ALBERT

Description: Background: Induction chemoimmunotherapy followed by autologous stem cell transplantation (ASCT) is a standard of care for transplant eligible (TE) patients (pts) with untreated mantle cell lymphoma (uMCL); however, there is no consensus on the optimal induction regimen. The addition of rituximab + high-dose cytarabine (RC) to an RCHOP-like regimen is associated with better outcomes. In addition, two randomized trials have demonstrated superior efficacy and tolerability for rituximab/bendamustine (RB) compared to RCHOP for uMCL. Based on this, we conducted a phase 2 trial of 3 cycles of RB followed by 3 cycles of RC in 23 TE pts with uMCL, with encouraging preliminary results (Armand, BJH 2016). Pts continued to be followed for relapse and survival. Meanwhile, RB/RC became the standard frontline regimen at Dana-Farber Cancer Institute (DFCI). Simultaneously, investigators at Washington University in St. Louis (WUSTL) initiated a similar study of alternating cycles of RB/RC for uMCL. Herein, we report the results of both phase 2 trials as well as the off-trial experience. Methods: In the DFCI trial, TE pts (age 18-69) with uMCL were treated with 3 cycles of RB (R 375 mg/m2 d1, B 90 mg/m2 d1-2) followed by 3 cycles of RC (R 375 mg/m2 d1, C 3gm/m2 BID d1-2 with dose reductions for age, renal dysfunction, or pre-existing neurotoxicity). Off-trial pts treated with RB/RC at DFCI or in consulting community practices were retrospectively identified using clinical and pharmacy databases. In the WUSTL trial, TE pts (age 18-65) received alternating cycles of RB (cycles 1, 3, 5) and RC (cycles 2, 4, 6) (same dosing as above). Response assessments were made using CT scans for the DFCI trial and PET/CT for the WUSTL trial and DFCI off-trial pts. Results: In total, 86 pts (23 DFCI trial, 49 DFCI off-trial, 14 WUSTL trial) were treated with RB/RC. The median age was 57 (range 30-72). Pts in the WUSTL cohort were more likely to be male, have a high MIPI score, and have blastoid variant (Table). 94% of pts completed 6 cycles of RB/RC therapy. Off-trial pts were more likely to receive a lower starting dose (≤ 2gm/m2) of cytarabine (76%) compared to trial pts (38%). At the EOI, the overall response rate and CRR were 98% and 92%, respectively, with similar response rates across cohorts (Table). 73 pts (85%) subsequently underwent ASCT and 4 additional pts (5%) have ASCTs planned. 9 pts did not undergo ASCT because of persistent or PD (n=3), prolonged cytopenias (n=3), an incidentally identified ASXL1 mutation without cytopenias (n=1), pt preference (n=1), and inadequate stem cell collection (n=1). Delayed platelet engraftment after ASCT was seen for pts receiving alternating cycles of RB/RC compared to sequential RB/RC at day 30 (plts

Description: Background: Primary mediastinal large B-cell lymphoma (PMBCL) is a subset of aggressive B-cell non-Hodgkin lymphoma (B-NHL) with distinct biological and clinical features. Although most patients are cured with frontline chemoimmunotherapy with or without radiation therapy (RT), relapsed or refractory (rel/ref) PMBCL is much harder to control. Standard treatment of rel/ref PMBCL is similar to other aggressive B-NHLs, including salvage therapy and autologous (auto) stem cell transplantation (SCT) in chemosensitive patients. Recently, immunotherapy with PD-1 blockade and chimeric antigen receptor modified T-cells has proven to be effective in rel/ref PMBCL. Despite this, allogeneic (allo) SCT retains an important potential role as it has curative potential for patients with advanced aggressive B-NHLs. However, there are scant modern data on alloSCT outcomes in patients with PMBCL, limited to case reports or small series. We therefore performed a multicenter retrospective study to evaluate alloSCT outcomes in patients with rel/ref PMBCL. Methods: We retrospectively studied consecutive patients with rel/ref PMBCL who underwent alloSCT at Fred Hutchinson Cancer Center, Dana-Farber Cancer Institute, Massachusetts General Hospital, or City of Hope between 1/2000 and 5/2014. Baseline and transplant characteristics are reported descriptively. Progression-free survival (PFS) and overall survival (OS) were calculated using the Kaplan-Meier method. Incidence of relapse and non-relapse mortality were calculated using competing risks methods. Results: 28 patients with rel/ref PMBCL underwent alloSCT at