Interneuron's PRO 2000 To Be Tested In NIH-Supported Phase II/III HIV Prevention Trial.

Business Editors & Health/Medical Writers

LEXINGTON, Mass.--(BW HealthWire)--Feb. 28, 2001

Interneuron Pharmaceuticals, Inc. (NASDAQ: IPIC) today announced that PRO 2000, its candidate vaginal microbicide for sexually transmitted disease prevention, will be tested in a large government-funded Phase II/III clinical trial to evaluate long-term safety and protective efficacy against HIV (human immunodeficiency virus) infection, the cause of AIDS (the acquired immunodeficiency syndrome). Scheduled to begin later this year, the study will take place in four countries with high rates of heterosexual HIV transmission: Zimbabwe, Malawi, South Africa and India.

The study will be conducted by the HIV Prevention Trials Network (HPTN), a program established by the National Institutes of Health (NIH) to develop and test non-vaccine strategies to prevent the spread of HIV infection and AIDS. The HPTN comprises a global network of medical research centers with supporting operational, data management and laboratory core facilities. First-year funding for all HPTN activities totals over $30 million, including the sums allocated to the Phase II/III clinical trial and other microbicide research. Interneuron will supply PRO 2000 for the study.

"Selection of PRO 2000 for testing within the HPTN represents a significant milestone in the development of this drug," said Albert Profy, Ph.D., Interneuron's vice president of preclinical development. "Access to HPTN's considerable resources and state-of-the-art expertise should speed the collection of vital safety and effectiveness data on the product."

In October 2000, an NIH-supported Phase I/II safety and acceptability trial of PRO 2000 was completed at medical centers in the United States and South Africa. This study involved 50 healthy, sexually active women and 13 HIV-infected women who agreed to remain sexually abstinent while using the product. No serious adverse events were reported during the study, and a detailed analysis of the data is underway.

PRO 2000 is being developed as a vaginal gel that may one day offer a female-controlled safer-sex option. Laboratory studies have shown that the drug is active against HIV, herpes simplex virus, chlamydia and gonorrhea. Furthermore, vaginally applied PRO 2000 has been shown to provide protection in a monkey model for HIV transmission and a mouse model for genital herpes.

Interneuron Pharmaceuticals is a biopharmaceutical company engaged in the development and commercialization of a diversified portfolio of product candidates, including multiple compounds in late-stage clinical development.

Except for the descriptions of historical facts contained herein, this press release contains forward-looking statements that involve risks and uncertainties that could cause the Company's actual results and financial condition to differ materially from those anticipated by the forward-looking statements. These risks and uncertainties are set forth in the Company's filings under the Securities Act of 1933 and the Securities Exchange Act of 1934 under "Risk Factors" and elsewhere, and include, but are not limited to, risks relating to the Redux-related litigation; uncertainties relating to clinical trials, regulatory approval and commercialization of the Company's products; the early stage of products under development; need for additional funds and corporate partners; history of operating losses and expectation of future losses; product liability; dependence on third parties for manufacturing and marketing; competition; government regulation; risks associated with contractual arrangements; limited patents and proprietary rights; dependence on key personnel; uncertainty regarding pharmaceutical pricing and reimbursement and other risks.