Researchers at Gilead Sciences say they are unblinding the ongoing drug trial of Zydelig. The reason, announced in a recent press release, was because its leukemia drug was working so well that it should be made available to patients in the trial who were receiving standard treatment without the drug.
When used in combination with standard therapy for chronic lymphocytic leukemia (CLL), Zydelig increased progression-free survival as well as overall survival. Progression-free survival refers to the length of time, during and after treatment, that a patient lives with the cancer without it getting worse.
The Phase III randomized, double-blind, placebo-controlled study was designed to investigate the efficacy and safety of Zydelig in combination with Bendamustine and Rituximab an antibody that has previously been used in treated CLL compared to those receiving a placebo in addition to standard therapy.
The test group consisted of 416 patients who had previously treated for CLL. A interim analysis revealed a statistically significant benefit to patients who were in the study arm that got Zydelig plus standard therapy in progression-free survival. So much so that an independent Data Monitoring Committee recommended that the study be unblinded, thus allowing the CLL patients within the placebo group to share in the clinical benefit.
Zydelig was approved by the FDA in 2014 for use in cases of relapsed CLL in combination with Rituxan, as well as for two specific types of relapsed non-Hodgkin's lymphomas. Researchers noted that the safety profile of the drug in the current trial is similar to that of prior studies.
Of the 54,270 new cases of leukemia in 2015, CLL accounts for approximately one quarter of them, according to the the American Cancer Society. The organization's estimates for 2015 indicate 14,620 new cases of CLL in the U.S., as well as 4,650 deaths attributable to CLL. The disease primarily affects adults, with an average age at diagnosis being 71 years.