A Study to Evaluate Preventive Treatments for Talquetamab-related Oral Toxicity

Inclusion Criteria:

• Multiple myeloma (MM) according to IMWG diagnostic criteria

• Were triple-class exposed (received prior treatment with a PI, an IMiD, and antiCD38 mAb)

• Documented evidence of progressive disease based on investigator's determination ofresponse by IMWG criteria on or after their last regimen

• Have an Eastern Cooperative Oncology Group-performance status (ECOG-PS) of 0 or 1 atscreening. Participants with ECOG-PS 2 or 3 are eligible for the study if theECOG-PS score is related to stable physical limitations (e.g., wheelchair-bound dueto prior spinal cord injury) and not related to multiple myeloma or associatedtherapy

• Be willing and able to adhere to the lifestyle restrictions specified in theprotocol

Exclusion Criteria:

• Contraindications or life-threatening known allergies, hypersensitivity, orintolerance to any study drug or its excipients

• Stroke, transient ischemic attack, or seizure within 6 months prior to screening

• Any of the following within 6 months prior to the first dose of study treatment:severe or unstable angina, myocardial infarction; major thromboembolytic event (e.g., pulmonary embolism, cerebrovascular accident), clinically significantventricular arrythmia or heart failure New York Heart Association functionalclassification Class III or IV. Uncomplicated deep vein thrombosis is not consideredexclusionary

• Major surgery or had significant traumatic injury within 2 weeks prior to the startof administration of talquetamab, or will not have fully recovered from surgery, orhas major surgery planned during the time the participant is expected to be treatedin the study or within 2 weeks after administration of the last dose of studytreatment

• A WETT score suggesting severe dysgeusia at screening. Also unresolved/severedysgeusia referred by the participant or a finding in the physical examination/oralcavity inspection. Some examples include leukoplakia, prior mouth cancers, extensivedental caries, severe periodontitis, active oral infections, candidiasis, paroticgland removal, or radiotherapy with resultant xerostomia