Outcomes of Patients with Refractory Peripheral T-Cell Lymphoma, Angioimmunoblastic and Other Nodal Lymphomas of T Follicular Helper-Cell Origin (OPerA)

Introduction: T cell lymphomas are heterogenous with an overall poor prognosis. Peripheral T cell lymphoma not otherwise specified (PTCL-NOS) and angioimmunoblastic T cell lymphoma (AITL) are the two most common subtypes in the US accounting for 45% of diagnoses. Based on overlapping recurrent molecular and cytogenetic abnormalities, the WHO created an umbrella category of nodal T-cell lymphomas with T-follicular helper phenotype (TFH lymphoma), which includes AITL and PTCL with TFH phenotype (Swerdlow SH, et al. Blood. 2016). 25-30% of patients (pts) are refractory to initial therapy and even amongst responders to initial therapy, relapse is common. Survival after relapse or progression (R/P) is typically measured only in months. Outcomes have not changed significantly even with the introduction of several new agents in the last 10 years (Chihara D, et al. Br J Haematol. 2017). There remains no standard 2nd line therapy or guidance on sequencing of therapies as interpretation of clinical data in T-cell lymphoma is frequently hampered by the heterogeneity of the patient population and small sample size. The aim of our study was to determine outcomes in a large, well-defined group of pts with either primary refractory PTCL-NOS or TFH lymphoma.

Methods: We performed a multi-center retrospective study to determine outcomes to 2nd line therapy for adult pts diagnosed between 1.1.09-6.30.18 with PTCL-NOS or TFH lymphoma, who were primary refractory defined by either induction failure, less than CR to initial therapy, or relapse within 6 months (mo) of completion of initial therapy. We performed time to event analysis using Kaplan-Meier method and compared groups using log-rank test. All other statistics were descriptive.

Results: Patient and disease characteristics at diagnosis and relapse are summarized in Table 1. We identified 80 eligible pts from 7 US academic centers. Median FU was 17.2 mo from diagnosis (0.5-70). Overall, pts had mostly advanced stage with multiple high-risk features including bone marrow (BM) or extranodal (EN) involvement and B symptoms at diagnosis and R/P. Most pts received CHOP (52%) or CHOEP (24%) as initial therapy. 60% of patients did not attain a CR, while 40% of pts relapsed after initial CR.14% had received a consolidative transplant in 1^st CR prior to relapse (almost all autologous hematopoietic cell transplant [HCT]). At R/P, 48% received single agent therapy [mostly romidepsin (15/38)], while 36% received multi-agent salvage therapy [mostly ICE (9/29)]. 13/80 pts were placed on hospice or only received local therapy after R/P. Median OS from diagnosis and following R/P was 19 mo/12.9 mo respectively. Median PFS2 (defined as time from 2^nd line therapy to 2^nd progression) for pts receiving systemic therapy was 73 days (d) (range 41-175). On univariate and multivariate analysis, there was no significant difference in PFS2 by histologic subtype (74 d for PTCL and 73 d for TFH lymphoma; p=0.29), platelet count <150,000 (75 d vs 59 d; p=0.37), presence of B symptoms at R/P (78 d vs. 63 d, p=.16), ECOG PS ≥2 (75 d vs 57 d, p=0.62), elevated LDH (63 d vs 75 d, p=0.31) and EN disease at R/P (59 d vs 75 d, p=0.72). There was a trend towards longer PFS2 with single agent salvage therapy compared to combination salvage therapy (97 d vs. 51 d; p=0.09). There was no statistically significant difference in survival if pts had relapsed disease or induction failure (75 d vs. 50 d, p=0.97). Although numerically longer, OS did not differ statistically if pts underwent HCT as consolidation after 2^nd line therapy (allogeneic HCT 29.1 mo, autologous HCT 48.5 mo vs. 16.1mo for no HCT; p=0.61, n=8). Median number of therapies after salvage was 1 (range 1-6).

Conclusions: Outcomes in this large, well-defined population of primary refractory PTCL-NOS and TFH lymphoma were poor, but better compared to most other retrospective series in R/R T-cell lymphoma. EN disease and advanced stage were common in this cohort of primary refractory pts. Relapse after HCT in CR1 had a particularly poor prognosis. Our findings suggest that single agent therapy following R/P in primary refractory pts and transplant may be beneficial, though our statistical power was limited due to small sample size. In a next step, we plan to expand the cohort and perform genetic/molecular characterization of available biospecimens following central pathology review.

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