Kalshi and Polymarket Are Now Taking Bets on Clinical Trials. Researchers Say That Is a Structural Integrity Problem.

Kalshi currently accepts bets on whether a weight-loss drug and a breast cancer treatment will receive FDA approval. Polymarket is taking wagers on cancer treatment approvals and related regulatory questions. Both platforms describe the markets as generating useful information about the drug development pipeline — Kalshi's white paper, co-authored by 23andMe founder Anne Wojcicki, argues that open trial probability data could be 'extremely promising and empowering' for patients who lack access to information about clinical options. Polymarket declined to comment. Neither platform holds UK regulatory authorisation, and neither the MHRA nor the FCA has yet addressed clinical trial prediction markets specifically — but the ethical questions raised in the US apply with equal force to any regulatory regime that might eventually authorise them.

Researchers who run trials are not persuaded by the information-aggregation argument. David Tsai, who manages trials at a Bay Area biotech, has launched a petition calling for the bets to be banned on integrity grounds. His concern is that prediction market payouts create a direct financial incentive for anyone with trial access — pharmacists, lab technicians, coordinators — to influence the outcome. 'A pharmacist who had placed a bet saying that it's going to work well, or doesn't work well, could obviously adjust the infusion rate, could adjust the source temperature of the drug,' Tsai told NPR. Nicholas Zaorsky, a radiation oncology professor at the Mayo Clinic, put the structural problem concisely: 'Investigators, coordinators, and sometimes even participants can directly influence aspects of the outcomes being wagered on. That creates financial incentives that risk undermining trial integrity.' For UK readers, this is comparable to asking whether a clinical trial investigator should be permitted to hold a financial derivative on their own trial's outcome — a conflict of interest that would be straightforwardly prohibited under FCA and MHRA standards.

Kalshi's counterargument is that this risk already exists in the stock market at orders of magnitude larger scale. Biotech short sellers profit from clinical trial failures; institutional funds with pharmaceutical sector exposure have far larger financial stakes in trial outcomes than any retail prediction market position. The argument has merit as far as it goes. But clinical trial investigators, coordinators, and pharmacists are not typically trading biotech equities — they are exactly the people who might be reached by a consumer-facing, gamified platform's marketing. Kalshi says it will verify employment and monitor for unusual activity, but the Bloomberg investigation published in July documented $200 million in suspicious wagers across Kalshi and Polymarket through June 2026, and detailed how safeguards have been circumvented via fresh accounts and proxy structures in other markets.

The patients enrolled in these trials are the most direct stakeholders, and the least visible in the platforms' framing. Joshua Pederson, a Boston University professor whose 12-year-old son is currently on a cancer clinical trial following a recurrence, describes the gamification as a category error. 'A clinical trial failing is a more sanitized euphemism for: people are going to suffer, people are going to die, people are going to have one fewer clinical option available to them,' he said. He called the concept 'quite ghastly.' Kalshi has said it will restrict markets to late-stage trials where participants are already enrolled and will not offer contracts where all subjects are minors — but acknowledged both limits could change. The regulatory question for UK policymakers, should prediction markets seek MHRA or FCA recognition, is not just whether to permit trial markets but whether permitting them changes trial integrity in ways that cannot be adequately monitored. Unlike sports betting, where Genius Sports and similar data providers can share integrity information with leagues in real time, there is no equivalent infrastructure for biomedical research — and the consequences of a corrupted trial outcome are measured in patient lives, not scorelines.

Operators mentioned in this article

CFTC-regulated

Kalshi

First fully CFTC-regulated US event-contract exchange.

Crypto / On-chain

Polymarket

USDC-settled on Polygon. Largest prediction market by volume.

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