Recently the FDA approved Zydelig (idelalisib) for the treatment of patients who experienced a relapse in their chronic lymphocytic leukemia (CLL). For patients with CLL, the approval of idelalisib is intended for use in combination with Rituxan (rituximab). Additionally, the FDA granted accelerated approval for the treatment of patients with relapsed follicular B-cell non-Hodgkin lymphoma (FL) and relapsed small lymphocytic lymphoma (SLL).
The effectiveness of idelalisib for these blood cancers was determined in several clinical trials. For CLL a trial with 220 patients established the safety and effectiveness of the drug by comparing idelalisib and rituximab to the combination of a placebo and rituximab. At the first analysis interval the study was stopped due to the efficacy displayed by the idelalisib and rituximab combination when compared to rituximab by itself. The progression free survival rates of patients who received idelalisib and rituximab was 10.7 months compared to the 5.5 months for patients who received the placebo and rituximab.
Further trials established the safety and effectiveness of idelalisib in the treatment of relapsed FL and SLL patients. 123 participants were evaluated for their overall response rate to idelalisib, with 54% of relapsed FL patients, and 58% of SLL patients achieving an objective response rate, which measures the partial or complete disappearance of cancer after treatment.