Background: Chronic lymphocytic leukemia (CLL) is an orphan disease that primarily affects the elderly. The majority of symptomatic patients eligible for frontline treatment are unfit for fludarabine based chemoimmunotherapy. Historical treatment includes chlorambucil (Chl), bendamustine/rituximab (BR), and chlorambucil/rituximab/ChlR combination. Clinical guidelines now recommend the use of novel agents, such as ibrutinib (Ibr), in both frontline and relapse settings and other novel agents, such as idelalisib (with rituximab), in relapse settings. Despite compelling clinical results for novel agents, follow-up in clinical trials is relatively short and, thus, the comparative long-term benefits are still unknown.
Materials and methods: The authors developed a simulation model to generate treatment specific lifetime estimates of Overall Survival (OS) and Quality Adjusted Life Years (QALYs) for treatment with BR, Chl, ChlR, and Ibr. Two potential clinical scenarios were modelled: with and without novel agents for treating CLL. The model was based on health states relating to first- and second-line progression-free survival (PFS), post-progression survival, and death.
Results: Where novel agents were assumed unavailable, mean OS ranged from 5.4-8.5 years and QALYs from 3.5-6.1. Where novel agents were available, the mean OS increased to 10.0 years, with a corresponding increase in QALYs to 7.6. Frontline Ibr use followed by Physician's Choice, including novel agents at relapse, resulted in projected increase in OS of between 18% (1.5 years) and 85% (4.6 years), corresponding to a 25-117% increase in QALYs, compared with currently available traditional therapies.
Limitations: The limitations of this analysis include immature OS data and the assumption of equivalent efficacy across all novel agents in terms of their impact on PFS and OS.
Conclusions: The use of novel agents is predicted to yield substantive gains in predicted lifetime OS and QALY improvements compared to traditional therapies in CLL patients who are ineligible for fludarabine-based chemoimmunotherapy.
Keywords: CLL; QALY; elderly; novel agents; overall survival; progression free survival; treatment naïve; unfit.