Stevens, Don A.

e19553 Background: The combination of tafa + LEN has accelerated approval in the United States (2020) and conditional approval in Canada and Europe (2021) for R/R DLBCL in ASCT-ineligible adult pts. A tolerable safety profile for R-CHOP + tafa ± LEN in pts with newly diagnosed DLBCL in the Phase Ib First-MIND study (NCT04134936) was previously reported, with numerically superior efficacy for R-CHOP + tafa + LEN (ASH 2021; #3556). We report PK, PD, and immunogenicity of R-CHOP + tafa ± LEN in this first line setting. Methods: Eligible pts ≥18 years with treatment-naïve DLBCL, IPI 2–5, and ECOG PS 0–2 were randomized 1:1 to either six 21-day (D) cycles (C) of R-CHOP (R-CHO, D1; P, D1–5) + tafa (12 mg/kg IV, D1, 8, 15) (Arm A) or R-CHOP + tafa + LEN (25 mg orally, D1–10) (Arm B). Secondary endpoints included tafa serum conc and number and percentage of pts developing anti-tafa Abs. Exploratory endpoints included natural killer (NK) cell, T-cell, and B-cell count in peripheral blood. Results: Data cut-off: 13 March 2021 for safety analysis, incl. ≥1 month follow-up after EoT visit for all pts; 15 September 2021 for efficacy. Tafa serum conc reached steady state by C3 (geometric mean trough conc: Arm A, 186.40–216.55 µg/mL; Arm B, 171.77–201.54 µg/mL) and steadily declined after treatment completion. Anti-tafa Abs were detected in 1/65 (1.5%) pts. This pt showed pre-existing tafa Abs at baseline, which decreased during treatment. Median NK cell count decreased from baseline at C1D8 but was at baseline or higher levels by EoT visit (Arm A) and C1D15 (Arm B; Table). T-cell count decreased from baseline at C1D8 in both arms but was at baseline level or higher by C1D15 (Arm A) and EoT visit (Arm B). Median B-cell count decreased from baseline to 0 cells/μL (Arm A, C1D15; Arm B, C1D8); at 6-month follow-up after EoT visit, B-cell count had recovered to measurable levels in ̃50% of pts. Conclusions: Tafa serum conc reached and maintained a therapeutic dose level in this first-line regimen and declined in line with known tafa half-life (̃16 days) after treatment completion; tafa levels were comparable between the two treatment arms. No pt developed treatment-induced or treatment-boosted anti-tafa Abs. Median NK-cell, T-cell, and B-cell counts were comparable between treatment arms in all cycles. Clinical trial information: NCT04134936. [Table: see text]

Abstract Introduction Tafasitamab is a humanized, Fc-modified, anti-CD19 monoclonal antibody (mAb) shown to enhance antibody-dependent cellular cytotoxicity and phagocytosis. It is approved by the FDA under accelerated approval (July 2020) in combination with lenalidomide (LEN) for treatment of relapsed/refractory diffuse large B-cell lymphoma (R/R DLBCL) in adult patients ineligible for autologous stem cell transplantation. To evaluate if newly diagnosed DLBCL patients would also benefit from this regimen, this Phase Ib study (First-MIND; NCT04134936) was designed to first assess the safety and tolerability of tafasitamab ± LEN in addition to rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone (R-CHOP) in newly diagnosed DLBCL patients. Methods Eligible patients were ≥18 years old, with treatment-naïve DLBCL, international prognostic index (IPI) 2-5 and Eastern Cooperative Oncology Group performance status (ECOG PS) 0-2. Patients with known double- or triple-hit and