Drug’s Poor Results Pull Down Stock

Shares of Protein Design Labs Inc. fell 19% on Monday after the company said a study found its Remitogen treatment for lymphoma shrank tumors in only one of 25 cases that were evaluated.

Shares of the Fremont-based biotechnology company fell $7.21 to $30.74 in Nasdaq trading.

The disappointing results come just days after a study of Protein Design’s most advanced product, leukemia treatment Zamyl, failed to meet its main goal in a study. That news sent the company’s shares down 6.5%.

The Remitogen data were from the second of three stages of human testing generally required for U.S. regulatory approval.

“It gives us pause on how we perceive the pipeline,” said SG Cowen analyst Bill Tanner, who dropped his rating on the stock from “strong buy,” to “buy.”

The Remitogen data are being discussed today at the American Society of Hematology conference in Florida. The company said one patient had a partial response to treatment, and none had full tumor regression. In 10 patients, the disease was stable, the company said.

Protein Design plans to see if Remitogen, which is being studied in 60 patients with non-Hodgkin’s lymphoma, may be effective in higher doses earlier in treatment.

Protein Design has seven products in human testing, including treatments for cancer, autoimmune disease and asthma.