Abstract: Introduction Patients with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL) who are not eligible for autologous stem cell transplant (ASCT) have a poor prognosis. Tafasitamab (MOR208) is an Fc-enhanced, humanized, monoclonal antibody that targets CD19, which is broadly expressed across B-cell malignancies, including DLBCL. Lenalidomide (LEN) is an immunomodulatory drug with antiproliferative and antiangiogenic effects. Combined tafasitamab + LEN has shown enhanced activity in in vitro and in vivo lymphoma models. L-MIND (NCT02399085) is an ongoing, open-label, single-arm, Phase II study of tafasitamab + LEN in patients with R/R DLBCL who are ineligible for ASCT. Here, we present results from prespecified patient subgroup analyses from L-MIND. Methods Patients aged ≥18 years with R/R DLBCL (1-3 prior systemic therapies, including ≥1 CD20-targeting regimen) with an Eastern Cooperative Oncology Group performance status 0-2, and who were ineligible for ASCT were enrolled. Patients received 28-day cycles of tafasitamab (12 mg/kg intravenously), once weekly during Cycles 1-3 with a loading dose on Cycle 1 Day 4, then every 2 weeks during Cycles 4-12. LEN (25 mg orally) was administered on Days 1-21 of Cycles 1-12. After Cycle 12, progression-free patients received tafasitamab every 2 weeks until disease progression. The primary endpoint is objective response rate (ORR; partial response [PR] + complete response [CR] ), assessed centrally by an independent review committee (IRC) per International Working Group criteria 2007, incorporating PET-based imaging. Secondary endpoints include ORR (investigator-assessed), duration of response (DOR), progression-free survival (PFS), overall survival (OS), safety and biomarker analyses. Results Of 81 patients enrolled, 80 patients received tafasitamab + LEN and were included in the full analysis set (FAS) for efficacy (data cut-off 30 Nov 2018). Median follow-up was 17.3 months. In the FAS, ORR was 60.0% (95% confidence interval [CI]: 48.4-70.8) (Figure 1A). The CR rate was 42.5% (n=34/80), of which 88.2% (n=30/34) were PET-confirmed. Median time to response (PR or CR) was 2.0 months and median time to CR was 7.1 months. Median DOR was 21.7 months (95% CI: 21.7-not reached [NR] ); median PFS was 12.1 months (95% CI: 5.7-NR); and median OS was NR (95% CI: 18.3-NR) with a median follow-up of 19.6 months. The 12-month DOR and OS rates were 71.6% (95% CI: 55.1-82.9) (Figure 1B) and 73.7% (95% CI: 62.2-82.2) (Figure 1C), respectively. In the subgroup analysis, patients with CR as best objective response (BOR) had better outcomes than those with PR: median DOR, NR (95% CI: 21.7-NR) vs 4.4 months (95% CI: 2.0-9.1); 12-month DOR rate, 93.2% (95% CI: 75.4-98.3) vs 14.4% (95% CI: 1.1-43.7); and 12-month OS rate, 97.1% vs 76.9%. Patients with one prior line of therapy had a trend for better outcomes than those with ≥2 prior lines: ORR, 70.0% vs 50.0%; and 12-month OS rate, 86.9% vs 60.1%. However, the 12-month DOR rate was similar regardless of the number of prior lines (one prior line: 70.5% [95% CI: 47.2-85.0] vs ≥2 prior lines: 72.7% [95% CI: 46.3-87.6] ). For patients who were refractory to primary therapy or their last line of therapy, similar ORRs were observed to non-refractory patients (60.0% vs 60.0%); 12-month DOR was similar regardless of refractory status to last therapy; and 12-month OS rates were higher in non-refractory patients (Figure 1C). As expected, patients with a low/low-intermediate International Prognostic Index (IPI) score had better outcomes than those with an intermediate-high/high score: ORR, 70.0% vs 50.0%; 12-month DOR rate, 86.5% vs 50.4%; and 12-month OS rate, 87.0% vs 59.9%. Based on Hans algorithm, encouraging outcomes were reported in patients with germinal center B-cell (GCB) DLBCL (n=37), and outcomes were even better in those with non-GCB DLBCL (n=21): ORR, 48.6% vs 71.4%; median DOR, NR vs 21.7 months; 12-month DOR rate, 53.5% vs 83.1%; and 12-month OS rate, 65.4% vs 84.2%. Conclusions Tafasitamab + LEN combination followed by tafasitamab monotherapy shows encouraging activity with durable responses in ASCT-ineligible patients with R/R DLBCL. L-MIND includes a substantial number of poor prognosis patient subgroups. While the influence of these risk factors is evident, the clinical activity of tafasitamab + LEN in these difficult-to-treat patients is promising, particularly in those who were refractory to prior therapies. Disclosures Duell: Regeneron