Correlation Between Serum Vitamin D Levels and the Incidence of Peripheral Neuropathy Among Multiple Myeloma Patients Who Have Previously Received Treatment With Bortezomib or Thalidomide

Study start date: June 1, 2012

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performance of any study-related procedure not part of normal medical care, with the understanding that consent may be withdrawn by the subject at any time without prejudice to future medical care.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.