The United States Food and Drug Administration (FDA) has approved Arzerra® (ofatumumab) as maintenance therapy for the treatment of advanced chronic lymphocytic leukemia (CLL). This product is already approved to treat patients with CLL who have not received prior therapy, or whose CLL has stopped responding to prior therapies.

CLL is a type of cancer that starts in immune cells called B-cells. It accounts for 1 in 4 cases of adult leukemia in Western countries. Often, CLL begins as a slow-growing cancer. However, it can progress to a more fast-growing type of leukemia as the disease advances.

There are several different types of treatment agents used for CLL. Although some treatment agents might be initially effective in producing anti-cancer responses, the cancer often stops responding to the agents after a period of time, and the disease progresses.

CLL is diagnosed most commonly in elderly patients (65 years or greater). Since these patients are often unable to tolerate the aggressive therapies compared to their younger counterparts due to additional medical conditions and/or differences in the metabolizing of the agents, the toxicity of treatment is an important issue.

Ofatumumab is a biologic agent that specifically targets a protein called CD-20, which is commonly found in greater abundance on the surface of B-cells than other cells. Therefore, ofatumumab directs its cancer killing effects on cancer cells while sparing other healthy cells in the body.

Researchers recently conducted a clinical trial to evaluate the effectiveness and tolerability of ofatumumab used as maintenance therapy among patients with CLL. Maintenance therapy refers to treatment that is given to reduce the risk of disease progression following effective initial therapy. It is typically administered while patients are in complete or partial remission following initial therapy, and is often given until the cancer progresses.

The trial referred to as the PROLONG study included 474 patients with CLL who were in partial or complete remission following 2 to 3 prior therapies. One group of patients was treated with maintenance ofatumumab, while the other group received no further treatment.

  • Patients treated with ofatumumab lived approximately 14.2 months longer without cancer progression compared to those who received no maintenance therapy (29.4 months versus 15.2 months).
  • The most common side effects associated with ofatumumab were reactions at the site of infusion, low levels of immune cells, and upper respiratory tract infections. However, there were no unexpected toxicities observed with ofatumumab.

Based on these results, the FDA approved the additional indication for CLL to include maintenance therapy, even though the trial has not yet been completed. Analysis of long-term results will provide additional information regarding ofatumumab being used as maintenance therapy for CLL.

In the press release from Genmab announcing this extended approval, Jan van de Winkel, Ph.D., Chief Executive Officer of Genmab, stated that “The approval of Arzerra in the U.S. as extended treatment provides patients with relapsed CLL with a new treatment option that can help delay disease progression.”

Reference: Genmab. Genmab Announces U.S. FDA Approval of Arzerra® (ofatumumab) as Extended Treatment for Recurrent or Progressive CLL. Available at: Accessed February 10, 2016.

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