Gov. Wolf on Friday signed a bill amending the Pennsylvania medical marijuana law so that the state's much-vaunted research program can proceed. The bill moved through the state House and Senate with uncharacteristic speed last week before landing on Wolf's desk.

The bill, HB 2477, was necessary to circumvent a lawsuit challenging the constitutionality of a section of the marijuana law referred to as Chapter 20. That provision allows medical schools to work with marijuana companies which will generate data for pharmacological research. Under the law, the medical schools can choose their own cannabis growing partners.

Opponents said the law improperly delegated the state's authority to the schools and allowed the companies to avoid the rigorous selection process under which existing commercial cannabis growers and dispensaries had been subjected.  The rewritten law also does not specify what constitutes research or call for disclosure about possible payments made from the companies to the medical schools. Critics said the lack of disclosure risked the possibility of pay-to-play.

"This is not the end of the story," said Judith Cassel, attorney for commercial growers who filed the suit. "It's likely we'll continue to pursue this since we feel it's in the best interest of Pennsylvania patients."

She said the rewritten law will require new regulations, but under the language of the new law, those regulations will bypass an independent review. A spokesperson for the Department of Health said the agency still will have the final word on whether a company is qualified to partner with a school.