RXDX - Prometheus surges 190% as inflammatory bowel disease drug shows efficacy in 2 trials

Prometheus Biosciences ( NASDAQ: RXDX ) said its medicine PRA023 showed strong efficacy and favorable safety in two mid stage trials in patients with ulcerative colitis (UC) and Crohn's disease (CD).

UC and CD are types of inflammatory bowel diseases.

ARTEMIS-UC :

The phase 2 study, dubbed ARTEMIS-UC, evaluated PRA023 in patients with moderate-to-severely active UC who have failed conventional or advanced therapy.

The company said PRA023 met the main and all ranked secondary goals including clinical, endoscopic, histologic, and patient-reported outcome measures in the initial group (Cohort 1) of the trial.

All, 68/68 PRA023-treated patients completed the Cohort 1 study, compared to 60/67 (89.6%) in the placebo group.

Prometheus added that 26.5% of patients on PRA023 reached the primary goal of clinical remission, compared to 1.5% on placebo, for a placebo-adjusted clinical remission rate of 25.0% on the primary endpoint.

About 36.8% of patients on PRA023 reached the secondary goal of endoscopic improvement (Mayo endoscopy subscore of ? 1), compared to 6.0% on placebo, for a placebo-adjusted endoscopic improvement rate of 30.8%, according to the company.

Prometheus noted that all secondary goals met with statistical significance. PRA023 was well tolerated in Cohort 1, with no treatment-emergent serious adverse events (SAEs), adverse events (AEs) leading to discontinuation, severe AEs, infections or infusion reactions reported in the PRA023 treatment group.

The only AE which happened in more than two patients and at a higher frequency in the PRA023 group (5/68), compared to placebo (3/67) was COVID-19.

The company said the expansion group (Cohort 2), which will evaluate PRA023 in companion diagnostic positive (CDx+) patients, will continue to enroll, and results are expected in Q2 2023.

APOLLO-CD :

The phase 2a trial called APOLLO-CD enrolled 55 patients with moderate-to-severely active CD with endoscopically active disease who had failed conventional or biologic therapy.

Prometheus said 26.0% of patients on PRA023 achieved endoscopic response, compared to 12% prespecified historical placebo rate. Meanwhile, 49.1% of patients on PRA023 saw clinical remission, compared to 16% prespecified historical placebo rate.

An alternative Crohn's-specific CDx algorithm showed 45.0% (9/20) endoscopic response relative to all-comers of 26% (13/50).

The company said that the original algorithm provided limited benefit on some of the goals, the alternative algorithm showed enhanced performance across both clinical and endoscopic outcomes, the company added.

In addition, Prometheus said that a reduction in markers of inflammation and fibrosis was seen between pre-treatment and post-treatment with PRA023, as measured by circulating cytokine levels, immunohistochemistry and gene expression in disease tissue.

PRA023 was well tolerated in the APOLLO-CD study with no TEAEs, AEs, leading to discontinuation. AEs that occurred in more than two patients included COVID-19, urinary tract infection, CD, anemia, nasopharyngitis and fatigue, according to the company.

"We are beyond enthusiastic with these study results and what they could mean for patients suffering from IBD. The performance of PRA023 in both UC and Crohn’s patients has surpassed our expectations," said Prometheus Chairman and CEO Mark McKenna.

Prometheus plans to advance PRA023 into phase 3 studies for UC and CD in 2023.

RXDX +195.23% to $106.46 premarket Dec. 7

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