Abstract 2080
Background
Trabectedin (T) and pazopanib (P) are approved treatments for locally advanced or metastatic leiomyosarcoma (L-mSTS). In the absence of head-to-head randomized controlled trials (RCTs); a matched indirect comparison (MAIC) was performed to assess potential differences in clinical efficacy between the treatment groups.
Methods
MAIC was performed by extracting baseline characteristics from two phase III RCTs: SAR 3007 (T) and PALETTE (P): individual patient level data (IPD) was available forT only aggregated was published for P. Excluding those T patients who did not meet inclusion criteria for PALETTE, a sample size of 372 L-mSTS patients (T = 263, P = 109) was generated. Of all baseline characteristics, only time since diagnosis (≥30 vs. < 30 months), age (≥65 vs. < 65 years), and body weight (≥77 vs. < 77 kilograms), were statistically significant outcome predictors with T. The generalized method of moments (GMM) was used to optimally match cohorts for evaluation of differences in overall survival (OS), progression-free survival (PFS), and safety. Statistical analysis was performed using “R”.
Results
There was no statistically significant difference in PFS [HR = 0.82, (95%CI 0.63-1.06, p = 0.13)], or OS [HR = 0.86, (95% CI 0.64-1.18, p = 0.36)]. The percentage of patients with post-progression therapies was higher in T (74.5%) vs. P (59%) group. In the subgroup with PFS ≥6 months, patients treated with T experienced significantly improved median PFS (11.2 months vs PFS 8.4 months HR: 0.47 (95% CI: 0.3007 – 0.7434), p = 0.002 and were significantly more likely to achieve long term survival (OS ≥ 18 months): 45.8% vs. 33.7% (95%CI: 23.5%-48.3%), p = 0.025. Increased myelosuppression and hepatotoxicity observed with T whereas diarrhea, hypertension, pulmonary toxicity/pneumothorax, and neurotoxicity were observed with P.
Conclusions
The MAIC model warrants further investigation and validation. No differences in mPFS or mOS were noted in a MAIC comparison. Among patients achieving long term disease control (PFS > 6 mo), T significantly increased mPFS and the proportion of patients achieving prolonged overall survival (OS ≥ 18 mo). Differences in the safety profile were highlighted by this indirect comparison.
Clinical trial identification
Legal entity responsible for the study
Janssen Scientific Affairs, LLC, Pharma Mar S.A., LLC
Funding
Janssen Scientific Affairs, LLC, Pharma Mar S.A., LLC
Disclosure
R.L. Jones: Consultant for: Adaptimmune, Blueprint, Eisai, Epizyme, Daichii, Deciphera, Janssen Scientific Affairs, LLC, Immunedesign, Lilly, Merck, Pharmamar. J-Y. Blay: Research Funding and honoraria from Novartis, GSK and Pharmamar. A. Lecesne: Honoraria: Pfizer, Novartis, Pharmamar, Amgen, Lilly. J. Martin-Broto: Advisory boards for Novartis, Lilly, PharmaMar, Eisai, Bayer. M.J. Pontes, J.M. Fernandez Santos, B. García San Andrés: Employee of Pharma Mar S.A. and own stock in Pharma Mar S.A. G. Wang, S. Wang, C.R. Shin: Employee of Janssen and own stock in Johnson & Johnson. R. Maki: Consulting or advisory role: SARC, ASCO, AADX, ARCUS, Bayer, GSAI, GEM, Novartis, GSK, Immune Design, Janssen, Kyropharm, Lilly Tracon and Presage. Research Funding, travel and accommodations, expenses: Tracon, Immune Design, Lilly and SARC. S. Patel: Consultant to: Janssen, Eisai, Novartis, CytRx, Epizyme, Bayer, Eli Lilly. Grants for clinical trial from: Janssen, Eisai, Morphotek. G.D.S. Demetri: Consulting: Novartis, Janssen, PharmaMar, Daiichi-Sankyo, Adaptimmune, Eisai Patent licensed to Novartis from Dana-Farber with royalty paid to Dana-Farber. Research support to Dana-Farber: Novartis, Janssen.