Two months after raising $30 million, Progenics Pharmaceuticals Inc. is adding about $29 million in a public offering to fund ongoing studies of its opioid receptor antagonist, methylnaltrexone, or MNTX.

Progenics priced its offering of about 1.5 million shares of common stock at $19.25 per share, and net proceeds are expected to be $28.5 million. UBS Investment Bank, of New York, is acting as sole manager for the offering.

The company could not be reached for comment. The financing adds to the $23.6 million the Tarrytown, N.Y.-based company had in its coffers as of March 31, plus the $29.4 million in net proceeds from its follow-on public offering in April. (See BioWorld Today, April 4, 2005.)

Progenics reported a net loss of $13.2 million for the first quarter. Its expenses for the three-month period totaled nearly $16 million, much of it attributed to the development of MNTX. Shares of Progenics (NASDAQ: PGNX) lost $1.20 Friday to close at $19.28.

Funds from public offering will be used to continue the clinical work for MNTX, the company's lead product in development to treat the side effects of opioid use without interfering with pain relief. Progenics is evaluating the product in three formulations and indications.

Derived from naltrexone, a drug often prescribed for narcotic and alcohol dependence, MNTX is administered along with opioids, and has so far shown promising results. Data reported earlier this year from a Phase III trial in patients with opioid-induced constipation showed a laxative effect within an hour after being subcutaneously administered to patients with advanced medical illness. Progenics has said that likely will be the first indication to be submitted for regulatory approval, and a new drug application is expected around the end of the year.

An intravenous form of MNTX is in development to treat patients with post-operative bowel dysfunction. Progenics reported positive Phase II results in January, and plans to meet with the FDA to design a Phase III trial later this year.

A Phase I study evaluating an oral version of MNTX in patients taking opioids for chronic pain is expected to wrap up during the second half of the year, followed by the initiation of a Phase II trial.

Proceeds from the financing also will be used to advance compounds in HIV and prostate cancer, as well as fund other research and development activities.

In HIV, Progenics has two compounds in development, PRO 542 and PRO 140, both viral entry inhibitors designed to block different stages of the viral entry process. PRO 542, an antibody-like candidate that aims to neutralize HIV by preventing it from attaching to the CD4 receptor on the surface of immune system cells, is in Phase II studies in patients with advanced disease levels who no longer are responding to standard antiretroviral therapy. Progenics entered Phase I studies last year with PRO 140, a humanized monoclonal antibody designed to block HIV from infecting cells by inhibiting its ability to bind to the CCR5 co-receptor.

In a collaboration with the Weill/Cornell Medical College of Cornell University, the company is conducting research on an HIV vaccine candidate, ProVax.

The company's work in prostate cancer has focused on vaccines to prevent the relapse and occurrence of as the disease, which have started Phase I studies, as well the development of monoclonal antibodies to the prostate-specific membrane antigen (PSMA), which are expected to enter the clinic next year in metastatic prostate cancer.

Progenics has established a joint venture - PSMA Development Co. LLC - with Princeton, N.J.-based Cytogen Corp. to develop treatments based on PMSA. Under the agreement, Progenics has exclusive worldwide rights to develop in vivo immunotherapies based on PMSA, which is expressed on the surface of prostate cancer cells but not on normal cells.