We report a multicentre retrospective study that analysed clinical characteristics and outcomes in 117 patients with primary plasma cell leukaemia (pPCL) treated at the participating institutions between January 2006 and December 2016. The median age at the time of pPCL diagnosis was 61 years. Ninety-eight patients were treated with novel agents, with an overall response rate of 78%. Fifty-five patients (64%) patients underwent upfront autologous stem cell transplantation (ASCT). The median follow-up time was 50 months (95% confidence interval [CI] 33; 76), with a median overall survival (OS) for the entire group of 23 months (95% CI 15; 34). The median OS time in patients who underwent upfront ASCT was 35 months (95% CI 24·3; 46) as compared to 13 months (95% CI 6·3; 35·8) in patients who did not receive ASCT (P = 0·001). Multivariate analyses identified age ≥60 years, platelet count ≤100 × 10 /l and peripheral blood plasma cell count ≥20 × 10 /l as independent predictors of worse survival. The median OS in patients with 0, 1 or 2-3 of these risk factors was 46, 27 and 12 months, respectively (P < 0·001). Our findings support the use of novel agents and ASCT as frontline treatment in patients with pPCL. The constructed prognostic score should be independently validated.

Prophylaxis is commonly used to prevent central nervous system (CNS) relapse in diffuse large B cell lymphoma, with no clear standard of care. We retrospectively evaluated 1162 adult patients across 21 US academic centers with DLBCL or similar histologies who received single-route CNS prophylaxis as part of frontline therapy between 2013-2019. Prophylaxis was administered intrathecally (IT) in 894 (77%) and using systemic high-dose methotrexate (HD-MTX) in 236 (20%); 32 patients (3%) switched route due to toxicity and were assessed separately. By CNS-International Prognostic Index (IPI), 18% were considered low-risk, 51% moderate, and 30% high. Double-hit lymphoma (DHL) was confirmed in 243 of 866 evaluable patients (21%). Sixty-four patients (5.7 %) had CNS relapse, after median 7.1 months from diagnosis, including 15 of 64 (23%) within the first 6 months. There was no significant difference in CNS relapse between IT and HD-MTX recipients (5.4 vs 6.8%, p=0.4), including after propensity score matching to account for differences between respective recipient groups. Weighting by CNS-IPI, expected versus observed CNS relapse rates were nearly identical (5.8 vs 5.7%). Testicular involvement was associated with high risk of CNS relapse (11.3%) despite most having lower CNS-IPI scores. DHL did not significantly predict for CNS relapse after single-route prophylaxis, including with adjustment for treatment regimen and other factors. This large study of CNS prophylaxis recipients with DLBCL found no significant difference in CNS relapse rates between routes of administration. Relapse rates among high-risk subgroups remain elevated and reconsideration of prophylaxis strategies in DLBCL is of critical need.

This multicenter retrospective study included 101 patients (median age 62 years) with secondary plasma cell leukemia (sPCL). The median time from initial multiple myeloma diagnosis to sPCL was 31 months. Fifty-five out of 72 patients (75%) who received any therapy were treated with immunomodulators (IMiDs) and/or proteasome inhibitors (PIs), and 14/72 (19%) underwent salvage autologous stem cell transplantation (ASCT). The overall response rate in patients who received ASCT or PI (either alone or in combination) was higher than in those who did not (93% vs. 36% and 60% vs. 30%, respectively). The median overall survival (OS) in patients who received therapy was 4.2 months (95% CI: 1.3; 8.0) with a 1-year OS of 19%. Platelet count ≤100 × 10/L at sPCL diagnosis was the only independent predictor of a poorer OS in treated patients (HR = 3.98, p = .0001). These findings suggest that patients with sPCL may benefit from salvage ASCT- and PI-based regimens.

Most patients receiving CAR T-cell therapy (CAR-T) for aggressive B-cell lymphoma (B-NHL) will not experience a durable remission. There are several novel agents approved for the treatment relapsed, refractory aggressive B-NHL; however, it remains unclear how to sequence these therapies pre- and post-CAR-T (peri-CAR-T). We conducted a multicenter retrospective analysis for the purpose of describing peri-CAR-T practice patterns and survival predictors for patients receiving CD19-directed CAR-T. Patients (n=514) from thirteen centers treated with CAR-T for aggressive B-NHL between 2015-2021 were included. Clinical characteristics, CAR-T outcomes and treatment regimens administered pre- and post-CAR-T were collected. Survival curves were constructed using Kaplan Meier method. Multivariate Cox regression was used to determine the impact of variables on survival outcomes. For all patients receiving CAR-T, a greater number lines of therapy prior to CAR-T apheresis and receipt of bridging therapy were predictive of inferior progression-free survival (PFS) and overall survival (OS). From time of CAR-T infusion, median PFS and OS were 7.6 and 25.6 months (n=514). From time of progression post-CAR-T (n=254), median OS was 5.5 months. The median PFS of treatments given in the first-line post-CAR-T failure (n=167) was just 2.8 months. Patients with refractory disease at day 30 had inferior OS and were less likely to receive subsequent treatment(s) compared to other patients with CAR-T failure. AlloHCT for select patients at any time following CAR-T failure (n=16) led to durable responses in over half at one-year. These data provide a benchmark for future clinical trials in patients with progression post-CAR-T, an unmet clinical need.

A small proportion of patients with multiple myeloma (MM) are diagnosed at a very young age. The clinicopathological characteristics and prognosis of these patients are not well known. This analysis included 52 patients diagnosed with MM at the age of ≤30 years (range: 8-30 years). 68% of patients had International Scoring System (ISS) 1 MM; 22% presented with the light chain-only disease, and 48% with elevated serum lactate dehydrogenase (LDH). 85% of patients were treated with novel agents, and 62% received front-line autologous stem cell transplantation (ASCT). Overall response rate (ORR) to front-line treatment and ASCT were 71% and 90%, respectively. The group was followed-up for the median period of 86 months. The median overall survival (OS) was 166 months (95% CI: 53-222), with 5-year OS rate of 77% (95% CI: 61.0-87.9). This findings suggest that the prognosis in young MM patients may be as good if not better than in the general population of MM patients.