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Zonagen Reports FDA Reaction to Preliminary Findings From Ongoing Rat Study
THE WOODLANDS, Texas--(BW HealthWire)--Aug. 10, 1999--Zonagen, Inc. (Nasdaq: ZONA) (PLX: ZNG) today announced that the Food and Drug Administration (FDA) has advised the Company that further clinical trials of Zonagen's phentolamine-based drugs have been placed on clinical hold until certain issues surrounding the Company's two-year rat study are satisfactorily resolved. FDA is allowing Schering-Plough to complete the fully enrolled ongoing 12-week study in humans of Vasomax for erectile dysfunction.
FDA's decision was based on preliminary findings from an ongoing two-year, rat carcinogenicity study being conducted by Zonagen. The study, which is scheduled to be completed in the fourth quarter of this year, has yielded preliminary results which suggest that male rats receiving long term daily doses of phentolamine mesylate develop a higher incidence of proliferation of brown fat tissue than control rats. The implications of these findings need to be further evaluated with regard to their potential for adverse effects on humans. To date, such abnormalities have not been observed in female rats in the study.
Prior to these latest findings, Zonagen had completed and submitted to the FDA a complete genotoxicity profile as well as results from a six month mouse p53 assay and six month daily usage studies in dogs and rats. None of these studies showed any abnormal effects, including brown fat tissue proliferation.
"Phentolamine has been on the market for 50 years," said Joseph S. Podolski, President and Chief Executive Officer of Zonagen. "Given this and the fact that our previous trials showed no abnormalities, we believe we can provide sufficient information to the FDA to remove the clinical hold. We are pleased that our licensee, Schering-Plough, will be able to complete its ongoing trial. We believe we will be able to continue the clinical development of our phentolamine products for both men and women in a timely fashion."
Zonagen Inc. is engaged in the development of pharmaceutical products for the reproductive system, including sexual dysfunction, urology, contraception and infertility. |
