Bristol Myers Squibb (BMY 1.22%), or BMS for short, is starting the week off on a sour note. Specifically, the drugmaker's shares fell by as much as 4% in early action Monday. BMS' stock has rebounded modestly as today's session has progressed, but the pharmaceutical company's shares were still in the red by 2.16% as of 10:28 a.m. ET Monday.

What's weighing on the big pharma's stock price?

German drugmaker Bayer (BAYR.Y -1.36%) announced early this morning that it is halting a late-stage trial for the blood thinner asundexian after the drug showed a lack of efficacy against a control arm, according to an independent data monitoring committee. Asundexian belongs to the same class of therapeutics (factor XIa inhibitors) as BMS' and Johnson & Johnson's experimental cardiovascular drug milvexian.

Thus, investors appear to be concerned that asundexian's underwhelming phase 3 results may be a harbinger of things to come for milvexian. Milvexian is presently in a trio of phase 3 studies for various forms of cardiovascular disease. Top-line readouts from these trials are on track for late 2026 and early 2027, according to clinicaltrials.gov.

Milvexian has been billed as a potential $5 billion-a-year drug by both BMS' management and some analysts covering its stock. So if the drug fails to reach the market due to a lack of efficacy, the drugmaker will lose one of its most promising future growth drivers.

Is BMS a bad news buy?

The bottom line is that BMS sports one of the deeper, more robust pipelines in the industry. So if you're inclined to bargain hunt, this big pharma stock may be worth adding to your portfolio today.