Liposomal Cytarabine and Daunorubicin (CPX-351) in Combination with Gemtuzumab Ozogamicin (GO) in Relapsed Refractory (R/R) Patients with Acute Myeloid Leukemia (AML) and Post-Hypomethylating Agent (Post-HMA) Failure High-Risk Myelodysplastic Syndrome (HR-MDS)
Twenty pts have been enrolled between November 2018 and July 2019. At the time of data cut off 19 pts were evaluable for response, with one patient too early to assess for response. Patient characteristics are summarized on Table 1; of note 14 (70%) pts had previously been treated with venetoclax in different combinations with HMA’s and/or chemotherapy. We observed an overall response rate (ORR) of 42% (n=8), including CR (n=5), CRi (n=1) and PR (n=2). Responses are summarized in Table 2. Among the eight responders there were 4 pts with MRD negative (by flow cytometry) remission. One patient who was considered in CR was taken off study on day 40 because of an underlying invasive fungal sinus infection and concerns of myelosuppression. This patient was transitioned to a lower intensity regimen and remains in remission. Four pts completed 2 inductions, 5 pts received consolidation and 2 pts received GO maintenance before progressing. Unfortunately, none could be transitioned to transplantation due to age or comorbidities. Among responders, median time to ANC >500 was 39 days (30-56) and PLT >50k was 40 days (33-46), median time to ANC >1K was 40 days (31-74) and PLT >100K was 43 days (34-53) after induction (Table 3). With a median follow up of 18.6 months, median OS is 9.1 months (Figure 1) and median duration of response was 10.5 months (figure 2). Adverse events regardless of causality (Table 4) were mainly due to infectious complications. We have not observed treatment related grade 3-4 non-hematological toxicity. Thirty-day mortality was 10% (n=2); both pts died from complications of septicemia. Three additional pts (15%) died within 60 days of treatment, including 2 pts with progressive disease and 1 patient on day 58 after withdrawing care due to infections and 2 aplastic bone marrow examinations on days 14 and 46 of treatment, respectively.