The authorization applies to patients with relapsed or refractory CD22-positive B-cell acute lymphoblastic leukemia, or B-ALL. It covers Philadelphia chromosome positive (Ph+) patients who have failed to respond to at least one treatment with tyrosine kinase inhibitors. The approval also covers Besponsa as a treatment for adults with Philadelphia chromosome negative (Ph-) B-ALL.
“The European Commission’s approval of Besponsa represents an important milestone for patients, the oncology community and Pfizer,” Dr. Andreas Penk, regional president of Pfizer Oncology, said in a press release. “This is the first approval for Besponsa, and provides patients in the EU who are battling an especially hard-to-treat leukemia with a new treatment option beyond chemotherapy.”
Pfizer and Celltech, now known as UCB, developed Besponsa as an antibody-drug conjugate. The therapy, formerly known as inotuzumab ozogamicin, targets a cell surface molecule called CD22. It releases a toxic agent inside the cell, triggering a series of events that leads to the cell’s death.
Pfizer said the EU approval was based partly on results of the Phase 3 INO-VATE ALL clinical trial (NCT01564784), which compared Besponsa’s effectiveness, safety, and tolerability with those of standard of care chemotherapy.
The trial covered 326 adult patients with relapsed or refractory B-ALL. They were randomized to receive either Besponsa or one of three other stand-alone or combo therapies. One treatment option was fludarabine plus cytarabine with G-CSF (FLAG), the second was high-dose cytarabine (HIDAC), and the third cytarabine plus mitoxantrone.
Almost 81 percent of those who received Besponsa achieved complete remission, almost three times the 29 percent of those who received standard chemo, researchers said.
Also, the median time for a patient’s disease to progress increased from 1.8 months with standard chemotherapy to five months with Besponsa. And median overall survival was 7.7 months in the Besponsa group, compared with 6.7 in the chemotherapy arm.
Researchers published the results in The New England Journal of Medicine. The article was titled “Inotuzumab Ozogamicin versus Standard Therapy for Acute Lymphoblastic Leukemia.”
“Acute lymphoblastic leukemia that has recurred or is refractory following first-line therapy is a rare and rapidly progressive disease with poor prognosis,” said Professor David Marks of Bristol, England. “The approval of Besponsa provides a much-needed treatment option for physicians and patients alike that may help improve outcomes for some of the most vulnerable leukemia patients in Europe,” said Marks, who is with the Department of Hematology at University Hospitals Bristol’s NHS Foundation Trust facility.
The U.S. Food and Drug Administration has granted Besponsa breakthrough therapy designation. In March of this year, Pfizer filed a Biologics License Application requesting that the FDA approve Besponsa as a treatment for adults with relapsed or refractory B-ALL. The FDA is giving the application priority review, a status aimed at accelerating its approval.