The practice involves having a patient try a cheaper medication before stepping them up to something more expensive if the cheaper brand fails.
Supporters of the bill said step therapy can hurt those who are already on a medication that works well for them.
That's the fear of one mother whose daughter has epilepsy.
"It's always scary thinking about changing a medication and the possibility of having seizures again," said Peg Mitschele from South Portland.
The bill would not ban step therapy outright, keeping it as a practice for those looking for a new medication or procedure.
Instead the bill's cosponsor said it would protect those who already have something that works for them.
"We need to be really careful about putting cost control efforts on the backs of individual consumers," said Sen. Heather Sanborn, D - Portland.
Officials that represent insurance companies like Aetna and Anthem Blue Cross Blue Shield are against the bill.
"It's our responsibility to try to find the most appropriate and affordable medication," said Katherine Pelletreau, the executive director of Maine Association of Health Plans.
According to Pelletreau, step therapy keeps patients from dangerous care, and from high healthcare costs.
"Health plans have a responsibility to keep care as affordable as possible, both in terms of premiums and in terms of out of pocket expenses," she said.
But one woman found step therapy problematic, after she had to change medication that worked for her rheumatoid arthritis and autoimmune hepatitis.
"I went into anaphylaxis," said Lori Schnieders, a Cutler resident, "which was a hospital visit and had to have cost the insurance company more than my meds."
Republican Senator Robert Foley of Wells said some provisions need to be worked on, but overall he supports the bill.
"Ultimately our concern is with the patient," said Sen. Foley.
Similar legislation was previously passed through the legislature, but was vetoed by former Governor Paul LePage.