Jamie Dimon, chairman and chief executive officer of JPMorgan Chase & Co., listens during a Business Roundtable CEO Innovation Summit discussion in Washington, D.C., Dec. 6, 2018.

J.P. Morgan Chase CEO Jamie Dimon hosted a private dinner for pharmaceutical executives on Sunday night, ahead of the bank's health-care conference in San Francisco. There was one company not in attendance that received a lot of attention: Amazon.

About 25 industry leaders attended from companies including Eli Lilly, Pfizer and Johnson & Johnson, along with some of the J.P. Morgan's investment bankers, according to two people with knowledge of the event who asked not to be named because it was private.

Dimon gave some details around what he hopes to accomplish through the bank's health partnership, announced last year, with Amazon and Berkshire Hathaway.

He told the room, "We are not happy with health-care costs and want to help," the people said. It's a theme that's gained resonance in Washington, D.C., with President Donald Trump and politicians from both sides of the aisle calling for drugmakers to lower prices.

Dimon was peppered with additional questions about Amazon and its ambitions in the health-care market, after the e-retailer purchased online pharmacy PillPack last year. Amazon also has plans for delivering medical supplies, and the company has reportedly been experimenting in areas like electronic medical records and telemedicine.

Some view Amazon as a potential collaborator, while others see the technology giant as a threat.