Amgen snags a lightning-fast approval for its leukemia immunotherapy

The FDA approved Amgen's ($AMGN) new leukemia treatment more than 5 months ahead of schedule, green-lighting the first contender among a new class of immunotherapies that promise to change the standard of care in blood cancer.

The drug, blinatumomab, is an antibody developed through Amgen's bispecific T cell engager (BiTE) system, designed to direct the body's disease-fighting immune cells to attack cancerous growth. The agency's approval, handed down just two months and change after Amgen's filing, covers Philadelphia chromosome-negative precursor B-cell acute lymphoblastic leukemia (ALL), a rare form of the cancer. The company plans to market its therapy as Blincyto.

Amgen's treatment works by connecting CD19, a protein commonly found on cancer cells, to CD3, which is expressed by the immune system's T cells. By drawing the two proteins together, blinatumomab can redirect the body's natural defenses to home in on malignancies. And, in Phase II data submitted to support its approval, the drug met its primary endpoint of significantly improving rates of complete remission among ALL patients.

Blinatumomab's success marks the first approval for any CD19-targeting agent, a class that includes promising immunotherapies from Novartis ($NVS), Juno Therapeutics, Kite Pharma ($KITE) and others. And the FDA's move, coming well ahead of blinatumomab's May 19 decision deadline, affirms oncology chief Richard Pazdur's willingness to hurry along new treatments that could change the standard of care, cause for optimism among developers of similar drugs.

"Immunotherapies, especially Blincyto with its unique mechanism of action, are particularly promising for patients with leukemia," Pazdur said in a statement. "Recognizing the potential of this novel therapy, the FDA worked proactively with the sponsor under our breakthrough therapy designation program to facilitate the approval of this novel agent."

Amgen has moved quickly with blinatumomab since picking it up in a $1.2 billion buyout of Micromet in 2012, and the immunotherapy is also in development as a treatment for chronic lymphocytic leukemia, B-cell lymphoma and other blood and marrow cancers. Beyond blinatumomab, the company is investigating a slew of new BiTE candidates, and Amgen believes its technology has applications in a wide range of cancers.

The drug is a major pillar of Amgen's late-stage pipeline, standing alongside the much-heralded cardio treatment evolocumab, the cancer vaccine T-Vec and the psoriasis drug brodalumab, all of which could be up for FDA approval next year.

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