Circulating tumour DNA predicts response to anti-PD1 antibodies in metastatic melanoma
Menée sur 76 patients atteints d'un mélanome métastatique et recevant un traitement par inhibiteurs de PD1 en combinaison ou non avec l'ipilimumab, cette étude met en évidence une association entre le niveau de l'ADN tumoral circulant et la réponse au traitement
Background : Programmed death 1 (PD1) inhibitors are now a foundation of medical management of metastatic melanoma. This study sought to determine whether circulating tumour DNA (ctDNA) provides useful early response and prognostic information.
Patients and methods : We evaluated the relationship between pre-treatment and early on treatment ctDNA and outcome in melanoma patients treated with PD1 inhibitors alone or in combination with ipilimumab.
Results : ctDNA was detected in 40/76 patients (53%) at baseline, and correlated with stage, LDH levels, disease volume and ECOG performance. RECIST response was 72% (26/36) in Group A (undetectable ctDNA at baseline), 77% (17/22) in Group B (elevated ctDNA at baseline but undetectable within 12 weeks of therapy) and 6% (1/18) in Group C (elevated ctDNA at baseline and remained elevated during treatment). The median PFS was not reached in groups A and B and was 2.7 months for Group C (hazard ratio (HR) 0.09; p < 0.001 for Group A vs C, and 0.16; p < 0.001 for Group B vs C). The median OS was not reached for Groups A and B and was 9.2 months for Group C (HR 0.02; p < 0.001 for Group A vs C and 0.14; p < 0.001 for Group B vs C). The poor outcome measures associated with Group C remained significant in multivariate analysis adjusted for LDH, performance status, tumour stage and disease volume. The predictive value for ctDNA for response was confirmed in a separate validation cohort (n = 29, p < 0.01).
Conclusion : Longitudinal assessment of ctDNA in metastatic melanoma patients receiving treatment with PD1 inhibitors is an accurate predictor of tumour response, PFS and OS. Patients who had a persistently elevated ctDNA on therapy had a poor prognosis, and this may guide combination and sequencing of subsequent therapies.
Annals of Oncology , résumé, 2016