RGENIX Presents Initial Results of Combination Trial of RGX-104 at the 2020 AACR Annual Meeting

NEW YORK–(BUSINESS WIRE)–#biotech–RGENIX, Inc., a clinical stage biopharmaceutical company developing first-in-class small molecule and antibody cancer therapeutics, announced today it is presenting an abstract on RGX-104, RGENIX’s lead therapy in development. RGENIX’s abstract, “RGX-104, a first-in-class immunotherapy targeting the liver-X receptor (LXR); Initial results from the phase 1b RGX-104 plus Docetaxel combination dose escalation cohorts” was accepted for the 2020 American Association for Cancer Research (AACR) Annual Meeting, which this year was scheduled as two virtual meetings. The abstract results will be presented as a virtual poster presentation (CT-146) during the VPO.CT01 – Phase I Clinical Trials session on April 27, by clinical investigator Dr. Emerson Lim from Columbia University Herbert Irving Comprehensive Cancer Center, who is lead author on the study.

For the dose escalation stage of this Phase 1b study, RGX-104 was tested in combination with docetaxel across three different dose escalation cohorts. The presentation will outline the safety profile, pharmacodynamic effects, and clinical activity of the combination in unselected heavily pre-treated patients with refractory or relapsed solid tumors. The results support further development of this regimen.

RGX-104 is a small-molecule LXR agonist that modulates innate immunity via transcriptional activation of the ApoE gene. RGX-104 inhibits tumor angiogenesis and depletes myeloid derived suppressor cells (MDSC), thereby activating cytotoxic T-lymphocytes. MDSCs are associated with resistance to both checkpoint inhibitors (CPI) and chemotherapy, including docetaxel, providing a rationale for combination therapy with RGX-104. Consistent with this, RGX-104 plus docetaxel combination therapy is highly efficacious in pre-clinical models that demonstrate MDSC-associated docetaxel resistance.

As of February 7, 2020, 11 patients with refractory solid tumors were treated with the combination across 3 different dosing cohorts. The safety profile was consistent with the individual profiles of RGX-104 and docetaxel, with neutropenia the most common drug-related adverse event observed, but dose-limiting in only one patient in cohort one, where RGX-104 was administered at 80mg BID every day with docetaxel administered at 35mg/m² weekly x 3. In cohorts two and three, in which patients received RGX-104 dosing five consecutive days out of seven (at either 80mg or 100mg BID) and a reduced dose of docetaxel (28mg/m²), no dose-limiting toxicity was observed, and sustained pharmacodynamic activity (ApoE activation and MDSC depletion) was achieved. The overall response rate (ORR) in all evaluable patients was 22%, with a disease control rate (DCR) of 56%. Across cohorts 2 and 3, where target RGX-104 pharmacodynamic effects were achieved, the ORR was 33% with a 67% DCR. Clinical responses included partial responses (PRs) in CPI refractory/resistant patients, including an ongoing confirmed PR in a CPI resistant melanoma patient treated in cohort 2 that remains on study at 10 months. Clinical activity was associated with increases in T cell activation markers exceeding that generally observed with RGX-104 alone.

As a result, the RGX-104/docetaxel regimen is being evaluated in a phase 1b/2 expansion study that has begun enrolling patients with relapsed/refractory extensive stage small-cell lung cancer (ES-SCLC) or high grade-neuroendocrine tumors (HG-NET).

Emerson Lim, M.D., principal investigator from Columbia University Herbert Irving Comprehensive Cancer Center and lead author and presenter of the poster, said, “The clinical activity seen in the dose escalation of RGX-104 combined with Docetaxel is quite encouraging; especially notable is the ongoing PR of greater than 10 months duration in a patient with metastatic melanoma who had previously progressed with combination Nivolumab and Ipilimumab as his second line therapy. I am hopeful this combination will provide a therapeutic option for patients with ES-SCLC/HG-NET as currently being tested in the expansion phase.”

RGX-104 is also being evaluated in combination with the front-line standard-of-care regimen of pembrolizumab plus carboplatin/pemetrexed in a phase 1b/2 study currently enrolling patients with advanced non-squamous non-small cell lung cancer (NSCLC).

Masoud Tavazoie, M.D., Ph.D., and Chief Executive Officer of RGENIX, said, “The data from the RGX-104/docetaxel combination dose escalation cohorts are encouraging, providing early safety and efficacy data that support further development of the combination. Though we are still in the early stages of the RGX-104 Phase 1b/2 studies, the results show the potential of RGX-104 to provide durable clinical activity in refractory patients through a novel mechanism-of-action. We look forward to sharing additional findings from these ongoing studies.”

About RGENIX

RGENIX, Inc., is a privately-held clinical-stage biopharmaceutical company focused on the discovery and development of novel cancer drugs that target key pathways in cancer progression. The company is pursuing several first-in-class drug candidates to treat cancers of high unmet need. RGENIX identifies novel cancer targets using a microRNA based target discovery platform originally developed by RGENIX’s scientific co-founders at The Rockefeller University and now exclusively licensed to RGENIX. The company brings together distinguished scientific founders, a seasoned Board, and a leadership team comprised of experienced drug developers. The company is funded by leading biotechnology investors, including Novo Holdings A/S, Sofinnova Partners, Lepu Holdings Limited, Oceanpine Capital, WuXi PharmaTech Healthcare Fund I, LP, Alexandria Venture Investments,LLC, and the Partnership Fund for New York City. For more information, please visit www.rgenix.com.

About RGX-104

RGX-104 is an orally-administered potent small molecule agonist of the Liver X Receptor (LXR) that is currently being evaluated in a Phase 1b/2 clinical study. Activation of the LXR-ApoE pathway by RGX-104 stimulates the innate immune response in cancer via depletion of myeloid-derived suppressor cells and activation of dendritic cells, leading to stimulation of T cells and anti-tumor immunity. LXR activation also blocks the ability of tumors to recruit blood vessels. The LXR-ApoE pathway was originally identified as a cancer target using a novel microRNA-based discovery platform developed by RGENIX’s scientific co-founders at The Rockefeller University.

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