Seattle Genetics will shelve AML drug after PhIIb failure

Seattle Genetics has decided to put its therapy for acute myloid leukemia--lintuzumab, or SGN-33--on the shelf after revealing this morning that the drug failed a Phase IIb study. Analysts quickly concluded that while the trial failure was a setback for the developer, the primary focus would remain on Seattle Genetics' (SGEN) lead therapy SGN-35, which will deliver key data in a matter of weeks and could be submitted for an approval next year.

"We're disappointed about the data, but this was the right study, it was executed very well and gave us a clear answer," Seattle Genetics CEO Clay Siegall told both TheStreet and Xconomy in the lead-up to this morning's release. Investors, however, were hardly in a party mood after seeing the answer. SGEN's shares slid 13.5 percent in a matter of minutes this morning, but by Monday afternoon the stock had cut most of those losses and was trading down about 4 percent.

Lintuzumab was always up against tough odds. The fast-developing AML is one of the hardest targets in the cancer field. The antibody was combined with low-dose chemotherapy and provided to a group of patients over 60. But it failed to demonstrate improved survival when compared to a group of patients receiving chemo alone.

"We are on track to report top-line data from two brentuximab vedotin clinical trials within the next six weeks, positioning us for a regulatory submission in the first half of 2011," said Siegall in a statement. "In addition, our strong financial position allows us to continue to invest in advancing our multiple other programs, including two antibody-drug conjugates, SGN-75 and ASG-5ME, which are both in ongoing phase I clinical trials."

- here's the SGEN release
- see the Reuters story
- read TheStreet's report
- and here's the story from Xconomy