BMS pays $800M upfront for antibody-drug conjugate, opening new front in Merck rivalry

Bristol Myers Squibb has filled the antibody-drug conjugate (ADC) shaped hole in its pipeline by following the increasingly well-trodden path to China, handing SystImmune $800 million upfront for a phase 2 solid tumor candidate as part of a deal worth up to $8.4 billion.

Until now, BMS has been notably absent from the ADC dealmaking frenzy, staying on the sidelines while rivals for the cancer drug market such as AstraZeneca, Gilead and Merck & Co. hoovered up assets. BMS outlined work on ADC degraders at its R&D day in September, explaining how using an antibody to direct a CELMoD to its target could improve efficacy and tolerability but has mostly stayed out of the main fray.

That changed after the market closed Monday when the Big Pharma unveiled a deal for the ex-China rights to the EGFRxHER3 bispecific BL-B01D1. BMS is betting big on the candidate, paying $800 million upfront and committing up to $500 million in near-term milestones to land the asset.

In return, BMS is gaining control of a candidate that is designed to both block EGFR and HER3 signals to cancer cells, tackling proliferation and survival, and use the targets to deliver a cytotoxic payload without causing intolerable toxicity in healthy tissues. SystImmune expects (PDF) the candidate to be “superior to anti-EGFR and anti-HER3 ADCs,” a group that includes one of the molecules covered by Merck’s massive deal with Daiichi Sankyo.

SystImmune and its Chinese parent company have begun to validate the asset in the clinic. Earlier this year, researchers reported first-in-human phase 1 data in multiple solid tumor types. The candidate has shown the most promise in EGFR-mutant non-small cell lung cancer (NSCLC), a setting in which it was linked to a 63.2% response rate in patients who had received a median of three prior lines of treatment.

BL-B01D1 has shown promise in other settings, racking up a 53.6% response rate in nasopharyngeal cancer, for example, but NSCLC is the focus. SystImmune is bullish on the prospects in that setting, using the phase 1 data to argue the “therapeutic impact” of BL-B01D1 in NSCLC could be “similar” to that of AstraZeneca and Daiichi’s game-changing Enhertu in breast cancer. 

In a statement, BMS' Chief Medical Officer Samit Hirawat, M.D., said BL-B01D1 “adds yet another ADC to our diverse pipeline.” But his colleagues have previously framed ADCs as an area in which the company has limited exposure. 

Responding to an analyst who said the drug class was “glaringly” absent from the portfolio at an investor event last month, Timothy Power, VP and head of investor relations at BMS, said: “The fact is that we, as Bristol, don't have a lot of ADC exposure today. I think that's a fair observation. We have a few assets here and there.”

Power indicated that a deal may be on the cards, telling the analyst that “clearly as we think about our portfolio there may be opportunities for us to complement that with other modalities, and ADCs is a modality we want to pay attention to.” That thinking has manifested in the deal with SystImmune.

The deal is another victory for China’s blossoming ADC sector. SystImmune works out of Redmond, Washington, but is a subsidiary of China’s Sichuan Biokin Pharmaceutical and the Asian country has been the focus of BL-B01D1 development to date. Fifteen of the 16 clinical trials of BL-B01D1 are only enrolling patients in China. The exception is a phase 1 lung cancer trial that SystImmune is running at sites in the U.S.

Many of BMS’ peers have turned to China to add ADCs to their pipelines. Over the past two years, AstraZeneca, BioNTech and Merck have all struck multiple deals for Chinese ADCs. The BMS deal stands out, though, with the upfront portion of the pact exceeding the maximum value of some of the other agreements.