Ibrutinib for Waldenstrom’s – pro
Ibrutinib is an oral Bruton’s tyrosine kinase (BTK) inhibitor. The effectiveness and safety of ibrutinib alone or in combination with other treatments is being studied in several B-cell malignancies. There is evidence that it is effective for CLL. Most recently, in January of 2014, Lancet published a positive study in elderly patients with CLL and FFA approval for CLLwas then granted.
There is much less evidence to support thisdrug for Waldesntrom’s. It rapidly reduced serum immunoglobulin M (IgM) levels and improved hematocrit levels in patients with relapsed or refractory Waldenström’s macroglobulinemia (WM), and the responses to ibrutinib were durable, as reported by Steven Treon, MD, PhD, at the 55th annual meeting of the American Society of Hematology. A major response to ibrutinib was less likely in patients who harbored a WHIM-like mutation of CXCR4, present in about 30% of patients with WM. Several small studies with similar results are referenced.
The effectiveness of ibrutinib alone or in combination with other treatments is being studied in several B-cell malignancies, including chronic lymphocytic leukemia/small lymphocytic lymphoma, mantle cell lymphoma, diffuse large B-cell lymphoma, follicular lymphoma, Waldenstrom’s macroglobulinemia and multiple myeloma. To date six Phase III trials have been initiated with ibrutinib and a total of 31 trials are currently registered on www.clinicaltrials.gov.
Nevertheless, NCCN has included ibrutinib in its guidelines for salvage and it should be considered medically necessary off-label,.
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