Serum Vitamin D Levels and Peripheral Neuropathy Among Multiple Myeloma Patients

Inclusion Criteria:

• Voluntary written informed consent before performance of any study-related procedure not part of normal medical care, with the understanding that consent may be withdrawn by the subject at any time without prejudice to future medical care.
• Prior diagnosis of multiple myeloma based on standard criteria (Durie 1986)
• Received consecutive, prior treatment for MM with a regimen consisting of at least 16 consecutive weeks of bortezomib or 16 consecutive weeks of thalidomide prior to the Day of Assessment

• The 16 weeks of consecutive treatment must have included at least one of the following doses and schedules:

  • Bortezomib: ≥ 1.0 mg/m² dosed 3 or more times per each 4-week period
  • Thalidomide: ≥ 50 mg/day dosed daily
• The qualifying regimen may include both bortezomib and thalidomide. However, the above inclusion requirements need only be satisfied by either one of the agents.
• Age ≥18 years at the time of signing the informed consent form
• Able to adhere to the study visit schedule and other protocol requirements

Exclusion Criteria:

• Plasma cell dyscrasia with polyneuropathy, organomegaly, endocrinopathy, monoclonal protein (M-protein) and skin changes (POEMS) syndrome (Bardwick 1980)
• Plasma cell leukemia
• Primary amyloidosis
• Vitamin D level assessment occurring within the 12 months preceding the Day of Assessment
• Vitamin D non-dietary oral supplementation > 1200 IU per day for > 30 total days within the 12 month period preceding the Day of Assessment
• Serious medical or psychiatric illness likely to interfere with participation in this clinical study.
• Any serious medical condition, laboratory abnormality, or psychiatric illness that would prevent the subject from signing the informed consent form
• Any condition, including the presence of laboratory abnormalities, which places the subject at unacceptable risk if he/she were to participate in the study or confounds the ability to interpret data from the study.