Just filed in the Northern District of Ohio. (HT Jacob Sullum, of Reason.) Lead attorney is Jonathan Emord, formerly a Vice-President at Cato, and head of a firm with extensive experience in litigation against the Food and Drug Administration and other federal agencies on medical issues. The complaint is here.
In the complaint, the material about the interstate commerce power and the tax power is fairly standard. What makes the lawsuit significance is a well-developed argument (subject, of course, to the caveat that a complaint is not a brief) on medical privacy issues. Primarily, that the compelled disclosure to insurance corporations and insurance agents of private medical information (as well as urine or DNA samples and so on) is a violation of Fifth Amendment liberty, and of the constitutional right of privacy. Further, coercing individuals to associate with insurance companies and insurance agencies is a violation of the right of association, a right derivative of the First Amendment, but, as developed in later case law, not at all limited to classic First Amendment associations such as political or expressive organizations.