Viral Meningitis Drug Misses Primary Endpoint

ViroPharma Stock Nosedives On Preliminary Phase III Data

ViroPharma Inc.'s stock plummeted 40 percent after the company reported that a look at preliminary data from a Phase III study of pleconaril for viral meningitis in children showed the trial failed to meet its primary endpoint.

Kori Beer, spokeswoman for Exton, Pa.-based ViroPharma, said the primary endpoint - time to absence of headache, which is one of the disease's main symptoms - is only "a piece of the whole pie. We capture all components in the secondary endpoints," two of which did reach statistical significance in the preliminary analysis.

"We've affected those other symptoms," Beer said, which include neck or back stiffness, fever, nausea, myalgia, vomiting and malaise.

ViroPharma's shares (NASDAQ:VPHM) closed Thursday at $11.875, down $7.187.

The secondary endpoints in the study included total morbidity score (a composite measurement of all disease symptoms) and a global assessment score (which measures a caregiver's evaluation of a patient's illness). Statistical significance was achieved in the first, and in the second at the lower of two dosage levels, and in certain subset analyses of the primary and secondary endpoints.

Pleconaril is an oral liquid formulation of an active inhibitor of several RNA viruses - the type responsible for most human viral infections. They grow by replicating RNA, a process different from the survival cycles of DNA viruses, retroviruses and cells. ViroPharma's small molecules are designed to block enzymes essential for the viruses' replication.

The pediatric study in viral meningitis, for which there is no cure, is the first of four - two in children and two in adults - which are ongoing. Beer said it was "difficult to tell" whether the second pediatric trial would be changed in light of what the company has learned.

"We're going to consider all the options," she said, but the company intends to file a new drug application based on the four studies with the FDA.

ViroPharma also has ongoing Phase II studies in viral respiratory infection, of which the common cold is one type, and a compassionate-use study is under way in chronic meningoencephalitis. In the preclinical stage are compounds for hepatitis C and respiratory syncytial virus.

Vincent Milano, ViroPharma's vice president of finance and administration, said the $32.5 million cash on hand at the end of the second quarter is expected to carry the company through next year.

"Clinical trial schedules that we run are not constant, so we have fluctuating burn rates by quarter," Milano said. "But we expect that, without any additional financing, we'll get through 1999 and be able to execute our current business strategy."

The company went public in 1996, raising $15 million, and raised another $27 million in an offering the following year. (See BioWorld Today, Nov. 21, 1996, p. 1, and July 25, 1997, p. 1.) n