A more than 70% stock slide shows that investors are concerned about three as-yet unexplained deaths in a Phase II study of the US firm’s lead candidate.

The ranks of B7-H3-targeting antibody-drug conjugates under development in China have seen their first dropout, although elsewhere there are two FGFR2b-directed ADCs with first-in-class potential on the horizon. Meanwhile, there have been other discontinuations of KRAS G12C inhibitors and anti-BCMA CAR-T cell therapies in the country, while new players have surfaced in the areas of mRNA cancer vaccines and amyloid-beta-targeting antibodies for Alzheimer’s disease.

The acquisition of Mariana will complement Novartis’s lutetium-based radioligand therapies with candidates using actinium. Lilly, Bristol and AstraZeneca all have made recent high-priced buys in the space.

Revlimid and Eliquis beat expectations in the first quarter, but the products have dwindling exclusivity, making new drugs the main focus for Bristol. So the company will reinvest cost savings in R&D.