New drug shows sustained benefit at 2 years in rare blood cancer

the Oncology Nurse Advisor take:

Recent results from a clinical trial show that ibrutinib (Imbruvica) continued to control Waldenstrom macroglobulinemia, a rare blood cancer.

In addition, 95% of patients receiving the newly approved drug are experiencing progression-free survival 2 years after initiating treatment. When progression did occur, it began at a median of 9.6 months after the start of treatment.

Waldenstrom macroglobulinemia is caused by an abnormality in the B lymphocytes in bone marrow that causes the overproduction of IgM, an immunoglobulin protein that thickens the blood.

It is driven by the MYD88 and CXCR4 genetic mutations. MYD88 mutation triggers abnormal activity of Bruton’s tyrosine kinase. Ibrutinib targets a pathway involving Bruton’s tyrosine kinase protein.

The trial included 63 patients who had received at least one prior treatment. The drug is administered as an oral drug taken daily.

Treatment continued until the disease worsened or unacceptable toxic effects occurred. Response rate in the study refers to the degree of reduction in IgM in the blood.