participating institutions during the study period. Among these patients, median age at SCT was 36 years, 54% were female, median number of prior therapies was 4 (range, 2-7), 57% were refractory to frontline therapy, 86% received prior RT, and 71% had prior autoSCT. At alloSCT, 1 (4%) patient was in complete response (CR), 21 (75%) were in partial response (PR), and 6 (21%) were refractory to pre-alloSCT therapy (18 patients were assessed with PET). Most patients (86%) received reduced intensity conditioning, most commonly fludarabine/melphalan +/- ATG or Zevalin (25%), fludarabine/TBI200 (21%), or fludarabine/busulfan (14%). GVHD prophylaxis most frequently consisted of a calcineurin inhibitor (CNI) with mycophenolate mofetil (12, 43%), CNI with sirolimus +/- methotrexate (8, 29%), or CNI with MTX (4, 14%). 15 (54%) patients had a matched (8/8) related donor, 8 (29%) had a matched unrelated donor, 2 had a mismatched unrelated donor (7/8), and 3 had umbilical cord donors. All patients received peripheral blood stem cell grafts except for the 3 cord recipients. The median follow-up time in survivors was 5.0 (range 0.5-14.0) years. The 2 year PFS and OS in the cohort were 39% and 45%, respectively, while non-relapse mortality (NRM) and cumulative incidence of relapse (CIR) were 32% and 29%, respectively. The 5-year PFS, OS, NRM, and CIR were 34%, 45%, 32%, and 33%, respectively. The cumulative incidence of grade II-IV and III-IV acute GVHD were 39% and 4% at day 100, while the incidence of chronic GVHD at 1 year was 21% (18% extensive). Among patients in CR/PR at the time of alloSCT, the 2-year PFS and OS were 50% and 58%, respectively, as compared to a 2-year PFS and OS of 0% in patients who were refractory at the time of alloSCT (p=0.046 for PFS, p=0.014 for OS). One patient received post-alloSCT lenalidomide as maintenance therapy and remained in ongoing CR. Of the 9 patients who relapsed after alloSCT, 3 out of 4 patients exhibited a response to immunosuppression taper, while 4 out of 5 patients responded to subsequent systemic therapy. 2 patients underwent a donor lymphocyte infusion (DLI) and both developed subsequent GVHD - 1 patient had a CR documented 64 days after DLI while the other had continued disease progression. In the 9 patients who relapsed after alloSCT, the 2-year OS was 33%. Conclusions: AlloSCT can produce durable remissions in a subset of patients with heavily treated, rel/ref PMBCL. Patients with refractory disease at alloSCT had dismal outcomes. Despite the expanding treatment options available for these patients, alloSCT should be considered in the management of patients with rel/ref PMBCL who are sensitive to salvage therapy. Figure 1A PFS and OS After AlloSCT in Patients with Rel/Ref PMBCL Figure 1B PFS in Patients with Sensitive versus Refractory PMBCL at AlloSCT Disclosures Herrera: Merck, Inc.: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; AstraZeneca: Research Funding; Gilead Sciences: Research Funding; KiTE Pharma: Consultancy, Research Funding; Immune Design: Research Funding; Seattle Genetics: Research Funding; Pharmacyclics: Consultancy, Research Funding. Maloney:Roche/Genentech: Honoraria; GlaxoSmithKline: Research Funding; Juno Therapeutics: Research Funding; Seattle Genetics: Honoraria; Janssen Scientific Affairs: Honoraria. Ho:Jazz Pharmaceuticals: Consultancy. Soiffer:Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees. Antin:Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees. Forman:Mustang Therapeutics: Other: Licensing Agreement, Patents & Royalties, Research Funding. Chen:Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees; REGiMMUNE: Consultancy; Magenta Therapeutics: Consultancy; Takeda Pharmaceuticals: Consultancy. Armand:Otsuka: Research Funding; Affimed: Consultancy, Research Funding; Pfizer: Consultancy; Infinity: Consultancy; Merck: Consultancy, Research Funding; Adaptive: Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Roche: Research Funding; Tensha: Research Funding. Shadman:Acerta Pharma: Research Funding; AbbVie: Consultancy; Genentech: Research Funding; Beigene: Research Funding; Verastem: Consultancy; Qilu Puget Sound Biotherapeutics: Consultancy; Mustang Biopharma: Research Funding; Gilead Sciences: Research Funding; AstraZeneca: Consultancy; TG Therapeutics: Research Funding; Pharmacyclics: Research Funding; Celgene: Research Funding; Genentech: Consultancy.