Growth modulation index as metric of clinical benefit assessment among advanced soft tissue sarcoma patients receiving trabectedin as a salvage therapy
Penel, N × Demetri, G D Blay, J Y Cousin, S Maki, R G Chawla, S P Judson, I von Mehren, M Schöffski, Patrick Verweij, J Casali, P Rodenhuis, S Schütte, H J Cassar, A Gomez, J Nieto, A Zintl, P Pontes, M J Le Cesne, A #
Kluwer Academic Publishers
Annals of Oncology vol:24 issue:2 pages:537-42
BackgroundThe growth modulation index (GMI) is the ratio of time to progression with the nth line (TTP(n)) of therapy to the TTP(n)(-1) with the n-1th line. GMI >1.33 is considered as a sign of activity in phase II trials.Patients and MethodsThis retrospective analysis evaluated the concordance between the GMI and the efficacy outcomes in 279 patients with advanced soft tissue sarcoma (ASTS) treated with trabectedin 1.5 mg/m² (24-h infusion every 3 weeks) in four phase II trials.ResultsOne hundred and forty-two (51%) patients received one prior line and 137 ≥2 lines. The median TTP(n) was 2.8 months (range 0.2-26.8), whereas the median TTP(n)(-1) was 4.0 months (0.3-79.5). The median GMI was 0.6 (0.0-14.4). Overall, 177 patients (63%) had a GMI <1; 21 (8%) a GMI equal to 1-1.33 and 81 (29%) a GMI >1.33, which correlated with the median overall survival in those patients (9.1, 13.9 and 23.8 months, respectively, P = 0.0005). A high concordance rate between the GMI and response rate (P < 0.0001) and progression-free survival (PFS, P < 0.0001) was observed. Good performance status (PS) was the only factor associated with GMI >1.33 (PS = 0; P < 0.04).ConclusionsA high GMI was associated with favorable efficacy outcomes in patients treated with trabectedin. Further research is needed to assess GMI as an indicator in this setting.