A Collaborative Community Effort Using Belantamab Mafodotin in Relapsed/Refractory Myeloma

This is a research study to find out if a drug called belantamab mafodotin in combination with dexamethasone, a steroid, can be safely and effectively given in the community setting. Belantamab mafodotin (BLENREP) was approved in the US in August 2020 under an FDA program called accelerated approval. In November 2022, belantamab mafodotin was removed from the market because a study to further confirm its activity in relapsed/refractory multiple myeloma did not deliver a supporting result. However, this confirmatory study demonstrated that some patients may still benefit from treatment with belantamab mafodotin, and that this benefit can be long lasting. Belantamab mafodotin is often given at large academic medical centers every 3 weeks. This study will assess whether it is possible to administer belantamab in the community setting every 6 weeks. It is unknown if administering belantamab every 6 weeks versus every 3 weeks will result in improved safety and/or reduced efficacy.

Inclusion Criteria: * 1\. Participant must have histologically or cytologically confirmed diagnosis of MM as defined by IMWG, 2016 criteria, have had at least 4 prior therapies, and is relapsed or refractory to an anti-CD38 antibody, an IMID, and a proteasome inhibitor. 1. Refractory myeloma is defined as disease that is nonresponsive while on therapy or progresses within 60 days of last therapy. Nonresponsive disease is defined as either failure to achieve at least minimal response or development of progressive disease (PD) while on any therapy. 2\. Participant must have an Eastern Cooperative Oncology Group (ECOG) performance status of ≤ 2 3. Participant must be ≥ 18 years of age 4. Participant must have adequate organ function, defined as follows: 5. Female participants: a. A female participant is eligible to participate if she is not pregnant or breastfeeding and at least one of the following conditions applies: i. Is not a woman of childbearing potential (WOCBP) OR ii. Is a WOCBP and using a contraceptive method that is highly effective (with a failure rate of \