Pfizer picks up the pieces after its armed antibody crashes in PhIII

Just a few months ago, Pfizer's inotuzumab was a key exhibit in CEO Ian Read's case for a new wave of drugs that could continue to  build on a slate of new approvals for 2012. But that case just got weaker. Pfizer ($PFE) says inotuzumab failed a Phase III study for aggressive CD22+ non-Hodgkin's lymphoma. The monitoring committee concluded that inotuzumab in combination with rituximab was not going to deliver the data needed on overall survival.

Pfizer, though, hasn't given up on the program for inotuzumab. It's still in the clinic for hematologic malignancies and Pfizer wants to sort through the lymphoma data to see if they can get a better idea of other ways it could prove effective.

Inotuzumab is an interesting failure. It's part of a new wave of antibody-drug conjugates that's following a trail blazed by T-DM1, an armed antibody directed against breast cancer. In this case the antibody is built to target CD22, an antigen commonly found on malignant B-cells. Once it docks on the cancerous cells it bombs the cancer with the highly toxic calicheamicin. Now Pfizer researchers have to go back and find out why it didn't work in this instance. 

"We are working to better understand the findings from this review to determine if there are any patterns of outcome that may help us gain greater understanding of the potential effect of inotuzumab ozogamicin in specific patient subsets within the heterogeneous patient population enrolled in this trial," said Dr. Mace Rothenberg, senior vice president of clinical development and medical affairs for Pfizer's oncology business unit. "Hematologic cancers are a complex group of diseases, with more than 70 different types of lymphomas, leukemias or myelomas that require unique treatment options. We remain committed to evaluating inotuzumab ozogamicin in patients with hematologic malignancies."

The setback for Pfizer follows the company's three-year effort to chop billions out of its R&D budget. But even after the downsizing Pfizer plans to continue to spend between $6.5 billion and $7 billion a year on research. And the pharma giant counted an impressive 5 new drug approvals for 2012 after a lengthy drought on the regulatory front. 

- here's the press release

Special Reports: Pfizer - The Biggest R&D Spenders In Biopharma | Ian Read - The 25 most influential people in biopharma today

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