Nearly half of patients involved in a study for Amgen Inc.’s BiTE drug, an experimental cancer treatment, experienced adverse effects, according to data released Wednesday from its phase 1 study for myeloma.

Nineteen of 43 patients in the study showed a negative reaction to the drug – 16 of those patients required hospitalization.

Two patients died during the study; the deaths are not considered to be treatment-related, the Thousand Oaks biotech giant said.

“Our BiTE immuno-oncology platform offers unique versatility, with the potential to treat various tumors through targeting tumor-associated antigens,” said Dr. David M. Reese, vice president of research and development at Amgen, in a statement.

“We continue to investigate and advance more than a dozen BiTE molecules across a broad range of hematologic malignancies and solid tumors,” Reese said, adding that the data “reinforce the potential of BiTE technology for difficult-to-treat cancers like multiple myeloma and prostate cancer."

Amgen shares on Nasdaq closed down 18 cents, or 0.1 percent, to $174.55 on Wednesday, a day when that market was up 0.6 percent.