MedImmune Inc. posted a loss in the second quarter largely because of the cost of dissolving a partnership with Wyeth to market the nasal-spray influenza vaccine FluMist, the company said yesterday.

The Gaithersburg biotechnology company lost $100 million (40 cents a share), compared with a profit of $13.5 million (5 cents) during the same period a year ago. Excluding charges associated with ending the Wyeth partnership, MedImmune lost $29 million, or 12 cents a share.

Revenue fell 17 percent, to $93.7 million. The company said second-quarter 2003 earnings included $30 million in non-product revenue, including one-time payments from Wyeth after FluMist was approved and from Abbott Laboratories after Synagis exceeded a sales milestone. Synagis, a treatment for infant lung infections, was developed by MedImmune and marketed with Abbott.

Product sales jumped 13 percent, to $91 million, driven primarily by higher demand for Synagis. Sales of the drug rose 10 percent. Sales of the cancer treatment Ethyol grew 4 percent, to $25 million, while sales of the infection treatment CytoGam more than doubled, to $8 million.

The company said its second-quarter results are generally lower, partly because of seasonal drugs Synagis and FluMist, which are generally prescribed in the fall and winter.

Research and development costs rose 90 percent, to $57 million from $30 million, after the company initiated human tests for experimental drugs, including a new, non-frozen version of FluMist, which the company says should reach consumers by 2007. FluMist now must be stored in a freezer, which has hurt sales.

FluMist has so far flopped, selling fewer than 500,000 doses during its 2003 debut. The company said it does not expect the vaccine to generate significant revenue until the new version is approved.

For now, MedImmune is cutting FluMist's price by nearly half, to $23.50, ditching its consumer marketing campaign and focusing on winning over skeptical doctors. In April, MedImmune ended its marketing agreement with Wyeth and predicted the decision would cost it $105 million.

For the third quarter, the company forecast a loss of between 26 cents and 29 cents a share and revenue of between $85 million and $90 million.

Shares of MedImmune closed yesterday at $23.18, up 68 cents, or about 3 percent.