Pharmaceuticals, Inc.: Research Funding. Maddocks:Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees; Teva: Membership on an entity's Board of Directors or advisory committees; Novartis: Research Funding; Merck: Research Funding; BMS: Research Funding. González-Barca:Janssen: Consultancy, Honoraria; Kiowa: Consultancy; Celtrion: Consultancy; Celgene: Consultancy; AbbVie: Consultancy, Honoraria; Roche: Consultancy, Honoraria; Takeda: Honoraria. Jurczak:TG Therapeutics: Research Funding; Roche: Research Funding; Takeda: Research Funding; Servier: Research Funding; Celtrion: Research Funding; Novo Nordisk: Research Funding; Incyte: Research Funding; Bayer: Research Funding; Loxo: Membership on an entity's Board of Directors or advisory committees, Research Funding; AstraZeneca: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Research Funding; Sandoz: Membership on an entity's Board of Directors or advisory committees, Research Funding; MorphoSys: Research Funding. Liberati:Incyte: Consultancy; Janssen: Honoraria; Servier: Honoraria, Membership on an entity's Board of Directors or advisory committees; AbbVie: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria; Takeda: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Bristol & Mayer: Honoraria. de Vos:Bayer: Consultancy; Verastem: Consultancy; Portola Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees. Nagy:Janssen: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees. Gaidano:AbbVie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sunesys: Consultancy, Honoraria; Astra-Zeneca: Consultancy, Honoraria; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Abrisqueta:Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Other: Travel, Accommodations, expenses, Speakers Bureau; Roche: Consultancy, Honoraria, Other: Travel, Accommodations, expenses, Speakers Bureau; Abbvie: Consultancy, Honoraria, Other: Travel, Accommodations, expenses, Speakers Bureau. André:Takeda: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers-Squibb: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees, Other: Travel grants; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Roche: Other: Travel grants, Research Funding; Amgen: Other: Travel grants, Research Funding; Johnson & Johnson: Research Funding; Takeda Millenium: Research Funding; Chugai: Research Funding; Celgene: Other: Travel grants, Research Funding. Dreyling:Celgene: Other: Scientific advisory board, Research Funding, Speakers Bureau; Gilead: Other: Scientific advisory board, Speakers Bureau; Janssen: Other: Scientific advisory board, Research Funding, Speakers Bureau; Mundipharma: Other: Scientific advisory board, Research Funding; Novartis: Other: Scientific advisory board; Roche: Other: Scientific advisory board, Research Funding, Speakers Bureau; Sandoz: Other: Scientific advisory board; Acerta: Other: Scientific advisory board; Bayer: Other: Scientific advisory board, Speakers Bureau. Menne:Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Kite/Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel grant, Research Funding, Speakers Bureau; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel grant, Research Funding, Speakers Bureau; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel grant; Daiichi Sankyo: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel grant, Research Funding, Speakers Bureau; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Bayer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel grant, Research Funding, Speakers Bureau; Jazz: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel grant, Research Funding, Speakers Bureau; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Astra Zeneca: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Kyowa Kirin: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel grant, Research Funding, Speakers Bureau. Dirnberger-Hertweck:MorphoSys: Employment. Weirather:MorphoSys: Employment. Ambarkhane:MorphoSys: Employment. Salles:Merck: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Other: Educational events; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Educational events; Roche, Janssen, Gilead, Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Educational events; Epizyme: Consultancy, Honoraria; Novartis, Servier, AbbVie, Karyopharm, Kite, MorphoSys: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Educational events; Autolus: Consultancy, Membership on an entity's Board of Directors or advisory committees; BMS: Honoraria.

