A Phase I Study of CC-90002, a Monoclonal Antibody Targeting CD47, in Patients with Relapsed and/or Refractory (R/R) Acute Myeloid Leukemia (AML) and High-Risk Myelodysplastic Syndromes (MDS): Final Results

Background : CD47 is a transmembrane protein ubiquitously expressed in human cells. CD47 is overexpressed in various malignancies and is correlated with negative prognosis in AML and MDS (Chao et al. Curr Opin Immunol.2012; Majeti et al. Cell.2009). Interaction of CD47 with signal-regulatory protein alpha (SIRPα) expressed on macrophages inhibits phagocytosis (Kim et al. Leukemia.2012). CC-90002, a humanized anti-CD47 monoclonal antibody, blocks CD47/SIRPα interactions, thereby enabling macrophage-mediated killing of tumor cells. In preclinical studies, CC-90002 demonstrated antibody-mediated phagocytosis of several hematologic cancer cell lines, including AML cells. CC-90002 also demonstrated a rapid and substantial reduction in tumor burden in AML xenograft models. Herein, we report results from CC-90002-AML-001 evaluating CC-90002 in patients (pts) with R/R AML and high-risk MDS. Methods : In this phase I multicenter study (NCT02641002), CC-90002 was administered intravenously once/week for 4 weeks of each 42-day cycle during cycles 1−4 then once every 4 weeks during a maintenance phase of 28-day cycles. Pts were enrolled in cohorts of escalating dose levels using a modified 3+3 design. The primary objectives were to determine preliminary safety and tolerability, non-tolerated dose (NTD), maximum tolerated dose (MTD), and/or recommended phase 2 dose. Secondary objectives were to measure preliminary efficacy, pharmacokinetics, and the presence and frequency of anti-drug antibodies (ADAs). Results: As of July 18, 2018, 24 pts with R/R AML and 4 pts with high-risk R/R MDS were enrolled. Pts received CC-90002 at 0.1 mg/kg (n=6), 0.3 mg/kg (n=6), 1 mg/kg (n=6), 2 mg/kg (n=4), and 4 mg/kg (n=6). Median age was 70 years (range, 28-85) and 16 (57%) were male. The most common AML subtypes were AML with myelodysplasia-related changes (n=9) and AML not otherwise specified (n=9). All 4 pts with MDS were classified as having refractory anemia with excess blasts-2 and high- or very high-risk disease per the Revised International Prognostic Index Scoring System. The median number of prior systemic anticancer regimens was 3 (range, 1-10), and 29% of pts had prior stem cell transplants. The median treatment duration was 6.9 weeks (range, 2-44). Four pts experienced a dose-limiting toxicity, consisting of grade 4 disseminated intravascular coagulation and grade 4 cerebral hemorrhage in 1 pt (0.1 mg/kg), grade 3 purpura in 1 pt (0.3 mg/kg), grade 4 congestive cardiac failure and grade 4 acute respiratory failure in 1 pt (1 mg/kg), and grade 4 sepsis in 1 pt (4 mg/kg). The most common (≥30%) any-grade treatment-emergent adverse events (TEAEs) were diarrhea (46%); thrombocytopenia (39%); febrile neutropenia and aspartate aminotransferase increased (36% each); and anemia, alanine aminotransferase increased, and cough (32% each). A total of 23 pts (82%) had serious TEAEs with febrile neutropenia (n=10), bacteremia (n=4), pneumonia (n=4), and general physical health deterioration (n=3) occurring in2 pts. No TEAEs led to dose reductions; however, 7 pts (25%) discontinued due to TEAEs. Overall, 82% of pts were dependent on red blood cell (RBC) transfusions and CC-90002 treatment did not interfere with continued RBC transfusion in pts on study. No pts experienced hemolysis, tumor lysis syndrome, or macrophage activation/cytokine release syndrome. Sixteen pts died during the study. The best overall response observed was stable disease in 2 pts with MDS. CC-90002 serum exposures appeared to increase with doses above 0.3−4.0 mg/kg and the terminal half-life ranged from 4.6−17.0 hours. Development of ADAs targeting CC-90002 occurred at all dose levels tested and the proportion of pts testing positive for ADAs in cycle 1 increased over time (4/27 pts at day 8, 6/25 pts at day 15, and 8/22 pts at day 22). ADAs continued to be present across different doses with increases in median serum ADA titers after cycle 1. No apparent dose-ADA relationship was observed. Conclusion: CC-90002 showed a lack of objective responses in pts with R/R AML and high-risk MDS. The MTD and NTD were not established. The CC-90002-AML-001 study was discontinued in dose escalation