ROLE OF UP-FRONT AUTOLOGOUS STEM CELL TRANSPLANTATION IN PERIPHERAL T-CELL LYMPHOMAS: a PROPENSITY SCORE MATCHING ANALYSIS OF PATIENTS FROM LYSA CENTERS

Introduction: Despite years of attempts to improve the prognosis of patients, peripheral T-cell lymphoma (PTCL) remains a therapeutic challenge. Due to the rarity and the heterogeneity of PTCL, no consensus has been achieved regarding the type of first-line treatment. The benefit of autologous stem cell transplant (ASCT) as a consolidation procedure for patient in partial or complete response (PR or CR) is still intensely debated. Methods: Patient age, disease severity, and induction regimen are known potential confounding factors undermining the formal assessment of ASCT in first-line settings. Moreover, no retrospective study has focused on patients in response after induction, leading to strong bias in favor of the consolidation procedure. In the absence of randomized trials addressing the role of ASCT, we used a Cox proportional hazard model and a propensity score matching approach to correct for sample selection bias between patients allocated or not allocated to ASCT in intention-to-treat. Among 527 patients with peripheral PTCL-NOS, AITL or ALK- ALCL screened from 14 centers in France, Belgium, and Portugal, a final cohort of 269 patients with partial or complete responses after induction was identified and information about treatment allocation was carefully collected before therapy initiation. Results: With a median follow-up of 5.3 years, the median PFS was 3.7 years, and the median OS was 8.4 years for the entire cohort. At 5 years, PFS was 45.0% (95% confidence interval (CI): 37.8-50.6%), and OS was 60.4% (95% CI: 53.6-66.5%). Patients with ALK- ALCL experienced a slightly longer time to progression compared to patients with PTCL-NOS or AITL, although the difference did not reach significant difference. No OS difference was observed according to histology subtype. Multivariate analysis demonstrated that only remission status (CR vs. PR) at the end of induction was associated with significantly prolonged PFS and OS. In the final matched population of 146 patients, no difference regarding progression-free survival (PFS) or overall survival (OS) was observed (P = .33 and P = .40). No difference according to the use of up-front ASCT in ITT was further noted when patients with advanced stage disease (III or IV), with aaIPI > 1 or reaching a PR only at the end of induction were considered (data not shown). Conclusion: The present data do not support the use of ASCT for up-front consolidation for patients with PTCL-NOS, AITL or ALK- ALCL with partial or complete response after induction. Keywords: autologous stem cell transplantation (ASCT); peripheral T-cell lymphomas (PTCL).