Abstract: 7514 Background: The Fc-enhanced CD19 antibody MOR208 and the immunomodulatory drug LEN have demonstrated single agent activity in patients (pts) with R-R DLBCL. MOR208 and LEN have shown synergy in vitro and in vivo in preclinical lymphoma models. This ongoing phase II study assesses the safety and efficacy of MOR208 + LEN in pts with R-R DLBCL. Methods: Pts 〉 18 years old with R-R DLBCL, ECOG 0–2, adequate organ function, having previously received ≥1 but not more than 3 prior therapies, including ≥1 CD20-targeting regimen and who are not candidates for autologous stem cell transplant (ASCT), are eligible. Treatment comprises up to 12, 28-day (d) cycles (C) of MOR208 12 mg/kg IV, weekly during C1–3 (loading dose d4 of C1); every second week C4–12 + LEN 25 mg po d1–21, C1–12. Pts progression-free after 12 cycles receive up to 12 additional cycles of MOR208 (every second week). The primary endpoint is the overall response rate (ORR) by central radiology assessment. Secondary endpoints include disease control, duration of response, progression-free and overall survival, safety, and response by cell of origin and other biomarkers. A preplanned safety evaluation was undertaken. Results: 31 of 80 planned pts were enrolled prior to data cutoff (3 January 2017). Median age was 74 years (range 47–82); 45% of pts received ≥2 prior lines of therapy; 23% had rituximab refractory disease; 74% had Ann Arbor stage ≥III disease; 65% had elevated lactate dehydrogenase level, and 52% had a poor revised International Prognostic Index (3-5). The most common treatment-emergent adverse events (any grade/grade ≥3 [% pts]) were neutropenia (39/26), anemia (23/0) thrombocytopenia (16/6), infections (26/10) diarrhea (13/0), pyrexia (13/0), and rashes (13/6). Of 26 response evaluable pts (median follow-up 3.3 months), ORR (investigator assessed) was 58% (15 pts), with 7 (27%) complete responses. Median time to response was 1.8 months. Conclusions: The combination of MOR208 + LEN is well tolerated and shows promising activity in pts with R-R DLBCL. Accrual and follow-up of pts is ongoing, as are cell of origin and other biomarker analyses. Clinical trial information: NCT02399085.

Abstract: 7521 Background: MOR208, an Fc-enhanced, humanized, anti-CD19 monoclonal antibody has shown single agent activity in patients (pts) with R-R DLBCL and encouraging activity when combined with LEN in the phase II L-MIND study. Here we report an update with primary endpoint and subgroup analyses (cut off June 5, 2018). Methods: Key inclusion criteria were adequate organ function, ≤3 prior lines of therapy, including ≥1 anti-CD20 therapy, and ineligibility for stem cell transplantation. Treatment comprised up to 12, 28-day (d) cycles (C) of MOR208, 12 mg/kg IV, q1w C1–3 (loading dose on d4 of C1), and q2w C4–12 + LEN 25 mg PO d1–21, C1–12. Pts progression-free after 12 C received MOR208 q2w until progression. The primary endpoint was independent review committee (IRC)-assessed ORR as per Cheson 2007 criteria. Results: Recruitment is complete (N = 81): median age 72 years (range 41–87), median of 2 prior therapies, 19 (23%) of pts had early relapse (≤12 months [mo] from diagnosis), 32 (40%) were rituximab (RTX) refractory (no response to or progression during or within 6 mo of a prior RTX therapy), 34 (42%) were refractory to their last therapy, 21/40 (26%/49%) pts had non-germinal center B cell-like (GCB)- / GCB-DLBCL, and 42 (52%) had an International Prognostic Index (IPI) of 3–5. MOR208 + LEN therapy was well tolerated; 72% of pts stayed on a LEN dose of ≥20 mg/day. Treatment-related serious adverse events, mainly infections (10%) or neutropenic fever (5%), occurred in 17% of pts. Investigator (INV)-assessed complete response (CR) and partial response rates were 33% and 25%, respectively, giving an ORR of 58%, comparable to the IRC assessment (ORR 54%; CR 32%). ORR was 46% in pts with ≥2 prior therapies, 59%/56% in rituximab- / last treatment-refractory pts, 58% in early relapse pts, 57% in pts with a baseline IPI of 3–5, and 71% in pts with non-GCB- vs 53% with GCB-DLBCL. INV-assessed median PFS and OS (ITT analysis) were 16.2 mo (95% CI: 6.3–NR) and not reached (95% CI: 18.6–NR), respectively. Conclusions: MOR208 + LEN shows encouraging activity including a durable PFS in R-R DLBCL, and in pt subgroups with poor prognosis. Clinical trial information: NCT02399085.

