Synbiotic (Pendulum WBF-038) and bone health in Caucasian postmenopausal women: rationale and design of the OsteoPreP trial
This is a trial protocol — no efficacy data were reported; the direction of effect on BMD and metabolic health remains insufficient pending trial completion.
| Population | 160 Caucasian postmenopausal women aged 40–65, without diagnosed osteoporosis, hypertension, or diabetes, residing in Melbourne, Australia |
|---|---|
| Intervention | Oral synbiotic Pendulum WBF-038 (Akkermansia muciniphila, Anaerobutyricum hallii, Clostridium butyricum, C. beijerinckii, Bifidobacterium infantis Bi26 + chicory inulin) for 12 months |
| Comparator | Identical oral placebo for 12 months (double-blind) |
| Outcome | Bone mineral density (DXA); Bone remodeling markers; Glycaemic parameters (fasting glucose, OGTT); Body composition (lean and fat mass); Muscle function; Cognition; Gut microbiota composition |
Summary of findings
| Outcome | Effect | 95% CI | Certainty | Clinical relevance | Notes |
|---|---|---|---|---|---|
| Bone mineral density (DXA) | not yet reported — protocol only | — | Low | — | |
| Bone remodeling markers | not yet reported — protocol only | — | Low | — | |
| Glycaemic parameters (fasting glucose, OGTT) | not yet reported — protocol only | — | Low | — | |
| Body composition (lean and fat mass) | not yet reported — protocol only | — | Low | — | |
| Muscle function | not yet reported — protocol only | — | Low | — | |
| Cognition | not yet reported — protocol only | — | Low | — | |
| Gut microbiota composition | not yet reported — protocol only | — | Low | — |
Context
Osteoporosis affects 200 million women globally; only 30% of high-risk Australian women receive specific treatment. Gut microbiota influences bone metabolism via short-chain fatty acids (SCFAs), especially butyrate, which regulates osteoclasts and regulatory T cells. No prior RCT has tested this specific five-strain probiotic plus inulin combination over 12 months in women at risk of osteoporosis.
What the study showed
The article describes exclusively the trial rationale and protocol; no efficacy or safety results were presented. Planned sample size is n=160 (80 per arm), with a musculoskeletal subgroup of 30 participants for OGTT and regulatory T-cell counts. Primary outcome data (BMD by DXA) will be obtained after 12 months of intervention.
How it was done
Double-blind, placebo-controlled RCT with 1:1 allocation via block randomization (80 blocks, 2 per block). Assessments at baseline and five follow-up visits over 12 months. Partial sponsorship from Pendulum Therapeutics Inc., which also generated the randomization list — a relevant risk of bias to be assessed with RoB 2 after publication of results.
Effect magnitude
No calculable effect size; the article provides only the sample size calculation (n=160 to detect a clinically meaningful difference in BMD), with no outcome data.
Risk of bias
Protocol without efficacy data: no conclusions about effect can be drawn at this stage. Recruitment restricted to Caucasian women in Melbourne limits generalizability. Industrial sponsor (Pendulum Therapeutics) generated the randomization and supplies the product, representing a structural conflict of interest — RoB 2 tool must be applied to the final report. Musculoskeletal subgroup (n=30) is insufficient for confirmatory analyses.
What this study does NOT prove
This study does NOT prove efficacy, safety, or any direction of effect of the synbiotic on BMD or metabolic parameters — it is solely a protocol. It is not generalizable to non-Caucasian women, men, or women with established osteoporosis.
In clinical practice
No change in clinical practice is justified based on this protocol. Clinicians should await publication of primary results before considering this synbiotic for osteoporosis prevention. Current use of probiotics/synbiotics for BMD in postmenopause carries at most grade C evidence.
Limitations
Protocol without efficacy data: no conclusions about effect can be drawn at this stage. Recruitment restricted to Caucasian women in Melbourne limits generalizability. Industrial sponsor (Pendulum Therapeutics) generated the randomization and supplies the product, representing a structural conflict of interest — RoB 2 tool must be applied to the final report. Musculoskeletal subgroup (n=30) is insufficient for confirmatory analyses.
What is still missing
Publication of primary and secondary results of OsteoPreP after completion of 12-month follow-up. Individual participant data meta-analyses will be needed to confirm generalizability to other ethnic groups and age ranges.
Technical appendix
Version history
- 1.0 · 2026-06-24 — Auto-generated under Evidence Standard v1.0