Gilead hands Arcellx $285M to expand BCMA cell therapy deal, sparking fresh push for congested market

Gilead Sciences' Kite Pharma is paying Arcellx $285 million to inject a SparX into its pursuit of BCMA. In return for the outlay, $200 million of which is being invested in Arcellx, Kite has secured rights to an early-phase BCMA CAR-T candidate and expanded its existing midphase cell therapy collaboration to cover lymphomas. 

Kite paid Arcellx $225 million to co-develop BCMA-directed CAR-T drug candidate CART-ddBCMA at the start of the year. The deal, which features up to $335 million in clinical milestones, plus three times that in regulatory and commercial paydays, gives Kite the option to negotiate deals to license additional autologous CAR-T cell candidates. Kite has taken up its option.

Through the expanded deal, Gilead’s cell therapy wing is buying rights to ACLX-001 in multiple myeloma. Arcellx has designed the early-phase BCMA-targeted CAR-T cell therapy so that physicians can activate, silence and reprogram the treatment in vivo by administering soluble protein adapters. 

Arcellx’s ARC-SparX platform creates T cells that are only directed to the target when the protein binds to the receptor. Physicians could dial the efficacy of the T cells up and down by changing the protein dose and redirect cells to other targets to counter antigen escape. In theory, the technology can make CAR-T cell therapies, which have been hard to control to date, more like traditional, titratable medicines. 

The use of the ARC-SparX platform differentiates ACLX-001 from the more advanced CART-ddBCMA. The FDA put a phase 2 clinical trial of CART-ddBCMA on partial hold earlier this year after a patient died. But the hold was brief, with Arcellx resolving the situation by August, and Kite remains interested in the asset despite taking up its option on ACLX-001.

Arcellx will be challenging a crowded market, with a number of BCMA-directed drugs already available for multiple myeloma. The FDA approved Pfizer’s Elrexfio, or elranatamab, in August, which will go up against Johnson & Johnson’s Tecvayli. Both drugs are bispecific antibodies that engage T cells to target BCMA-expressing cancer cells.

Kite shared details of the ACLX-001 move alongside news of the expansion of its CART-ddBCMA deal. The expanded collaboration covers the use of the midphase CAR-T candidate in lymphomas. Arcellx and Kite originally negotiated a deal in multiple myeloma. Cindy Perettie, executive vice president of Kite, set out the thinking behind the decision to expand the partnership.

“We are pleased to see the momentum with the CART-ddBCMA multiple myeloma program, enabling Kite to enter an area of high unmet need and bring a new, potentially best-in-class cell therapy to patients. Given this, we are deepening our relationship with Arcellx to further support advancement of CART-ddBCMA, bolster our pipeline in multiple myeloma, as well as access opportunities in lymphoma,” Perettie said. 

The $200 million investment will give Gilead a 13% stake in Arcellx. A standstill agreement is in place to stop Gilead “acquiring beneficial ownership of Arcellx’s capital stock up to a certain percentage.” Arcellx said the investment will extend its cash runway into 2027. Kite is also paying Arcellx $85 million and is on the hook for milestone payments down the line.