A phase 1b/2 study evaluating efficacy and safety of MP0250, a designed ankyrin repeat protein (DARPin) simultaneously targeting vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF), in combination with bortezomib and dexamethasone, in patients with relapsed or refractory multiple myeloma

MP0250 is a designed ankyrin repeat protein that specifically inhibits both vascular endothelial growth factor A (VEGF‐A) and hepatocyte growth factor (HGF), aiming at potentiating cancer therapy by disrupting the tumour microenvironment. Encouraging results from a phase 1 trial of MP0250 in patients with solid tumours prompted further investigation in multiple myeloma (MM) as both MP0250 targets are reported to be drivers of MM pathogenesis. In this open‐label, single‐arm phase 1b/2 study (NCT03136653) in patients with proteasome inhibitor‐ and/or immunomodulatory drug‐relapsed or refractory MM, MP0250 was administered every 3 weeks with standard bortezomib/dexamethasone regimen. Thirty‐three patients received at least one dose of MP0250. The most frequent treatment‐related adverse events were arterial hypertension (58.1%), thrombocytopenia (32.3%), proteinuria (29.0%) and peripheral oedema (19.4%). Of the 28 patients evaluable for response (median age: 60 [range 44–75]), nine achieved at least partial response, corresponding to an overall response rate of 32.1% (95% confidence interval [CI]: 17.9%, 50.7%), with a median duration of response of 8 months (95% CI 5–NR). An additional three patients achieved minimal response and nine stable diseases as the best overall response. Overall median progression‐free survival was 4.2 months (95% CI 1.9–7.1). These findings are in line with the results of recent trials testing new agents on comparable patient cohorts and provide initial evidence of clinical benefit for patients with refractory/relapsed MM treated with MP0250 in combination with bortezomib/dexamethasone. Further clinical evaluation in the emerging MM treatment landscape would be required to confirm the clinical potential of MP0250.