transformed lymphoma were excluded. Patients were randomized 1:1 to either six 21-day [D] cycles of R-CHOP (R-CHO, D1; P, D1-5) + tafasitamab (12 mg/kg IV, D1, 8, 15) (Arm A) or R-CHOP + tafasitamab + LEN (25 mg orally, D1-10) (Arm B). Granulocyte colony-stimulating factor and venous thromboembolism prophylaxis was mandatory. The primary safety endpoint was incidence of treatment-emergent adverse events (TEAEs); secondary endpoints included overall response rate (ORR), positron emission tomography (PET)-complete response (CR) rate, and partial response (PR) rate at end of treatment (EOT). Tumor measurements by PET/CT or PET/MRI at EOT were performed according to Lugano 2014 criteria within 6±2 weeks after Day 21 of the last treatment cycle the patient started. Results From December 2019 to August 2020, 83 patients were screened in nine countries across 34 sites in Europe and the US; 66 were randomized (Arm A, n=33; Arm B, n=33). Data cut-off for this analysis: 13 March 2021. Median age was 64.5 years (range 20-86). Many patients had high-risk disease: IPI 2: 24/66 (36.4%), IPI 3: 29/66 (43.9%), IPI 4: 11/66 (16.7%), IPI 5: 2/66 (3.0%); ECOG PS ≥2: 6/66 (9.1%). Most patients had Stage III/IV disease 62/66 (93.9%); 29/66 (43.9%) had bulky disease. All patients experienced at least one TEAE. The most frequent Grade ≥3 TEAEs by system organ class were blood and lymphatic disorders (81.8% patients overall), experienced by 24 patients (72.7%) in Arm A and 30 patients (90.9%) in Arm B. Grade ≥3 neutropenia and thrombocytopenia occurred in 19/33 (57.6%) and 4/33 (12.1%) (Arm A), and 28/33 (84.8%) and 12/33 (36.4%) (Arm B) patients, respectively; Grade ≥3 febrile neutropenia was experienced by 6/33 (18.2%) patients in each arm. Grade ≥3 infusion-related reactions to both rituximab and tafasitamab occurred in no patients in Arm A and one patient (3.0%) in Arm B, and 7/33 (21.2%) (Arm A) and 9/33 (27.3%) (Arm B) patients had a Grade ≥3 infection and/or infestation (Figure 1). Serious TEAEs occurred in 14/33 (42.4%) patients in Arm A and 17/33 (51.5%) patients in Arm B. Two out of 33 (6.1%) and one out of 33 (3.0%) patients discontinued study treatment due to TEAEs in Arms A and B, respectively. There were four deaths unrelated to tafasitamab and/or LEN (COVID-19 pneumonia, sepsis, and urosepsis). The average relative dose intensity of R-CHOP in each cycle was maintained in both arms. ORR at EOT was observed in 25/33 patients (75.8%; 95% confidence interval [CI]: 57.7-88.9) in Arm A and 27/33 patients (81.8%; 95% CI: 64.5-93.0) in Arm B. Conclusion These data suggest that both regimens are tolerable and do not impair dosing and scheduling of R-CHOP. Toxicities were similar to those expected with R-CHOP with or without LEN. With tumor follow-up still ongoing, the ORR at EOT suggests that patients with treatment-naïve DLBCL may achieve clinically meaningful efficacy tafasitamab and LEN in addition to standard treatment. A Phase III, multicenter, randomized, double-blind, placebo-controlled trial will assess efficacy and safety of R-CHOP + tafasitamab + LEN vs R-CHOP in newly diagnosed patients with high intermediate and high risk DLBCL, and is currently recruiting (frontMIND study; NCT04824092). Funding: MorphoSys AG. Figure 1 Figure 1. Disclosures Belada: Roche: Consultancy, Other: Travel, Accommodations, Expenses, Research Funding; Gilead