FDA approves Pfizer's drug for rare blood cancer

Henrietta Strickland
August 18, 2017

(PFE) said that the U.S. Food and Drug Administration has approved Besponsa (inotuzumab ozogamicin) for the treatment of adults with relapsed or refractory B-cell precursor acute lymphoblastic leukemia or ALL.

B-cell precursor ALL is an aggressive cancer in which an excess of B-cell lymphocytes are produced.

Besponsa is a targeted therapy by binding to B-cell ALL cancer cells that contain the CD22 antigen, blocking the growth of cancer cells. Nearly 6,000 people in the United States are likely to be diagnosed with the disease this year, and more than 1,400 are projected to die from it, according to estimates from the U.S. National Cancer Institute.

The approval included data from the randomized, open-label, international, multicenter INO-VATE ALL study, created to compare inotuzumab ozogamicin with standard-of-care chemotherapy in 326 patients with relapsed or refractory B-cell precursor ALL. Patients were randomized to receive treatment with Besponsa or an alternative chemotherapy regimen.

"Bespona will help address a significant need for new treatment options in B-cell acute lymphoblastic leukemia, and may help more patients reach stem cell transplant, which provides the best chance for long-term remission", Barrett said. Patients received either the ADC or standard chemotherapy, and the primary endpoint was the proportion of patients who achieved complete response (CR, no evidence of disease with full recovery of blood-cell counts).

Of the 218 evaluated patients, 35.8 percent who received Besponsa experienced CR for a median 8.0 months.

More-common side effects include fatigue, severe bleeding, fever, nausea and headaches.

The FDA granted the approval to Pfizer, following previous approvals for priority review, breakthrough therapy, and orphan drug status. VOD, including fatal and life-threating forms, occurred in 14 percent of patients treated with Besponsa, plus a higher post-HSCT non-relapse mortality rate (39 percent) vs. chemotherapy (23 percent).

The prescribing information for Besponsa includes a warning that severe liver damage (hepatotoxicity), including blockage of veins in the liver (veno-occlusive disease), occurred in some patients who took Besponsa.

Based on the typical duration of treatment, the total cost of the drug will be $168,300, before discounts to purchasers, Pfizer told Reuters.

Other reports by Click Lancashire

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