Another Day Pharma announces successful Phase II trial results for BZ371A in post-prostatectomy erectile dysfunction

Published: 23-May-2025

First-in-class therapeutic peptide BZ371A confirmed as effective and well-tolerated

Another Day Pharma, a company developing innovative therapies for sexual dysfunction in both men and women, has announced Phase II results for its new treatment BZ371A in post-prostatectomy erectile dysfunction.

Trial results show that BZ371A in gel form can improve men’s ability to have an erection that allows sexual intercourse following radical prostatectomy due to prostate cancer. 

In the Phase II clinical trial in 74 men between 40 and 68 years, BZ371A met its primary endpoint of assisted erectile dysfunction (ED) either as monotherapy or in combination with tadalafil, the current standard of care.

ED was assessed using the International Index of Erectile Function (IIEF) Questionnaire, domain A (erectile function section) (IIEF-EF) and success was defined as the percentage of men experiencing an increase of more than 4 points.

The men who were randomised to receive combination therapy (BZ371A + tadalafil) after surgery were 10 times more likely to respond after 30 days of treatment compared with tadalafil alone: 38% success rate vs 4% success rate (p<0.05).

BZ371A monotherapy was also superior to tadalafil alone: 15% success rate at 30 days compared with 4%, and 32% success rate at 60 days compared with 13%.

Owing to its localised topical application, BZ371A was shown to be well-tolerated with no serious adverse events and no adverse events that led to discontinuation of the medication. 

BZ371A is a synthetic non-hormonal peptide derived from the venom of the Phoneutria nigriventer spider, known for causing priapism - long-lasting painful erection - in bite victims.

BZ371A can induce an erection even in the absence of sexual stimulation. It stimulates the production of nitric oxide (NO), triggering the production of cyclic guanosine 3’,5-monophosphate  (cGMP) which provokes endothelial muscle relaxation and increased blood flow, leading to an erection.

This new and unique mechanism of action makes BZ371A particularly valuable for men whose neural pathways have been compromised, such as after prostatectomy. 

Although BZ371A has the potential to function independently, its mechanism of action is complementary to phosphodiesterase type 5 (PDE5) inhibitors such as tadalafil, so the two treatments can be taken together, leading to a stronger erection. 

“We are delighted that these trial results show that BZ371A is proving to be a well-tolerated, effective option for men undergoing radical prostatectomy, either as monotherapy or concomitantly with tadalafil,” said Paulo Lacativa, Clinical Researcher at Biozeus Biopharmaceuticals in Brazil who developed the treatment.

“The results support the advancement of BZ371A into Phase III trials and reinforce its potential to address other forms of ED.” 

“BZ371A offers a new way of treating ED that we hope will benefit, in the future, the many men who don’t respond to or are unable to take PDE5-inhibitors,” said Carlos Sanchez, Director at Another Day Pharma.

“We are now seeking strategic partnerships with pharmaceutical companies interested in licensing or co-developing this product.” 

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