Sciences: Consultancy, Other: Travel, Accommodations, Expenses, Research Funding; Janssen-Cilag: Consultancy, Research Funding; Takeda: Consultancy, Other: Travel, Accommodations, Expenses, Research Funding; MorphoSys AG: Consultancy, Research Funding; Debiopharm Group: Consultancy; Pharmacyclics: Research Funding; Archigen Biotech: Research Funding; Reddys: Research Funding. André: Johnson & Johnson: Research Funding; Roche: Other: Travel/accomodation/expenses, Research Funding; Incyte: Consultancy; Gilead: Consultancy, Other: Travel/Accommodations/Expenses; Karyopharm: Consultancy; Bristol-Myers-Squibb: Consultancy, Other: Travel/Accommodations/Expenses; Takeda: Consultancy, Research Funding; Celgene: Other: Travel/accomodation/expenses; AbbVie: Other: Travel/accomodation/expenses. Pérez Persona: Amgen: Consultancy, Other: Support for attending meetings and/or travel, Speakers Bureau; BMS/Celgene: Consultancy, Other: Support for attending meetings and/or travel, Speakers Bureau; AbbVie: Other: Support for attending meetings and/or travel, Speakers Bureau; Takeda: Speakers Bureau; Sanofi: Consultancy, Speakers Bureau; AstraZeneca: Speakers Bureau; GSK: Consultancy; Incyte: Consultancy. Staber: Roche: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Astra Zeneca: Consultancy, Honoraria; Takeda: Consultancy, Research Funding; MSD: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Incyte: Consultancy, Honoraria, Research Funding; Beigene: Consultancy, Honoraria. Trneny: AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses; Amgen: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses; Gilead Sciences: Consultancy, Honoraria, Other: Travel, Accommodations, Expenses; Incyte: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses; MorphoSys: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses; Celgene: Consultancy; 1st Faculty of Medicine, Charles University, General Hospital in Prague: Current Employment; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Portola: Honoraria, Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Honoraria. Brackertz: MorphoSys AG: Current Employment. Shah: MorphoSys AG: Current Employment. Sporchia: MorphoSys AG: Current Employment. Burke: MorphoSys: Consultancy; Adaptive Biotechnologies: Consultancy; Verastem: Consultancy; AstraZeneca: Consultancy; Bristol Myers Squibb: Consultancy; Kymera: Consultancy; X4 Pharmaceuticals: Consultancy; AbbVie: Consultancy; SeaGen: Consultancy, Speakers Bureau; Kura: Consultancy; Roche/Genentech: Consultancy; Epizyme: Consultancy; Beigene: Consultancy, Speakers Bureau. Nowakowski: Celgene, NanoString Technologies, MorphoSys: Research Funding; Celgene, MorphoSys, Genentech, Selvita, Debiopharm Group, Kite/Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees. OffLabel Disclosure: Tafasitamab is a humanized Fc-modified cytolytic CD19 targeting monoclonal antibody. In combination with lenalidomide (LEN), it received accelerated approval in July 2020 for adult patients with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL) not otherwise specified (NOS), including arising from lowâ€'grade lymphoma, who are ineligible for autologous stem cell transplant (ASCT). Following FDA approval, we are now evaluating the safety and efficacy of tafasitamab in combination with LEN as an add-on to first-line therapy with R-CHOP in newly diagnosed patients with DLBCL.

