- Shares of Prometheus Biosciences nearly tripled Wednesday morning, raising the market value of the San Diego-based drugmaker by roughly $2.5 billion. The reason: its most advanced experimental medicine scored positive results in a pair of studies testing it as a treatment for two kinds of inflammatory bowel disease.
- One of those studies focused on moderate-to-severe ulcerative colitis, and found a significantly greater percentage of patients who took Prometheus’ drug, called PRA023, achieved the main goal of “clinical remission” compared to those on a placebo. The other study enrolled patients with hard-to-treat Crohn’s disease. It found treatment with PRA023 led to a higher “endoscopic response” rate than what’s been seen historically with placebo groups in this setting.
- With those results in hand, Prometheus intends to meet with regulars and, afterward, push its drug into pivotal testing.
If the pivotal tests generate positive results, Prometheus could have a chance at becoming the first company with an approved therapy targeting TL1A, a protein that helps regulate inflammation and fibrosis.
Yet, other drugmakers are hoping to take that title for themselves. Pfizer and Roivant Sciences, for example, just last week established a new company meant to develop and commercialize an anti-TL1A medicine now known as RVT-3101. That medicine has already advanced into mid-stage testing as a treatment for moderate-to-severe ulcerative colitis.
An experimental drug from Teva Pharmaceutical is also being evaluated for Crohn’s disease and ulcerative colitis in a study that’s aiming to enroll 280 participants.
To analysts, the results Prometheus released Wednesday set a high bar. Dennis Ding, who covers Roivant for Jefferies, wrote in a note to clients that data are “very strong” and better than what Wall Street had expected. And Thomas Smith from SVB Securities wrote that PRA023 showed “potentially best-in-class efficacy” in ulcerative colitis alongside “remarkably clean” safety and tolerability.
Prometheus reported that, in the ulcerative colitis study, 26.5% of patients given its drug achieved clinical remission, versus 1.5% of the placebo arm. The drug also performed significantly better than placebo on all secondary goals. To participate in the study, patients had to have already failed conventional or advanced therapy.
The Crohn’s disease trial, too, enrolled patients with hard-to-treat disease that wasn’t adequately treated through conventional or biologic therapy. The trial didn’t have a placebo arm but rather compared results to historical placebo rates of 12% for endoscopic response and 16% for clinical remission. Prometheus said the rates for patients treated with its drug were 26% and 49%, respectively.
Chris Howerton, a Jefferies analyst who covers Prometheus, wrote that Pfizer has been left “in the rearview mirror” following the latest results for PRA023, which Howerton called a “game-changer” for irritable bowel disease.
Ding, though, highlighted how, when not adjusting for the placebo, the clinical remission rate in Prometheus’ ulcerative colitis trial is close to the approximately 24% seen in a Phase 2a study of Pfizer’s drug from a few years ago.
Pfizer leadership previously said it will have data from another, larger trial of RVT-3101 by the end of the year.
With that study, expectations “are now much higher ... and the data needs to be stellar to be in the same ballpark,” Ding wrote.
Promethus shares were trading at near $100 apiece mid-Wednesday morning, up 177% from the prior day’s closing price.