Uh Oh, Opaxio!: BioBuzz

SEATTLE (TheStreet) -- Cell Therapeutics(CTIC) is having enough trouble with its lymphoma drug pixantrone, yet Thursday morning broke to news that the company's ovarian cancer drug Opaxio is now essentially irrelevant.

Genentech,, the U.S. arm of Swiss drug giant Roche, announced positive results from a phase III study of its blockbuster cancer drug Avastin in patients with advanced ovarian cancer.

With this successful study, Avastin is likely to become the standard of care in ovarian cancer treatment, which leaves little or no room for Cell Therapeutics' Opaxio, even if an ongoing phase III study of the drug in ovarian cancer were also to be successful.

According to Genentech, the phase III study demonstrated that women with advanced ovarian cancer treated with Avastin plus chemotherapy who then continue to take Avastin for so-called "maintenance therapy" lived longer without their tumors growing any larger compared to women treated with chemotherapy alone.

The independent Gynecologic Oncology Group (GOG), a cooperative cancer drug research organization, conducted the Avastin study.

GOG is also running a maintenance treatment study of Opaxio, comparing monthly doses of Opaxio versus placebo in patients with advanced ovarian cancer. Interim results are expected later this year.

But whatever those Opaxio data yield, it won't matter much because of Avastin's benefit for ovarian cancer patients as both as a first-line and maintenance therapy obviates the need for Opaxio.

And with that, Cell Therapeutics loses the key backup cancer drug in its pipeline. More than ever, then, Cell Therapeutics needs to get its lead drug, the lymphoma drug pixantrone, approved by the U.S. Food and Drug Administration. The likelihood of that happening also took a big hit earlier this month.

-- Reported by Adam Feuerstein in Boston.

Follow Adam Feuerstein on Twitter.

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