Cyclacel's cancer drug isn't working in Phase III, but that won't stop the trial

Cyclacel Pharmaceuticals' ($CYCC) in-development leukemia drug has little chance of meeting its primary goal in a late-stage study, independent advisers said. But, because the treatment isn't leading to serious side effects, the company is keeping the trial running anyway.

After an interim analysis of 486-patient trial on Cyclacel's sapacitabine, the study's data and safety monitoring board informed management that the drug hit its prespecified futility boundary, meaning it's unlikely to significantly improve survival compared to intravenous decitabine in acute myeloid leukemia. But the independent committee also charted no safety concerns, Cyclacel said, citing no reason to discontinue treatment.

And so the biotech, despite being "surprised and disappointed" by sapacitabine's futility, is going to keep the study going until it reaches its planned conclusion of 424 patient deaths, Vice President Judy Chiao said. That should take place some time between the second half of 2015 and first half of 2016, Cyclacel said.

The study, dubbed SEAMLESS, ran into trouble quickly, the company said. Of the 247 trial deaths recorded so far, 70% of them came within 6 months of enrollment, according to Cyclacel, stacking the deck against future success.

But it's not impossible, Cyclacel cautions. Decitabine, the active comparator in SEAMLESS, failed to demonstrate a statistically significance versus chemotherapy in its AML trial, and that didn't prevent developer Johnson & Johnson ($JNJ) from winning approval in that indication, the company said. (Eisai, which held U.S. rights to the drug, failed to convince the FDA to approve it for AML.)

Cyclacel CEO Spiro Rombotis

"Absence of early benefit in this Phase III study does not preclude emergence of a late benefit with longer follow up," CEO Spiro Rombotis said in a statement. "As the well-being of patients is a paramount concern and the DSMB recommends that patients remain on study, we are encouraged that patients on the sapacitabine regimen are not disadvantaged to those on the control arm."

Investors were far less optimistic, sending Cyclacel's shares more than 70% earthward on Tuesday morning, saddling the company to an all-time low valuation.

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