An antibody drug conjugate is a type of immunotherapy being explored in multiple myeloma. Glaxo-Smith Klein is developing a new antibody drug conjugate in myeloma called Belantamab mafodotin (or “belmaf” for short). These drugs use the immune system to find the right myeloma-specific target and then drop a toxic payload in a targeted way. At the recent IMW conference in Boston, Natalie Callander, MD of the University of Wisconsin shared an update on this approach.
Dr. Callander mentions the first Phase I/II trial run two years ago for 35 patients who had a subset of patients who had been exposed to daratumumab. In this study, there was a 60% response rate to the GSK drug.
This GSK drug targets BCMA, commonly found on the surface of myeloma cells. The drug binds to myeloma cells, is internalized and then delivers its toxic payload to the selected cells. More detail about this study will be presented at the upcoming American Society of Hematology (ASH) meeting in December, but at the IMW meeting, Dr. Callander mentioned the DREAMM-2 study of 180 patients that will all have become resistant to daratumumab and suggests that the overall response rate is expected to be similar to the Phase I/II earlier study.
This is exciting and interesting because most new drug approvals are looking for 25-30% overall response rate. This drug is given by IV every three weeks and most patients will be able to continue the treatment indefinitely. One of the uncommon side effects include dry or cloudy eyes and researchers want to learn more about mitigating these types of side effects.