FDA accepts Pfizer’s blood cancer candidate for speedy review

The drug could be approved as early as August in the U.S. if all goes to plan for Pfizer.

Pfizer said the FDA has given its experimental leukemia med inotuzumab ozogamicin a priority review as it gets to work on assessing the medication for approval, which could come as early as August.

The U.S. Big Pharma is hoping for the green light in adult patients with relapsed or refractory B-cell precursor acute lymphoblastic leukemia (ALL).

This new drug is aiming to build on its blood cancer offering Bosulif (bosutinib), which has an FDA approval for chronic myelogenous leukemia (CML), a blood and bone marrow disease.

Pfizer's latest breakthrough-designated drug, which is also being looked at by the EMA in Europe, has seen its submissions based on the phase 3 INO-VATE 1022 trial, which looked at relapsed or refractory B-cell ALL and compared inotuzumab ozogamicin to standard-of-care chemo.

The data from over 300 patients, published last summer in the NEJM, showed it hit its first primary endpoint of complete response (80.7% versus 29.4%) but failed to reach statistical significance in its second primary endpoint of overall survival (OS).

Pfizer did say at the time, however, that OS “demonstrated a strong trend toward longer OS,” with the median overall survival at 7.7 months for Pfizer’s med versus 6.7 months. The two-year OS rate for inotuzumab ozogamicin was 23% compared to chemotherapy at just 10%.

Progression-free survival, meanwhile, was significantly longer in the inotuzumab ozogamicin group (median 5 months versus 1.8 months).

On the safety side, veno-occlusive liver disease was a “major adverse event associated with inotuzumab ozogamicin,” the trial data showed. This form of the liver disease of any grade occurred in 15 patients (11%) who received inotuzumab ozogamicin, and in 1 patient (1%) who received standard therapy.

The med, an antibody-drug conjugate comprised of a monoclonal antibody, targets CD22, a cell surface antigen expressed on nearly all B-cell malignancies. The candidate originally came out of a collaboration between Pfizer and Celltech (now UCB), although Pfizer has sole responsibility for all manufacturing and clinical development activities.

“ALL that has recurred after, or is refractory to, first-line therapy is a rapidly progressing and deadly disease,” said Mace Rothenberg, chief development officer of oncology at Pfizer’s global product development.

“Based on the positive results of the INO-VATE 1022 phase 3 trial, we believe inotuzumab ozogamicin, if approved, represents a new treatment option for adult patients with relapsed or refractory B-cell precursor ALL.”