Abstract: We herein report the case of a 73‐year‐old male patient who was diagnosed with leukemic non‐nodal MCL. This patient had received six cycles of bendamustine, which resulted in a transient remission, and a second‐line therapy with ibrutinib, which unfortunately failed to induce remission. We started a treatment with single‐agent obinutuzumab at a dose of 20 mg on day 1, 50 mg on day 2‐4, 330 mg on day 5, and 1000 mg on day 6. The laboratory analysis showed a rapid decrease of leukocyte count. Four weeks later, we repeated the treatment with obinutuzumab at a dose of 1000 mg q4w and started a therapy with venetoclax at a dose of 400 mg qd, which could be increased to 800 mg qd from the third cycle. This combination therapy was well tolerated. The patient achieved a complete remission (CR) after three cycles of obinutuzumab and venetoclax. To date, the patient has a progression‐free survival of 17 months under ongoing obinutuzumab maintenance q4w. This is the first report about obinutuzumab and venetoclax induced CR in rituximab‐intolerant patient with an ibrutinib‐resistant MCL. This case suggests that obinutuzumab‐ and venetoclax‐based combination therapy might be salvage therapy in patients with ibrutinib‐resistant MCL.

Abstract: Introduction Patients with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL) who are not eligible for autologous stem cell transplant (ASCT) have a poor prognosis. Tafasitamab (MOR208) is an Fc-enhanced, humanized, monoclonal antibody that targets CD19, which is broadly expressed across B-cell malignancies, including DLBCL. The immunomodulatory drug lenalidomide (LEN) has antiproliferative and antiangiogenic effects. L-MIND (NCT02399085) is an ongoing, open-label, single-arm, Phase II study of tafasitamab + LEN in patients with R/R DLBCL who are ineligible for ASCT. L-MIND results from prespecified patient subgroup analyses were presented previously (primary analysis: data cut-off Nov 30, 2018). Here, we report long-term clinical efficacy from the L-MIND study after a median follow-up of 31.8 months for overall survival (OS) (data cut-off: Nov 30, 2019). Methods Patients enrolled were aged ≥18 years with R/R DLBCL (1-3 prior systemic therapies, including ≥1 CD20-targeting regimen), ASCT-ineligible and with an Eastern Cooperative Oncology Group performance status of 0-2. Patients received 28-day cycles of tafasitamab (12 mg/kg intravenously), once weekly during Cycles 1-3 with a loading dose on Cycle 1 Day 4, then every 2 weeks during Cycles 4-12. LEN (25 mg orally) was administered on Days 1-21 of Cycles 1-12. After Cycle 12, progression-free patients received tafasitamab every 2 weeks until disease progression. The primary endpoint is objective response rate (ORR; partial response [PR] + complete response [CR] ), assessed centrally by an independent review committee. Secondary endpoints include duration of response (DOR), progression-free survival (PFS), OS and safety analyses. Results Of 81 patients enrolled, 80 patients received tafasitamab + LEN and were included in the full analysis set (FAS) for efficacy. Median follow-up was 22.7 months. In the FAS, ORR was 57.5% (95% confidence interval [CI]: 45.9-68.5) (Figure 1A). The CR rate was 40.0% (n=32/80), of which 90.6% (n=29/32) were PET-confirmed. Median time to response (PR or CR) was 2.0 months and median time to CR was 6.1 months. Median DOR was 34.6 months (95% CI: 26.1-34.6); median PFS was 12.1 months (95% CI: 6.3-not reached [NR] ); and median OS was 31.6 months (95% CI: 18.3-NR). The 24-month DOR and OS rates were 71.3% (95% CI: 52.8-83.7) (Figure 1B) and 57.2% (95% CI: 45.1-67.5) (Figure 1C), respectively. In the subgroup analysis, patients with CR as best objective response had better outcomes than those with PR: median DOR, NR (95% CI: 26.1-NR) vs 5.6 months (95% CI: 2.2-34.6); 24-month DOR rate, 86.4% (95% CI: 61.3-95.7) vs 38.5% (95% CI: 14.1-62.8); and 24-month OS rate, 90.6% vs 42.7%. Patients with 1 prior line of therapy had a trend for better outcomes than those with ≥2 prior lines: ORR, 67.5% vs 47.5%; 24-month OS rate, 67.9% vs 46.3%. The 24-month DOR rate was similar by the number of prior lines (1 prior line: 67.9% [95% CI: 42.5-84.0] vs ≥2 prior lines: 77.8% [95% CI: 51.1-91.0] ). ORR was similar by primary refractory vs non-primary refractory status (53.3% vs 58.5%); however, primary refractory status impacted 24-month DOR (50.0% vs 74.8%, respectively). Patients refractory to their last line of therapy achieved similar ORRs to those who were not (60.0% vs 55.6%). The 24-month DOR was similar regardless of refractory status to last therapy (Figure 1B), and 24-month OS rates were higher in non-refractory patients (Figure 1C). As expected, patients with a low/low-intermediate International Prognostic Index score had better outcomes than those with an intermediate-high/high score: ORR, 67.5% vs 47.5%; 24-month DOR rate, 92.1% vs 44.3%; and 24-month OS rate, 76.5% vs 36.5%. Based on the Hans algorithm, outcomes were encouraging independent of germinal center B-cell (GCB) DLBCL (n=38) or non-GCB DLBCL (n=22) disease: ORR, 47.4% vs 68.2%; median DOR, 34.6 vs 26.1 months; 24-month DOR rate, 66.7% vs 62.9%; and 24-month OS rate, 51.3% vs 65.0%. Conclusions Long-term L-MIND subgroup data show that encouraging activity observed at primary analysis remains durable after ≥2 years of follow-up; patients with CR continue to experience long DOR and high OS. Although the influence of poor prognosis risk factors is still evident, the clinical activity of tafasitamab in combination with LEN followed by tafasitamab monotherapy continues to show promise in difficult-to-treat ASCT-ineligible patients with R/R DLBCL. Disclosures Maddocks: Pharmacyclics: Consultancy, Honoraria; Seattle Genetics: Consultancy, Honoraria; Karyopharm: Consultancy; ADC Therapeutics, AstraZeneca: Consultancy; BMS: Consultancy, Research Funding; Morphosys: Consultancy, Honoraria; Celgene: Consultancy, Honoraria. Duell:Morphosys: Research Funding. González-Barca:Sandoz: Consultancy; Gilead: Consultancy; Janssen: Consultancy, Honoraria; Abbvie: Honoraria; Takeda: Honoraria; Roche: Honoraria; MorphoSys: Other; Celtrion: Consultancy; Kiowa: Consultancy; Celgene: Consultancy. Jurczak:Janssen, MeiPharma, Merck, Pharmacyclics, Roche, Tekeda, TG Therapeutics: Research Funding; Jagiellonian University: Ended employment in the past 24 months, Research Funding; Maria Sklodowska-Curie National Research Institute of Oncology: Consultancy, Current Employment. Liberati:Novartis: Research Funding; GSK: Research Funding; Incyte: Honoraria; Janssen: Honoraria, Research Funding; Oncopeptides: Research Funding; Morphosys: Research Funding; Karyopharm: Research Funding; Pfizer: Research Funding; Takeda: Research Funding; Roche: Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Honoraria, Research Funding; Onconova: Research Funding; Verastem: Research Funding. de Vos:Bayer: Consultancy; Verastem: Consultancy. Nagy:MorphoSys AG: Patents & Royalties. Obr:Roche: Honoraria. Gaidano:Sunesys: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Astrazeneca: Membership on an entity's Board of Directors or advisory committees. Abrisqueta:Roche: Consultancy, Honoraria, Speakers Bureau; Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Speakers Bureau; AbbVie: Consultancy, Honoraria, Speakers Bureau. André:Celgene: Other, Research Funding; Johnson & Johnson: Research Funding; Amgen: Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; Roche: Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; Abbvie: Consultancy; Seattle Genetics: Consultancy; Novartis: Consultancy, Research Funding; Gilead: Consultancy, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Bristol-Myers-Squibb: Consultancy, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Karyopharm: Consultancy; Takeda: Consultancy; CHU UCL Namur, site Godinne, Yvoir, Belgium: Current Employment. Dreyling:Celgene: Consultancy, Research Funding, Speakers Bureau; Roche: Consultancy, Research Funding, Speakers Bureau; Novartis: Consultancy; Janssen: