Cytokinetics (CYTK) shares plummeted 5.01% in intraday trading, despite the company announcing positive topline results from its Maple-HCM trial for its heart disease drug, aficamten. The stock's decline highlights ongoing investor concerns following the recent FDA delay in reviewing the drug's marketing application.

The company reported that aficamten met its primary endpoint in the late-stage study, significantly improving patients' exercise capacity compared to standard-of-care treatment. RBC Capital Markets estimates a $900 million opportunity for this indication by 2034, contributing to a total revenue opportunity of $3.9 billion for aficamten. However, these positive results were overshadowed by lingering worries about the FDA's decision to postpone its review of aficamten until December 26, 2025.

The stock's sharp decline today adds to its recent struggles, with Cytokinetics shares having tumbled 25% so far in May following the FDA delay announcement. The contradiction between positive trial results and the stock's downward movement suggests that investors remain cautious about the drug's regulatory prospects and potential market entry timeline. As the company approaches its new PDUFA date, market participants will be closely monitoring any updates on the FDA review process and additional clinical data.