First therapy approved for rare blood cancer

FDA granted accelerated approval for ibrutinib (Imbruvica, Janssen, Pharmacyclics, an AbbVie Company), the first treatment for patients with a certain type of lymphoma.

Imbruvica is for patients with marginal zone lymphoma (MZL) who require systemic therapy and have received at least 1 prior anti-CD20-based therapy. While accelerated approval was granted for this indication based on overall response rate (ORR), continued approval for the indication may be contingent upon verification of clinical benefit in a confirmatory trial.

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"Patients with relapsed/refractory marginal zone lymphoma are in critical need of treatment options to manage living with this rare, serious blood cancer," said Ariela Noy, MD, hematologic oncologist at Memorial Sloan Kettering Cancer Center in New York and lead investigator of the study, in a Janssen statement. "This approval of Imbruvica represents a welcome new oral option for the MZL community and is the first approved therapy for these patients." 

MZL is a slow-growing B-cell lymphoma occurring in white blood cells (lymphocytes) at the edges of lymph nodes and various tissues, including the stomach, salivary glands, thyroid gland, eyes, lungs and spleen. MZL accounts for approximately 12% of all cases of non-Hodgkin's lymphoma in adults.

The approval is based on results from a multicenter, phase 2 trial assessing the safety and efficacy of Imbruvica in 63 patients with MZL who received at least 1 prior therapy, including all 3 subtypes: mucosa-associated lymphoid tissue, nodal MZL (NMZL), and splenic MZL (SMZL).

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Patients taking Imbruvica had a 46% ORR. While 3.2% of patients achieved complete responses (CR), 42.9% achieved partial responses (PR).  Efficacy was observed across all three MZL subtypes (ORR of 46.9%, 41.2%, and 50% for MALT, nodal and splenic subtypes, respectively). The median time to initial response was 4.5 months.

Warnings and precautions for Imbruvica include hemorrhage, infections, cytopenias, atrial fibrillation, hypertension, second primary malignancies, tumor lysis syndrome and embryo-fetal toxicity. Common adverse events include thrombocytopenia, fatigue, anemia, diarrhea, bruising, musculoskeletal pain, hemorrhage, rash and nausea. 

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