Assessing Response With Novel Agents in CLL

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In addition to the already approved new agents, such as ibrutinib and idelalisib, several novel therapies are under exploration as potential treatments for patients with chronic lymphocytic leukemia (CLL), including venetoclax (ABT-199) and duvelisib (IPI-145), suggests John C. Byrd, MD.

As a single agent, venetoclax demonstrated an objective response rate (ORR) of 79%, with a 22% complete response rate. In relapsed/refractory CLL, single-agent duvelisib demonstrated an ORR of around 50%. Both of these agents are under exploration in phase III studies for patients with CLL and other types of B cell malignancies.

With the high level of activity seen with newly approved and investigational therapies in CLL, the next question facing researchers is the measurement of response. Assays that assess minimal residual disease (MRD) have shown promise as prognostic tools of long-term outcomes for patients with CLL.

Trials have suggested that patients with MRD-negativity in the peripheral blood have better outcomes than patients who are in complete remission but are MRD-positive. However, Thomas J. Kipps, MD, suggest that bone marrow MRD assessment is a much more reliable way of measuring MRD compared with peripheral blood tests. In addition, the prognostic value of MRD will vary based on which therapy has been administered.

CT and MRI scans can be used to ascertain the size of lymph nodes and to assess the spleen. Additionally, scans can be used to detect Richter's transformation.