Palatin stock minimally aroused by sexual dysfunction data for bremelanotide
This article was originally published in Scrip
Palatin Technologies may be able to start a Phase III clinical trial for its female sexual dysfunction (FSD) drug bremelanotide by the fourth quarter of 2013 based on statistically significant Phase IIb results.
The Cranbury, New Jersey-based company's penny stock rose nearly 15% on 1 March based on detailed Phase IIb data presented at the International Society for the Study of Women's Sexual Health (ISSWSH) conference in New Orleans. However, Palatin's stock ended the day up just $0.02, or 3.3%, at $0.63 per share, keeping the stock below the mid-point of its $0.40 to $1.20 range over the past year.
Bremelanotide is a first-in-class melanocortin agonist and a synthetic peptide analog of the naturally occurring hormone alpha-MSH (melanocyte-stimulating hormone).
The drug showed a statistically significant increase in the number of satisfying sexual events (SSEs) versus placebo with a mean increase of 0.8 (2.9 total) for the 1.75mg dose (p=0.0215) and 0.7 (2.4) when data from the 1.25mg and 1.75mg arms of the Phase IIb study were pooled (p=0.0180) compared with 0.2 (2.3) for the placebo group.
A 0.75mg dose also was tested, but results for the low-dose and the 1.25mg dose on its own were not significant.
Of the 394 premenopausal women dosed for 16 weeks during the clinical trial, 26 patients discontinued treatment due to predefined blood pressure criteria.
Palatin discontinued development of an intranasal formulation of bremelanotide in 2008 due to blood pressure concerns, but initiated development of a subcutaneous formulation in 2010 (scripintelligence.com, 21 May 2008 and 29 September 2010).
Facial flushing, nausea and vomiting were the most common adverse events for the Phase IIb subcutaneous bremelanotide study, and the side effects were characterized as mainly mild-to-moderate. However, 12 patients, including two in the placebo arm of the study, discontinued therapy due to nausea and vomiting.
In other Phase IIb data reported at ISSWSH, Palatin reported statistically or clinically significant trends versus placebo for women diagnosed with hypoactive sexual desire disorder (HSDD) or a combination of HSDD and female sexual arousal disorder (FSAD).
The mean change in Female Sexual Function Index (FSFI) score was 4.4 for 1.75mg of bremelanotide (p=0.0021) and 3.6 in the pooled 1.25mg and 1.75mg data group versus 1.88 for placebo.
Mean change in the Female Sexual Distress Scale-Desire/Arousal/Orgasm (FSDS-DAO) score was -13.1 in the 1.75mg group (p=0.0005) and -11.1 for 1.25mg/1.75mg group versus -6.8 in the placebo arm of the study.
"We believe that the pieces are falling into place nicely for Palatin as we believe the large positive Phase IIb data set has significantly de-risked the story," Roth Capital Partners analyst Joseph Pantginis said in a 1 March research note.
Dr Pantginis added: "The company is set to conduct an End-of-Phase II meeting with the FDA shortly and is expecting feedback related to proposed Phase III program design in 2Q13. We also believe that partnering potential this year has significantly increased based on both the data and the significant unmet medical need in FSD patients."
Sagient Research, an affiliate of Scrip, estimates the size of the FSAD market at 47 million women in the US with no FDA-approved drugs available. The advisory firm said in a 1 March BioMedTracker report that the drug has a 32% chance of FDA approval, which was 2% higher than therapies in similar stages of development.