Ibrutinib as Treatment for Patients With Relapsed/Refractory Follicular Lymphoma: Results From the Open-Label, Multicenter, Phase II DAWN Study
Mené sur 110 patients atteints d'un lymphome folliculaire réfractaire et/ou récidivant, cet essai de phase II évalue l'effcacité, du point de vue du taux de réponse globale, et la toxicité de l'ibrutinib, après l'échec de plusieurs lignes de traitements (nombre médian de thérapies antérieures : 3 ; durée médiane de suivi : 27,7 mois)
Purpose : The Bruton's tyrosine kinase inhibitor ibrutinib has demonstrated clinical activity in B-cell malignancies. The DAWN study assessed the efficacy and safety of single-agent ibrutinib in chemoimmunotherapy relapsed/refractory follicular lymphoma (FL) patients. Methods : DAWN was an open-label, single-arm, phase II study of ibrutinib in patients with FL with two or more prior lines of therapy. Patients received ibrutinib 560 mg daily until progressive disease/unacceptable toxicity. The primary objective was independent review committee–assessed overall response rate (ORR; complete response plus partial response). Exploratory analyses of T-cell subsets in peripheral blood (baseline/cycle 3) and cytokines/chemokines (baseline/cycle 2) were performed for available samples. Results : Between March 2013 and May 2016, 110 patients with a median of three prior lines of therapy were enrolled. At median follow-up of 27.7 months, ORR was 20.9% (95% CI, 13.7% to 29.7%, which did not meet the 18% lower-bound threshold for the primary end point). Twelve patients achieved a complete response (11%; 95% CI, 5.8% to 18.3%). Median duration of response was 19.4 months (range, 1 to ≥ 33 months), with a median progression-free survival of 4.6 months and a 30-month overall survival of 61% (95% CI, 0.51% to 0.70%). Lymphoma symptoms resolved in 67%. Seven of 32 patients who experienced initial radiologic progression responded upon continuing therapy (pseudoprogression). The most common adverse events were diarrhea, fatigue, cough, and muscle spasms; 48.2% of patients reported serious adverse events. In patients who experienced a response, regulatory T cells were downregulated at C3D1 (P = .02), and Th1-promoting (antitumor) cytokines interferon-γ and interleukin-12 increased (P ≤ .035). Conclusion : With an ORR of 20.9%, ibrutinib failed to meet its primary efficacy end point in chemoimmunotherapy in patients with relapsed/refractory FL, although responses were durable and associated with a reduction in regulatory T cells and increases in proinflammatory cytokines.