United States regulators are standing by their decision that parents were not properly informed of the risks of a clinical trial in which premature babies received different levels of oxygen supplementation.

From 2005 to 2009, the Surfactant, Positive Pressure, and Oxygenation Randomized Trial (SUPPORT) trial randomly assigned 1,316 premature babies to receive one of two levels of oxygen supplementation in an effort to test which level was best. Even though the lower level was associated with increased risk of brain damage and possibly death, and the higher level with blindness, the study leaders said that they did not disclose these risks to parents because all ranges of oxygen used in the trial were considered to be within the medically appropriate range at the time.

The study was supported by the US National Institutes of Health (NIH). On 7 March 2013, the US Office of Human Research Protections (OHRP) issued a letter determining that the trial investigators had not adequately informed parents about the risks to their babies in the SUPPORT trial. The NIH and many researchers disputed the decision, arguing that it would impede “comparative effectiveness research” studies that are designed to test the best use of approved interventions. Parents of children in the trial, however, and others supported the OHRP’s determination that parents hadn’t received adequate information. The two sides clashed at a meeting convened by the NIH and the OHRP in August 2013.

Today, 24 October 2014, the OHRP has issued guidance reiterating and clarifying its position on what types of risks must be disclosed to study subjects in comparative effectiveness research studies such as SUPPORT. The agency has determined that risks of the intervention must be disclosed to study participants even if the risks are considered acceptable according to current medical guidelines, if the study intends to evaluate these risks and if the patients’ risks will change when they enrol in the study.

The OHRP said that even though both the low and high levels of oxygen supplementation were considered within the acceptable range, “the key issue is that the treatment and possible risks infants were exposed to in the research were different from the treatment and possible risks they would have been exposed to if they had not been in the trial”.

“[F]or the great majority of infants in the trial, it is likely that their participation altered the level of oxygen they received compared to what they would have received had they not participated,” the OHRP added.

The agency said further that if a trial is designed to compare the risks of potential side effects of a treatment already in use, then the risks are “reasonably foreseeable” and that prospective study participants should be made aware of it.

“If a specific risk has been identified as significant enough that it is important for the Federal government to spend taxpayer money to better understand the extent or nature of that risk, then that risk is one that prospective subjects should be made aware of so that they can decide if they want to be exposed to it,” OHRP said.

The guidance is open to comments until 24 December.