Abstract Introduction: Patients with relapsed or refractory diffuse large B-cell lymphoma (RR DLBCL) who cannot tolerate or who are not eligible for autologous or chimeric antigen receptor T cell (CAR-T) therapy have limited therapeutic options and suboptimal long-term outcomes. In patients who were not eligible for HSCT, the rituximab plus gemcitabine, dexamethasone and cisplatin (R-GDP) regimen (and variations using methylprednisolone or carboplatin/oxaliplatin) have shown an overall response rates (ORR) of ~50%, a complete response (CR) rate of ~25% (Gopal, Leuk Lymphoma, 2010), and a median progression-free survival (PFS) and an overall survival (OS) of 3 and 9 months, respectively (Crump, Hematol Oncol Clin N Am. 2016; Gopal Leuk Lymphoma, 2010; Ng, Br J Cancer, 2005; Sirohi, Hematology, 2007; Barton, Eur J Haematol. 2015; Moccia Leuk Lymphoma, 2017). Selinexor is an oral small molecule selective inhibitor of exportin-1 (XPO1) mediated nuclear export (SINE) compound leading to activation of tumor suppressor proteins and reduction in oncoprotein levels. It also reduces the expression of deoxyribonucleic acid (DNA) damage repair proteins and therefore potentiates DNA damage-based therapies leading to an increased death of cancer cells. Selinexor has synergistic effects with gemcitabine and cisplatin, and enhanced anti-lymphoma effects with dexamethasone. In the SADAL study (n=134), single-agent oral selinexor 60 mg twice weekly induced an ORR of 29% and a CR rate of 13% in patients with RR DLBCL. The response rates were consistent across various subgroups including patients <70 vs ≥70 years old, those with de novo and transformed DLBCL, and GCB and non-GCB subtypes of DLBCL. The median duration of response (DOR) was 9.3 months, and 23 months for patients who achieved CR. OS was 9.0 months. In June 2020, selinexor monotherapy was approved in the US for the treatment of adult patients with RR DLBCL, not otherwise specified, including DLBCL arising from follicular lymphoma, after at least 2 lines of systemic therapy. Selinexor in combination with R-GDP was evaluated in a Phase 1 clinical trial (SELINDA), in which patients with DLBCL received either 40 or 60 mg selinexor once or twice weekly in combination with standard dose R-GDP. The recommended phase 2 dose for further exploration was 40 or 60 mg once weekly with an ORR of 60-80%. Therefore, combining selinexor with R-GDP is expected to improve response rates, and continuation of treatment with single-agent selinexor is expected to prolong the duration of responses, improve PFS (and potentially OS) in patients with RR DLBCL. Materials and methods: XPORT-DLBCL-030 is a Phase 2/3, multicenter study. The Phase 2 portion of the study is an open-label randomized study to identify the optimal dose of selinexor (40 or 60 mg) in combination with R-GDP in patients (n=120) with RR DLBCL. Patients ≥18 years with 1-3 prior lines of therapy and ECOG performance status ≤2 who are not intended for HSCT or CAR-T therapy are randomized 1:1:1 to one of 3 treatment arms: Arm 1: selinexor 40 mg+R-GDP (S40+R-GDP); Arm 2: selinexor 60 mg+R-GDP (S60 + R-GDP); Arm 3: R-GDP. Combination treatment will be given for up to 6 cycles (21 days/cycle). After completing the SR-GDP combination therapy (EoC), patients in Arms 1 and 2 who reach at least partial response (PR), will receive weekly single-agent selinexor 60 mg (28 days/cycle) as "continuous therapy" until disease progression (PD) or unacceptable toxicity. After PD, patients will be followed up for survival. Patients in the R-GDP arm will be followed up for PD and survival. Patients who are ineligible for HSCT due to an active disease, or those who have primary refractory DLBCL, defined as no response or relapse within 6 months after ending first-line treatment, will be allowed to enroll in the study (up to 15% and 25%, respectively of all patients enrolled). The primary endpoint of the study is ORR according to the Lugano 2014 criteria. Secondary endpoints include PFS, OS, ORR-EoC, DOR and incidence and severity of adverse events. Figure 1 Figure 1. Disclosures Pinto: Takeda: Consultancy; MSD: Honoraria; Incyte: Honoraria; Roche: Honoraria, Speakers Bureau; Bristol Myers Squibb-CELGENE: Honoraria. Yimer: Texas Oncology: Current Employment; Pharmacyclics: Speakers Bureau; Amgen: Speakers Bureau; Sanofi: Speakers Bureau; GSK: Speakers Bureau; Beigene: Speakers Bureau; Janssen: Speakers Bureau; Astrazeneca: Speakers Bureau; Karyopharm: Current equity holder in publicly-traded company, Speakers Bureau. Manda: Morphosys: