House Speaker Nancy Pelosi’s senior adviser on healthcare pitched the California representative’s drug plan to a ballroom full of insurance industry players Monday and called on them to support the bill.

While the insurance lobby has already praised the effort as a bold approach, Wendell Primus tried to convince the crowd that a united coalition could weather pharma’s influence if it included insurers, doctors, hospitals, the public and the AARP.

“I have no reason to underestimate the influence of pharma in this town, and they are going to work very hard to defeat this bill,” Primus said in Washington during a conference held by the insurance lobby America’s Health Insurance Plans, or AHIP.

The proposed legislation is an ambitious plan to alter the way drug prices are negotiated, giving the government an essential role in negotiating prices for up to 250 drugs that could influence pricing in the commercial market. Primus said it’s possible to have the bill on the floor by the end of next month. Despite the enthusiasm, the Republican-led Senate has rival approaches to take aim at drug prices.

Jennifer Bryant, senior vice president of policy and research for PhRMA, the lobbying group for the pharmaceutical industry, said the bill would give the government sweeping authority that she said should give those in the ballroom pause.

“The thing that is astounding to me is why AHIP is not leading the charge for an alternative,” Bryant said, putting AHIP CEO Matt Eyles and fellow panelist on the spot. “I don’t know why AHIP has laid down arms.”

“I don’t know if I’d characterize our position that way,” Eyles said.

Following Pelosi’s unveiling of the bill last week, AHIP commended House leadership.

“For too long, Big Pharma has taken advantage of government-granted monopolies to set outrageous launch prices, eliminate competition and increase prices on the same products year after year,” the lobby said in a statement last week.

Experts on the panel teed off in a debate over how to arrive at the right price for new drugs, many calling out the exorbitant launch price of new pharmaceuticals, sometimes with little measurable benefit to patients.

“I see no evidence that the pricing is correct right now. The price is wow, the data is humdrum,” Peter Bach, director of the Center for Health Policy and Outcomes at Memorial Sloan Kettering, said.

On the flip side, others called out payers over the lack of patient access to drugs when there is evidence of a measurable benefit even though they carry an expensive price tag, Sarah Emond, executive vice president and chief operating officer of the Institute for Clinical and Economic Review, said.

As Bryant tried to assuage the crowd of her position, Mark Miller, executive vice president with Arnold Ventures, said pharma is in the crosshair of lawmakers because of slow pace in tackling prices with plans and others.

“You’ve been slow to come to the table, and this is what happens when you don’t come to the table,” Miller said.