Patients with chronic lymphocytic leukemia (CLL) who have mild residual lymphadenopathy are more likely to have a partial response (PR) after treatment with venetoclax-obinutuzumab (VenG), a study found. This finding provides a potential prognostic indicator for poor prognosis in patients VenG-treated patients with CLL.
Results of this study were presented by Othman Al-Sawaf, MD, of the University Hospital Cologne, at the 62nd American Society of Hematology Annual Meeting & Exposition. In the study, Dr. Al-Sawaf and colleagues randomly assigned 432 patients with previously untreated CLL to 12 cycles of venetoclax with six cycles of obinutuzumab (n=216) or 12 cycles of chlorambucil with six cycles of obinutuzumab (n=216). The primary endpoint of the study was progression-free survival (PFS).
Over the median follow up of 39.6 months, approximately 45.8% of patients in the VenG arm experienced a complete response (CR), whereas 36.1% of patients had a PR at the end of treatment. Around 55.2% of patients with PR and undetectable minimal residual disease (MRD) had a PR because of residual lymphadenopathy >15 mm and <72 mm.
No bone marrow biopsy had been performed in 18 patients. Due to the missing bone marrow biopsy, the investigators were unable to identify a CR.
A total of 90 patients with a CR at the end of treatment had undetectable MRD levels in peripheral blood, and 13 of these patients were MRD-positive. There was no difference between patients with undetectable MRD compared with patients with undetectable MRD and CR in terms of PFS. In contrast, patients with undetectable MRD and PR had a more prolonged PFS compared with patients with detectable MRD and CR.
The researchers concluded that their data show patients with a PR following VenG treatment experience a similar outcome as patients with CR when undetectable MRD is achieved.