Comparing overall survival (OS) outcomes in patients with newly diagnosed chronic lymphocytic leukemia (CLL) with normal life expectancy.

Abstract

7 Background: CLL is an orphan hematologic malignancy but also accounts for the most common adult leukemia in the Western Hemisphere, with a median age at diagnosis of 72 years. Median OS for symptomatic, treatment-naïve, elderly patients with CLL is approximately 5.3 years (CLL5; Eichhorst, et al. Blood 2009), whereas the life expectancy of a 72 year old (yo) is around 12 years (US Life Tables, 2006). Ibrutinib, an oral, first-in-class, covalent Bruton’s tyrosine kinase inhibitor, significantly improves OS. Early results from a phase 1/2 study in treatment-naïve elderly patients with CLL (PCYC-1102; median age, 71 years) suggest that single-agent ibrutinib extends OS, with survival at 3 years of approximately 97% (Byrd, et al. Blood 2015). Here we compare the OS in newly diagnosed patients with CLL treated with single-agent ibrutinib or chlorambucil with the normal life expectancy of a 72 yo adult. Methods: OS outcomes for patients treated with chlorambucil from the CLL5 study conducted in Germany (Eichhorst, et al. Blood 2009) were compared with long-term OS results from PCYC-1102 (Byrd, et al. Blood 2015). Life expectancy data were obtained from US Life Tables. Results: Results from CLL5 suggest that single-agent chlorambucil has a median OS of 5.3 years (median age, 71 years), with approximately 75% of patients alive at 3 years. The median OS for ibrutinib has not been reached (median follow-up, 3 years), with an estimated progression-free survival of 96% and OS of 97% at 3 years. Life expectancy for a 72 yo healthy person at 3 years is approximately 95%. Naïve comparisons suggest that single-agent ibrutinib may be altering the natural history of CLL, providing a longer OS versus chlorambucil and a similar OS as expected in a 72 yo in the general population. Conclusions: Treatment outcomes in CLL are fundamentally changing with the advent of new targeted therapies. This indirect naïve comparison between ibrutinib-treated patients and a general population suggests we may be moving from palliative care for elderly patients with CLL to chronic care management. Implications for chronic care management of patients with CLL will be discussed.