Study record
Danazol and telomere attrition in telomere disease: a single-arm study (Townsley et al., 2016)
Human clinical-outcome trial — disease population (single-arm)
Two caveats govern every page on this site. (1) Telomere length is a contested aging biomarker — it is measured differently by different methods, varies between tissues, and "longer" is not straightforwardly "healthier"; changing a telomere-length or telomerase-activity number in a trial is not the same as slowing human aging. (2) Activating telomerase is not risk-free — telomerase expression is low in many differentiated normal tissues, while some normal proliferating cells can express it. Cancer can also use telomere maintenance; the included human records do not resolve long-term cancer risk from pharmacological activation. Tellingly, the FDA-approved telomerase inhibitor — imetelstat (RYTELO, 2024) — inhibits telomerase to treat cancer (lower-risk MDS), the opposite direction from the anti-aging "activation" narrative.
○ Evidence tier 2 — Human clinical-outcome trial — disease population
Record verify: source publication identified; see evidence and limitations
| Design | Prospective single-arm clinical trial (disease-outcome; telomere-attrition endpoint) |
| N | 27 |
| Registry | NCT01441037 |
| PMID | 27192671 |
| DOI | 10.1056/NEJMoa1515319 |
| Citation status | Original publication identity matched by title, author and DOI; relevant full-text sections, results and limitations examined 2026-10-14. The original article reports NCT01441037; its current registry record has not been independently verified. |
Five-qualifier claim
| Species / population | 27 patients with clinical telomere disease, median age 41 (range 17–66). Table 1 reports 19 with moderate aplastic anemia, 4 with severe aplastic anemia and 2 with myelodysplastic syndrome; eligibility also allowed pulmonary fibrosis. Six had no identified pathogenic mutation. |
| Exposure, route, schedule | Oral danazol 800 mg/day for up to 24 months. |
| Comparator / duration | Single-arm prospective trial with a pre-specified 24-month telomere-attrition endpoint. The institutional review board closed it early after observing the results; no efficacy stopping rule had been pre-specified. |
| Endpoint / numeric result | At 24 months, 12/12 evaluable patients met the primary reduced-attrition endpoint; intention-to-treat response was 12/27 (44%). Telomere elongation occurred in 11/12 evaluable patients (92%), a separate result. Hematologic response was 19/24 at 3 months and 10/12 at 24 months. Elevated liver enzymes and muscle cramps were reported in 41% and 33%. No randomized control group. |
| What it did NOT establish | This uncontrolled study concerns clinical telomere disease, not healthy aging. It cannot establish a causal survival benefit or benefits in the general population. Some participants had no identified pathogenic mutation. Liver-enzyme elevations, cramps and other adverse events limit interpretation of tolerability. |
Interventions
Primary reference
https://doi.org/10.1056/NEJMoa1515319
Each identifier above was confirmed against the primary record; the citation status names the source and the date. An identifier that could not be confirmed is left empty and named as such in the record, never filled in from a secondary source.