What constitutes meaningful benefit of cancer drugs in the context of LMICs? A mixed-methods study of oncologists' perceptions on endpoints, benefit, price, and value of cancer drugs

Background: The importance of surrogate endpoints, magnitude of clinical benefit of cancer drugs, and their prices have often been debated in the oncology world. No study, however, has systemically explored oncologists' perception regarding these issues.

Methods: We conducted a mixed-methods study including in-depth qualitative interviews of medical oncologists prescribing cancer drug therapy in India. Quantitative data were collected using a predetermined proforma. Qualitative in-depth interviews were audio-recorded, transcribed verbatim, anonymized, subsequently coded, and analyzed by generating basic and global themes.

Results: We interviewed 25 medical oncologists. Twenty-eight percent of oncologists rarely used cancer drugs that improved response rate (RR) but not overall survival (OS), and an equal percentage mostly/often used such drugs. For cancer drugs that improved progression-free survival (PFS) but not OS, 20% never/rarely used them while 48% mostly/often used them. Oncologists in India considered a 4.5-month (range, 1.5-12 months) advantage in median PFS as meaningful, and considered price of ∼120 United States Dollars (USD) per month (range, 48-720 USD per month) for those PFS gains as justified. For OS, median gains of 4.5 months (range, 2-24 months) and at a monthly price of ∼360 USD (range, 48-900 USD) was considered justified. Oncologists in India were aware and concerned that RR only meant tumour shrinkage not survival benefit, but many assumed that tumour shrinkage meant better quality of life. Many oncologists acknowledged the limitations of PFS but would use a drug with PFS benefit if it was cheaper than the drug with OS benefit.

Conclusions: Oncologists in India showed awareness of the limited surrogacy between RR/PFS and OS but assumed that RR/PFS correlated with improved quality of life and acknowledged price as a factor in deciding treatment choices. This is the first study providing a benchmark for minimum clinical benefit (4.5 months in PFS or OS) and maximum monthly price (120 USD for PFS, 360 USD for OS) deemed justifiable by oncologists practicing in low-and-middle-income countries.