The U.S. Food and Drug Administration has approved Imbruvica (ibrutinib) capsules for first-line treatment of patients with chronic lymphocytic leukemia (CLL). Imbruvica targets and blocks Bruton's tyrosine kinase (BTK), inhibiting cancer cell survival and spread.
Imbruvica has previously been approved for the treatment of Waldenstrom's macroglobulinemia, the treatment of patients with mantle cell lymphoma who have received one prior therapy (OT 12/10/13 issue), and patients with chronic lymphocytic leukemia who carry a deletion in chromosome 17 (OT 3/10/14 issue and 8/25/14 issue).
This expanded indication for Imbruvica for the treatment of patients with CLL is based on safety and efficacy data from the multicenter, open-label, Phase III RESONATE-2 trial of 269 patients with treatment-naive CLL or small lymphocytic leukemia. The patients were randomized to receive Imbruvica (420mg orally) once daily until progression or unacceptable toxicity or chlorambucil (0.5-0.8mg/kg) on days one and 15 of each 28-day cycle for up to 12 cycles (with an allowance for intrapatient dose increases up to 0.8mg/kg based on tolerability).
Median progression-free survival for patients treated with Imbruvica was not reached compared with 18.9 months for patients treated with chlorambucil. Additionally, the overall response rate for patients treated with Imbruvica was 82.4 percent compared with 35.3 percent for patients treated with chlorambucil. And five patients treated with Imbruvica (3.7%) had a complete response compared with two patients treated with chlorambucil (1.5%).
The safety of Imbruvica for this study was consistent with previously reported studies. Warnings and precautions include hemorrhage, infections, cytopenias, atrial fibrillation, hypertension, second primary malignancies, tumor lysis syndrome, and embryo-fetal toxicity, according to a news release from the drug companies marketing the drug, Janssen and AbbVie. The most common adverse events were diarrhea, musculoskeletal pain, cough, and rash. The most common grade 3/4 adverse event was pneumonia.
Clinical Quick Facts
Drug: Imbruvica (ibrutinib)
Approved Indication: First-line treatment of patients with chronic lymphocytic leukemia (CLL)
Serious Side Effects: Pneumonia
Common Side Effects: Diarrhea, musculoskeletal pain, cough, and rash