MacroGenics Suffers Major Setback Following Patient Deaths in Prostate Cancer Drug Trial

Biotech Firm MacroGenics Faces a Crisis

MacroGenics, a biotech company based in Rockville, Maryland, saw its stocks plummet in premarket trading in New York. This came in the wake of the company disclosing five fatalities during a clinical trial of its experimental prostate cancer treatment, as reported by Bloomberg.

About the TAMARACK Phase 2 Study

In November 2023, MacroGenics completed the enrollment of participants for the TAMARACK Phase 2 study of vobra duo. The study focused on patients suffering from metastatic castration-resistant prostate cancer who had already undergone one treatment targeting the androgen receptor pathway. Some of these patients might have also received one prior treatment, including taxane, but no other chemotherapy. The study's objective was to evaluate the effects of two different dosages of vobra duo, either 2.0 mg/kg or 2.7 mg/kg, administered every four weeks.

Statements from Professor Johann DeBono

Johann DeBono, Regius Professor of Cancer Research and Professor in Experimental Cancer Medicine at The Institute of Cancer Research, London and The Royal Marsden NHS Foundation Trust, expressed optimism about the initial safety and anti-tumor activity observed in the TAMARACK study. He noted that the innovative ADC molecule could potentially become the first therapy targeting B7-H3 in patients with prostate cancer, providing a significant new treatment option for this group.

Deaths in the Study

However, MacroGenics later revealed in a release that five participants in the study had died. Two of these deaths were deemed unrelated to the study, while the other three are currently under investigation.

A total of five fatal events occurred as follows: one Grade 5 event in the 2.0 mg/kg dosing cohort: acute myocardial infarction (considered unrelated to the study drug by the investigator); three Grade 5 events in the 2.7 mg/kg dosing cohort: one cardiac arrest (considered unrelated to study drug by the investigator) and two events of pneumonitis. Additionally, a patient in the 2.7 mg/kg dosing cohort had a Grade 3 pleural effusion that resulted in a fatal outcome. The latter three deaths are still under investigation, as the trial is ongoing.

Market Response

Following the disclosure of the deaths, MacroGenics' shares crashed by 67% in premarket trading due to concerns about the updated efficacy and safety information from the clinical trial.

Wall Street Analysts' Reactions

Wall Street analysts reacted negatively to the news. BMO Capital Markets downgraded MacroGenics to market perform from outperform, citing lower conviction on the company's prostate cancer program. Stifel also downgraded the company to buy from hold, expressing concerns about the safety and tolerability data. SVB Securities noted a significantly deteriorated safety profile, describing it as one of the worst case scenarios. This led to a high volume trading day and extreme volatility.

Final Thoughts

These developments pose significant challenges for MacroGenics and its experimental prostate cancer treatment. It's a stark reminder of the inherent risks involved in drug development and the importance of rigorous clinical trials. What are your thoughts on this situation? Share this article with your friends and let's discuss. And don't forget, you can sign up for the Daily Briefing, which is delivered every day at 6pm.