EBMT 2021 | HORIZON: melflufen plus dexamethasone shows efficacy in R/R myeloma
Maria-Victoria Mateos, MD, PhD, University Hospital of Salamanca, Salamanca, shares an update on the Phase II HORIZON trial (NCT02963493) investigating the efficacy of melflufen in combination with dexamethasone in patients with multiple myeloma who are refractory to pomalidomide and/or an anti-CD38 monoclonal antibody. The study reported a median duration of response of 5.5 months and a median progression-free survival of 4.2 months. The median overall survival was 11.6 months at a median follow-up of 14 months. Dr Mateos reports that this therapeutic combination demonstrated clinically meaningful efficacy with a manageable safety profile, and is fulfilling an unmet medical need for this population of patients with relapsed/refractory (R/R) multiple myeloma. This interview took place during the 47th Annual Meeting of the European Group for Blood and Marrow Transplantation (EBMT) 2021.
Transcript (edited for clarity)
The HORIZON study is a Phase II clinical study conducted in relapsed and/or refractory myeloma patients with a novel agent, melflufen, in combination with dexamethasone. And melflufen is the first-in-class peptide-drug conjugate that targets amino peptidases, and amino peptidases are over-expressed into the plasma cells. So melflufen is going to do the liver and alkylator moiety into the tumor cells resulting into a high activity within the tumor niche, avoiding in principle of targeted toxicity...
The HORIZON study is a Phase II clinical study conducted in relapsed and/or refractory myeloma patients with a novel agent, melflufen, in combination with dexamethasone. And melflufen is the first-in-class peptide-drug conjugate that targets amino peptidases, and amino peptidases are over-expressed into the plasma cells. So melflufen is going to do the liver and alkylator moiety into the tumor cells resulting into a high activity within the tumor niche, avoiding in principle of targeted toxicity.
Important to remark that the population of patients included in the HORIZON study were relapsed and/or refractory myeloma patients to pomalidomide and/or anti-CD38 monoclonal antibodies. The population is crucial because it represents an unmet medical need for us today, and melflufen plus dexamethasone in this population covered the unmet medical need.
157 patients were included in this clinical study and approximately 75% of the patients were triple-class refractory. And in addition, approximately one-third of the patients presented with extramedullary disease. The overall response rate was approximately 30% in the whole treated of the population, and it was maintained in the triple-class refractory population. The median duration of the response was of approximately six months, median progression-free survival around four months, and important median overall survival of approximately one year. And I think that this efficacy data clearly put in context how melflufen and dexamethasone is again covering the unmet medical need that we have for this population.
From the safety point of view, hematological toxicity, neutropenia and thrombocytopenia are the most relevant melflufen-related adverse events that are manageable with a G-CSF prophylaxis with antibiotics as well as transfusional support. And, of course, we can do some dose modification in case of severe toxicity.
So, in summary, I would say that melflufen in combination with dexamethasone showed clinically meaningful efficacy and a manageable safety profile in patients with a heavily pre-treated relapsed and/or refractory myeloma patients, including those triple-class refractory and extramedullary disease. And hopefully melflufen and dexamethasone will be a new standard of care for the management of this population here in Europe because as you know, this combination has just been approved by the FDA in the United States.
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