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Gilead Sciences, Inc.
The European Medicines Agency’s Pharmacovigilance Risk Assessment Committee (PRAC) has completed its review of the PI3Kδ inhibitor idelalisib (Zyedelig) and concluded that the drug’s benefits outweigh its risks in the treatment of chronic lymphocytic leukemia (CLL) and follicular lymphoma.
However, the PRAC also confirmed that the drug increases the risk of serious infections, including Pneumocystis jirovecii pneumonia.
And the committee updated its previous recommendations to manage this risk.
The PRAC’s recommendations will now be sent to the Committee for Medicinal Products for Human Use, which will adopt the EMA’s final opinion. The final stage of the review procedure is the adoption by the European Commission of a legally binding decision applicable in all member states of the European Union (EU).
About idelalisib
In the EU, idelalisib is approved for use in combination with rituximab to treat adults with CLL who have received at least 1 prior therapy or as first-line treatment in the presence of 17p deletion or TP53 mutation in CLL patients unsuitable for chemo-immunotherapy.
Idelalisib is also approved as monotherapy for adults with follicular lymphoma that is refractory to 2 prior lines of treatment.
About the review
The PRAC’s review of idelalisib began after a higher rate of serious adverse events, including deaths, was seen in 3 clinical trials evaluating the addition of idelalisib to standard therapy in first-line CLL and relapsed indolent non-Hodgkin lymphoma (NHL).
Most of the deaths were related to infections such as Pneumocystis jirovecii pneumonia and cytomegalovirus infection. Other excess deaths were related mainly to respiratory events.
The NHL studies (NCT01732926 and NCT01732913) included patients with disease characteristics different from those covered by the currently approved indications for idelalisib and investigated combinations of drugs that are not currently approved in the EU—idelalisib plus rituximab for NHL and idelalisib plus bendamustine and rituximab for NHL.
The CLL trial (NCT01980888) involved patients who had not received previous treatment, some of whom had the 17p deletion or TP53 mutation. However, the trial also investigated a combination of drugs not currently approved in the EU—idelalisib plus bendamustine and rituximab.
PRAC’s recommendations
The PRAC noted that, although the aforementioned trials did not all use idelalisib as currently authorized, the risk of serious infection is considered relevant to the authorized use.
Therefore, the PRAC recommends that all patients treated with idelalisib receive antibiotics to prevent Pneumocystis jirovecii pneumonia during treatment and for up to 2 to 6 months after treatment has stopped.
Patients should also be monitored for infection and have regular blood tests for white cell counts because low counts can increase their risk of infection.
Furthermore, idelalisib should not be started in patients with a generalized infection.
At the beginning of its review, the PRAC had said idelalisib should not be started in patients with previously untreated CLL and 17p deletion or TP53 mutation.
Now, the PRAC has concluded that idelalisib can be initiated in these patients, provided they cannot take any alternative treatment and that the recommended measures to prevent infection are followed.
