The phase 2 HORIZON study is a pivotal, single-arm, multicenter, phase 2 study evaluating the safety and efficacy of melflufen in combination with dexamethasone in patients with relapsed refractory multiple myeloma. The study included 157 heavily pretreated patients, who had received >2 earlier lines of therapy with immunomodulatory agents (IMiDs) and proteasome inhibitors (PIs) and were refractory to pomalidomide and/or daratumumab.

The HORIZON study started in January 2017 and was completed in November 2021. The study results led to an accelerated approval by the FDA in Feb 2021 and full approval in EU and UK in Aug and Nov 2022, respectively.

The complete top-line results from the pivotal phase 2 HORIZON study were presented at the European Hematology Association meeting, in June 2020. The results have also been published in the Journal of Clinical Oncology.