Repeat BCG vaccination in established T1D
What this study tests
Adult phase 2 randomized trial of repeated BCG in established T1D, with juvenile-onset disease as the primary population and an exploratory LADA cohort. Active, not recruiting. An ADA 2026 five-year subgroup report provides within-BCG changes but no placebo-adjusted outcome estimate.
Editorial review: .
Registry checked: 2026-09-17. Registry’s own update: 2026-04-13.
Most recent recorded citation date: 2026-06-05. Only explicit date metadata is included; an undated citation may be newer. This does not mean every claim was reviewed on that date.
Trial status, labels and access can change between reviews. How we review the evidence · How to read the evidence
Evidence at a glance
- Who can enter the study?
- Registry inclusion: adults 18–65 with insulin-treated T1D and specified residual C-peptide; exclusions include prior BCG/TB exposure, immunosuppression, pregnancy, significant complications and HbA1c outside the protocol range. Juvenile-onset disease is the primary efficacy population; LADA is exploratory. The trial is not recruiting. Registered eligibility ↗Enrollment criteria describe who may enter. They do not establish who was analyzed or the denominator for a reported result.
- Reported benefit and results
- No structured ClinicalTrials.gov results are posted. ADA 2026 abstract 2862-LB reports a five-year juvenile-onset subgroup (34 BCG/24 placebo): BCG-group HbA1c 7.84%→7.30% and insulin 0.68→0.63 units/kg/day, without placebo outcome values or a between-group effect estimate. C-peptide did not improve. These conference results do not establish insulin independence or a completed 150-person efficacy analysis.Read the result sources and their limitations →
- Important harms
- Read the reported results, safety discussion and original sources. A separate harms summary is not available; this does not establish safety.
- Research access and approval
- Study regions: United States. A trial listing does not establish product approval or current recruitment at a particular site. Check the study’s current entry requirements.
- What remains uncertain?
- Read the full discussion and original sources for study limitations. Planned endpoints and completion dates are not results.
Research status alone does not establish approval, clinical benefit or local availability. This record cites company or conference reports. Those sources may describe interim findings; their source type is shown in the source list.
Primary endpoints
- Change in HbA1c in juvenile-onset T1D, compared with self at years 1–5 after initial BCG/placebo injection (registry wording); randomized between-arm interpretation requires a reported comparison.
The full picture
Registry design and current status
NCT02081326 is a phase 2 randomized, parallel, placebo-controlled study sponsored by Massachusetts General Hospital. The current registry lists active, not recruiting, estimated enrollment of 150, and ages 18–65. Its listed primary population is adults with juvenile-onset T1D; the registry separately describes LADA as an exploratory population. A study summary's mechanistic assertions are investigator hypotheses, not proof of treatment benefit.1
The registry describes six vaccinations/injections over five years: two four weeks apart in the first year, then one in each of the next four years. Its primary outcome is HbA1c change compared with self at years 1–5. Other measures include insulin use, C-peptide/proinsulin and autoimmunity. The registry also describes later unblinding and optional crossover follow-up; it should not be read as a single unchanged five-year protocol.1
The last update was posted 13 April 2026. Estimated primary completion is July 2029 and estimated study completion July 2031. These are registry planning dates, not dates on which a paper must appear. The registry's structured results section remains absent, although a primary conference report is already available.1
What the ADA 2026 abstract actually reports
The original abstract 2862-LB, published 5 June 2026, reports on 34 BCG and 24 placebo adults whose T1D began before age 21, in a five-year analysis. It reports six doses of the Tokyo 174 BCG strain or placebo. This 58-person subgroup is not the registry's estimated 150-person total, which includes additional populations.2
The BCG group had reported mean HbA1c of 7.84% at baseline and 7.30% at year 5 (p=0.0006), and insulin use of 0.68 and 0.63 units/kg/day, respectively (p=0.024). The abstract does not give the corresponding placebo values, a between-group difference or an adjusted treatment-effect estimate. These within-arm changes should not be described as proof that BCG outperformed placebo. C-peptide remained low or undetectable and did not improve.2
Its CGM outcome concerns 70–99 mg/dL (3.9–5.5 mmol/L), a narrower range than standard 70–180 mg/dL (3.9–10.0 mmol/L) time in range. Absolute starting/ending percentages and a CGM analysis denominator are not supplied. The abstract characterizes treatment as safe and reports no increase in hypoglycemic episodes, but provides no detailed adverse-event counts. The full trial report is needed to assess efficacy comparisons, attrition, subgroup selection and harms.2
Sources
- [1]Repeat BCG vaccinations for established type 1 diabetes (NCT02081326) · Trial registry — Current API last update posted 13 April 2026. Active, not recruiting; estimated enrollment of 150 and July 2029 primary completion. No structured registry results; separate conference outcomes exist.
- [2]2862-LB: Phase II Clinical Trial of BCG Immunotherapy for Type 1 Diabetes with Juvenile Onset: Five-Year Analysis of Safety, HbA1c, Time in Range, and Insulin Use · Conference finding · 2026-06-05 — Original published ADA abstract and publisher-deposited abstract checked. Juvenile-onset adult subgroup: 34 BCG and 24 placebo. Reported outcomes are within-BCG changes, without placebo values or a between-arm effect estimate.