Lenvatinib for Follicular Thyroid Carcinoma
Yes, lenvatinib is an appropriate and FDA-approved systemic therapy for follicular thyroid carcinoma that is progressive, locally recurrent or metastatic, and radioactive iodine-refractory. 1
Regulatory Approval and Indication
Lenvatinib is FDA-approved for the treatment of adult patients with locally recurrent or metastatic, progressive, radioactive iodine-refractory differentiated thyroid cancer (DTC), which includes follicular thyroid carcinoma. 1 The European Medicines Agency (EMA) has granted the same approval. 2
Evidence Supporting Use
Pivotal Trial Data
The SELECT trial (NCT01321554) established lenvatinib as a standard first-line systemic therapy for RAI-refractory DTC with Level I, Grade A evidence. 2
Key efficacy outcomes from SELECT:
- Progression-free survival: 18.3 months with lenvatinib versus 3.6 months with placebo (HR 0.21; 99% CI 0.14-0.31; P<0.001) 2, 3
- Absolute PFS gain: 14.7 months 2
- Overall response rate: 64.8% with lenvatinib versus 1.5% with placebo (P<0.001) 3
- PFS benefit was observed across all prespecified subgroups, including patients with follicular carcinoma 3
Real-World Evidence
Recent real-world data from Japan demonstrated that follicular thyroid carcinoma patients treated with lenvatinib achieved a median PFS of 18 months, confirming the trial results translate to clinical practice. 4 Another real-world study showed median PFS of 2.4 years and overall survival of 5.1 years with optimized management strategies. 5
ESMO Guidelines Position
Lenvatinib and sorafenib are considered the standard first-line systemic therapy for RAI-refractory DTC (which includes follicular carcinoma). 2 The ESMO-Magnitude of Clinical Benefit Scale (ESMO-MCBS) assigns lenvatinib a score of 2-3, reflecting meaningful clinical benefit. 2
Dosing and Administration
The recommended starting dose is 24 mg orally once daily. 1 A randomized study comparing 18 mg versus 24 mg starting doses demonstrated that 18 mg was not noninferior to 24 mg, with objective response rates of 40.3% versus 57.3% respectively. 6, 7 Therefore, the 24 mg starting dose should be maintained, with dose modifications as needed for adverse events. 7
When to Initiate Treatment
Lenvatinib should be initiated when patients meet the following criteria:
- Progressive disease documented by RECIST v1.1 criteria (20% increase in sum of target lesions or new lesions) 2
- RAI-refractory disease (non-RAI-avid lesions, loss of RAI uptake, or progression despite RAI avidity) 2
- Presence of symptoms, high tumor burden, or lesions near vital structures 2
Initiate treatment earlier in the disease course when tumor burden is low and performance status is good, as this yields better outcomes. 7 Avoid waiting for significant performance status deterioration. 7
Safety Profile and Management
Common Adverse Events (>40% incidence):
- Hypertension (67.8%) 3
- Diarrhea (59.4%) 3
- Fatigue/asthenia (59.0%) 3
- Decreased appetite (50.2%) 3
- Weight loss (46.4%) 3
- Nausea (41.0%) 3
Critical Safety Considerations:
Grade ≥3 treatment-emergent adverse events occurred in approximately 60% of patients. 6 However, with appropriate management including planned drug holidays (79.1% of patients) and dose modifications, only 14.2-19.8% of patients discontinued due to adverse events. 5, 3
Treatment-related deaths: The SELECT trial reported 6 treatment-related deaths among 20 deaths during the treatment period, representing >2% treatment-related mortality. 2 This underscores the importance of careful patient selection and monitoring.
Specific Warnings:
Fistula formation and organ perforation risk: Exercise caution in patients with tumor infiltration into the trachea or other organs, as these are risk factors for serious complications. 7 Withhold lenvatinib at least 1 week before planned surgery due to impaired wound healing. 1
Cardiovascular monitoring: Control blood pressure before treatment initiation and monitor continuously. Withhold for Grade 3 hypertension despite optimal therapy; discontinue for Grade 4 hypertension. 1
Optimization Strategies
To maximize clinical benefit:
- Start at 24 mg daily with dose modifications as needed rather than starting at lower doses 6, 7
- Implement planned drug holidays to manage adverse events 5
- Minimize dose interruption duration, as shorter interruptions correlate with better outcomes 7
- Consider dose escalation at systemic disease progression (23.1% of patients in real-world practice) 5
- Apply local therapy for oligoprogressive disease when applicable (12.1% of patients) 5
Alternative for RAI-Eligible Patients
Notably, lenvatinib may be effective even in DTC patients who have not received RAI therapy. Real-world data showed median PFS of 46 months in RAI-naive patients versus 19 months in RAI-treated patients (though not statistically significant, p=0.243). 4 This suggests lenvatinib can be considered when RAI treatment is not feasible. 4, 8
Second-Line Options
If patients progress on lenvatinib, cabozantinib is approved as second-line therapy for RAI-refractory DTC following prior VEGFR-targeted therapy (including lenvatinib), with a median PFS not reached versus 1.9 months for placebo (HR 0.22). 2