# Clinical trial outcome prediction

Before the European Society of Cardiology Congress 2026 opened, three large language models locked predictions of whether each trial's primary endpoint would be met, using only design information public at registration. Of 48 scorable trials, 28 were positive; Claude, GPT and Gemini separated positive from negative trials with AUCs of 0.80, 0.79 and 0.74, all above chance. Among 26 trials whose effect was reported exactly as locked, the direction was correct in 88% of predictions, and the median multiplicative error of ratio estimates was about 15%.

Before the European Society of Cardiology Congress 2026 opened, three large language models locked predictions of whether each trial's primary endpoint would be met, using only design information public at registration. Of 48 scorable trials, 28 were positive; Claude, GPT and Gemini separated positive from negative trials with AUCs of 0.80, 0.79 and 0.74, all above chance. Among 26 trials whose effect was reported exactly as locked, the direction was correct in 88% of predictions, and the median multiplicative error of ratio estimates was about 15%.