The litigation focuses on the accuracy of MacroGenics’ statements regarding data from its Phase 2 TAMARACK study of the antibody-drug conjugate MGC018, known as “vobra duo,” in patients with metastatic castration-resistant prostate cancer (mCRPC).
On Mar. 7, 2024, MacroGenics set investor expectations for preliminary TAMARACK data at the upcoming meeting of the American Society of Clinical Oncology (“ASCO”). Management said “[g]iven the dosing right now of 2.7 mg/kg Q4 and 2 mg/kg Q4 and with the expectations if the safety is improved as we expect we should be actually delivering as much or more of the 2.7 mg/kg Q4 as compared to historical treatment with the 3 mg/kg Q3.”
On Apr. 3, 2024, MacroGenics released interim safety data from the TAMARACK study, as detailed in an abstract submitted to ASCO on Feb. 6, 2024. The company stated, “Preliminary safety data from TAMARACK suggest that reducing the dose and frequency of vobra duo improves its safety and tolerability in men with mCRPC.” This announcement led to a significant increase in MacroGenics’ share price, which rose by $4.11, or approximately 30%, on Apr. 4, 2024.
However, the positive sentiment was short-lived. On May 10, 2024, MacroGenics disclosed that five patients in the study had died. This revelation caused the company’s share price to plummet by $11.36, or about 77%, on the same day, prompting numerous analyst downgrades.
Additionally, Seeking Alpha reported that “Stifel was quick to downgrade MacroGenics (MGNX) after the TAMARACK readout, which, according to the firm, raised concerns over the drug’s safety and tolerability and appeared vastly different from previously disclosed abstract results.”
While the company said it was investigating the deaths of three patients in the study, it has not yet provided an update to investors.