Effect of Vitamin D Supplementation on Bone Turnover Markers During PrEP in MSM (CCTG595VitD)

University of California San Diego

Status and phase: Completed; Phase 4

Conditions: Patient Adherence

Treatments: Drug: Vitamin D Supplement

Study type: Interventional

Funder types: Other; Industry

Identifiers

NCT02367599

CCTG 595 Vitamin D Sub-Study

Details and patient eligibility

About

CCTG 595 is an open-label clinical trial of the effect of a text messaging intervention vs. standard of care on adherence to Truvada as PrEP in MSM at increased risk for HIV infection (ClinicalTrials.gov Identifier: NCT01761643). Eligible subjects for this matched case control substudy will receive vitamin D 4000 IU/day for 24 weeks, from week 24 through week 48. In CCTG 595, plasma from participants are being collected and stored at entry and every 12 weeks. These plasma samples will be used to measure P1NP, CTX, PTH, and vitamin D levels in both cases and controls at entry, week 24, and week 48.

Full description

A total of 50 HIV-uninfected men who have sex with men (MSM) and male to female (M to F) transgender individuals already enrolled in CCTG 595 will be offered participation in the sub-study at Week 24 of the main study. All subjects enrolled into the sub-study will be provided Vitamin D 4000 IU/day supplements in addition to their PrEP at Weeks 24 and 36; clinic visits will proceed normally per main study protocol. Upon completion of the sub-study subjects will continue on the main study.

The primary endpoint, bone turnover markers, will be measured from Week 24 to Week 48 via plasma samples collected through the main study. Concurrent controls who are not enrolled in the vitamin D substudy who are reporting supplementation with < 400 IU of vitamin D/day will be matched 1:1 by randomization arm in the CCTG 595 main study (text messaging arm vs. standard of care), age (± 5 years), race/ethnicity, season of study entry, and BMI (± 3 kg/m2).

Enrollment: 48 patients

Sex: Male

Ages: 18+ years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• All subjects must meet CCTG 595 inclusion criteria.

Exclusion criteria

• All subjects must meet CCTG 595 exclusion criteria.
• Current or prior use of bisphosphonate therapy.
• Current use of Vitamin D supplements greater than 400 IU/day.
• Current use of androgenic hormones or growth hormones.
• History of nephrolithiasis (kidney stones).
• History of fragility fracture.
• No use of tenofovir prior to entry into CCTG 595

Trial design

Primary purpose: Other

Allocation: Non-Randomized

Interventional model: Single Group Assignment

Masking: None (Open label)

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48 participants in 2 patient groups

Vitamin D Supplement + PrEP

Active Comparator group

Description:

Subjects enrolled into this sub-study will be provided Vitamin D 4000IU/day for 24 Weeks in addition to their PrEP provided through the main study.

Treatment:

Drug: Vitamin D Supplement

PrEP Only

No Intervention group

Description:

Subjects not enrolled into this sub-study will continue receiving PrEP through the main study. Subjects taking unsupplemented PrEP may still be used as matched controls to sub-study subjects.