Why Is MacroGenics Stock Sinking Tuesday?

MacroGenics Inc. (NASDAQ:MGNX) shares are down during Tuesday’s premarket session following the announcement of a partial clinical hold on its Phase 2 LINNET study. The stock’s decline comes as the company is working closely with the FDA to resolve safety concerns related to recent events in the trial. The U.S. Food and Drug Administration (FDA) on Monday placed a partial clinical hold on MacroGenics’ LINNET study, which evaluates lorigerlimab in patients with gynecologic cancers. Reports One Patient Death The hold was initiated due to recent safety events affecting four patients, including death, prompting the company to pause enrollment of new participants until the hold is lifted. The safety events that prompted the enrollment pause occurred across four patients and included Grade 4 thrombocytopenia (platelet deficiency) (N=2), Grade 4 myocarditis (inflamed heart muscles) (N=1), and Grade 4 neutropenia (low white blood cells) and concurrent septic shock (N=1), which led to a Grade 5 event (patient death). To date, 41 study participants have been dosed at 6 mg/kg every 3 weeks across the platinum-resistant ovarian cancer (PROC) and clear cell gynecologic cancer (CCGC) cohorts. The primary endpoint of the trial is the objective response rate, with the study designed to potentially expand enrollment based on initial results. Management Commentary “At MacroGenics, our top priority is patient safety,” said Eric Risser, President and CEO. “MacroGenics is fully committed to working closely with the FDA to resolve the partial clinical hold and we intend to resume study enrollment as soon as possible.” Prior Setback In May 2024, MacroGenics released interim data from the TAMARACK Phase 2 study of vobramitamab duocarmazine (vobra duo) for metastatic castration-resistant prostate cancer (mCRPC). It reported five deaths (fatal outcome) during the trial. It also reported over 50% rate of grade 3, or worse, adverse events in both dose cohorts (2 mg/kg and 2.7 mg/kg every four weeks). Earnings & Analyst Outlook MacroGenics is slated to provide its next financial update on March 19, 2026. EPS Estimate: Loss of 18 cents (Up from Loss of 25 cents) Revenue Estimate: $26.32 million (Up from $19.35 million) MGNX Price Action: Macrogenics shares were down 18.29% at $1.43 during premarket trading on Tuesday, according to Benzinga Pro data. Photo by Tada Images via Shutterstock