Cyclacel Pharmaceuticals Inc said its lead experimental drug did not help elderly patients with acute myeloid leukemia live longer in a late-stage study.
The drug developer's stock was down about 19 percent in light premarket trading on Thursday.
The treatment, sapacitabine, was tested on patients aged 70 years or more who are not candidates for chemotherapy or have refused it, Cyclacel said.
An improvement in remission rates - a secondary goal - was there for patients who had discontinued therapy at the time of analysis, the company added.
Cyclacel said it was going to reevaluate its continued investment in sapacitabine for blood cancer.
(Reporting by Akankshita Mukhopadhyay in Bengaluru; Editing by Savio D'Souza and Shounak Dasgupta)