Poster presentation will highlight Phase 1b data on RDX-002, an investigational, first-in-class, gut-restricted inhibitor of intestinal MTP in development for atypical antipsychotic-induced weight gain, a leading driver of treatment discontinuation among patients on atypical antipsychotics
FALLS CHURCH, Va.--(BUSINESS WIRE)--
#AIWG
--Response Pharmaceuticals, Inc., a clinical-stage biopharmaceutical company developing therapies for weight management and metabolic health in high-need populations, today announced that data from its Phase 1b clinical trial evaluating RDX-002 in subjects receiving olanzapine will be presented at the American Psychiatric Association (APA) 2026 Annual Meeting, taking place May 16-20 in San Francisco, CA. RDX-002 is the company’s investigational, first-in-class, gut-restricted small molecule inhibitor of intestinal microsomal triglyceride transfer protein (iMTP), the protein responsible for packaging dietary fat and cholesterol into chylomicrons for absorption into the body. RDX-002 is in development for the prevention of antipsychotic-induced weight gain (AIWG).
“Highly effective antipsychotic treatments are often hampered by rapid weight gain and associated increases in cardiometabolic risk factors that can ultimately result in treatment discontinuation and significant increases in cardiovascular risk," said William Sasiela, PhD, Chief Medical Officer of Response Pharmaceuticals. "In this study, we looked to shed light on one of the drivers of that weight gain and provide initial evidence for RDX-002 as a potential preventative treatment.”
The APA presentation will provide the full data set from a Phase 1b trial, in which RDX-002 met its primary endpoint and reduced postprandial triglycerides by 82% versus olanzapine alone (p<0.001), while limiting body weight gain to 0.4 kg in subjects receiving RDX-002 added to olanzapine, compared with 1.7 kg in subjects on olanzapine alone (p=0.016), over the second week of treatment.
Presentation Details
Title:
RDX-002, a Novel Intestinal Microsomal Triglyceride Transfer Protein Inhibitor, Prevented Olanzapine-Induced Weight Gain in Human Volunteers
Abstract Number:
5044
Presenter:
William J. Sasiela, PhD, Chief Medical Officer, Response Pharmaceuticals
Authors:
William J. Sasiela, PhD; Kurt Rasmussen, PhD; Elliot Ehrich, MD
Poster Session:
6
Session Date and Location: Sunday May 17, 2026 from 1:30-3:30 pm PDT, Moscone Center Hall A
“Psychiatrists are on the front line of managing antipsychotic-induced weight gain, and the data we are presenting at APA represent important findings supporting the potential of RDX-002 to address this clinically meaningful side effect," said Eric Keller, Chief Executive Officer of Response Pharmaceuticals. "We are continuing to develop RDX-002 in antipsychotic-induced weight gain and look forward to advancing RDX-002 into a planned Phase 2 study in patients taking atypical antipsychotics
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About Antipsychotic-Induced Weight Gain (AIWG)
Atypical antipsychotics (AAPs), including olanzapine, clozapine, quetiapine, and others, are foundational treatments for schizophrenia, bipolar disorder, and major depressive disorder. They are commonly associated with rapid weight gain, hyperlipidemia, and hyperglycemia, a constellation of metabolic effects that is a leading driver of treatment non-adherence and discontinuation. Approximately 4 million U.S. patients are treated with AAPs, and up to 70% experience clinically meaningful weight gain, with 20 to 35 pounds of weight gain frequently observed within the first year of therapy. Antipsychotic-induced weight gain contributes meaningfully to the cardiometabolic morbidity and reduced life expectancy seen in patients with serious mental illness, and no therapy has been approved specifically to prevent it.
About Response Pharmaceuticals
Response Pharmaceuticals is a clinical-stage biopharmaceutical company developing therapies for weight management and metabolic health in high-need populations. The company’s lead programs focus on addressing antipsychotic-induced weight gain (AIWG) in patients with serious mental illness and supporting individuals transitioning off weight loss drugs in maintaining their weight loss and cardiometabolic benefits. Adjunctive Phase 2 studies are being explored in settings marked by significant weight gain or metabolic disruption, including potential combination use with other therapies. The company is planning to initiate a Phase 2 study evaluating RDX-002 in antipsychotic-induced weight gain, a population with elevated cardiometabolic risk and limited treatment options.
About RDX-002
RDX-002, Response Pharmaceuticals’ lead candidate, is an investigational first-in-class, potent, selective, and gut-specific small molecule inhibitor of intestinal microsomal triglyceride transfer protein (iMTP). The overall effect of iMTP inhibition is a reduction in the post-meal uptake of triglycerides (fat)—and thus calories—and cholesterol by the body. RDX-002 is being developed as a therapy to address drug-induced weight gain and decrease cardiometabolic risk, including a 9-month study in patients discontinuing GLP-1 RAs for the treatment of obesity. In a recently completed study, RDX-002 achieved a clinically meaningful mean preservation of 57% of the weight loss seen with a GLP-1 RA at 36 Weeks. RDX-002 has been studied in multiple Phase 1 and Phase 2 clinical trials in more than 450 healthy subjects and patients dosed up to 252 days. In these studies, RDX-002 lowered post-prandial triglyceride levels and circulating levels of low-density lipoprotein cholesterol (LDL-C), and reduced weight. RDX-002 was generally well-tolerated, with adverse events restricted to mostly mild to moderate gastrointestinal effects. No serious adverse events have been attributed to RDX-002. RDX-002 is being developed under an exclusive world-wide license from Sanofi S.A.
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Contacts
Press and Investor Contact
Sabine Bisson, PhD
Chief Operating Officer, Response Pharmaceuticals Inc.
press@responsepharmaceuticals.com
