US biotech Cytokinetics and partner GlaxoSmithKline suffered a setback after their experimental lung cancer drug ispinesib failed to meet its objectives in a Phase II trial.
Ispinesib, a kinesin spindle protein inhibitor, had been given to patients with platinum-sensitive non-small cell lung cancer in the study, but failed to achieve any sort of tumour response, although some patients receiving it showed signs of disease stabilisation.
Earlier, an arm of the study conducted in patients with platinum-refractory NSCLC also failed to show a benefit on response rate, and taken together the two results effectively end hopes that ispinesib would be effective as a single drug therapy for the disease.
But GSK and Cytokinetics still believe ispinesib could have a role when used in combination with other drugs for NSCLC, as it is relatively well-tolerated compared to other drugs that act by blocking cell division, such as the taxanes and vinca alkaloids.
Although it did cause neutropenia, ispinesib did not cause the nerve damage that often limits treatment with other so-called anti-mitotic drugs. Results of Phase Ib trials involving ispinesib are ongoing, said Cytokinetics in a statement.
Meanwhile, the drug is in Phase II trials in various other tumour types, including breast and ovarian cancer. A follow-up, SB-743921, is in Phase I testing.