Pharmaceutical companies have contributed more than $16 million this month to oppose a ballot measure that aims to limit the price the state pays for prescription drugs.

After being approved by a key committee last week, a bill that would have required drug companies to justify treatment costs and price hikes was pulled by its author on Wednesday.

Nearly three-quarters of Californians who didn’t have health coverage before the Affordable Care Act are now insured, yet many are still concerned about their medical expenses, according to a report released Thursday.

Patients who gained health coverage through the Affordable Care Act are filling significantly more prescriptions while paying less for their drugs, according to a new study that credits the health law and adds to evidence of its benefits for previously uninsured Americans and those with chronic conditions such as asthma, diabetes and high blood pressure.

Roughly 20 million more Americans have health insurance now than whenPresident Obama’s health care law was passed in 2010.

The 2010 health law was meant to expand insurance coverage so that Americans could get medical care they would otherwise go without — and not spend a fortune doing so. Though it’s still early, new evidence suggests this scenario is playing out.