Introduction
Cancers cause worldwide morbidity and mortality, affecting over 19 million individuals and leading to nearly 10 million deaths in 2020, with a disproportionate death toll in low-income and middle-income countries (LMICs).1–3 Over the past half-century, better understanding of the biology of cancers has led to development of new cancer treatments, some of which have greatly improved the survival of cancer patients in high-income countries.4–7 The situation differs for patients in LMICs who have limited access to advanced cancer care, including diagnostics, cancer drugs and well-trained personnel, and well-equipped facilities.8 In middle-income countries where the services and facilities may exist, access to medicines and opportunities for better outcomes remain limited to those who can pay for the highly-priced treatments.8
Since 1977, the WHO publishes and updates every 2 years the List of Essential Medicines (EML). The WHO EML is intended as a guide for countries and regional authorities, especially in low-income and middle-income settings, to design national essential medicines lists for medicines approval, procurement and reimbursement decisions.9 The original WHO EML recommended six cancer drugs, and new cancer drugs were added in 1984, 1995 and 1999.10–12 Given the discrepancy in cancer burden between high-income and LMICs and advances in the treatment of some cancers in high-income countries, there was a strong call for narrowing the gap in access to cancer drugs worldwide.13 Compared with other classes of drugs, the selection process of cancer drugs has been more challenging due to the large volume of newly developed drugs approved rapidly with uncertain benefits and marketed with high and increasing prices. To ensure the clinical benefits of the recommended cancer drugs in EMLs, the WHO has launched a series of evidence-based updates.14 In 2014, WHO commissioned the Union for International Cancer Control to undertake a comprehensive review of cancer drugs in the 18th EML published in 2013 and of new medicines proposed for inclusion by researchers and organisations.15 16 ‘Meaningful improvements in overall survival (OS) compared with the existing standard of care’ was a criterion for the 2015 additions of new, highly priced targeted cancer drugs.14 Different from traditional chemotherapy, target-specific proteins that control cancer cells’ growth and spread.17 Targeted cancer drugs constitute the majority of newly approved cancer therapies18 and since 2015, an increasing number of cancer drugs have been recommended for inclusion on the WHO EML.15 19–21 Magnitude of benefit was one of the criteria considered since the 2015 cancer drug listings22 and quantified in 2018 in two metrics: (1) a threshold for OS benefit of at least 4–6 months and (2) a score on the European Society for Medical Oncology-Magnitude of Clinical Benefit Scale (ESMO-MCBS) of A or B in the curative setting and of 4 or 5 in the non-curative setting. These criteria have been recommended for the 2019 and 2021 (21st and 22nd) WHO EMLs.19 There is debate about the clinical benefit of new cancer drugs which often are approved based on surrogate outcome measures or on pivotal studies that do not permit inference about clinical benefit.23–25 Despite WHO proposed two specific criteria for selecting cancer drugs, lack of fidelity may occur because these are guiding principles for selection, among other criteria. However, WHO’s goal is to list only drugs with meaningful clinical benefit and these adopted guiding principles are important to achieve this goal. To our knowledge, no studies have examined the documented clinical benefit of targeted cancer drugs in the WHO EML or how approval decisions for the latest WHO EMLs align with WHO’s recent magnitude of benefit criteria for selecting cancer drugs. We address these knowledge gaps by assessing documented clinical benefits of WHO-EML cancer drugs. Our specific aims are to (a) assess documented OS benefit for targeted cancer drugs proposed for EML inclusion since 2015 and assess OS benefit magnitude and ESMO-MCBS scores for targeted cancer drugs proposed for listing in the WHO EML since 2019 and (b) assess the consistency of latest listing decisions with WHO criteria for WHO EML cancer drugs.