Ibrutinib For CLL Receives Accelerated FDA Approval
Janssen Biotech, Inc. and Pharmacyclics’ ibrutinib has received accelerated approval from the U.S. Food and Drug Administration (FDA) for expanded use. Ibrutinib (marketed as Imbruvica) can now be prescribed to patients with chronic lymphocytic leukemia (CLL) who have previously received at least one therapy.
Richard Pazdur, MD, Director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research, said, “Today’s approval provides an important new treatment option for CLL patients whose cancer has progressed despite having undergone previous therapy. The FDA completed its review of Imbruvica’s new indication under the agency’s accelerated approval process, which played a vital role in rapidly making this new therapy available to those who need it most.”
CLL is the most frequently occurring form of leukemia in adults. The disease affected 15,580 adults in 2013 and claimed 4,580 lives.
The FDA approved the expanded use of ibrutinib based on a Phase 1b-2 open-label, multi-center study that determined the pharmacokinetics, pharmacodynamics, safety, and efficacy of Imbruvica in patients with relapsed or refractory CLL or small lymphocytic lymphoma. The study involved 48 patients diagnosed with CLL on an average of 6.7 years prior to the trial.
The patients received orally administrated 420 mg ibrutinib to the point of unacceptable toxicity or until their disease progressed. Cancer shrinkage was observed in 58% of participants over the course of 5.6 to 24.2 months.
The drug works by inhibiting the downstream protein Bruton’s tyrosine kinase (BTK), which has been shown to promote cell survival through activation of Akt, ERK, and the NK-kB signaling pathways along with the activation of cytokine-driven homing and adhesion of B-cells. Ibrutinib is an orally bioavailable BTK inhibitor notable for its lack of toxic effects, but still has yet to establish impact on survival or CLL-related symptoms in patients.
Trials for Imbruvica are still ongoing, which include randomized trials comparing the drug’s safety profile with existing CLL therapies including two phase III studies (RESONATE; ClinicalTrials.gov number NCT01578707 and RESONATE-2, NCT01722487).
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