Climate change and the prescription pad

Projected environmental and public health benefits of extended-interval dosing: an analysis of pembrolizumab use in a US national health system

BACKGROUND

Health care is a major source of greenhouse gas emissions, leading to climate change and public health harms. Changes are needed to improve the environmental sustainability of health-care practices, but such changes should not sacrifice patient outcomes or financial sustainability. Alternative dosing strategies that reduce the frequency with which specialty drugs are administered, without sacrificing patient outcomes, are an attractive possibility for improving environmental sustainability. We sought to inform environmentally sustainable cancer care by estimating and comparing the environmental and financial effects of alternative, clinically equivalent strategies for pembrolizumab administration.

METHODS

We conducted a retrospective analysis using a cohort of patients from the Veterans Health Administration (VHA) in the USA who received one or more pembrolizumab doses between May 1, 2020, and Sept 30, 2022. Using baseline, real-world administration of pembrolizumab, we generated simulated pembrolizumab use data under three near-equivalent counterfactual pembrolizumab administration strategies defined by combinations of weight-based dosing, pharmacy-level vial sharing and dose rounding, and extended-interval dosing (ie, every 6 weeks). For each counterfactual dosing strategy, we estimated greenhouse gas emissions related to pembrolizumab use across the VHA cohort using a deterministic environmental impact model that estimated greenhouse gas emissions due to patient travel, drug manufacture, and medical waste as the primary outcome measure.

FINDINGS

We identified 7813 veterans who received at least one dose of pembrolizumab-containing therapy in the VHA during the study period. 59 140 pembrolizumab administrations occurred in the study period, of which 46 255 (78·2%) were dosed at 200 mg every 3 weeks, 12 885 (21·8%) at 400 mg every 6 weeks, and 14 955 (25·3%) were coadministered with infusional chemotherapies. Adoption of weight-based, extended-interval pembrolizumab dosing (4 mg/kg every 6 weeks) and pharmacy-level stewardship strategies (ie, dose rounding and vial sharing) for all pembrolizumab infusions would have resulted in 24·7% fewer administration events than baseline dosing (44 533 events vs 59 140 events) and an estimated 200 metric tons less CO2 emitted per year as a result of pembrolizumab use within the VHA (650 tons vs 850 tons of CO2, a relative reduction of 24%), largely due to reductions in distance travelled by patients to receive treatment. Similar results were observed when weight-based and extended-interval dosing were applied only to pembrolizumab monotherapy and pembrolizumab in combination with oral therapies.

INTERPRETATION

Alternative pembrolizumab administration strategies might have environmental advantages over the current dosing and compounding paradigms. Specialty medication dosing can be optimised for health-care spending and environmental sustainability without sacrificing clinical outcomes.

FUNDING

None.

Challenges to decarbonizing medication prescribing and use practices: A call to action

Climate change undeniably impacts the social and environmental determinants of one's health. The healthcare sector, encompassing medications and the pharmaceutical industry supply chain, accounts for a significant portion of global health care contributions to greenhouse gas (GHG) and waste production. Despite these realities, healthcare professionals - physicians, pharmacists, nurses, and others - may be unaware of GHG emissions and the long-term environmental effects of the medications they prescribe, dispense, and administer daily. In this commentary, we identify existing challenges and explore potential strategies to recognize and reduce the climate change impacts associated with medication use.

Environmental sustainability and the paradox of prevention

The carbon emissions of global healthcare activities make up 4%-5% of total world emissions, with the majority coming from industrialised countries. The solution to healthcare carbon reduction in these countries, ostensibly, would be preventive healthcare, which is less resource intensive than corrective healthcare in itself and, as a double benefit, reduces carbon by preventing diseases which may require higher healthcare carbon to treat. This leads to a paradox: preventive healthcare is designed to give humans longer, healthier lives. But, by extending life spans, the carbon emissions of a person increase both over a lifetime and in the medical industry overall. At the same time, the need for higher carbon end-of-life care does not disappear, particularly in resource intensive countries. This article will first identify sources of healthcare carbon, focusing on the industrialised world, and explain various efforts towards healthcare carbon reduction, which include preventive healthcare. Second, it will develop the 'paradox of prevention'-that preventive healthcare may save healthcare carbon by proximally reducing the need for medical treatments, but also, paradoxically, result in more healthcare carbon both in an individual's life and in the medical industry. The third section will offer ethical principles for approaching the paradox of prevention. The conclusion will emphasise the need for institutional approaches to healthcare carbon reduction in the industrialised world, which will relieve some of the tensions of healthcare industry decarbonisation and individual healthcare carbon use.

Alternative Trastuzumab Dosing Schedules Are Associated With Reductions in Health Care Greenhouse Gas Emissions

PURPOSE

Cancer care-related greenhouse gas (GHG) emissions harm human health. Many cancer drugs are administered at greater-than-necessary doses, frequencies, and durations. Alternative dosing strategies may enable reductions in cancer care GHG emissions without compromising patient outcomes.

MATERIALS AND METHODS

We used streamlined life-cycle analysis in a case-control simulation to estimate the relative reductions in GHG emissions that would be expected to result from using each of three alternative dosing strategies of trastuzumab (6-month adjuvant treatment duration, once every 4-week dosing, and both) in human epidermal growth factor receptor 2 (HER2)+ breast cancer. Using primary data and conversion factors from the environmental science literature, we estimated per-patient relative reduction in GHG emissions and, using SEER data, health impacts (in terms of disability-adjusted life-years [DALYs] and excess mortality per kg CO2) on bystanders for each alternative dosing strategy.

RESULTS

Compared with the trastuzumab dosing strategy commonly used at baseline (12-month duration of adjuvant therapy and once every 3-week dosing in all settings), adoption of both 6-month adjuvant trastuzumab and once every 4-week trastuzumab dosing would reduce GHG emissions by 4.5%, 18.7%, and 14.6% in the neoadjuvant, adjuvant, and metastatic settings, respectively. We estimate that US-based adoption of alternative trastuzumab dosing would reduce annual DALYs and excess lives lost due to environmental impact of US-based trastuzumab therapy for HER2+ breast cancer by 1.5 and 0.9, respectively.

CONCLUSION

Alternative dosing strategies may materially reduce the population health impacts of cancer care by reducing environmental impact. Regulatory decision making and health technology assessments should consider a treatment's environmental and population health impacts. Clinical trials of alternative dosing strategies are justified on the basis of environmental and population health impacts.