Honoraria; Genmab: Current equity holder in publicly-traded company. Canales: Sanofi: Consultancy; Incyte: Consultancy; Novartis: Consultancy, Honoraria; Sandoz: Honoraria, Speakers Bureau; iQone: Honoraria; Karyopharm: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Speakers Bureau; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau; Gilead/Kite: Consultancy, Honoraria; Eusa Pharma: Consultancy, Honoraria; Celgene/Bristol-Myers Squibb: Consultancy, Honoraria. Jurczak: European Medicines Agency, Sandoz-Novartis, Janssen China R&D, BeiGene, Epizyme, Acerta, AstraZeneca: Consultancy; AbbVie, AstraZeneca, Bayer, BeiGene, Celtrion, Celgene, Debbiopharm, Epizyme, Incyte, Janssen, Loxo Oncology, Merck, Mei Pharma, Morphosys, Novo Nordisk, Roche, Sandoz, Takeda, TG Therapeutics, Pharmacyclics, Affirmed, Gilead Sciences, Nordic Nanovecto: Research Funding; Jagiellonian University: Ended employment in the past 24 months; Maria Sklodowska-Curie National Research Institute of Oncology: Current Employment; AstraZeneca, BeiGene, Janssen, Loxo Oncology, Sandoz, Roche: Membership on an entity's Board of Directors or advisory committees. Sureda: Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Kite, a Gilead Company: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; MSD: Consultancy, Honoraria, Speakers Bureau; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; GSK: Consultancy, Honoraria, Speakers Bureau; Roche: Other: Support for attending meetings and/or travel; Bluebird: Membership on an entity's Board of Directors or advisory committees; Mundipharma: Consultancy; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Support for attending meetings and/or travel, Research Funding, Speakers Bureau; BMS/Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Support for attending meetings and/or travel, Speakers Bureau. Ma: Karyopharm Therapeutics Inc.: Current equity holder in publicly-traded company, Ended employment in the past 24 months. Li: Karyopharm Therapeutics Inc.: Current Employment, Current equity holder in publicly-traded company. Ingalls: Karyopharm Therapeutics Inc.: Current Employment, Current equity holder in publicly-traded company. Arriola: Karyopharm Therapeutics Inc.: Current Employment, Current equity holder in publicly-traded company. Arazy: Karyopharm Therapeutics Inc.: Current Employment, Current equity holder in publicly-traded company. Shah: Karyopharm Therapeutics Inc.: Current Employment, Current equity holder in publicly-traded company. Shacham: Karyopharm: Current Employment, Current equity holder in publicly-traded company, Patents & Royalties: (8999996, 9079865, 9714226, PCT/US12/048319, and I574957) on hydrazide containing nuclear transport modulators and uses, and pending patents PCT/US12/048319, 499/2012, PI20102724, and 2012000928) . Kauffman: Karyopharm Therapeutics Inc.: Current Employment, Current equity holder in publicly-traded company. Nowakowski: Celgene, NanoString Technologies, MorphoSys: Research Funding; Celgene, MorphoSys, Genentech, Selvita, Debiopharm Group, Kite/Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees.

SummaryFimepinostat (CUDC‐907), a first‐in‐class oral small‐molecule inhibitor of histone deacetylase and phosphatidylinositol 3‐kinase, demonstrated efficacy in a phase 1 study of patients with relapsed/refractory (R/R) diffuse large and high‐grade B‐cell lymphomas (DLBCL/HGBL), particularly those with increased MYC protein expression and/orMYCgene rearrangement/copy number gain (MYC‐altered disease). Therefore, a phase 2 study of fimepinostat was conducted in this patient population with 66 eligible patients treated. The primary end‐point of overall response (OR) rate for patients with MYC‐IHC ≥40% (n = 46) was 15%. Subsequently, exploratory pooled analyses were performed including patients treated on both the phase 1 and 2 studies based upon the presence of MYC‐altered disease as well as a biomarker identified by Virtual Inference of Protein activity by Enriched Regulon analysis (VIPER). For these patients with MYC‐altered disease (n = 63), the overall response (OR) rate was 22% with seven responding patients remaining on treatment for approximately two years or longer, and VIPER yielded a three‐protein biomarker classification with positive and negative predictive values of ≥85%. Prolonged durations of response were achieved by patients with MYC‐altered R/R DLBCL/HGBL treated with single‐agent fimepinostat. Combination therapies and/or biomarker‐based patient selection strategies may lead to higher response rates in future clinical trials.

