Histone deacetylase inhibitors (HDACi) are active agents for peripheral T-cell lymphoma (PTCL). Anecdotally angioimmunoblastic T-cell lymphoma (AITL) appears to respond better than PTCL–not otherwise specified (NOS) to HDACi. The new World Health Organization classification shows that a subgroup of PTCL carries similarities in phenotype and gene expression profiling to AITL, comparable to T follicular helper (TFH) cells. The disease might behave similarly to AITL when treated with HDACi. We analyzed 127 patients with AITL or PTCL-NOS treated with HDACi at relapse as a single agent or in combination. We re-reviewed the pathology of all PTCL-NOS to identify the TFH phenotype. Patients received HDACi at relapse as a single agent in 97 cases (76%, 59 TFH, 38 non-TFH) or in combination in 30 cases (24%, 18 TFH, 12 non-TFH) including duvelisib, lenalidomide, lenalidomide plus carfilzomib, and pralatrexate. Seven PTCL-NOS had TFH phenotype; 2 PTCL-NOS were reclassified as AITL. Overall response rate (ORR) was 56.5% (28.9% complete response [CR]) in TFH and 29.4% (19.6% CR) in non-TFH phenotype patients (P = .0035), with TFH phenotype being an independent predictor of ORR (P = .009). Sixteen patients sufficiently responded to HDACi or HDACi in combination with another agent to proceed directly to allogeneic transplantation; 1 of 16 responded to donor lymphocyte infusion (12 TFH, 4 non-TFH). Our results, although retrospective, support that HDACi, as a single agent or in combination, may have superior activity in TFH-PTCL compared with non-TFH PTCL. This differential efficacy could help inform subtype-specific therapy and guide interpretation of HDACi trials.

Gao et al report that early use of extracorporeal photopheresis improves time to next treatment and survival in patients with Sézary syndrome.

Despite increasing availability of therapies, patients with Sezary syndrome (SS) commonly endure multi-line treatment journeys, mostly with partial responses of short duration. Measuring clinical benefit is challenging; time-to-next-treatment (TTNT) provides a robust, objective measurement of efficacy. This international observational study examines patterns of clinical care and therapeutic benefit as measured by TTNT. TTNT was calculated for monotherapies and combination therapies, with consideration to treatment line. 178 patients with SS (73% de novo, 27% secondary) were included, receiving 721 lines of systemic therapy, with median follow-up of 56.9 months. Across all lines, 58 different therapeutic regimens were prescribed (54 were systemic therapies) and classified into 17 treatment groups. The most common first-line treatments were extracorporeal photopheresis (ECP)–containing combination therapy (20%) and retinoid monotherapy (19%). Median TTNT for all first-line therapies was short (5.4 months). First-line, combination therapies had longer median TTNT than monotherapies, 10.0 vs 5.0 months (P = .004), respectively. Later delivery of combination therapies was associated with shorter clinical benefit, with median TTNT reduced to 6.2 and 2.2 months for mid-line (2nd-4th line) and late-line (≥5th line), respectively (P < .001). First-line ECP-containing treatments were associated with longer median TTNT than non-ECP–containing treatments, 9.0 vs 4.9 months (P = .007). For both ECP-monotherapy and ECP–containing combination therapy, significant reductions in TTNT were seen in later lines. These data suggest therapeutic benefit from first-line delivery of combination therapy for SS and favor early inclusion of ECP in the treatment algorithm for those who can access it.

Introduction: Brentuximab vedotin is an antibody-drug conjugate, which combines a CD30 monoclonal antibody with the microtubule disrupting agent monomethylauristatin E. The utility of brentuximab vedotin has been explored in a number of diseases, with a recent focus on T-cell lymphoma, particularly systemic anaplastic large-cell lymphoma (sALCL) and cutaneous T-cell lymphoma (CTCL), as well as other peripheral T-cell lymphoma (PTCL) histologies. Areas covered: This review surveys current data on the efficacy of brentuximab vedotin in T-cell lymphoma, as well as embedding it in a therapeutic context by reviewing potential competitor agents in the clinic. Data is drawn from published literature, with a focus on clinical trial data rather than preclinical studies or case reports. Expert opinion: Brentuximab vedotin has a clear clinical benefit in CTCL and sALCL, and can achieve durable responses in a number of patients. Toxicities, particularly peripheral neuropathy, may limit treatment in some patients; however, the agent is generally well tolerated. In this context, brentuximab vedotin has been globally approved for use in sALCL and certain CTCL subtypes, however, further information is required to enhance our understanding of when and in whom to best employ this agent, as well as exploring rational combinations to augment responses.

Variances in global access to drugs and treatment practices make it challenging to understand the benefit of contemporary therapies in patients with relapsed and refractory (R/R) mature T-cell and natural killer–cell lymphomas (MTCL and MNKCL). We conducted an international retrospective cohort study of 925 patients with R/R MTCL and MNKCL. In peripheral T-cell lymphoma–not otherwise specified and anaplastic lymphoma kinase–negative anaplastic large cell lymphoma (ALK– ALCL), patients with relapsed lymphoma demonstrated a superior median overall survival (OS) relative to refractory from the time of second-line treatment. We identified several independent predictors of OS for R/R lymphoma including age >60 years, primary refractory disease, histological subtype other than angioimmunoblastic T-cell lymphoma (AITL), extranodal sites >1, Ki67 ≥40%, and absolute lymphocyte count less than the lower limit of normal. A multivariable model incorporating these formed the basis for a prognostic index for R/R TCL, in which patients are stratified into low-risk (0-1 risk factor), intermediate-risk (2-3 risk factors), or high-risk (≥4 risk factors) groups, which were associated with 3-year OS of 57.14%, 23.3%, and 7%, respectively. Patients received either a "novel" single agent (SA; 35%) or cytotoxic chemotherapy (CC; 60%) for their second-line treatment. Higher progression-free survival was observed with SA over CC for the entire cohort with a higher 3-year OS in AITL and ALK– ALCL. Among the SA, small-molecule inhibitors demonstrated OS advantage relative to CC in AITL. Our results highlight continued efficacy of novel drugs globally and the potential of a new prediction model in informing heterogeneous prognosis within the R/R population of MTCL and MNKCL.

Summary: Traditionally, Sezary syndrome (SS) has been associated with few therapeutic options and poor prognosis, with 5‐year disease‐specific survival (DSS) less than one‐third in historical cohorts. However, newer therapies and combinations are associated with impressive time‐to‐next‐treatment (TTNT), particularly allogeneic stem‐cell transplantation (AlloSCT) and combination therapies notably those including extracorporeal photopheresis. In this multicentre, international study, we explored the prognostic outcomes of 178 patients exclusively managed for SS, diagnosed between 2012 and 2020, and treated in the modern therapeutic era. In this cohort, 58 different therapies were delivered, with 13.5% of patients receiving AlloSCT. Long‐term survival exceeded historical reports with 5‐year DSS and OS of 56.4% and 53.4% respectively. In those receiving AlloSCT, prognosis was excellent: 5‐year DSS and OS were 90.5% and 78.0% respectively. Confirming the results from the Cutaneous Lymphoma International Consortium (CLIC), LDH and LCT had significant prognostic impact. Unlike earlier studies, stage did not have prognostic impact; we speculate that greater relative benefit favours patients with extensive lymphomatous nodal disease (Stage IVA2) compared to historical reports. For patients ineligible for AlloSCT, the prognosis remains relatively poor (5‐year DSS 51.4% and OS 49.6%), representing ongoing unmet needs for more effective novel agents and investigation of improved therapeutic combinations.