Exposure-Response Analysis of Sonidegib (LDE225), an Oral Inhibitor of the Hedgehog Signaling Pathway, for Effectiveness and Safety in Patients With Advanced Solid Tumors

Sonidegib selectively inhibits smoothened protein, suppresses the growth of Hedgehog pathway-dependent tumors, and has recently been approved in the indication of locally advanced basal cell carcinoma. A comprehensive exposure-response analysis was conducted to further characterize the relationship of sonidegib exposure to efficacy and safety. Minimum observed plasma concentration at predose (C-min), peak concentration (C-max), and area under the curve were used as exposure endpoints. Exposure-efficacy analyses included data from 190 patients who received sonidegib 200mg or 800 mg once daily in the primary efficacy study. Objective response rate (ORR) (complete response [CR] or partial response [PR]), progression-free survival (PFS), and time to tumor response (TTR) were assessed by logistic regression, Cox regression, and Kaplan-Meier analyses. Exposure-safety (creatine phosphokinase [CK] elevation) analyses included data from 336 patients pooled from 4 clinical trials and included doses across ranges of 100 to 3000 mg once daily and 250 to 750mg twice daily. Similar plasma exposure was observed between responders and nonresponders. The logistic regression model of week 5 C-min vs ORR indicated no relationship between sonidegib exposure resulting from 200mg or 800 mg doses and the probability of CR or PR. A similar conclusion of no exposure-efficacy relationship was drawn from the PFS and TTR analyses. Increased exposure was associated with a greater risk of grade 3 or 4 CK elevation, with lower risk in females than in males when C-min was used in the model. These analyses support the sonidegib dose recommendation for registration and are consistent with clinical observations.