Posted by Michael Wonder on 19 Sep 2016
Real-world evidence: a comparison of the Australian Herceptin Program and clinical trials of trastuzumab for HER2-positive metastatic breast cancer
19 September 2016 - Estimating the real-world cost-effectiveness of a new drug relies on understanding the differences between clinical trial data (pre-reimbursement) and clinical practice (post-reimbursement).
This is important for decision makers when reviewing reimbursement decisions, prices, and considering other drugs for the same condition. Differences can arise from differences in patient characteristics, but also from the availability of new evidence and evolving treatment practices. In the this month's issue of PharmacoEconomics, Parkinson et al. examine these issues using trastuzumab (Herceptin) as a case study.
Compared to participants in the clinical trials, patients were older, received more prior chemotherapies and a broader range of co-administered chemotherapies. Treatment practices differed from the clinical trials, but also changed over time. For example, in situ hybridization testing, rather than immunohistochemistry testing, and a three weekly administration schedule, rather than one weekly, were increasingly used. Compared to the clinical trials, patients administered trastuzumab with a concomitant chemotherapy generally experienced longer overall survival (151.3 weeks, 95 % CI: 142.6, 163.4), while those who received trastuzumab as a monotherapy experienced shorter overall survival (94.4 weeks, 95%CI: 86.4, 102.9). These findings may be due to a differing relative treatment effect in clinical practice, but may also be due to a range of other factors.
This analysis demonstrates the challenges for decision makers that arise because new evidence and evolving treatment practices create a gap between clinical trial data and real-world clinical practice and outcomes.
