The European Commission has granted marketing authorization for Zydelig ( Idelalisib ), 150 mg tablets, a first-in-class oral treatment for two incurable blood cancers, chronic lymphocytic leukemia ( CLL ) and follicular lymphoma ( FL ).
For the treatment of chronic lymphocytic leukemia, Zydelig has been approved for use in combination with Rituximab ( MabThera, Rituxan ) for patients who have received at least one prior therapy; or as first-line treatment in the presence of 17p deletion or TP53 mutation in patients unsuitable for chemo-immunotherapy.
For the treatment of follicular lymphoma, Zydelig has been approved as a monotherapy in patients who are refractory to two prior lines of treatment.
Zydelig inhibits PI3K delta, a protein that is overexpressed in many B-cell malignancies and plays a role in the viability, proliferation and migration of these cancer cells.
Chronic lymphocytic leukemia and follicular lymphoma are slow-growing incurable blood cancers that can lead to life-threatening complications such as anemia, serious infection and bone marrow failure requiring treatment.
The goal of therapy for patients with these cancers is to improve overall survival and quality of life.
Although chemo-immunotherapy is initially used to treat both chronic lymphocytic leukemia and follicular lymphoma, relapse is common and many patients run out of treatment options to treat the disease as it progresses.
Further, a chromosome 17 deletion - del (17p) or a mutation in the TP53 gene in CLL cells have been linked to poor prognosis and a more rapid disease progression. For these patients most conventional chemotherapy treatments are not effective and deliver poor responses of relatively short duration. Treatment options are limited for these patients.
The approval of Zydelig in chronic lymphocytic leukemia is supported primarily by data from a randomized, placebo-controlled phase 3 trial ( Study 116 ) of Idelalisib plus Rituximab in 220 patients with relapsed chronic lymphocytic leukemia who were not able to tolerate standard chemotherapy.
Study 116 was stopped early in October 2013 by an independent Data Monitoring Committee due to a highly statistically significant benefit in progression-free survival ( PFS ) in the Idelalisib plus Rituximab arm compared with the Rituximab only treatment arm ( hazard ratio, HR= 0.18; p less than 0.0001 ).
Median progression-free survival was not reached in the Idelalisib plus Rituximab arm and was 5.5 months in the placebo plus Rituximab arm.
The approval in follicular lymphoma, the most common type of indolent non-Hodgkin lymphoma ( iNHL ), is supported by data from a single-arm phase 2 study ( Study 101-09 ) of Idelalisib monotherapy in 125 iNHL patients refractory to Rituximab and alkylating-agent-containing chemotherapy.
In the 72 patients with follicular lymphoma in this study, Idelalisib achieved an overall response rate of 54% and the median duration of response was not reached.
Adverse drug reactions ( including grade greater than or equal to 3 ) reported in clinical studies in patients with hematological malignancies receiving Zydelig included infections, neutropenia, pneumonitis, diarrhea / colitis, increased transaminase ( indicator of liver function ), rash and pyrexia.
Zydelig is an oral inhibitor of phosphoinositide 3-kinase ( PI3K ) delta, a protein that plays a role in the activation, proliferation and viability of B cells, a critical component of the immune system.
PI3K delta signalling is active in many B-cell leukemias and lymphomas, and by inhibiting the protein, Zydelig blocks several cellular signalling pathways that drive B-cell viability.
In the European Union ( EU ), Zydelig is indicated in combination with Rituximab for the treatment of adult patients with chronic lymphocytic leukemia who have received at least one prior therapy; or as first-line treatment in the presence of 17p deletion or TP53 mutation in patients unsuitable for chemo-immunotherapy.
Zydelig has also been approved as a monotherapy for the treatment of adult patients with follicular lymphoma that is refractory to two prior lines of treatment.
Zydelig is administered orally twice-daily and is available as 150 mg and 100 mg dose strengths. ( Xagena )
Source: Gilead, 2014