Non-maleficence
The ethical principle most relevant to this situation is non-maleficence ("do no harm"), as the physician is ensuring that the patient will not be harmed by being denied standard treatment if assigned to the placebo arm. 1
Why Non-maleficence is the Primary Principle
The physician's reassurance directly operationalizes the principle of non-maleficence by guaranteeing that participants in the placebo group will continue receiving best current practice for their disease. 1 This ensures that the patient's health status will be no worse than it would be outside the trial, which is the core definition of non-maleficence in research contexts. 1
Clinical trial ethical frameworks explicitly mandate that control-arm participants must receive standard care aligned with "best current practice" to prevent additional harm from study participation. 1 The American Journal of Respiratory and Critical Care Medicine guidelines state that investigators must design control-arm protocols that faithfully reflect usual care specifically to avoid harming control participants. 1
Why Other Principles Are Less Applicable
Beneficence vs. Non-maleficence
While beneficence (maximizing benefits) and non-maleficence (minimizing harm) are related principles, they have distinct obligations. 2 Beneficence focuses on actively promoting patient welfare and maximizing potential benefits, whereas non-maleficence emphasizes the obligation to avoid causing harm. 2 In this scenario, the physician is not promising additional benefits but rather preventing harm by ensuring standard treatment continues—this is the essence of non-maleficence. 1
Autonomy
Autonomy relates to the patient's right to make informed decisions about their care after receiving adequate information. 2 While the physician's explanation supports informed consent, the core reassurance addresses harm prevention rather than decision-making capacity. 1 The physician is not primarily discussing the patient's right to choose but rather guaranteeing protection from harm. 1
Justice
Justice concerns the fair distribution of research burdens and benefits across populations. 2 This principle is less applicable here because the focus is on protecting an individual participant from harm rather than ensuring equitable distribution of research participation. 1
Critical Clinical Context
The physician's statement serves as a protective measure ensuring that participation in research does not expose the patient to worse care than they would receive outside the trial. 1 This directly fulfills the ethical requirement that researchers must minimize potential harm while conducting studies. 2
The principle of non-maleficence has been central to medical ethics since the Hippocratic tradition established "Primum non nocere" (first, do no harm). 3 In modern clinical research, this translates to the requirement that control groups receive standard care to prevent harm from study participation. 1
Answer: B. Non-maleficence