This is a an ancillary study designed to explore whether an additional cell signaling pathway (prenylation of Rap1) that was recently identified as being under beta-adrenergic control may be affected by beta-blocker use.

This is a proof of concept randomized controlled pilot study assessing whether prenylation and membrane localization of Rap1 in PBMCs can be altered in individuals undergoing autologous Hematopoietic Cell Transplant (HCT) for Multiple Myeloma by administering a daily beta-blocker (propranolol) to 20 participants. Outcomes of patients on this clinical trial will be compared to 20 participants in a control arm.

Inclusion Criteria:

Patients with multiple myeloma receiving an autologous HCT are eligible when the following criteria are met:

1. 18-75 years of age
2. ≤ 1 year since initiation of systemic anti-myeloma therapy
3. Patient is scheduled for autologous hematopoietic stem cell transplant as the upfront therapy for their multiple myeloma
4. Karnofsky Performance Status of ≥90 %; patients eligible for HCT are eligible for the study
5. All men and women must agree to practice effective contraception during the study period if not otherwise documented to be infertile.

Exclusion Criteria:

1. Prior autologous HCT
2. Non secretory multiple myeloma
3. Concurrent beta-blocker therapy at or within 3 weeks of study entry.
4. Previous intolerance to beta-blocker therapy
5. Any medical contraindications to beta-blocker therapy including, but not limited to, symptomatic hypotension; drug hypersensitivity; sinus bradycardia, sick sinus syndrome, or 2nd or 3rd degree atrioventricular block without a pacemaker; uncompensated heart failure; or uncontrolled asthma
6. Active, untreated depression screened for by the HCT physician (Patients who screen positive will be offered a referral to the MCW Psycho-Oncology program for further evaluation and treatment)
7. Concurrent use of medications as specified in the protocol throughout the study or within one week of study entry.
8. Pregnant or lactating women

Patients who are enrolled in the parent study (NCT02420223) are eligible for this ancillary study.