OraVax Inc., cutting six months of the timeline for its respiratorysyncytial virus (RSV) candidate, began a Phase III study of themonoclonal antibody product in the Southern Hemisphere.

The Cambridge, Mass., company said late Thursday it initiated apivotal Phase III to be conducted at 25 centers in Australia, NewZealand, Argentina and South Africa, areas where winter is justgetting under way. The placebo-controlled, double-blind study isexpected to enroll 500 infants at high risk of developing RSV.

The product, HNK20, administered via nose drops, usesimmunoglobulin A antibodies to neutralize the virus, which leads toviral pneumonia in infants. Winter months are when there is greatestrisk of infection.

"With five clinical trials completed we're very confident of theproduct and very hopeful and excited about the Phase III trial," saidLance Gordon, president and CEO of OraVax.

A 57-infant Phase II study was completed last month in the U.S. TheFDA has access to that data, Gordon said, and the Phase III trial isbeing run under an agency-approved application.

OraVax said HNK20, because of the once-a-day nose-dropadministration, has an advantage over existing products because itcan be done at home and isn't given intravenously. It said anotherpotential advantage is that it prevents not only pneumonia but upperrespiratory tract infection.

The Phase III study will run through September 1996, with resultsavailable within a month or two after completion since the primaryendpoint is incidence of hospitalization with confirmed RSV disease.

Gordon said the company is seeking regional marketing partners forthe product but OraVax intends to participate in marketing. In thefirst quarter OraVax purchased a manufacturing facility in Canton,Mass., from ImmunoGen Inc., of Cambridge, to produce HNK20.

OraVax is under registration for a proposed follow-on offering of 2.5million shares. The company on March 31, 1996, reported $22.5million in cash and equivalents and 7.6 million shares outstanding. Itlost 5.3 million in the first quarter, more than in previous quarters dueto increased clinical activity. (A urease-based vaccine forHelicobacter pylori is in Phase II.)

OraVax stock (NASDAQ:ORVX) was unchanged Friday at $13. n

-- Jim Shrine

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