How would you manage a patient with minimal residual disease (<1% of CD25 positive cells) six months after completing therapy with 2-CDA for Hairy Cell Leukemia?

This is a challenging question. Patients with HCL who have MRD after treatment with cladribine or pentostatin have shorter remissions than those who have pathologic remissions. Several studies have shown eradication of MRD with subsequent treatment with rituximab. Thus, utilization of rituximab after recovery from cladribine could be an attractive treatment option. Nonetheless, there is no threshold MRD level to know what should trigger subsequent treatment and no prospective data that evaluates...

I completely agree with @Dr. First Last that this is challenging and that there is no clear benefit to acting on minimal residual disease at this interval. I think he outlined the data and the situation very well. While it is tempting to treat this with rituximab, I also favor observation, as it is not clear that late eradication of these residual leukemia cells is helpful; and we are discussing a benefit in terms of time to next treatment in a chronic disease and not an improvement in survival....