Patent subject matter eligibility under Section 101 of the Patent Act has proven controversial for patents in the U.S. thanks in no small part to Supreme Court jurisprudence in cases such as Alice v. CLS Bank and Mayo v. Prometheus. In the latest development, the court has declined to hear the American Axle case, leaving many observers despairing of any chance of restoring a decent patent system for personalized medicine, companion diagnostics and even the use of artificial intelligence in drug development.