Biomarkers
Serum samples taken at C1D1 and C2D1 were analyzed for a panel of >250 circulating biomarker proteins including soluble Axl (sAxl)
As previously reported 12, pretreatment sAXL levels are associated with response. 6/7 patients with clinical benefit (CR/CRi/PR/SD) had sAXL levels below the previously reported cut-off (ASH, 2018).
Differential expression analysis of C1D1 (pretreatment) serum samples identified biomarker candidate BGBM033 to be significantly associated with response to bemcentinib. BGBM033 levels were significantly lower in both responder and SD patients in both the bemcentinib-LDAC combination and bemcentinib monotherapy cohorts in this study.
Notably BGBM033 was also found to be downregulated in responders to bemcentinib treatment in lung cancer
Data is still maturing and transcriptional analysis of PBMC and bone marrow samples is ongoing
Conclusions
The bemcentinib-LDAC combination showed promising efficacy among elderly newly-diagnosed and relapsed AML patients
Durable responses and successful treatment beyond progression could be due to an immune-modulatory effect of bemcentinib
Consistent with results in the bemcentinib monotherapy cohort, pretreatment sAXL levels are associated with clinical benefit from LDAC + bemcentinib
Bemcentinib is safe and well tolerated in combination with LDAC in elderly AML patients
The overall response rate and duration surpass historical benchmarks and compare favorably to other LDAC combinations
A comprehensive biomarker program comprising Axl expression and signalling analysis in tumour and immune compartments is underway to identify both predictive and pharmacodynamic biomarkers
Further clinical development of this combination is warranted