OPKO Health, Inc. today announced an update on the ongoing development plans of OPK-88004, a selective androgen receptor modulator (SARM).
OPK-88004 has the ability to serve as an antagonist to androgen receptors in the prostate, resulting in decreased prostate specific antigen (PSA) levels, and as an agonist resulting in increased anabolic effects, such as increased lean body mass and physical function and decreased fat mass. Promising clinical data from prior studies suggest that OPK-88004 can be used for the treatment of a number of symptoms such as frailty, physical function and quality of life parameters for various indications.
OPKO is currently conducting a Phase 2 clinical trial that evaluates the effect of 15mg and 25mg doses of OPK-88004 on prostate volume in patients with Benign Prostatic Hyperplasia. In reviewing the blinded data, it has been noticed that to measure one of the study’s primary endpoints (decreases in prostate volume), the trans-rectal ultrasound method proved to be too imprecise to reliably determine the drug effect. Also, although most of the laboratory changes were consistent with this class of drugs, increases in liver enzymes were observed in several men at these higher doses. The increases were transient in patients that completed the trial and returned to normal once the drug was withdrawn. Importantly, no increases in liver enzymes were observed in a previous large Phase 2 study of 420 men taking lower doses of OPK-88004 (1mg and 5mg). OPKO plans to suspend the current trial but continue to analyze data relating to the other primary endpoint, the effect of OPK-88004 on serum PSA levels, and the secondary endpoints, changes in lean body mass (LBM) and fat mass. The results of this data analysis are expected in Q2 2019.
OPKO is planning additional exploratory Phase 2 clinical studies to assess the feasibility of OPK-88004 in other indications. One of the trials is designed to study the safety and efficacy of OPK-88004 in prostate cancer patients treated with Androgen Deprivation Therapy (ADT). ADT results in the reduction of testosterone to castration levels in men with prostate cancer. However, ADT is associated with side effects such as decreased LBM, physical function, bone quality and increases in body fat, frailty and hot flashes. The diminished quality of life results in approximately one-third of men treated with ADT stopping treatment within six months of initiation. OPKO’s trial data in aging men indicate that OPK-88004 increases LBM, decreases fat and increases physical function. Because OPK-88004 decreases PSA levels due to its antagonistic effects on the prostate, it may be well-suited to treat men on ADT therapy. The contemplated Phase 2 study is designed to show that OPK-88004 improves ADT-associated symptoms and quality of life of prostate cancer patients. Approximately one million men are receiving ADT therapy in the U.S.
Because of OPK-88004’s significant increase of muscle mass (LBM) and strength, and because of OPKO’s strong interest in the therapy of chronic kidney disease (CKD) patients, another Phase 2 trial is planned to treat kidney dialysis patients who have low testosterone levels and commonly suffer from muscle weakness and general frailty. Approximately 500,000 CKD patients are on dialysis therapy in the U.S.