ATRA

Atara Biotherapeutics' stock price has been significantly impacted by several key events over the past six months. In January 2025, the company announced a Complete Response Letter (CRL) from the FDA regarding its tabelecleucel Biologics License Application (BLA), citing manufacturing facility issues, which led to a 40.5% drop in stock price. Five days later, the FDA placed a clinical hold on Atara's active Investigational New Drug (IND) applications due to inadequately addressed good manufacturing practice (GMP) compliance issues, causing a further 7.91% decline in the stock. In January 2026, Atara announced a second CRL for the tabelecleucel BLA, stating that the single-arm ALLELE trial was no longer considered adequate for accelerated approval due to issues with trial design, conduct, and analysis, resulting in a significant 56.99% plummet in the stock price. These regulatory setbacks also led to the filing of a securities fraud class action lawsuit against Atara Biotherapeutics. In May 2026, Atara Biotherapeutics provided a positive regulatory update on tabelecleucel, indicating that FDA discussions keep the resubmission and regulatory pathway open, causing the stock to surge.