Top cancer researchers unconvinced by Xyotax trials so far
By Luke Timmerman
Seattle Times business reporter
ORLANDO, Fla. — Dr. Corey Langer zipped through his presentation about Xyotax, and there was no roar of applause at the end, and no public follow-up questions.
At the world's biggest showcase for cancer therapy, the meeting of the American Society of Clinical Oncology, hundreds of physicians and stock analysts listened to Langer talk about how a drug from Seattle-based Cell Therapeutics performed for terminal lung-cancer patients.
When it was over, some walked out quietly shaking their heads, seemingly let down by the results. The gist of the story was already known from reports earlier this spring: All three clinical trials of Xyotax failed to show it could extend patients' lives better than standard chemotherapy. But this was the first time researchers had detailed the results for other cancer specialists.
In a cavernous conventional hall, Langer, of Fox Chase Cancer Center in Philadelphia, said the 400-patient Xyotax trial called Stellar 3 found "there was no significant difference" in patient survival. Patients lived a median time of 7.8 months on Xyotax and carboplatin, a chemotherapy drug, versus 7.9 months for patients on the conventional chemo combination of paclitaxel and carboplatin.
Xyotax, a molecule made of a polymer that binds to paclitaxel, is supposed to be more stable and less toxic in the blood than straight paclitaxel. But in the Stellar 3 trial, there were some worse side effects: slightly more cases of severe peripheral nerve damage and white blood-cell damage in the patients receiving Xyotax.
Those patients did have less hair loss and fewer heart problems, though, and they spent less time getting infusions — an average of 48 minutes versus nearly four hours.
Langer said he's encouraged by another Xyotax trial, Stellar 4, which studied the drug as a single agent, at a lower dose. He said the side effects were significantly better in that setting.
Earlier this month, after unveiling initial Stellar 4 results, Cell Therapeutics said it would pursue Food and Drug Administration (FDA) approval for Xyotax based on its milder side effects and its ability to improve quality of life, rather than any claim of improving patient survival.
Langer said there are "disparate opinions" among his peers about whether the better side effects will be enough for Xyotax to win FDA approval.
Cell Therapeutics Chief Executive James Bianco sounded upbeat after the presentation, saying the Stellar 4 trial "will get this drug approved." He ascribed some of the side effects in Stellar 3 to the carboplatin used in tandem with Xyotax.
Full results on Stellar 4 are expected to be presented in July at the World Conference on Lung Cancer in Barcelona, Spain.
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