for lack of preliminary monotherapy activity and evidence of ADAs in most pts. CC-90002 in combination with rituximab is being explored in CD20+ NHL to enhance efficacy of CD47 blockade while reducing ADAs (CC-90002-ST-001; NCT02367196). Disclosures Zeidan: BeyondSpring: Honoraria; Seattle Genetics: Honoraria; Acceleron Pharma: Consultancy, Honoraria, Research Funding; Celgene Corporation: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Honoraria, Research Funding; Otsuka: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria, Research Funding; Medimmune/AstraZeneca: Research Funding; Boehringer-Ingelheim: Consultancy, Honoraria, Research Funding; Trovagene: Consultancy, Honoraria, Research Funding; Incyte: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; ADC Therapeutics: Research Funding; Jazz: Honoraria; Ariad: Honoraria; Agios: Honoraria; Novartis: Honoraria; Astellas: Honoraria; Daiichi Sankyo: Honoraria; Cardinal Health: Honoraria. DeAngelo:Novartis: Consultancy, Research Funding; Jazz Pharmaceuticals Inc: Consultancy; Shire: Consultancy; Incyte: Consultancy; Blueprint: Consultancy, Research Funding; Pfizer: Consultancy; Amgen: Consultancy; GlycoMimetics: Research Funding; Celgene: Consultancy; Abbvie: Research Funding; Takeda Pharmaceuticals: Consultancy. Seet:University of California, Los Angeles: Employment. Tallman:Rigel: Consultancy, Membership on an entity's Board of Directors or advisory committees; Nohla: Consultancy, Membership on an entity's Board of Directors or advisory committees; BioLineRx: Consultancy, Membership on an entity's Board of Directors or advisory committees; Nohla: Consultancy, Membership on an entity's Board of Directors or advisory committees; Rigel: Consultancy, Membership on an entity's Board of Directors or advisory committees; Daiichi-Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees; ADC Therapeutics: Research Funding; Cellerant: Research Funding; Delta Fly Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees; Tetraphase: Consultancy, Membership on an entity's Board of Directors or advisory committees; ADC Therapeutics: Research Funding; Rigel: Consultancy, Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees; UpToDate: Patents Oncolyze: Consultancy, Membership on an entity's Board of Directors or advisory committees; Delta Fly Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees; Cellerant: Research Funding; Nohla: Consultancy, Membership on an entity's Board of Directors or advisory committees; ADC Therapeutics: Research Funding; Delta Fly Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees; Oncolyze: Consultancy, Membership on an entity's Board of Directors or advisory committees; Delta Fly Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees; Cellerant: Research Funding; Delta Fly Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees; Biosight: Research Funding; Orsenix: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Biosight: Research Funding; Biosight: Research Funding; Daiichi-Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees; Daiichi-Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees; KAHR: Consultancy, Membership on an entity's Board of Directors or advisory committees; UpToDate: Patents KAHR: Consultancy, Membership on an entity's Board of Directors or advisory committees; Oncolyze: Consultancy, Membership on an entity's Board of Directors or advisory committees; BioLineRx: Consultancy, Membership on an entity's Board of Directors or advisory committees; BioLineRx: Consultancy, Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees; Oncolyze: Consultancy, Membership on an entity's Board of Directors or advisory committees; Daiichi-Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees; Tetraphase: Consultancy, Membership on an entity's Board of Directors or advisory committees; Rigel: Consultancy, Membership on an entity's Board of Directors or advisory committees; Biosight: Research Funding; Daiichi-Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees; Daiichi-Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees; KAHR: Consultancy, Membership on an entity's Board of Directors or advisory committees; Rigel: Consultancy, Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Jazz Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees; Orsenix: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Consultancy, Membership on a