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Response Pharmaceuticals Announces Successful Completion of Phase 1B Clinical Trial for RDX-002, a Novel Small Molecule for the Treatment of Antipsychotic-Induced Weight Gain

Falls Church, Virginia, August 17, 2023


Response Pharmaceuticals, Inc. today announced the successful completion of its Phase 1B clinical trial for the company's lead drug candidate, RDX-002, a first-in-class inhibitor of intestinal microsomal triglyceride transfer protein (iMTP).  While full results are being analyzed, RDX-002 was generally well tolerated, and the study met its primary objective. The company is working with its scientific team and advisory board to complete the data analysis and prepare the final full results.


Response Pharmaceuticals’ Phase 1B trial was a 2-week open-label study in antipsychotic-naïve, healthy volunteers.  All subjects were initially treated with olanzapine, a widely used anti-psychotic with a well-documented side effect of weight gain, for one week, before one cohort continued to receive olanzapine alone and the second cohort received RDX-002 and olanzapine.   The study’s primary objective was to measure the effect of RDX-002 on postprandial triglyceride levels. The study’s results will be used to direct the design of a robust Phase 2 study where RDX-002 will be co-administered in patients with schizophrenia initiating treatment with olanzapine.     


“We are extremely excited about completing this first clinical trial of RDX-002 for the indication of antipsychotic-induced weight gain.  This serious side effect is commonly observed with multiple antipsychotic drugs which treat debilitating mental diseases and often results in non-compliance with treatment.”  said Chief Medical Officer Bill Sasiela, who continued “Intestinal MTP is an exciting therapeutic target with potential to address unmet needs in a wide range of metabolic indications. We are extremely pleased that we have met our primary objective in this first trial and are working to complete analysis of the complete data package.”


The Company expects to be able to report complete trial results and Phase 2 development plans in September 2023.


About Response Pharmaceuticals & RDX-002


Response Pharmaceuticals, Inc. is a clinical stage biotechnology company developing RDX-002 as an adjunctive therapy for patients taking first-line antipsychotic therapy. RDX-002 is a first-in-class, potent, and selective inhibitor of intestinal MTP.  iMTP is a protein believed to be a key driver of weight gain and metabolic dysregulation in patients treated with antipsychotic drugs for schizophrenia, bipolar disorder, and major depressive disorder. The small-molecule compound has been in multiple Phase 1 and Phase 2 clinical trials including over 500 volunteer and patient subjects dosed for up to 90 days. In these trials, RDX-002 was well tolerated and resulted in a lowering of post-prandial triglyceride levels, lowering of circulating levels of LDL-C, and reducing weight. By addressing treatment-limiting side effects of atypical antipsychotics, we believe (subject to the successful completion of further clinical trials) that RDX-002 will allow for much more widespread use of clozapine and olanzapine, as well as other effective but underutilized antipsychotics while reducing the burdens of non-compliance, weight gain, and long-term metabolic disease. Additionally, it remains our intent to explore the use of RDX-002 in other areas of unmet medical need in the near future. RDX-002 is being developed under an exclusive world-wide license from Sanofi S.A.


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