Consultancy, Research Funding, Speakers Bureau; Abbvie: Research Funding; Astra Zeneca: Consultancy; Beigene: Consultancy; Gilead: Consultancy, Research Funding, Speakers Bureau; Bayer: Consultancy, Speakers Bureau. Menne:Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Kite/Gilead: Honoraria, Speakers Bureau; Novartis: Honoraria, Other: Travel costs, Speakers Bureau; Pfizer: Honoraria, Other: Travel costs, Speakers Bureau; Celgene: Honoraria, Other: Travel grants; Roche: Speakers Bureau; Janssen: Honoraria, Research Funding, Speakers Bureau; Astra Zeneca: Research Funding; Takeda: Honoraria, Speakers Bureau. Dirnberger-Hertweck:MorphoSys AG: Current Employment. Weirather:MorphoSys AG: Current Employment. Ambarkhane:MorphoSys AG: Current Employment. Salles:Takeda: Honoraria; BMS/Celgene: Honoraria, Other: consultancy or advisory role; Autolos: Other: consultancy or advisory role; Abbvie: Other: consultancy or advisory role; Roche: Honoraria, Other: consultancy or advisory role; Novartis: Honoraria, Other: consultancy or advisory role; MorphoSys: Honoraria, Other: consultancy or advisory role; Janssen: Honoraria, Other: consultancy or advisory role; Epizyme: Honoraria, Other: consultancy or advisory role; Kite, a Gilead Company: Honoraria, Other: consultancy or advisory role ; Debiopharm: Consultancy, Honoraria, Other: consultancy or advisory role; Genmab: Honoraria, Other; Karyopharm: Honoraria.

Abstract: Introduction Patients with diffuse large B-cell lymphoma (DLBCL) that is refractory to primary immunochemotherapy are well recognized as a high-risk population with poor prognosis, and have a typical median overall survival (OS) of 6-13 months [Farooq U, et al. 2017]. Patients with 'double-hit' (MYCand eitherBCL2orBCL6) and 'triple-hit' (MYC, BCL2andBCL6) genetic aberrations are also considered to be a high-risk/poor prognosis group [Davies A. 2019] . Tafasitamab (MOR208) is an Fc-enhanced, humanized, monoclonal anti-CD19 antibody that is under investigation in combination with lenalidomide (LEN) in autologous stem cell transplant (ASCT)-ineligible patients with relapsed/refractory (R/R) DLBCL in the Phase II L-MIND study (NCT02399085) [Salles G, et al. 2020]. We report efficacy data for patients with high-risk DLBCL (primary refractory disease and double/triple-hit lymphoma [DHL/THL] ) who received tafasitamab + LEN in L-MIND (data cut-off: Nov 30, 2019; median follow-up for OS, 31.8 months). Methods In the L-MIND study, patients enrolled were aged ≥18 years with R/R DLBCL (1-3 prior systemic therapies, including ≥1 CD20-targeting regimen), with an Eastern Cooperative Oncology Group performance status of 0-2 and ineligible for ASCT. Patients received 28-day cycles of tafasitamab (12 mg/kg intravenously), once weekly during Cycles 1-3 with a loading dose on Cycle 1 Day 4, then every 2 weeks during Cycles 4-12. LEN (25 mg orally) was administered on Days 1-21 of Cycles 1-12. After Cycle 12, progression-free patients received tafasitamab every 2 weeks until disease progression. The primary endpoint was objective response rate (ORR) (partial response [PR] + complete response [CR] ), assessed centrally by an independent review committee. Primary refractory disease was defined as no response (CR or PR) to or progression during or within 6 months of frontline DLBCL therapy.MYC,BCL2andBCL6aberrations were determined via fluorescencein situhybridization using tumor biopsy. Results The L-MIND cohort included 15 patients with primary refractory DLBCL and two patients with DHL/THL. Patients with primary refractory DLBCL at baseline had a median age of 73 years (range 48-82; n=9 ≥70 years) and were previously exposed to a median of 2 lines of treatment (range 1-4). Of these patients, ten had stage III/IV disease, ten showed lactate dehydrogenase greater than the upper normal limit, 12 patients had germinal center B-cell DLBCL and eight exhibited intermediate-high or high-risk International Prognostic Index (IPI) status at study baseline. All 15 patients received R-CHOP or equivalent as