Boston, MA – MacroGenics Inc, a biopharmaceutical company based in Maryland, faced a significant drop in its shares after releasing interim data from the TAMARACK Phase 2 study. The study focused on vobramitamab duocarmazine (vobra duo), a treatment targeting B7-H3, an antigen commonly found in various solid tumors. Conducted on patients with metastatic castration-resistant prostate cancer, the trial reported alarming results that caused a drastic decline in the company’s stock value.
The data revealed a high rate of adverse events, with over 50% of patients experiencing grade 3 or worse side effects in both dose cohorts. In addition, five deaths were reported during the trial, leading to concerns about the safety and efficacy of the treatment. On the data cutoff date of April 12, 2024, the incidence of treatment-emergent adverse events in the low and high dose arms was notably high, marking a significant increase compared to earlier data.
MacroGenics’ latest update also highlighted a rise in treatment-related interruptions at both dose levels, raising further questions about the drug’s tolerability. Investigators identified specific causes of death, including two cardiovascular-related deaths and three deaths currently under investigation. With overall response rates varying between dose levels, the company faces challenges in addressing the concerns raised by the trial results.
Investors reacted strongly to the news, causing MGNX shares to plummet by 73% to $3.92 at the close of trading on Friday. The steep decline reflects the market’s apprehension towards the study’s outcomes and the potential impact on MacroGenics’ future prospects. As the company navigates through the aftermath of the trial, stakeholders will be closely monitoring developments in the coming days to assess the implications on its pipeline and overall business strategy.