The court's ruling reversed the decision [text, PDF] of the US Court of Appeals for the Federal Circuit. During oral arguments [JURIST report] in December, petitioner Mayo Collaborative argued that the respondent's patent attempts to protect a "law of nature" instead of the "application of a law of nature," which restricts doctors' ability to make treatment judgments based on patients' reactions to drugs. Respondent Prometheus Labs argued that the courts have permitted similar patents in the past, that the current patent involves only a narrow range of drugs and that it will not prevent future improvements in the field. The Supreme Court accepted a case on this issue before in Laboratory Corp. of America v. Metabolite Laboratories [Duke Law case backgrounder; JURIST report] but dismissed it as "improvidently granted" because the petitioner had not adequately preserved the question.