first-line therapy; two patients previously achieved no response, whereas 13 patients had relapsed within 6 months (ten had achieved a CR and 3 a PR) after frontline therapy. Six patients had received only 1 prior therapy, whereas nine patients had ≥2 lines before L-MIND enrollment. Median time to progression after first-line therapy was 162 days (range 28-182 days); two of 15 patients had progressed within 90 days. Of the 15 patients, 13 were refractory to their last line of therapy before L-MIND. In the 15 patients with primary refractory disease, ORR was 53.3% (95% confidence interval [CI]: 26.6-78.7) and the CR rate was 33.3%, with a 30-month duration of response (DOR) rate of 50% (95% CI: 15.2-77.5) - median DOR not reached (NR). Individual response duration is shown in Figure 1 (swimmer plot): four patients who achieved CR remain in remission after & gt;30 months. Median progression-free survival (PFS) was 5.3 months (95% CI: 0.9-NR) and PFS rate at 30 months was 33.9% (95% CI: 11.0-58.8). Median OS was 13.8 months (95% CI: 1.3-NR) and OS at 36 months was 38.1% (95% CI: 14.6-61.6). Regarding patients with DHL/THL: one with DHL achieved PR only; another patient with THL (also part of the primary refractory subgroup) achieved CR and remains in remission after & gt;30 months. Conclusions The combination of tafasitamab + LEN showed encouraging activity, with a clinically meaningful ORR and CR rate in patients with primary refractory DLBCL, and positive responses in DHL and THL. Patients with primary refractory disease were frequently ≥70 years with stage III/IV disease and poor-risk IPI scores. Although these data should be interpreted with caution due to the small patient subgroup sizes, these clinically relevant results warrant further research with this immunotherapy in patients with difficult-to-treat DLBCL. Disclosures González-Barca: MorphoSys:Other;Janssen:Consultancy, Honoraria;Sandoz:Consultancy;Gilead:Consultancy;Roche:Honoraria;Takeda:Honoraria;Abbvie:Honoraria;Celgene:Consultancy;Kiowa:Consultancy;Celtrion:Consultancy.Duell:Morphosys:Research Funding.Sancho:Bristol-Myers Squibb:Honoraria;Celgene:Consultancy, Honoraria;Gilead:Consultancy, Honoraria;Janssen:Consultancy, Honoraria;Kern-Pharma:Consultancy, Honoraria;Novartis:Consultancy, Honoraria;Roche:Consultancy, Honoraria;Takeda:Honoraria;Celltrion:Consultancy;Sandoz:Consultancy.Nagy:MorphoSys AG:Patents & Royalties.Abrisqueta:Celgene:Consultancy, Honoraria;AbbVie:Consultancy, Honoraria, Speakers Bureau;Roche:Consultancy, Honoraria, Speakers Bureau;Janssen:Consultancy, Honoraria, Speakers Bureau.Panizo:Clínica Universidad de Navarra:Current Employment;Bristol-Myers Squibb, Kyowa Kirin:Speakers Bureau;Janssen, Roche:Membership on an entity's Board of Directors or advisory committees.Augustin:Morphosys:Research Funding;AstraZeneca:Consultancy, Research Funding;Roche:Consultancy;Novartis:Consultancy, Research Funding;Merck:Consultancy;IPSEN:Consultancy, Research Funding;Pfizer:Consultancy, Research Funding;BMS:Consultancy, Research Funding.Weirather:MorphoSys AG:Current Employment.Ambarkhane:MorphoSys AG:Current Employment.Maddocks:Seattle Genetics:Consultancy, Honoraria;Celgene:Consultancy, Honoraria;Pharmacyclics:Consultancy, Honoraria;Morphosys:Consultancy, Honoraria;ADC Therapeutics, AstraZeneca:Consultancy;BMS:Consultancy, Research Funding;Karyopharm:Consultancy.Kalakonda:Celgene:Research Funding.Salles:BMS/Celgene:Honoraria, Other: consultancy or advisory role;Takeda:Honoraria;Karyopharm:Honoraria;Genmab:Honoraria, Other;Debiopharm:Consultancy, Honoraria, Other: consultancy or advisory role;Autolos:Other: consultancy or advisory role;Abbvie:Other: consultancy or advisory role;Roche:Honoraria, Other: consultancy or advisory role;Novartis:Honoraria, Other: consultancy or advisory role;MorphoSys:Honoraria, Other: consultancy or advisory role;Janssen:Honoraria, Other: consultancy or advisory role;Epizyme:Honoraria, Other: consultancy or advisory role;Kite, a Gilead Company:Honoraria, Other: consultancy or advisory role .