Register Log-in Investor Type

News

RTW gets boost from Prometheus trial success

221209 rtw prometheus

RTW Venture Fund has drawn investors’ attention to positive data updates on two clinical trials of Prometheus Biosciences, Inc. (NASDAQ: RXDX), its third largest holding, representing about 7.5% of NAV.

Prometheus is a clinical-stage biotechnology company pioneering a precision medicine approach for the discovery, development, and commercialization of novel therapeutic and companion diagnostic products for the treatment of immune-mediated diseases. PRA023, the lead program, is a monoclonal antibody that has been shown to block tumor necrosis factor (TNF)-like ligand 1A (TL1A) and has the potential to substantially improve outcomes for moderate-to-severe inflammatory bowel disease (IBD) patients predisposed to increased TL1A expression. Prometheus is developing PRA023 for the treatment of immune-mediated diseases including ulcerative colitis (UC), Crohn’s Disease (CD), and systemic sclerosis-associated interstitial lung disease (SSc-ILD).

On the 7th of December, Prometheus shared two positive data readouts from its Phase 2 study in UC and Phase 2a study in CD of PRA023 demonstrating strong efficacy and favourable safety results in both studies, positioning PRA023 as potentially best- and first-in-class therapeutic for IBD.

As of last published 31 October 2022 NAV, the Company’s holding in Prometheus represented c. 7.5% of NAV. Given the positive news on clinical trials progress, Prometheus’ share price traded up +165.7% on 07 December 2022, which ought to have a significant positive impact on the NAV.

RTW Venture together with other funds managed by RTW Investments, LP participated in a $130m financing round in Prometheus in November 2020 and then supported Prometheus’ IPO in March 2021.

Prometheus’s press release

Prometheus Biosciences, Inc. (Nasdaq: RXDX), a clinical-stage biotechnology company pioneering a precision medicine approach for the discovery, development, and commercialization of novel therapeutic and companion diagnostic products for the treatment of immune-mediated diseases, today reported results from its ARTEMIS-UC Phase 2 and APOLLO-CD Phase 2a studies of PRA023 demonstrating strong efficacy and favorable safety results in both studies. Based on the totality of the data in these two studies, Prometheus intends to advance PRA023 into Phase 3 studies for ulcerative colitis (UC) and Crohn’s disease (CD) in 2023.

Topline Results from the ARTEMIS-UC Phase 2 Study

Prometheus’ Phase 2 ARTEMIS-UC clinical trial was a 12-week, double-blind, placebo-controlled, randomized study to evaluate the efficacy and safety of PRA023 in patients with moderate-to-severely active UC who have failed conventional or advanced therapy. PRA023 met the primary and all ranked secondary endpoints including clinical, endoscopic, histologic, and patient-reported outcome measures in the initial cohort (Cohort 1) of the trial. 68/68 (100%) of PRA023-treated patients completed the Cohort 1 study, compared to 60/67 (89.6%) in the placebo group. The topline results for the key endpoints were as follows:

· 26.5% of patients on PRA023 reached the primary endpoint of clinical remission (per modified Mayo Score), compared to 1.5% on placebo, for a placebo-adjusted clinical remission rate of 25.0% on the primary endpoint (p<0.0001)

· 36.8% of patients on PRA023 reached the secondary endpoint of endoscopic improvement (Mayo endoscopy subscore of ≤ 1), compared to 6.0% on placebo, for a placebo-adjusted endoscopic improvement rate of 30.8% on the secondary endpoint (p<0.0001)

· All secondary endpoints 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, opportunistic infections or infusion reactions reported in the PRA023 treatment group. The only AE that occurred in more than two patients and at a higher frequency in the PRA023 group compared to placebo was COVID-19 (5/68 [7.4%] and 3/67 [4.5%], respectively).

Based upon confidence in its precision approach and speed to market, the company conducted an interim companion diagnostic (CDx) analysis of Cohort 1 to evaluate the effectiveness of the CDx candidate in ARTEMIS-UC. Although from limited patient numbers, data from the subset of patients who tested positive on the CDx in Cohort 1 (N=32) demonstrated a placebo-adjusted clinical remission rate of 37.5%, compared with the placebo-adjusted remission rate of 25.0% for all-comers. The expansion cohort (Cohort 2), which is statistically powered to further assess the treatment effect of PRA023 in CDx+ patients will continue to enroll, and the company expects results in the second quarter of 2023.

Results from the APOLLO-CD Phase 2a Study

Prometheus’ Phase 2a APOLLO-CD clinical trial was a 12-week open-label study that enrolled 55 patients with moderate-to-severely active CD with endoscopically active disease who had failed conventional or biologic therapy. The study enrolled a highly refractory patient population with 70.9% of patients previously treated with at least one biologic therapy and 52.7% treated with two or more biologic therapies. The results on the key endpoints were as follows:

· 26.0% of patients on PRA023 achieved endoscopic response (p=0.002 compared to 12% prespecified historical placebo rate)

· 49.1% of patients on PRA023 achieved clinical remission (p<0.001 compared to 16% prespecified historical placebo rate)

PRA023 was well tolerated in the APOLLO-CD study. There were no treatment-emergent serious adverse events (SAE), adverse events (AE) leading to discontinuation, or severe AEs assessed as related to PRA023 by the investigator. There were no opportunistic infections or infusion reactions reported. AEs that occurred in more than two patients included COVID-19, urinary tract infection, CD, anemia, nasopharyngitis and fatigue.

The predictive power of the company’s prespecified genetic markers was validated using an alternative Crohn’s-specific CDx algorithm which showed 45.0% (9/20) endoscopic response relative to all-comers of 26% (13/50). While the original algorithm provided limited benefit on some of the endpoints, the alternative algorithm demonstrated enhanced performance across both clinical and endoscopic outcomes. The company plans to advance this alternative algorithm in registrational studies for CD.

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

“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 Mark McKenna, Chairman and CEO of Prometheus Biosciences. “We believe PRA023 and our precision medicine approach has the potential to change the paradigm of IBD treatment and we look forward to discussions with regulatory agencies as we prepare to advance into Phase 3 studies in Ulcerative Colitis and Crohn’s Disease.”

“PRA023 has clearly demonstrated clinical proof-of-concept in CD and remarkable efficacy for the treatment of UC,” added Allison Luo, MD, Chief Medical Officer. “We are grateful to all of our investigators and patients for their participation and look forward to further evaluating PRA023 in Phase 3 studies with the goal of bringing this promising candidate to the market.”

Next Steps

As a result of these positive data, Prometheus plans to advance PRA023 into pivotal development in 2023, following discussions with regulators. The full data sets from these studies will be presented at a future medical meeting.

RTW : RTW gets boost from Prometheus trial succes

Leave a Reply

Your email address will not be published. Required fields are marked *

Please review our cookie, privacy & data protection and terms and conditions policies and, if you accept, please select your place of residence and whether you are a private or professional investor.

You live in…

You are a…