Idelalisib (trade name: Zydelig) has been approved in Germany since September 2014 for the treatment of chronic lymphocytic leukemia (CLL) in adults. The drug is combined with rituximab or ofatumumab.

CLL is a rare type of cancer. It typically arises when B cells of the immune system mutate and start multiplying uncontrollably in the blood, bone marrow and lymphatic system. If CLL reaches an advanced stage, it may also spread to organs such as the liver or spleen.

Idelalisib is a treatment option in the following cases:

  • As a subsequent treatment in people who have had unsuccessful treatment for CLL and are able to have chemotherapy
  • As a subsequent treatment in people who have had unsuccessful treatment for CLL and are not able to have chemotherapy
  • As first-line treatment in people whose leukemia cells have certain genetic traits (17p deletion or TP53 mutation) and who are not able to have other treatments A 17p deletion means that a particular gene segment is missing, while a TP53 mutation means that a specific gene is defective.

Idelalisib inhibits an enzyme that B cells need for reproduction and survival. The drug aims to prevent CLL from progressing by stopping the leukemia cells from multiplying.


The drug is taken twice a day in tablet form (150 mg). The dosage depends on how well the patient tolerates the drug and on the side effects, and can be adapted individually. Treatment is terminated if the disease progresses or if very severe side effects arise.

Other treatments

Depending on their situation, adults with CLL may have individually optimized chemotherapy, treatment with the drug ibrutinib, or best supportive care (BSC). Supportive care should be tailored to individual needs, relieve symptoms such as pain, and improve quality of life.


In 2016, the Institute for Quality and Efficiency in Health Care (IQWiG, Germany) wanted to look into the advantages and disadvantages of idelalisib compared with the standard treatments for people with CLL.

However, the manufacturer did not provide suitable data about any of the patient groups so it wasn’t possible to carry out an assessment.

More information

This information summarizes the main results of reviews produced by the Institute for Quality and Efficiency in Health Care (IQWiG, Germany). The reviews were commissioned by the German Federal Joint Committee (G-BA) as part of the “early benefit assessment of medications.” On the basis of this review and the hearings received, G-BA passed a resolution on the added benefit of idelalisib (Zydelig).