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‹ Fri · 22 May 2026
Novel or significantly improved treatment

Use of circulating tumour DNA to prospectively guide a switch from targeted to immune therapy in BRAF mutant advanced melanoma: the randomised phase II CAcTUS trial

Blood tumor DNA levels can reliably guide melanoma patients to switch treatments within a week, potentially improving outcomes when resistance develops.

The CAcTUS randomized phase II feasibility trial demonstrated that ctDNA BRAF-VAF monitoring can reliably guide real-time treatment switching from targeted therapy to immunotherapy in advanced melanoma within clinically actionable timeframes (100% within 7 days). Post-hoc analysis showed ctDNA at nadir predicted a favorable immunological profile prior to checkpoint inhibitor initiation, supporting ctDNA-guided treatment optimization in BRAF mutant melanoma.

What the study was

Study design
Parallel-arm randomized phase II feasibility trial
Population
BRAF mutant advanced melanoma patients
Sample size
21
Category
Treatment Innovation
Maturity
Validated
Journal
Nat Commun

Why it surfaced

First randomized trial demonstrating ctDNA-guided prospective treatment sequencing in BRAF mutant melanoma; Nat Commun publication; feasibility primary endpoints met 100%; ctDNA as actionable real-time biomarker for immunotherapy sequencing decisions.

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