Trial Outcomes & Findings for Study of Efficacy and Safety of Dabrafenib in Combination With Trametinib in Previously Treated Patients With Metastatic, Radio-active Iodine Refractory BRAF V600E Mutation Positive Differentiated Thyroid Cancer (NCT NCT04940052)

The study is conducted globally across 11 countries.

Participants were randomized in a 2:1 ratio to either Dabrafenib plus Trametinib or placebo. Randomization was stratified by the number of prior VEGFR targeted therapies (1 vs. 2) and prior lenvatinib treatment (yes vs. no).

Study of Efficacy and Safety of Dabrafenib in Combination With Trametinib in Previously Treated Patients With Metastatic, Radio-active Iodine Refractory BRAF V600E Mutation Positive Differentiated Thyroid Cancer

Progression Free Survival (PFS) was defined as the time from the date of randomization to the date of the first documented progression according to RECIST 1.1 based on Blinded Independent Review Committee (BIRC) assessment, or death due to any cause. The primary analysis was conducted after all patients had either completed a minimum of 16 weeks of treatment or discontinued earlier, and following the occurrence of approximately 95 PFS events (Data cut-off date for the primary analysis was 22 January 2025).

Overall Response Rate (ORR) was defined as the proportion of participants who had a Best Overall Response (BOR) of confirmed Complete Response (CR) or Partial Response (PR) according to RECIST 1.1.

Overall Survival (OS) is defined as the time from the date of randomization to the date of death due to any cause.

Duration of Response (DOR) applied only to patients whose Best Overall Response (BOR) was a confirmed Complete Response (CR) or Partial Response (PR) according to RECIST 1.1. The start date was defined as the date of the first documented confirmed CR or PR, and the end date corresponded to the date of the first documented confirmed progression or death from any cause. Patients who remained without progression or death from any cause were censored at the date of their last adequate tumor assessment prior to the initiation of any new antineoplastic therapy.

The distribution of adverse events will be conducted through the analysis of frequencies for treatment-emergent adverse events (TEAEs) and serious adverse events (TESAEs), based on the monitoring of relevant clinical and laboratory safety parameters. Treatment-emergent adverse events (TEAEs) in this study will be defined as events that begin after the first dose of study treatment and continue until 30 days after the last dose, or events that are present prior to the first dose and increase in severity based on preferred term within 30 days following the last dose.

Analysis of the optical coherence tomography data was performed to assess the incidence, type, and severity of trametinib-associated serous retinopathy ocular events, using the Common Terminology Criteria for Adverse Events (CTCAE) version 4.03 grading system: Grade 1 (mild), Grade 2 (moderate), Grade 3 (severe), Grade 4 (life-threatening), and Grade 5 (death related to adverse event).