Evaluating the accuracy of extrapolated overall survival for pembrolizumab: a comparison with long-term observed data in the Australian reimbursement context

  • 0HTANALYSTS, Sydney, Australia.

Summary

This summary is machine-generated.

Statistical models predicting cancer drug survival often underestimate real outcomes. This study found both Sponsor and PBAC models for pembrolizumab tended to underestimate long-term patient survival, with PBAC models being more conservative.

Area Of Science

  • Health Economics
  • Oncology
  • Biostatistics

Background

  • Government funding decisions for new medicines rely on statistical models to predict patient survival.
  • Overall survival (OS) predictions are crucial for assessing the cost-effectiveness of cancer drugs.
  • Accuracy of these predictive models is vital for informed healthcare policy.

Purpose Of The Study

  • To compare the accuracy of statistical models used by pharmaceutical Sponsors and the Pharmaceutical Benefits Advisory Committee (PBAC).
  • To evaluate these models against real-world long-term follow-up (LTFU) data for the cancer drug pembrolizumab.
  • To assess survival prediction accuracy for pembrolizumab across various indications.

Main Methods

  • Reviewed publicly available PBAC Summary Documents (PSDs) for pembrolizumab funding decisions up to November 2022.
  • Included cases with at least three years of follow-up and 350+ patients treated annually.
  • Compared survival predictions from Sponsor and PBAC models against actual survival data at two time points.

Main Results

  • Five out of 15 pembrolizumab indications met the inclusion criteria.
  • Sponsor models underestimated real survival by 0.54% to 16.45%.
  • PBAC models underestimated real survival by 1.20% to 24.21%.

Conclusions

  • Both Sponsor and PBAC OS extrapolation methods tend to underestimate long-term survival for pembrolizumab.
  • PBAC-preferred models demonstrated a more conservative underestimation of survival.
  • Findings highlight the need for refining predictive models in drug funding decisions.

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