Experience with outcomes research into the real-world effectiveness of novel therapies in Dutch daily practice from the context of conditional reimbursement.

Policymakers more often request outcomes research for expensive therapies to help resolve uncertainty of their health benefits and budget impact at reimbursement. Given the limitations of observational data, we assessed its usefulness in evaluating clinical outcomes for bortezomib in advanced multiple myeloma patients. Data were retrospectively collected from patients included in the pivotal Assessment of Proteasome Inhibition for Extending Remissions trial (APEX; n=333) and two groups of daily practice patients treated with bortezomib following progression from upfront therapy (n=201): real-world patients treated as of May 2009 (RW-1; n=72) and June 2012 (RW-2; n=129). Prognosis, treatment, and effectiveness were compared. Outcomes research was useful for policymakers for addressing to whom and how bortezomib was administered in daily practice. It was limited however in generating robust evidence on real-world safety and effectiveness. The quality of real-world evidence on effectiveness was low due to missing data in patient charts, existing treatment variation and the dynamics in care during the novel drug's initial market uptake period. Policymakers requesting real-world evidence on clinical outcomes for reimbursement decisions should be aware of these limitations and advised to carefully consider beforehand the type of evidence that best addresses their needs for the re-assessment phase.