Developing a Common Language for Tumor Response to Immunotherapy: Immune-related Response Criteria using Unidimentional measurements
Menée sur 57 patients atteints d'un mélanome de stade avancé et inclus dans un essai de phase II évaluant l'ipilimumab, cette étude compare l'intérêt de deux méthodes, unidimensionnelle et bidimensionnelle, pour analyser des critères de réponse à une immunothérapie
Purpose: Immune-related response criteria (irRC) was developed to adequately assess tumor response to immunotherapy. The irRC are based on bidimensional measurements, as opposed to unidimensional measurements defined by RECIST, which has been widely used in solid tumors. We aimed to compare response assessment by bidimensional versus unidimensional irRC in advanced melanoma patients treated with ipilimumab.
Methods: Fifty-seven patients with advanced melanoma treated with ipilimumab in a phase II, expanded access trial were studied. Bidimensional tumor measurement records prospectively performed during the trial were reviewed to generate a second set of measurements using unidimensional, longest diameter measurements. The percent changes of measurements at follow-up, best overall response, and time-to-progression (TTP) were compared between bidimensional and unidimensional irRC. Interobserver variability for bidimensional and unidimensional measurements was assessed in randomly selected 25 patients.
Results: The percent changes at follow-up scans were highly concordant between the two criteria (Spearman r: 0.953-0.965, 1st -4th follow-up). The best immune-related response was highly concordant between the two criteria (κw=0.881). TTP was similar between the bidmensional and unidimensional assessments (progression-free at 6 months: 70% versus 81%, respectively). The unidimensional measurements were more reproducible than bidimensional measurements, with the 95% limits of agreement of (-16.1%, 5.8%) versus (-31.3%, 19.7%), respectively.
Conclusion: Immune-related response criteria using the unidimensional measurements provided highly concordant response assessment compared to the bidimensional irRC, with less measurement variability. The use of unidimensional irRC is proposed to assess response to immunotherapy in solid tumors, given its simplicity, higher reproducibility and high concordance with the bidimensional irRC.
Clinical Cancer Research , résumé, 2013