The rivalry between Novo Nordisk A/S (NVO) and Eli Lilly (LLY) in the oral GLP-1 weight-loss drug sector was prominently displayed during the recent American Diabetes Association scientific sessions.

CNBC conducted exclusive interviews with the CEOs of both pharmaceutical giants at the event, Novo Nordisk A/S's Mike Dustan and Eli Lilly's Dave Ricks.

A significant shift in patient access is imminent, as starting July 1st, millions of American seniors on Medicare will be able to obtain GLP-1 weight-loss medications for a monthly copay of just $50, a stark reduction from the previous out-of-pocket costs that could reach hundreds of dollars.

Market Competition Heats Up

The recent scientific conference served as a battleground for the two companies, both preparing for a major change in how patients access these drugs. Novo Nordisk A/S announced that prescriptions for its oral Wegovy have surpassed 3 million in the roughly five months since its U.S. launch. CEO Mike Dustan expressed excitement over this milestone in his CNBC interview, noting that prescription growth remained strong even after Eli Lilly launched its competing oral drug in April.

Conversely, Eli Lilly's CEO Dave Ricks told reporters that prescriptions for its oral drug, Foundayo, have risen significantly from the 20,000 reported six weeks prior, though he did not provide a new specific figure. He stated prescriptions are climbing weekly and the company is pleased with the market's progress.

This contest in the oral weight-loss arena is the latest chapter in a long-standing rivalry, evident throughout the conference venue with promotional materials for both drugs prominently displayed.

Strategic Positioning for Medicare Coverage

Both firms are now positioning their daily oral pills and weekly injectables for the senior demographic ahead of the new Medicare coverage. Novo Nordisk A/S sees this policy change as an opportunity to reclaim market share for its Wegovy injectable, which it believes was taken by Eli Lilly's Zepbound injection. Dustan emphasized that Novo will highlight Wegovy's label, which includes additional health benefits like reducing the risk of major cardiovascular events.

Eli Lilly, however, is focusing its appeal to seniors on convenience. Ricks highlighted that Foundayo can be taken at any time of day with food and other medications, unlike Novo's oral pill which requires specific fasting conditions.

Ricks expressed confidence in the rollout of the new Medicare policy through collaboration with the government and insurers like Humana. He believes the pilot program could help establish a broader consensus that obesity treatment should be a standard part of healthcare coverage.

Broader Insurance Coverage and Pipeline Developments

Both companies are actively advocating for broader commercial insurance coverage for GLP-1 drugs, despite some employers like Cigna recently ending coverage for their employees. Ricks mentioned that less than 20% of Eli Lilly's own insured employees use these drugs, with good adherence, and the company is conducting internal studies on health outcomes and costs.

Next-Generation Drug Pipelines

While preparing for the Medicare shift, both are advancing new obesity treatments. Eli Lilly presented Phase 3 data for retatrutide, a triple agonist showing substantial weight loss and benefits for obesity-related conditions. Ricks confirmed it would be available on LillyDirect upon approval.

Novo Nordisk A/S is progressing with CagriSema, a combination therapy. While its weight-loss efficacy has been seen as comparable to Zepbound but below retatrutide, disappointing some investors, CEO Dustan defended its clinical value and commitment to its development, with FDA feedback expected in Q4.

Dustan, who took over as CEO nearly a year ago amidst management changes and layoffs, is focused on boosting Wegovy sales, advancing the pipeline, and driving the stock. He stated Novo's long-term strategy is to deepen its focus on cardiometabolic diseases and diversify.

The successful early launch of oral Wegovy has helped Novo Nordisk A/S regain momentum. Dustan concluded that the pill has restored team confidence, signaling that the company's best days are ahead, and he is committed to sustaining this positive trajectory.