Introduction Approximately 15-20% of treatment-naïve patients with diffuse large B-cell lymphoma (DLBCL) have CD20-low tumors, while CD19 is homogeneously expressed in >90% of cases of DLBCL. CD20-low DLBCL is associated with poor response to rituximab-based regimens (Johnson NA, et al. 2009). CD19 functions as a positive regulator of B-cell receptor signaling and is important for B-cell activation and proliferation and is therefore an attractive therapeutic target in addition to CD20. Tafasitamab (MOR208) is a humanized, Fc-enhanced, anti-CD19 monoclonal antibody with improved antibody-dependent cellular cytotoxicity and phagocytosis. Monotherapy with tafasitamab has shown clinical activity in relapsed/refractory (R/R) non-Hodgkin's lymphoma (Jurczak W, et al. 2018). In the Phase II, single-arm L-MIND study (NCT02399085) in patients with R/R DLBCL, combined treatment of tafasitamab with lenalidomide resulted in a high proportion of patients having a complete response (Salles GA, et al. 2020). First-MIND (NCT04134936) is a Phase Ib, randomized study of tafasitamab + R-CHOP (Arm A) or tafasitamab + lenalidomide + R-CHOP (Arm B) in patients with newly diagnosed DLBCL. Here, we report data from the safety run-in phase. Study design and methods Patients must be aged ≥18 years, treatment naïve, with histologically confirmed DLBCL not otherwise specified and have intermediate- to high-risk disease (International Prognostic Index [IPI] 2-5) and an ECOG performance status of 0-2. Known double- or triple-hit lymphoma and transformed lymphoma are excluded. Treatment consists of six 21-day cycles of tafasitamab (12 mg/kg intravenously [IV], on Day [D] 1, 8 and 15) in addition to R-CHOP (Arm A) or tafasitamab (12 mg/kg IV, on D1, 8 and 15) + lenalidomide (25 mg orally, on D1-10) in addition to R-CHOP (Arm B). Granulocyte-colony stimulating factor prophylaxis was mandatory in all patients. The study includes a safety run-in phase and a main phase. In the safety run-in phase, 24 patients were enrolled. The primary objective is to assess safety; secondary objectives include ORR, PET-CR rate at end of treatment, PFS, event-free survival, long-term safety, pharmacokinetics and immunogenicity of tafasitamab. Exploratory objectives include the assessment of circulating cell-free tumor DNA. Approximately 60 patients will be recruited in 9 countries across Europe and the US. Results Recruitment is ongoing. Thirty-six patients were randomized; 18 in each arm. The data presented for the safety run-in phase consist of 24 patients: 13 patients in Arm A and 11 patients in Arm B. All completed the first treatment cycle; 88% of patients entered into Cycle 2 and 50% of patients entered into Cycle 3 of treatment. At baseline, their median age was 67 years (range: 47-76; Arm A) and 65 years (range: 40-74; Arm B). Overall, 33% of patients were male and 67% female; IPI scores were: IPI 2, 33%; IPI 3, 42%; IPI 4, 25%. Most patients had advanced stages III/IV (92%) and approximately 50% had bulky disease. Cell of origin was determined to be germinal center B-cell (GCB) DLBCL in 13%, non-GCB DLBCL in 42% and not yet classified in 46% of cases. A total of 248 treatment-emergent adverse events (AEs) by system organ class were documented: 111 in Arm A and 137 in Arm B. Grade ≥3 neutropenia was observed in 54% (Arm A) and 46% (Arm B) of patients. Thrombocytopenia Grade ≥3 was observed in 8% (Arm