THYROID CANCER · White paper
Thyroid Cancer Clinical Trials
Approved therapies, the pivotal-trial endpoints they were judged on, the magnitude of benefit — and the drugs that failed their endpoints, and why.
Indication overview
About thyroid cancer — and why its trials are hard
Thyroid cancer is the most common endocrine malignancy, with an estimated 586,000 new cases globally in 2020 and roughly 43,720 US diagnoses annually. Most cases are differentiated (papillary and follicular) carcinomas with excellent prognoses, but medullary (RET-driven) and anaplastic subtypes are far more aggressive, the latter with under 10% five-year survival. Surgery plus radioactive iodine (RAI) and lifelong levothyroxine with TSH suppression form the backbone of care for differentiated disease. For RAI-refractory and advanced tumors, molecularly targeted tyrosine kinase inhibitors dominate: sorafenib (DECISION) and lenvatinib (SELECT) in differentiated thyroid cancer, cabozantinib in medullary and later differentiated disease, and highly selective RET inhibitors such as selpercatinib for RET-altered tumors. For BRAF V600E-mutant anaplastic thyroid cancer, dabrafenib plus trametinib provided the first effective systemic option. Trials rely on progression-free survival and objective response rate (RECIST) as primary or accelerated-approval endpoints, with overall survival often confounded by placebo crossover. Persistent challenges include mutation heterogeneity, radiological assessment variability, and late-stage recruitment difficulty.
Approved therapies & pivotal evidence
What's been approved — and by how much it moved the endpoint
| Drug (brand) | Approved | Setting | Pivotal trial | Primary endpoint | Magnitude of benefit |
|---|---|---|---|---|---|
| Lenvatinib (Lenvima) | 2015 | Progressive, radioiodine-refractory differentiated thyroid cancer | SELECT (NCT01321554) | Progression-free survival (PFS) | Median PFS 18.3 vs 3.6 months (HR 0.21, p<0.001); ORR 65% vs 2% |
| Sorafenib (Nexavar) | 2013 | Progressive, radioiodine-refractory differentiated thyroid cancer | DECISION (NCT00984282) | Progression-free survival (PFS) | Median PFS 10.8 vs 5.8 months vs placebo (HR ~0.59) |
| Cabozantinib (Cometriq (MTC) / Cabometyx (DTC)) | 2012 | Metastatic medullary thyroid carcinoma (Cometriq, 2012); RAI-refractory differentiated thyroid cancer (Cabometyx, 2021) | EXAM (NCT00704730); COSMIC-311 (DTC) | Progression-free survival (PFS) | EXAM median PFS 11.2 vs 4.0 months (HR 0.28, p<0.0001); partial response 27% vs 0% |
| Selpercatinib (Retevmo) | 2020 | RET-mutant medullary thyroid cancer and RET fusion-positive thyroid cancer | LIBRETTO-001 (NCT03157128) | Objective response rate (ORR) and duration of response | RET-mutant MTC ORR 69% (pretreated) and 73% (treatment-naive); durable responses |
| Dabrafenib + trametinib (Tafinlar + Mekinist) | 2018 | BRAF V600E-mutant unresectable or metastatic anaplastic thyroid cancer | ROAR basket study (NCT02034110) | Objective response rate (ORR) | ORR approximately 56-61% in a subtype historically without effective systemic therapy |
| Levothyroxine (TSH suppression) (Synthroid and others) | Standard of care (long established) | Post-thyroidectomy hormone replacement and TSH-suppression to reduce recurrence in differentiated thyroid cancer | Standard-of-care; established through clinical practice guidelines | Recurrence risk reduction; biochemical TSH control | TSH suppression reduces recurrence risk in high-risk differentiated thyroid cancer (magnitude per risk-stratified guidelines) |
Where trials have failed
Drugs that missed their endpoint — and what contributed
The most instructive lessons in thyroid cancer development come from programmes that failed the endpoint that mattered.
| Drug / trial | Endpoint outcome | What contributed |
|---|---|---|
| Vandetanib — Advanced papillary thyroid cancer trial (NCT01876784) | Limited clinical benefit with inconsistent responses; PFS gains not statistically significant in PTC | Inadequate molecular patient selection; underscored the need for biomarker-driven enrollment |
| Donafenib — NCT02960182 | Early termination due to a concerning toxicity profile (hepatotoxicity, hypertension) | Sorafenib-derivative off-target effects; drove emphasis on more selective next-generation TKIs |
| PLX8394 — NCT02428712 | Limited efficacy in non-BRAF tumors and non-durable responses even in BRAF-positive disease | Mutation-specific activity without adequate stratification; highlighted need for combination strategies |
Choosing the right endpoint
Primary endpoints that matter in thyroid cancer trials
- Progression-free survival (PFS) — Common primary endpoint in advanced/RAI-refractory disease; depends on consistent RECIST imaging
- Overall survival (OS) — Gold standard but frequently confounded by placebo crossover (e.g., 83% crossover in SELECT) and long follow-up
- Objective response rate (ORR) — RECIST-based surrogate supporting accelerated approval, especially for RET and BRAF-targeted agents
- Duration of response (DoR) — Captures durability of targeted-therapy responses; limited early data can reduce reliability
- Quality of life (EORTC QLQ-C30 / FACT-G) — Increasingly weighted in regulatory decisions for incurable advanced disease
How iNGENū runs thyroid cancer trials
Physician-led design, built for FDA submission
Endpoint & biomarker strategy
Board-certified specialists design endpoints and patient selection aligned to current FDA guidance for this indication.
FDA-ready data
Built to ICH-GCP and 21 CFR 312.120, with direct FDA submission — data accepted by the FDA, EMA and MHRA.
Faster, lower-cost delivery
~4-week ethics via the TGA CTN scheme, up to 43.5% R&D rebate, and 80–90% below US CRO cost.
The full white paper: approved-product analyses, pivotal endpoints and trial-design strategy. Open-access · no sign-in.
Frequently asked questions
Thyroid Cancer clinical trials — FAQs
What is the standard treatment for differentiated thyroid cancer?
How are targeted therapies matched to thyroid cancer subtypes?
Why is overall survival hard to demonstrate in thyroid cancer trials?
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