Key Points
In relapsed PTCL response to salvage chemotherapy is poor with only a minority of patients proceeding to stem cell transplantation
Risk of second relapse is half for patients treated with brentuximab vedotin compared to chemotherapy independent of histological subtype
Optimal treatment in patients with refractory or relapsed peripheral T-cell lymphomas (R/R T-NHL) is unknown. In this population-based study, outcome in R/R PTCL not otherwise specified (PTCL NOS), angioimmunoblastic T-cell lymphoma (AITL) and ALK+ and ALK- anaplastic large cell lymphoma (ALCL) was evaluated. Patients with PTCL NOS, AITL, ALK+ ALCL and ALK- ALCL (≥18 years) diagnosed in 2014-2019 were identified using the Netherlands Cancer Registry. Endpoints were overall response rate (ORR), progression-free survival (PFS) and overall survival (OS). The 2-year PFS of 821 patients was 57%. Among 311 patients with a relapse, 243 received second-line treatment: 44% salvage chemotherapy, 20% brentuximab vedotin (BV) and 36% other treatment. In third-line, BV was most commonly used (38%). ORR following second-line treatment was 47%. Two-year PFS and OS after relapse were 25% and 34%, respectively. Risk of second relapse was negatively affected by early relapse (<12 months post-diagnosis), while BV reduced this risk compared to salvage chemotherapy (HR 0.55; 0.35-0.87; p=0.01). Reduced risk of relapse was independent of histological subtype. The best outcomes were observed for patients treated with salvage chemotherapy receiving consolidative autologous and allogeneic stem cell transplantation (SCT) (2-year OS 68%), patients treated with BV achieving a second complete remission (2-year OS 74%) and patients with allogeneic SCT (2-year OS 60%). The risk of second relapse was significantly lower for R/R T-NHL patients treated with BV compared to patients treated with salvage chemotherapy, and this was irrespective of subtype. Therefore, the use of salvage chemotherapy for R/R T-NHL patients is challenged.