“The clinical take-away from our study is that population-based statistics show a decline in mortality and an increase in survival that is concurrent with the introduction of new therapies for treating CLL,” said lead study author Nadia Howlader, PhD, of the Surveillance Research Program, Division of Cancer Control and Population Sciences, National Cancer Institute, Bethesda, Md.in Cancer Epidemiology, Biomarkers & Prevention.
From 1992 to 2011, CLL mortality decreased 1.1% annually, then the pace of the decline hastened to 3.6% per year from 2011 to 2021 among adults aged ≥ 20 years. Furthermore, 5-year survival rates among patients with CLL increased 0.7% per year on average from 1992 to 2016. To account for yearly random fluctuations in the number of cases detected, incidence data was fit to a model to determine the trend.
Although the study was not designed to specify which treatments were disseminated among patients or to estimate the impact of a specific drug, there were only six new drugs approved for CLL from 1991 to 2010. In contrast, between 2011 and 2018, 11 new CLL drugs (in particular the approval of new tyrosine kinase inhibitors (TKIs)) ushered in a period of more rapid annual decreases in mortality.
“The approval of ibrutinib  was a sea change in decreasing CLL mortality. Earlier therapies like chemoimmunotherapies were not as effective in patients with TP53 mutation and/or 17P deletions,” said Binsah George, MD, of McGovern Medical School at UTHealth, Houston, who was not associated with the study.
New TKIs not only decrease mortality, but also have fewer side effects than earlier cytotoxic therapies, do not require inpatient treatment, and are available to all patients on Medicare and Medicaid.
Although patients with relapsed CLL may benefit from bone marrow transplants or CAR T-cell therapy, these treatments are not available at many community oncology practices. Furthermore, some patients are too sick to receive them or don’t have the economic and social resources to get them.
Even though TKIs increase overall survival in patients with CLL, they are not curative and require lifelong treatment.
“The estimated cost for CLL treatment is around $600,000 in a lifetime per patient, possibly placing significant burden on patients and the health care system,” said Dr. George.
“Certain trials are looking at stopping TKI treatment after a fixed period of time. This will let us learn more about the disease and could possibly lead to a decrease in cost and side effects of therapy,” concluded Dr. George.
Due to the study’s retrospective nature and data being sourced from state cancer registries and federal statistics, authors posited that rates of CLL could be underestimated, due to miscoding and missing information, particularly from those who get treatment outside of hospital settings. Additionally, some of the improvement in mortality could be attributed to better supportive care and less toxicity in medications, rather than then efficacy of novel agents.
Dr. Howlader and Dr. Binsah reported no conflicts of interest.