A) and 18% (Arm B) of patients. Diarrhea, fatigue and vomiting were comparable between the two arms. Febrile neutropenia was uncommon in both arms, with one event each (Figure 1). To date, 23 serious AEs were observed: 11 in Arm A (Grade 2, 1; Grade 3, 6; Grade 4, 4) and 12 in Arm B (Grade 2, 3; Grade 3, 7; Grade 4, 2). One suspected unexpected serious adverse reaction was reported in Arm B - pneumocystis jirovecii pneumonia. No treatment-associated deaths occurred. Conclusions R-CHOP can be safely combined with tafasitamab or tafasitamab + lenalidomide in patients with treatment-naïve DLBCL. Toxicities appear to be similar to what is expected with R-CHOP alone or in combination with lenalidomide. Enrollment is ongoing and updated safety and early efficacy data will be presented at the meeting. Disclosures Belada: Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel expenses, Research Funding; Roche: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel expenses, Research Funding; Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel expenses, Research Funding; Celgene: Research Funding; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Nowakowski:NanoString: Research Funding; Seattle Genetics: Consultancy; Curis: Consultancy; MorphoSys: Consultancy, Research Funding; Celgene/BMS: Consultancy, Research Funding; Kite: Consultancy; Kymera: Consultancy; Ryvu: Consultancy, Membership on an entity's Board of Directors or advisory committees. André:Takeda: Consultancy; Karyopharm: Consultancy; Gilead: Consultancy, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Novartis: Consultancy, Research Funding; Seattle Genetics: Consultancy; Abbvie: Consultancy; Roche: Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; Amgen: Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; Johnson & Johnson: Research Funding; Celgene: Other, Research Funding; CHU UCL Namur, site Godinne, Yvoir, Belgium: Current Employment; Bristol-Myers-Squibb: Consultancy, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company). Stevens:Amgen, MorphoSys: Consultancy. Trněný:Takeda: Consultancy, Honoraria, Other: Travel Expenses; Bristol-Myers Squibb Company: Consultancy, Honoraria, Other: Travel Expenses; Amgen: Honoraria; Abbvie: Consultancy, Honoraria, Other: Travel Expenses; Roche: Consultancy, Honoraria, Other: Travel Expenses; MorphoSys: Consultancy, Honoraria; Incyte: Consultancy, Honoraria; Celgene: Consultancy; Janssen: Consultancy, Honoraria, Other: Travel Expenses; Gilead: Consultancy, Honoraria, Other: Travel Expenses. Pérez Persona:Celgene: Consultancy, Speakers Bureau; Roche: Consultancy, Speakers Bureau; Jannsen: Consultancy, Speakers Bureau; Amgen: Consultancy; Abbvie: Consultancy, Speakers Bureau; Takeda: Consultancy. Klöpfer:MorphoSys AG: Current Employment. Brackertz:MorphoSys AG: Current Employment. Lohrmann:MorphoSys AG: Current Employment. Lahiry:MorphoSys AG: Current Employment. Shah:MorphoSys AG: Current Employment. Fingerle-Rowson:MorphoSys AG: Current Employment. Brugger:MorphoSys AG: Current Employment. Burke:Epizyme: Consultancy; Roche: Consultancy; Bristol Myers Squibb: Consultancy; Kura: Consultancy; Celgene: Consultancy; Adaptive Biotechnologies: Consultancy; Gilead: Consultancy; Seattle Genetics: Speakers Bureau; AbbVie: Consultancy; Verastem: Consultancy; Bayer: Consultancy; Astra Zeneca: Consultancy; Adaptive: Consultancy; Morphosys: Consultancy.