By Mary Welch

For Vion Pharmaceuticals Inc., the failure of its Phase III product, Promycin, could have been worse.

"This has no bottom-line impact on us," said Thomas Klein, the company's vice president of finance and chief financial officer. "Of course we're disappointed. But last year, we renegotiated our agreement with BI [Boehringer Ingelheim] so that they'd pay the clinical costs and manage the trial while we accepted lower back-end royalties. That's probably why our stock isn't getting killed like it usually does when something like this happens."

Vion's stock (NASDAQ:VION), which had hung in most of the day, took somewhat of a hit in the last hour of trading Thursday, falling 20 percent, or $1.75, to close at $6.875.

"In hindsight, we look pretty good," he said. "We didn't expect anything like this to happen. The trial was very expensive and we wanted to focus on other products in our pipeline. That's why we renegotiated. It's also better [to have a drug fail in trials] than having the FDA tell you [it's not approvable]."

Promycin (porfiromycin) was in a Phase III randomized trial combined with radiotherapy vs. radiotherapy alone in patients with non-resectable head and neck cancer. An Interim Analysis Review Committee, which included independent external reviewers, looked over the data and said it did not meet the predetermined criteria necessary to continue the trial.

"We have only seen the summary presentation by the interim review committee, but it was prearranged that if the data didn't meet the endpoints we would halt recruitment," Klein said. He did not know how many of the planned 480 patients received treatment.

"But it was enough people so that the committee could look over the data and see there would be no statistical significance," he said. "We are also monitoring those who received Promycin because one of the endpoints was survival."

Follow-up of all patients enrolled is planned, and final results will be reported when the study surpasses the predetermined number of events needed for a full analysis. No more patients will be recruited for other studies.

Vion and BI, which is based in Ingelheim, Germany, had considered testing Promycin for cervical cancer. "It would have to be a joint decision on whether we would try Promycin for that indication," Klein said. "I think you could read into this that we would not have halted recruitment if we thought it was at all possible to proceed."

Promycin, a small-molecule, bioreductive alkylating agent that destroys hypoxic, or oxygen-depleted, cancer cells, was licensed to BI in a deal worth about $50 million plus royalties. (See BioWorld Today, Nov. 26, 1997, p. 1.)

Klein said the New Haven, Conn.-based company will focus on its Tumor Amplified Protein Expression Therapy (TAPET) technology, which delivers toxic anticancer agents to tumor sites with little effect on normal tissues, and Tirapine, a drug that blocks a critical step in DNA synthesis as a way to prevent replication of tumor cells.