- Until recently, there were no treatments for Waldenstroms macroglobulinemia (WM), a rare blood cancer; however, J&J's Imbruvica (ibrutinib) has just received approval for WM as a breakthrough therapy. There is a downside, however: Risk of tumor lysis syndrome (TLS).
- Imbruvica was approved in late 2013 for treatment of chronic lymphocytic leukemia. It is also used to treat Mantle cell lymphoma.
- WM is a type of non-Hodgkin lymphoma that progresses very slowly. This cancer causes B-lymphocytes (B-cells) to grown within bone marrow, lymph nodes, the liver, and the spleen.
Imbruvica could be considered a wonder drug in some respects in that it has utility in treating various blood disorders and cancers. It works by blocking the enzyme that allows abnormal B-cells to grow and divide.
However, there is a notable downside—the risk of TLS that has warranted inclusion of a black box warning on the label. TLS is potentially life threatening, and occurs when chemotherapy kills cancer cells so quickly that the kidneys can't breakdown the byproducts of this process that reside in the blood.
The medical community has become aware of the Imbruvica-associated TLS, as the number of cases have increased. Meanwhile, a competitor product being co-developed by AbbVie and Roche shows efficacy and a lower risk of TLS. Despite the black box warning, analysts are looking for Imbruvica to attain blockbuster status in 2015, with $1 billion in earnings.