Abstract: Introduction:CD38 is a type II transmembrane glycoprotein widely expressed in many hematological malignancies including multiple myeloma (MM). MOR202, a HuCAL-derived, human IgG1 CD38 monoclonal antibody, induces antibody-dependent cell-mediated cytotoxicity (ADCC) and antibody-dependent cell-mediated phagocytosis (ADCP). MOR202 does not induce complement-dependent cytotoxicity, which is suspected to be a major contributor to infusion-related reactions (IRRs). Preclinical models of MM demonstrate high single-agent antitumor activity of MOR202 and synergy in combination with immunomodulatory drugs (IMiDs), lenalidomide (LEN) or pomalidomide (POM). Methods: This is an interim analysis of a multicenter, dose-escalation phase I/IIa study of MOR202 in relapsed or refractory (RR)MM. Preliminary safety and efficacy data from 3 patient cohorts treated with clinically relevant doses of MOR202 (administered as an IV 2-hour infusion), alone or in combination with an IMiD are presented: MOR202 4, 8 and 16 mg/kg weekly; MOR202 8 or 16 mg/kg weekly with either LEN or POM. All patients in these cohorts also received low dose dexamethasone. Primary objectives were to evaluate the safety, maximum tolerated dose (MTD) and recommended phase II dose of MOR202. Secondary objectives included an assessment of overall response rate, duration of response and progression-free survival. Results: As of July 12, 2016, a total of 66 patients had been treated; 31 in clinically relevant cohorts, including 18 patients receiving MOR202 alone, 8 receiving MOR202 + LEN and 5 receiving MOR202 + POM. Patients treated with MOR202 alone and MOR202 + POM had both received a median of 4 prior lines of therapy; 78% and 100% had been refractory to last prior treatment, respectively. Patients treated with MOR202 + LEN had received a median of 2 prior lines of therapy and 50% had been refractory to last prior treatment. Most of the patients had received bortezomib, LEN, cyclophosphamide, and melphalan alone or in combination with autologous stem cell transplant as part of their prior regimens. In this trial the MTD has not been reached yet. MOR202 alone or in combination with an IMiD was well tolerated, with mainly hematological toxicity reported. A 2-hour MOR202 infusion was feasible in all patients. In the clinically relevant cohorts only 1 patient discontinued due to an adverse event considered to be related to MOR202 (platelet count decreased) and no deaths related to any of the study drugs occurred. IRRs were seen in only 3/31 (10%) patients, all occurring during the first infusion. All IRRS were ≤ grade 2. So far, 28 patients were evaluable for response in the MOR202 clinically relevant cohorts. Of 16 evaluable patients in the MOR202 alone cohort, 3 partial responses (19%) and 2 very good partial responses (13%) were reported. In the MOR202 + LEN cohort 5/7 partial responses were seen, and 3/5 patients responded to MOR202 + POM treatment including 2 complete responses. Median time to response was 4 weeks, with responses tending to deepen over time. Most responses (10/13) are ongoing with the longest duration of response currently being 48 weeks. Preliminary analysis in 5 patients revealed preservation of high CD38 levels on MM cells under MOR202 therapy, with a mean decrease of only 10% from baseline to day 1 cycle 2 (4 weeks). Conclusions: In this analysis, a 2-hour infusion of MOR202 (up to 16 mg/kg) alone, or in combination with POM or LEN showed a very good safety profile, particularly an excellent infusion tolerability in heavily pretreated patients with RRMM. Promising preliminary efficacy and long-lasting tumor control was seen for MOR202 +/- IMiDs. The data suggest that CD38 expression on patient MM cells is preserved during treatment. Disclosures Raab: Novartis: Consultancy, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy; Amgen: Consultancy, Research Funding. Goldschmidt:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Chugai: Honoraria, Research Funding; BMS: Membership on an entity's Board of Directors or advisory committees, Research Funding; Millennium: Honoraria, Research Funding; Onyx: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees. Agis:Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Einsele:Janssen: Consultancy, Honoraria, Speakers Bureau; Celgene: Consultancy, Honoraria, Speakers Bureau; Novartis: Consultancy, Honoraria; Amgen: Consultancy, Honoraria, Speakers Bureau. Engelhardt:Amgen: Research Funding; Janssen: Research Funding; MSD: Research Funding; Celgene: Research Funding. Ferstl:Novartis: Other: Case report presentation; Bristol Myers Squibb: Other: Advisory Board. Weisel:Janssen: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Onyx: Consultancy; BMS: Consultancy, Honoraria; Novartis: Honoraria; Celgene: Consultancy, Honoraria, Research Funding. Jarutat:MorphoSys AG: Employment. Weinelt:MorphoSys: Employment. Endell:MorphoSys AG: Employment, Patents & Royalties. Boxhammer:MorphoSys AG: Employment, Patents & Royalties. Peschel:MophoSys: Honoraria.

Abstract: 8024 Background: CD38 is a type II transmembrane glycoprotein expressed by MM cells. MOR202, a human IgG1 CD38 monoclonal antibody, has shown high single-agent activity in preclinical models of MM and synergy in combination with immunomodulatory drugs (IMiDs), lenalidomide (LEN) and pomalidomide (POM). Methods: This interim analysis of a multicenter phase I/IIa study reports safety and efficacy data from RRMM patient (pt) cohorts treated with clinically relevant doses of MOR202 (2-hour IV infusion; 4, 8 and 16 mg/kg q1w) + Dex (≤40 mg), or at 8 or 16 mg/kg q1w with an IMiD/Dex. Primary objectives were to evaluate the safety, maximum tolerated dose (MTD) and recommended phase II dose of MOR202. Results: As of January 2017, 79 pts had been treated, including 44 in clinically relevant cohorts: 18 received MOR202 + Dex, 15 MOR202 + LEN/Dex and 11 MOR202 + POM/Dex. Pts had received a median of 3, 2 and 3 prior treatment lines, respectively. The MTD of MOR202 was not reached. Combinations were generally well tolerated, with grade ≥3 adverse events (AEs) mainly hematological; 2 pts discontinued due to a MOR202-related AE (one grade 4 thrombocytopenia; one grade 3 acute kidney failure). Infusion-related reactions (all grade 1 or 2) were seen in only 3/44 (7%) pts, and mainly occurred during the first infusion. In the MOR202 + Dex cohort, 5/17 (29%) evaluable pts (receiving at least 1 cycle of treatment) had a response, including 3 with partial responses (PRs) and 2 with very good PRs (VGPRs). Responses were also seen in 11/13 (85%, 8 PRs, 3 VGPRs) evaluable pts in the MOR202 + LEN/Dex cohort and 5/9 (56%, 2 complete responses, 3 PRs) in the MOR202 + POM/Dex cohort. Longest response duration was 17 months (MOR202/Dex). Preliminary analysis showed preservation of high CD38 levels on MM cells under MOR202 therapy. Conclusions: In heavily pretreated pts with RRMM, a 2-hour infusion of MOR202 administered at up to 16 mg/kg with Dex or in combination with an IMiD/Dex, showed a favorable safety profile, including excellent infusion tolerability. Promising preliminary efficacy and long-lasting tumor control was seen. Clinical trial information: NCT01421186.