Pfizer's once-failed cancer drug wins the FDA's 'breakthrough' tag

Pfizer ($PFE) has found new hope for a former pipeline standout, picking up the FDA's coveted breakthrough therapy designation for a Phase III reclamation project in oncology.

With the agency's designation, Pfizer is guaranteed access to top FDA officials as it develops inotuzumab ozogamicin as a treatment for acute lymphoblastic leukemia, a rare and deadly form of blood cancer. The breakthrough designation is tied to Phase III results disclosed earlier this year in which Pfizer's therapy met its goal of beating out standard care in spurring remissions for ALL patients.

Inotuzumab ozogamic is a so-called antibody-drug conjugate, hitching a cytotoxic compound to an antibody targeting the antigen CD22 and thus shuttling a cancer-killing substance straight to its malignant target. The FDA's breakthrough tag is designed to speed up the development of a treatments for unmet needs, and ALL, which affects about 6,000 Americans a year, carries a 5-year survival rate of less than 10%, Pfizer said.

The treatment's recent success is a welcome reversal for Pfizer and its oncology pipeline. The company had long heralded inotuzumab ozogamicin as a cornerstone of its ambitions in cancer therapy, but the case came apart in 2013 when the drug failed in a Phase III trial against non-Hodgkin's lymphoma, dimming analysts' expectations for its future in other diseases.

Now Pfizer is pressing forward with inotuzumab ozogamicin's Phase III ALL program. April's top-line success in remission rate was one of two primary endpoints. The second goal, overall survival, can't be measured until more patients in the study die. Pfizer plans to submit the results to regulators for approval once the study concludes.

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