Abstract: 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 & gt;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.

Abstract: 7540 Background: Tafasitamab is a humanized, Fc-modified anti-CD19 monoclonal antibody that enhances antibody-dependent cellular cytotoxicity and phagocytosis. It is FDA-approved with LEN for adult patients (pts) with relapsed/refractory (R/R) DLBCL ineligible for autologous stem cell transplantation. First-MIND (NCT04134936) is a Phase Ib, open-label, randomized study of tafa + R-CHOP or tafa + LEN + R-CHOP in newly diagnosed DLBCL. Methods: Eligible pts were ≥18 years, treatment-naïve, with histologically confirmed DLBCL not otherwise specified, international prognostic index (IPI) 2–5 and ECOG performance status (PS) 0–2. Pts with known double- or triple-hit and transformed lymphoma were excluded. Treatment (Tx) comprised six 21-day cycles of tafa (12 mg/kg IV, Day [D] 1, 8, 15) + R-CHOP (arm A) or tafa (12 mg/kg IV, D1, 8, 15) + LEN (25 mg orally, D1–10) + R-CHOP (arm B). G-CSF and VTE prophylaxis was mandatory. Primary objective is safety; secondary objectives are ORR, PET-CR rate at end of Tx, PFS, long-term safety, pharmacokinetics, immunogenicity. Results: From Dec 2019 to Aug 2020, 83 pts were screened in Europe and the US; 66 were randomized (33 per arm). Data cut-off for this analysis: 9 Dec 2020; study is ongoing. Median age was 64.5 years (range 20–86). Overall, 30% (20/66) of pts were ≥70 years and many had high-risk disease: IPI 2 29%, IPI 3 46%, IPI 4 26%. ECOG PS: 47% of pts were ECOG PS 0, 44% PS 1, 9% PS 2. Most pts had stage III/IV disease (92%); 46% had bulky disease. All pts experienced a treatment-emergent adverse event (TEAE). Grade ≥3 neutropenia and thrombocytopenia occurred in 54.5% and 12.1% (arm A) and 66.7% and 30.3% (arm B) of pts, respectively (Table). Serious TEAEs occurred in 42.4% (arm A) and 51.5% (arm B) of pts. There were three deaths, unrelated to tafa and/or LEN (sepsis, urosepsis, and COVID-19 pneumonia). R-CHOP dose intensity was maintained in both arms. Among 60 pts who completed tumor assessments after cycle 3, ORR was 89.7% (arm A) and 93.5% (arm B). Conclusions: These data suggest R-CHOP + tafa or tafa + LEN is tolerable in pts with Tx-naïve DLBCL and that R-CHOP dosing is not affected. Toxicities are similar to those expected with R-CHOP or R-CHOP + LEN. Updated safety and early efficacy data will be presented at the conference. Clinical trial information: NCT04134936. [Table: see text]

Abstract: Anti-CD19 immunotherapy tafasitamab in combination with lenalidomide is used in patients with relapsed/refractory diffuse large B-cell lymphoma (DLBCL) ineligible for autologous stem cell transplant. Open-label, phase 1b, First-MIND study assessed safety and preliminary efficacy of tafasitamab + R-CHOP ± lenalidomide as first-line therapy in patients with DLBCL. Adults with newly-diagnosed, untreated DLBCL (ECOG PS 0-2, IPI 2-5), were randomly assigned to R­CHOP+tafasitamab (Arm T) or R-CHOP+tafasitamab+lenalidomide (Arm T/L) for six cycles. Primary endpoint was safety; secondary endpoints included overall response rate (ORR) and complete response (CR) rate at end of treatment (EoT). From Dec2019-Aug2020, 83 patients were screened, 66 treated (n=33 per arm). All patients had ≥1 treatment-emergent adverse event, mostly grade 1/2. Grade ≥3 neutropenia and thrombocytopenia occurred in 57.6% and 12.1% of patients (Arm T), and 84.8% and 36.4% (Arm T/L). Non-hematologic toxicities occurred at similar rates between arms. Mean relative dose intensity of R-CHOP was 89% or higher in both arms. ORR at EoT was 75.8% (CR 72.7%) in Arm T and 81.8% (CR 66.7%) in Arm T/L; best ORR across visits was 90.0% and 93.9%. Eighteen-month duration of response and duration of CR rates were 72.7% and 74.5% (Arm T), and 78.7% and 86.5% (Arm T/L); 24-month progression-free survival and overall survival rates were 72.7% and 90.3% (Arm T), and 76.8% and 93.8% (Arm T/L). Manageable safety and promising signals of efficacy were observed in both arms. Potential benefit of adding tafasitamab+lenalidomide to R-CHOP is being investigated in phase 3 frontMIND (NCT04824092).

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.