Use of low-dose immune checkpoint inhibitors in low- and middle-income countries: a national survey of oncologists and hematologists in Mexico.

Immune checkpoint inhibitors (ICIs) have transformed the treatment landscape for multiple cancers but remain largely inaccessible in low- and middle-income countries (LMICs) due to high costs and limited availability. Pharmacokinetic and pharmacodynamic data, together with emerging clinical evidence, suggest that standard approved doses may exceed the threshold required for therapeutic efficacy, supporting the biological plausibility of low-dose strategies. In LMICs, such approaches could broaden access, yet their adoption is still limited. Eighty-one Mexican oncologists and hematologists answered a web-based survey designed to examine the use of low-dose ICI, reasons for implementation and barriers to adoption. All respondents reported at least one barrier to prescribing ICI, most commonly economic limitations or lack of coverage (71.6%). Nearly half (45.7%) reported having treated at least one patient with low-dose ICI, most often with the intention of reducing treatment costs (75.7%). Nivolumab was the most frequently used drug in low-dose regimens (75.7%), followed by pembrolizumab (43.2%). Commonly perceived barriers to prescribing low-dose ICI included concerns about efficacy and safety (51.9%), insufficient knowledge of dosing protocols (51.9%) and insurance approval limitations (43.2%). Confidence in efficacy was higher in the palliative compared to the curative setting. Only 19.7% of respondents felt sufficient evidence and resources were available to support the implementation of low-dose ICI. This study provides evidence on the use of low-dose ICI among physicians in Mexico, reflecting strategies motivated by cost reduction but hindered by safety concerns and perceived lack of evidence. As access to ICI remains a significant challenge in LMICs, the rigorous evaluation and implementation of low-dose regimens should be considered a research and policy priority.