The European Medicines Agency (EMA) has recommended extending the use of Imbruvica (ibrutinib) for treatment of patients with Waldenstrom’s macroglobulinaemia. The medicine is indicated for adults who have received at least one prior therapy or as a first line treatment for patients unsuitable for chemo-immunotherapy.
Waldenström macroglobulinemia (also known as lymphoplasmacytic lymphoma or immunocytoma) is a rare, indolent (slow-growing) B-cell lymphoma that occurs in less than two percent of patients withnon-Hodgkin lymphoma. These abnormal cells produce large amounts of an immunoglobulin called IgM, which can make the blood thicker than normal. This cancer usually begins in people over 60 years of age.
Imbruvica was first authorised in the European Union in October 2014 for the treatment of two other types of blood cancer: chronic lymphocytic leukaemia and mantle cell lymphoma. Imbruvica represents a novel strategy in the treatment of malignancies involving B lymphocytes. The active substance contained in Imbruvica, ibrutinib, works by blocking an enzyme called Bruton’s tyrosine kinase (Btk), which has a key role in the survival of B lymphocytes and their migration to the organs where these cells normally divide. By blocking Btk, ibrutinib decreases survival and migration of B lymphocytes, thereby delaying the progression of the cancer.
The recommendation from EMA’s Committee for Medicinal Products for Human Use (CHMP) is based on the results of a phase 2 study in 63 patients with previously treated Waldenstrom’s macroglobulinaemia. Around 90% of the patients treated with Imbruvica responded positively to the treatment and approximately 80% of patients were alive without disease progression after 18 months. The adverse events reported during the clinical trial were similar to those observed in the already approved indications of Imbruvica. They include events affecting the blood and bone marrow such as neutropenia and thrombocytopenia.
Imbruvica received an orphan designation for this indication from the Committee for Orphan Medicinal Products (COMP) in 2014. The opinion adopted by the CHMP at its May 2015 meeting is an intermediary step on Imbruvica’s access to patients with Waldenstrom’s macroglobulinaemia. The CHMP opinion will now be sent to the European Commission for the adoption of a decision to change the marketing authorisation.
