Treatment with ibrutinib significantly reduces the risk of initiating next treatment in patients with chronic lymphocytic leukemia or small lymphocytic lymphoma compared with bendamustine/rituximab in a real-world setting.
Ibrutinib (Imbruvica) monotherapy in the first-line setting yielded a significantly lower risk of beginning an additional line of therapy among insured patients with chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL) compared with chemoimmunotherapy, according to findings from a poster presented at the 2023 Society of Hematologic Oncology (SOHO) Annual Meeting.
With a median follow-up of 26 months (interquartile range [IQR], 13-44) for patients receiving ibrutinib and 31 months (IQR, 14-52) for patients receiving chemoimmunotherapy, 13% and 26% of those in each respective treatment group went on to begin an additional line of therapy. The probability of not initiating next treatment in the ibrutinib and chemoimmunotherapy groups, respectively, were 92% (95% CI, 91%-93%) and 88% (95% CI, 87%-89%) at 12 months and 87% (95% CI, 86%-88%) and 79% (95% CI, 77%-81%) at 24 months. The corresponding rates in each respective group were 79% (95% CI, 77%-81%) and 63% (95% CI, 61%-66%) at 48 months and 70% (95% CI, 66%-74%) and 52% (95% CI, 48%-56%) at 72 months.
Overall, treatment with ibrutinib in the frontline setting correlated with a significantly lower risk of beginning an additional line of therapy compared with any type of chemoimmunotherapy (HR, 0.61; 95% CI, 0.55-0.69; P <.001). Investigators reported that the risk of initiating next treatment was lower with ibrutinib compared with bendamustine/rituximab (Rituxan; HR, 0.62; 95% CI, 0.55-0.72; P <.001) and fludarabine/cyclophosphamide/rituximab (HR, 0.52; 95% CI, 0.35-0.85; P = .001).
In this real-world study, the primary objectives were describing the clinical and demographic characteristics of patients with CLL or SLL who received first-line ibrutinib or chemoimmunotherapy and comparing the time to next treatment between these types of treatment. Investigators assessed information from the Komodo health payer-complete dataset concerning patients who did not receive any treatment for CLL or SLL for at least 12 months in the baseline period. Closed health insurance claims in the Komodo dataset went through insurance adjudication, with 53% of patients with closed claims being from community centers.
For the ibrutinib cohort, investigators included patients who received treatment with this agent as the first observed medication following a CLL or SLL diagnosis with a washout period of 12 or more months plus absence of another antineoplastic agent within 4 weeks of beginning ibrutinib therapy. For the chemoimmunotherapy cohort, eligible patients were those who received it as their first observed treatment with a washout period of at least 12 months and absence of a targeted therapy within 28 days of initiating treatment.
Investigators defined time to next therapy as the time from index date to the initiation of an additional line of treatment. In the ibrutinib cohort, next treatment was defined as beginning a new class add-on or switch that was initiated on or after 29 days from index date. In the chemoimmunotherapy cohort, beginning a new class add-on or switch or re-initiating a first-line chemoimmunotherapy regimen following a treatment gap of at least 120 days qualified as next treatment.
The study population consisted of 5961 eligible patients, including 3570 who received frontline ibrutinib and 2391 who received chemoimmunotherapy. Of those in the chemoimmunotherapy group, 1599 received bendamustine/rituximab and 443 received fludarabine/cyclophosphamide/rituximab.
Before implementing inverse probability of treatment weights (IPTW), investigators reported that patients in the ibrutinib cohort were, on average, older than those in the chemoimmunotherapy cohort. Additionally, patients receiving ibrutinib had lower mean Quan-Charlson Comorbidity Index scores and fewer disease-related symptoms at baseline. Baseline characteristics were comparable between the ibrutinib and chemoimmunotherapy groups after IPTW weighting.
Wang R, Ding Z, Lu X, et al. Real-world treatment outcomes in patients with chronic lymphocytic leukemia or small lymphocytic lymphoma who were treated with first-line single-agent ibrutinib or chemoimmunotherapy. Presented at: 2023 Society of Hematologic Oncology (SOHO) Annual Meeting; September 6-9, 2023; Houston, TX. Abstract CLL-587.