Kalshi and Polymarket are letting users wager on whether cancer drugs win FDA approval and whether clinical trials succeed, extending prediction markets into drug development.
Researchers, doctors, ethicists and patients say the bets could distort trial behavior, enable insider trading and weaken trust in studies that directly affect patients' lives.
Kalshi says the markets can aggregate expertise and steer investment toward promising treatments, and it bars trading by trial staff, regulators, drug company employees and enrolled patients.
Critics argue those safeguards are too narrow because companies cannot reliably identify everyone with confidential trial knowledge, making the markets a lightly regulated version of biotech stock trading.
The backlash adds to earlier calls for oversight, including a petition with more than 180 signatures and former FDA Commissioner Robert Califf's warning that the practice breaches scientific conduct.