto every bit of data that’s released from earlier trials—including this one.
When BMS first announced the acquisition in January, CEO Giovanni Caforio cited bb2121 as one of a half-dozen near-term product candidates that could together could bring $15 billion in revenues to the combined companies. Even as activist investors tried to scuttle the deal over the ensuing months, Caforio kept pointing to those pipeline assets as key to making the marriage work.
Celgene’s CAR-T is playing in a crowded field of drugs and other cell therapies for multiple myeloma with the same target, BCMA. At the American Society of Hematology (ASH) meeting in December, data showing a nearly 96% response rate to bb2121 and progression-free survival of 12 months led Jefferies analysts to declare that Celgene was “leading the pack” of experimental multiple myeloma therapies.
But questions about the durability of the CAR-T cells have been raised, and the newly released study is unlikely to quell those concerns, given that the follow-up period for tracking the cells was a short six months after infusion. Celgene reported that at that time, the CAR-T cells were still detectable in 57% of patients.
The data “provide the foundation for advancing the development of bb2121, which is currently being assessed in multiple clinical studies across different patient populations within multiple myeloma," said Dave Davidson, M.D., chief medical officer of Bluebird, in a statement.
The anti-BCMA field did shrink a bit earlier this year, when Gilead Sciences quietly dropped its experimental CAR-T for multiple myeloma. The company halted its trials of KITE-585 after realizing the cells wouldn’t produce a durable enough response to be able to compete with up-and-coming therapies.
Improving the durability of CAR-T cells for multiple myeloma is a priority for the remaining players, including Celgene. At ASH, Celgene and Bluebird presented early data on bb21217, its next-generation CAR-T, that showed hints of better durability than what’s been seen with bb2121 so far. Still, analysts raised questions about whether the newer version of the CAR-T treatment was any more effective than bb2121.
No doubt BMS investors will be watching both assets carefully as the integration of Celgene gets underway.