Phase 2 study launches of bremelanotide plus a PDE5 inhibitor for erectile dysfunction

A phase 2 study has been initiated to evaluate bremelanotide, a melanocortin 4 receptor, in combination with a phosphodiesterase 5 (PDE5) inhibitor in patients with erectile dysfunction (ED) who did not respond to prior PDE5 inhibitor monotherapy, Palatin Technologies announced in a news release.¹

Subcutaneous bremelanotide is currently approved in the US for the treatment of pre-menopausal women with generalized hypoactive sexual desire syndrome.

A novel co-formulation of bremelanotide and a PDE5inhibitor, developed by Palatin Technologies, allows the treatment to be administered to patients via a single injection.

"Approximately 30-40% of ED patients exhibit little or no response to PDE5i monotherapy, such as Viagra, Cialis, and Levitra," said Carl Spana, PhD, president and chief executive officer of Palatin, in the news release.¹ "These PDE5i monotherapy drugs account for over $4 billion of annual sales, yet PDE5i monotherapy does not work for a significant portion of ED patients. This represents a substantial unmet medical need for more effective ED treatments. Based on our clinical data and mechanisms of action research, we believe that [bremelanotide] combined with a PDE5i is synergistic and will be a clinically meaningful ED treatment for non-responders to current PDE5i monotherapy."

The initiation of the open-label, phase 2 dose escalation study for the combination therapy comes after an FDA acceptance of an investigational new drug (IND) application.

In total, the study plans to enroll approximately 50 patients. The primary outcome measures for the study are the safety and efficacy of the combination therapy in patients with ED who did not respond to prior therapy with a PDE5 inhibitor.

"ED has become more prominent over the last several decades, especially in younger adults, and represents a mounting health concern causing a significant effect on men's quality of life. Many patients in my practice are seeking better results from their ED treatment. Men with more severe ED do not respond as well using a PDE5i and have limited non-surgical options. I have used bremelanotide in my practice for men with ED. I believe the combination of bremelanotide with a PDE5i could potentially be an effective treatment option for the PDE5i non-responders suffering from ED,” said principal investigator Jed Kaminetsky, MD, FACS, in the news release.¹ Kaminetsky is a urologist and the director of research at Integrated Medical Professionals, a Division of Solaris Health, in New York, New York.

In addition to the phase 2 study, Palatin Technologies also plans to file an IND with the FDA later this year for a potential phase 3 study of bremelanotide plus a PDE5 inhibitor in patients with ED who were non-responders to PDE5 inhibitor monotherapy. Pending FDA acceptance of the IND application, the company hopes to begin the phase 3 study of the combination in the first half of 2025.

Subcutaneous bremelanotide 1.75 mg (Vyleesi) is currently approved in the US for the treatment of pre-menopausal women with generalized hypoactive sexual desire syndrome (HSDD). The FDA approved the therapy in 2019 based on data from 2 randomized, double-blind, placebo-controlled trials in which subcutaneous bremelanotide was shown to be superior to placebo in increasing sexual desire scores and decreasing distress scores in post-menopausal women with HSDD.²

References

1. Palatin announces the initiation of a phase 2 clinical study of bremelanotide co-administered with a PDE5i for the treatment of erectile dysfunction (ED). News release. Palatin Technologies, Inc. Published online and accessed June 20, 2024. https://palatin.com/press_releases/palatin-announces-the-initiation-of-a-phase-2-clinical-study-of-bremelanotide-co-administered-with-a-pde5i-for-the-treatment-of-erectile-dysfunction-ed/

2. FDA approves new treatment for hypoactive sexual desire disorder in premenopausal women. News release. June 21, 2019. Accessed June 20, 2024. https://www.fda.gov/news-events/press-announcements/fda-approves-new-treatment-hypoactive-sexual-desire-disorder-premenopausal-women