LIMITED-DURATION TECLISTAMAB

Inclusion Criteria:
*  Participants must be age ≥18 and able to give written, informed consent.
*  Participants must have initiated teclistamab (first full dose) 6-9 months prior to enrollment and received an average teclistamab dose of at least 1.5 mg/kg/month since the date of the first 1.5 mg/kg dose.
*  Participants must have received a teclistamab dose within 4 weeks prior to enrollment.
*  Participants must have had measurable disease according to IMWG criteria within 1 month prior to teclistamab initiation or first full teclistamab dose
*  Participants must have achieved a confirmed VGPR or better to teclistamab therapy at any assessment prior to enrollment and have ongoing response (i.e., no disease progression) at time of enrollment per IMWG consensus criteria (Appendix 14.3).
*  Prior to initiating teclistamab, participants must have received therapy with a proteasome inhibitor, thalidomide analog (lenalidomide or pomalidomide), and an anti-CD38 antibody and meet one of the following criteria: 1. ≥3 prior lines of therapy (with lines-of-therapy delineated according to IWMG guidelines) 2. Refractory to both a proteasome inhibitor and a thalidomide analog.
*  Participants must have had an ECOG performance status of 0-2 at time of teclistamab initiation; in addition, ECOG performance status must be 0-1 at time of enrollment.
*  Participants must not have known diagnoses of systemic amyloidosis or POEMS syndrome.