In patients with previously untreated mantle cell lymphoma (MCL), autologous stem cell transplantation (ASCT) plus ibrutinib maintenance outperformed ASCT alone with regard to failure-free survival. Furthermore, ASCT alone did not prove to be superior to ibrutinib maintenance, but ibrutinib appears to be favored over ASCT in terms of toxicity.

The phase 3 Triangle study randomized 870 patients younger than 66 with previously untreated MCL 1:1:1 to three study arms:

  • Arm A: R-CHOP/R-DHAP chemotherapy followed by ASCT and observation
  • Arm A+I: R-CHOP/R-DHAP chemotherapy followed by ASCT and 2 years of ibrutinib maintenance therapy
  • Arm I: R-CHOP/R-DHAP chemotherapy followed by ibrutinib maintenance therapy

Of note, rituximab maintenance was added to all three arms, following national guidelines. The primary endpoint was failure-free survival. Prof. Martin Dreyling (University Hospital Munich, Germany) presented the results1 at the 2022 annual meeting of the American Society of Hematology.

The A+I arm was superior to the A arm in terms of failure-free survival, with 3-year rates of 88% and 72% (HR, 0.52; P=0.0008). The A arm did not outperform the I arm: the 3-year failure-free survival rates were 72% in the A arm and 86% in the I arm (HR, 1.77; P=0.9979). Prof. Dreyling added that it was too soon to call whether the A+I arm was superior to the I arm. Similarly, the overall survival data were premature at time of the presentation.

Hematologic adverse events (AEs) of grade 3 or higher appeared to be higher in the A+I arm (50%) than in the I arm (28%) or in the A arm (21%). Likewise, the rate of infection grade 3 or higher was elevated in the A+I arm (25%) compared with the I arm (19%) and the A arm (13%). Importantly, 1.4% of participants in the A arm and 1% in the A+I arm died from therapy, whereas 0% died due to therapy in the I arm.

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