Examination of DLBCL Patient Flow and Treatment Patterns

Diffuse large B-cell lymphoma (DLBCL) accounts for nearly 80% of large B-cell lymphoma cases and nearly one-third of non-Hodgkin lymphomas in the United States. Though first-line treatment with R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) and second-line autologous stem-cell transplant (ASCT) are curative in many patients with DLBCL, 30%-40% of patients experience relapse or treatment-refractory disease, with worsening prognosis as they progress through additional lines of therapy.

The primary aim of this study was to estimate the number of patients with DLBCL requiring third-line treatment; however, with the recent approval of chimeric antigen T-cell (CAR-T) therapies for the second-line treatment of DLBCL, this study additionally sought to assess the impact of this newly available second-line therapy on the number of patients with DLBCL requiring third-line treatment.

An analytical model was developed to estimate DLBCL incidence in the United States by age based on data collected from the Surveillance, Epidemiology, and End Results (SEER) Program. Data from this published literature were purposed for the proportion of patients with DLBCL initiating first-line treatment, achieving cure, and progressing to second- and third-line treatment, and time on treatment. A mixture-cure approach was used to estimate time until second-line treatment initiation for individuals not cured by first-line therapy. The proportion of therapies used in second and third lines were extracted from published literature or derived from assumptions, yielding the estimated overall proportion, as well as segmentation under two scenarios: 1) no CAR-T utilization in the second line, and 2) CAR-T utilization in the second line. For CAR-T therapy utilization in the second line, published CAR-T survival curves were used to estimate the second line cure rate, which was then used to adjust the third line–treated population.

A total of 27,903 incident cases of DLBCL were projected for 2022 in the United States; of these, approximately 60% were estimated to be in patients aged 65 years or more. Estimates found that 25,932 of these patients (91%) would receive first-line treatment. Of those patients treated in the first line, 7871 (31%) were estimated to initiate second-line therapy after relapse or refractoriness to first-line therapy. When CAR-T therapy was not assumed in the second line (first scenario), it was estimated that 2746 patients (35%) would progress to third-line treatment. When CAR-T therapy was assumed in the second line (second scenario), it was estimated that 1930 patients (24%) would initiate CAR-T therapy in the second line, and that subsequent third-line patients would decrease by approximately 9.6% to 2482 following curative second-line treatment.

Researchers concluded that although the population of patients with relapsed or refractory DLBCL requiring third-line treatment may be relatively small, there remains a high unmet medical need for durable treatment options. Despite advances in the relapsed or refractory DLBCL treatment landscape, this study did not find that drastically fewer patients progress to third-line treatment. Investigators additionally noted that increased use of CAR-T therapies may impact third-line treatment, as patients previously exposed to CAR-T therapy may be difficult to treat and have fewer treatment options.

Source:

Johnston K, Jun M, Davies K, et al. Estimating the incidence of diffuse large B-cell lymphoma by line of therapy in the US using an epidemiologic model to examine patient flow and treatment patterns. Presented at: 2022 Academy of Managed Care Pharmacy Nexus Annual Meeting; October 11-14, 2022; National Harbor, MD. Poster C41.