Amgen antibody shows promise in a myeloma trial and gets fast-tracked by the FDA
Amgen , updating the first trial of its bispecific antibody for multiple myeloma, said on Monday seven out of 10 patients given the second-highest dose of AMG420 responded to the drug, including four with no detectable cancer.

Six patients were still responding at 7.5 months of follow-up, according to research presented in San Diego at the annual meeting of the American Society of Hematology (ASH).

The highest trial dose was discontinued due to toxicity. Nearly a third of trial patients developed serious infections and other side effects included nerve damage and liver failure.

Amgen said AMG420, which targets a protein linked to multiple myeloma known as BCMA, has been given fast track status by the U.S. Food and Drug Administration.

"Based on these data, we plan to open an expanded trial," David Reese, Amgen's head of research and development, said in an interview. "We want to begin exploring quickly enrollment in earlier lines of therapy."

Amgen's pipeline of bispecific antibodies, which are designed to attach to a cancer cell and an immune cell, bringing them together so the body's immune system can kill the cancer, are a cornerstone of the biotech company's oncology research.

Other companies are exploring different ways to attack the same BCMA target, including bluebird bio , Celgene , and Johnson & Johnson .

Earlier at the ASH meeting, bluebird and Celgene presented early trial data showing that experimental cell therapy bb21217 induced responses in 10 out of 12 heavily pre-treated myeloma patients.

Bb21217 is a next-generation version of bb2121, the companies' more advanced, but still experimental therapy in a class called CAR-T that requires harvesting a patient's own disease-fighting T-cells, modifying them in a laboratory so they target specific proteins on cancer cells and infusing them back into the patient. The manufacturing process for bb21217 is designed to improve the persistence of the altered cells.

J&J, which licensed BCMA-directed CAR-T LCAR-B38M from a unit of China-based GenScript Biotech, on Monday presented updated results from a Chinese study of the cell therapy in 57 previously treated myeloma patients. It showed that 88 percent of patients responded to the treatment, and 74 percent achieved remission.

J&J is currently enrolling patients in an international study aimed at validating those findings.

Amgen has suggested the "off the shelf" nature of its antibody platform could be an advantage from both a clinical and commercial standpoint, but oncologists say more data is needed.

Trial patients are hospitalized for their first cycle of AMG420, after which they receive the drug by continuous 24-hour infusion for four weeks, followed by two weeks off therapy, for up to 10 cycles.

Amgen has another BCMA-targeting antibody that lasts longer in the body, requiring less frequent infusions, but that research is at an earlier stage.

In the current study, 42 patients with multiple myeloma that worsened after at least two prior treatments were given AMG420 at varying doses. A total of 13 patients responded to the treatment, including seven who achieved remission.

Of the 20 patients with serious adverse events, 17 required hospitalization and four had prolonged hospitalization.