Okay, maybe not yet, but it looks like there are lots of new potential candidates for treating HCL that still have yet to be explored. Two posts ago, I mentioned a new third-generation antibody that has the potential of being 5 to 100 times more powerful than Rituxan but hasn't been used to treat HCL yet. I'm hoping some preliminary in-vitro studies will be conducted soon.
Today, I found another one -- a Btk ( Bruton's tyrosine kinase ) Inhibitor, PCI-32765 , that is currently in Phase I clinical trials in patients with B cell malignancies (specifically Non-Hodgkin Lymphoma). Btk is an essential signalling factor needed for the development of B-cells. By inhibiting it, the Btk protein production is blocked and B-cells can't develop. The inspiration for developing the drug was born from a disease, XLA , in which B-cells are absent from the peripheral blood because Btk is not produced due to a Btk gene defect.
What's great about this drug is that it's a pill, taken orally, that inhibits Btk production and thus B-cell production. Since HCL is a B-cell malignancy, I've asked the Hairy Cell Consortium if they are familiar with the drug and whether it may be a candidate for a Phase 1 trial to treat relapsed and refractory HCL patients. I'll let you know if they respond.
"This is a very selective compound for B-cells, and it could represent an important alternative to rituximab therapy for the treatment of B-cell NHL. Other obvious applications include autoimmune disorders such as rheumatoid arthritis and lupus, and Pharmacyclics also has strong preclinical efficacy with PCI-32765 in these disease models," said Dr. Mark Genovese, Professor of Medicine and Co-Chief of the Division of Immunology and Rheumatology at Stanford University Medical Center and member of Pharmacyclics' Scientific Advisory Board. [Taken from Pharmacyclics Press Release dated April 13, 2009]
Wouldn't it be great if we HCL'ers could knock out minimal residual disease (MRD) and then take a pill as maintenance therapy so that we'd never have to worry about it ever coming back?