Author: Richa Madurkar, PharmD, BCOP, Senior Clinical Oncology Pharmacist, OncoHealth
Until recently, standard first-line treatment options for CLL included indefinite therapy with a covalent BTK inhibitor (cBTKi) such as ibrutinib, acalabrutinib, or zanubrutinib ± obinutuzumab or fixed-duration (FD) therapy with venetoclax + obinutuzumab (VO).[1] While these therapies significantly improved response rates and survival with less toxicity compared to chemoimmunotherapy (CIT), there are notable limitations: cBTKi therapy is given indefinitely which can lead to long-term financial toxicity or adverse events, and while VO is given for a limited time, the clinic appointments for obinutuzumab infusions and the initial lab monitoring for tumor lysis syndrome can be burdensome.[1][2]
The AMPLIFY trial randomized patients to either FD acalabrutinib + venetoclax (AV), FD AV + obinutuzumab (AVO), or CIT.[2] The 36-month PFS was significantly longer with AV and AVO when both groups were compared to CIT. In higher risk CLL, MRD-guided AVO was found to induce deep remissions.[3] Similarly, the ongoing CLL2-BZAG trial has shown promising efficacy with the MRD-guided Zanubrutinib + VO regimen.[4] Unlike with FD regimens, MRD-guided therapy allows clinicians to adjust the duration of therapy based on the patient’s observed response, allowing for a more personalized approach. This method of monitoring has been incorporated into some cBTKi + venetoclax trials and is emerging.[5]
Data for other all-oral FD cBTKi + venetoclax doublet regimens have also emerged. In arm D of the SEQUOIA trial, venetoclax + zanubrutinib showed promising ORR and PFS benefits.[6] Similarly, venetoclax + ibrutinib demonstrated improved PFS compared to CIT in the GLOW trial, however ibrutinib combinations may be less attractive given the higher incidence of cardiovascular toxicities compared to the newer cBTKi.[7][8] While promising, these findings raise further questions. There are no randomized trials that directly compare cBTKi + venetoclax ± obinutuzumab to VO. The GAIA-CLL13 trial evaluated CIT compared to venetoclax combinations: venetoclax + rituximab, VO, and ibrutinib + VO (IVO). The investigators found improved 3-year PFS in the IVO and VO arms when separately compared to CIT (90.5%, 87.7%, and 75.5%, respectively).9 While the 3-year PFS numerically appears similar between VO and IVO, the study was statistically powered to assess the benefit of each of these arms over CIT, not to detect differences between the venetoclax-containing arms. Notably, there was a higher incidence of grade 3-4 infections with the triplet. It is also important to note that patients treated with FD regimens may initially achieve deep remissions but later relapse, and the use of cBTKi and BCL2i in the front-line setting may limit options in later lines.[10] It is currently unclear what benefit, if any, these newer regimens provide over the previously established FD standard-of-care.
Lastly, the use of front-line cBTKi + venetoclax may lead to an initial higher financial burden on patients and payors. This may be partly blunted by the FD nature of these newer combinations. A real-world comparison of health care costs for FD VO vs continuous cBTKi showed a monthly cost of approximately $14,000 for both regimens for the first 12 months of treatment, with monthly costs decreasing by 67% for VO compared to 10% for cBTKi for months 13-18 of treatment.[11] Although the study did not assess cBTKi + venetoclax ± obinutuzumab combinations, the observed cost advantages of FD therapy with VO are encouraging. Nevertheless, an assessment of the financial implications of utilizing two oral chemotherapy agents should be incorporated into the treatment planning process to ensure therapy is both clinically and economically sustainable for the patient.
In summary:
- Current evidence supports multiple options for 1L CLL, and the various choices involve clinical and financial trade-offs. One key consideration is treatment duration, as options exist for continuous, fixed-duration, and MRD-guided therapy. Shared decision-making between oncologists and patients is paramount.
- Most of the trials have compared novel therapy combinations to CIT rather than to other state-of-the-art agents, leaving uncertainty on the precise role and benefit of these newer doublet and triplet regimens over the current standard-of-care.
- The second generation cBTKi agents have better safety profiles compared to ibrutinib. Current data suggests there may be an increased toxicity when using triplet regimens combining BTKi with venetoclax and obinutuzumab. This should be considered when evaluating the risks versus benefits of the various 1L options.
- In addition to head-to-head trials of these novel agents, cost-effectiveness comparisons would be valuable additions to the literature.
References:
[1] Hallek M. Chronic lymphocytic leukemia: 2025 update on the epidemiology, pathogenesis, diagnosis, and therapy. Am J Hematol. 2025;100(3):450-480.
[2] Brown JR, Seymour JF, Jurczak W, et al. Fixed-duration acalabrutinib combinations in untreated chronic lymphocytic leukemia. N Engl J Med. 2025;392(8):748-762.
[3] Davids MS, Ryan CE, Lampson BL, et al. Phase II study of acalabrutinib, venetoclax, and obinutuzumab in a treatment-naïve chronic lymphocytic leukemia population enriched for high-risk disease. J Clin Oncol. 2025;43(7):788-789.
[4] Furstenau M, Robrect S, Schneider C, et al. MRD-guided zanubrutinib, venetoclax, and obinutuzumab in relapsed CLL: primary end point analysis from the CLL2-BZAG trial. 2025;145(12):1282-1292.
[5] Talha M, Girvan S, Cairns DA, et al. Measurable residual disease-guided therapy for chronic lymphocytic leukemia. N Engl J Med. 2025;393(12):1177-1190.
[6] Shadman M, Munir T, Ma S, et al. Zanubrutinib and venetoclax for patients with treatment-naïve chronic lymphocytic leukemia/small lymphocytic lymphoma with and without del(17p)/ TP53 mutation: SEQUOIA Arm D results. J Clin Oncol. 2025;43(21):2409-2417.
[7] Niemann CU, Munir T, Moreno C, et al. Fixed-duration ibrutinib-venetoclax versus chlorambucil-obinutuzumab in previously untreated chronic lymphocytic leukaemia (GLOW): 4-year follow-up from a multicentre, open-label, randomised, phase 3 trial. Lancet Oncol. 2023;24(12):1423-1433.
[8] Byrd JC, Hillmen P, Ghia P, et al. Acalabrutinib versus ibrutinib in previously treated chronic lymphocytic leukemia: results of the first randomized phase III trial. J Clin Oncol. 2021;39(31):3441-3452).
[9] Eichhorst B, Neimann CU, Kater AP, et al. First-line venetoclax combinations in chronic lymphocytic leukemia. N Engl J Med. 2023;388(19):1739-1754.
[10] Kagerer A, Thompson MC. Management of relapsed and/or refractory chronic lymphocytic leukemia. Hematol Oncol Clin North Am. 2025;39(5):935-950.
[11] Huntington SF, Manzoor BS, Jawaid D, et al. Real-world comparison of health care costs of venetoclax-obinutuzumab vs Bruton’s tyrosine kinase inhibitor use among US Medicare beneficiaries with chronic lymphocytic leukemia in the frontline setting. J Manag Care Spec Pharm. 2024;30(10):1106-1116.