Rheumatology
Seliciclib MTD is 400 mg in TNF-refractory RA (TRAFIC phase 1b)
Open access · cc by · source: Europe PMC
In an open-label UK dose-finding trial of 15 TNF-refractory RA patients, the CDK inhibitor seliciclib’s maximum tolerated dose was 400 mg, aiming at synovial fibroblast proliferation rather than classic immune-cytokine targets alone.
Study at a glance
- Design
- Human experiment — Phase 1b TRAFIC: non-randomised open-label Bayesian dose-finding of oral seliciclib
- N
- N=15 · Five dose cohorts; MTD 400 mg at 35% DLT target
- Population
- Adults with active RA despite ≥3 months stable anti-TNF therapy
- Outcome
- Maximum tolerated dose (dose-limiting toxicity)
Structured fields used in claim comparison tables when every cited study has a complete layer.
Key findings
Fifteen patients enrolled across five cohorts. The MTD was 400 mg (estimated DLT probability 0.35). Authors frame seliciclib as targeting synovial fibroblast proliferation — a cell type not yet standardly targeted by RA immune therapies that face ceiling effects.
Methodology
Phase 1b TRAFIC was a non-randomised, open-label, Bayesian dose-finding study in five UK NHS hospitals. Adults with active RA despite ≥3 months stable anti-TNF therapy received escalating oral seliciclib doses to estimate the MTD at a 35% dose-limiting toxicity target.
Limitations
MTD-finding is not proof of clinical efficacy. Open-label n=15 cannot establish remission rates. Phase 2 efficacy questions remain after dose selection.
How this study connects
Role on claims
Each row is a claim on a concept or method page where this paper supports, challenges, or qualifies the statement. Roles are hand-checked — not a model guess.
GSK2982772 (RIPK1) looked similar to placebo on RA activity at tested exposures.
In a 52-patient placebo-controlled experimental-medicine study on stable csDMARDs, safety was primary and DAS28-CRP/ACR outcomes were similar between GSK2982772 and placebo — authors conclude no meaningful clinical improvement at evaluated exposures.
Scope note — different development stage/target — open-label MTD for a CDK/fibroblast strategy, not RIPK1 efficacy
Limits the claim's scope: a different population, assay, or outcome.
Seliciclib’s MTD is 400 mg in TNF-refractory RA (TRAFIC phase 1b).
In 15 open-label patients with active RA despite TNF inhibitors, Bayesian dose-finding set seliciclib MTD at 400 mg, aiming at synovial fibroblast proliferation rather than classic immune-cytokine pathways alone.
Evidence for the claim as stated.
Early RA synovium already shows two expression/histology clusters.
Targeted arthroscopic biopsies from early RA clustered into two major gene-expression groups with different histological scores — molecular heterogeneity early in disease, not a treatment-assignment tool by itself.
Scope note — fibroblast-targeting rationale is related thematically, but TRAFIC is dose-finding in TNF-refractory disease, not early-biopsy clustering
Limits the claim's scope: a different population, assay, or outcome.
A null RIPK1 activity signal, an MTD for seliciclib, and early synovium clusters are different evidence types. Pathway interest does not transfer efficacy across programmes.
Evidence for the claim as stated.
Open questions
Tensions this paper is part of
From concept pages' “where studies disagree.” Disagreement means the same question; scope means different assays, populations, or outcomes.
A null RIPK1 activity signal, an MTD for seliciclib, and early synovium clusters are different evidence types. Pathway interest does not transfer efficacy across programmes.
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Same topic cluster — not a recommendation engine.