Acer Therapeutics Inc. announced the initiation of two Phase 2, single-arm investigator-sponsored trials evaluating ACER-801 (osanetant) in men with adenocarcinoma of the prostate. The POSH-MAP (Pilot of Osanetant for Severity of Hot Flashes in Men with Adenocarcinoma of the Prostate) and PORT-MAP (Pilot of Osanetant to Reduce Testosterone in Men with Adenocarcinoma of the Prostate) trials are being sponsored and conducted by The University of Kansas Cancer Center in partnership with Acer. POSH-MAP Trial: The POSH-MAP trial will evaluate the ability of ACER-801 to reduce hot flash frequency and severity and improve quality of life measures in men with prostate cancer following 28 days of therapy.

Approximately 10 participants will receive 200mg of osanetant twice daily. Following the completion of treatment on day 28 participants will re-test hormone levels and report final patient outcome measures. PORT-MAP Trial: The second trial, PORT-MAP, will evaluate the ability of ACER-801 to suppress testosterone production in men with prostate cancer within 28 days prior to a planned prostatectomy.

Approximately 10 participants will receive 200mg of osanetant twice daily for 28 days, followed by a one week wash out period. Following the one week wash out period, patients will undergo a prostatectomy between days 35-39. The overall effect of osanetant on testosterone levels and the proportion of men achieving castrate levels of testosterone (<50ng/ml) will be assessed, with hormone level assessment occurring on days 2, 3, 14, 28 and day 77.

Rationale for ACER-801 (osanetant) NK3R Antagonist Evaluation in Prostate Cancer: Prostate cancer is a hormonally driven cancer, and the management of this disease for many men is through suppression of testosterone production û called androgen deprivation therapy (ADT). Currently, most men on ADT are treated with medications that suppress hormone production which can cause dysfunctional thermoregulation and development of vasomotor symptoms (VMS), also known as hot flashes. Up to 75% of men on ADT experience VMS, resulting in high rates of distress and ADT treatment noncompliance, with approximately 20% of men with high-risk prostate cancer prematurely discontinuing ADT.3 Early pharmacokinetic studies in men and women with various NK3R antagonists have shown an inhibitory effect on the levels of luteinizing hormone and testosterone.

However, the degree of effect relative to a therapeutic goal of castrate levels of testosterone (= 50ng/mL) remains unexplored.1,2 A non-hormonal treatment to lower testosterone levels and manage induced VMS is needed as estrogen is contraindicated for the management of VMS in patients with hormone-positive tumors, including breast and prostate tumors. ACER-801 is an investigational product candidate which has not been approved by FDA or any other regulatory authority. There is no guarantee that this product candidate will receive regulatory authority approval in any territory or become commercially available for any indications
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