New York, NY – MacroGenics Inc. (NASDAQ: MGNX) faced a significant drop in shares following the release of interim data from the TAMARACK Phase 2 study on their drug targeting B7-H3, an antigen present in various solid tumors. The study, focusing on previously treated patients with metastatic castration-resistant prostate cancer (mCRPC), revealed alarming results that led to a plunge of over 50% in the company’s stock value.
The data, as of April 12, 2024, showed troubling findings, including five deaths during the trial and a high rate of grade 3 or worse adverse events in both dose cohorts. The rates of treatment-emergent adverse events (TEAEs) were notably high in both the low and high dose arms, indicating serious safety concerns with the drug.
Furthermore, the report highlighted a significant increase in TEAE-related interruptions compared to earlier data readouts. The study investigators noted two cardiovascular deaths and three other deaths under investigation, pointing to serious complications arising from the drug being tested.
Despite the adverse events, the company reported overall response rates in patients, along with specific prostate-specific antigen (PSA) reduction percentages. These statistics shed light on the drug’s efficacy in treating mCRPC but also raise concerns about its safety profile.
As a result of these concerning findings, MGNX shares experienced a sharp decline, down 73% at $3.92 by the end of trading on Friday. The market’s reaction to the interim data underscores the serious implications of the study results on MacroGenics Inc. and its future prospects in the pharmaceutical industry. Investors and stakeholders will be closely monitoring the company’s next steps and how it plans to address the issues raised by the TAMARACK study.