Investing.com -- Shares of Novo Nordisk (NYSE: NVO ) plummeted over 19% Friday after the results from its phase 3 trial of CagriSema, its next-generation obesity drug, disappointed.

Meanwhile, rival Eli Lilly (NYSE: LLY ) is up over 6% shortly after the open.

Novo Nordisk's REDEFINE 1 trial showed that people treated with CagriSema, a combination of cagrilintide and semaglutide, achieved a weight loss of 22.7% after 68 weeks.

While statistically significant and superior to the results achieved with either drug alone, the weight loss fell short of the target of 25%.

"This was achieved even though only 57% of patients reached the highest CagriSema dose," commented Martin Holst Lange, Novo Nordisk's executive vice president for Development.

Lange highlighted the drug's potential, noting the company's plans to "further explore the additional weight loss potential of CagriSema."

The trial involved 3,417 overweight or obese participants and evaluated the efficacy and safety of CagriSema. The trial achieved its primary endpoint by "demonstrating a statistically significant and superior weight loss at week 68 with CagriSema versus placebo."

While the results showed promise, the market reacted negatively to the below-expectation outcomes.

Conversely, the sharp rise in Eli Lilly's stock reflects growing confidence in its competing obesity treatments.

The results from Novo's second phase 3 trial, REDEFINE 2, in adults with type 2 diabetes and either obesity or overweight are expected during the first half of 2025.

"While we didn't expect CagriSema to be a formidable competitor to Lilly's Zepbound, we now see Lilly in a true class of its own with Zepbound, orforglipron and retatrutide," said Wolfe Research in a note reacting to the news.

Meanwhile, UBS analysts stated: "Overall we view the flexible dose adjustment design in REDEFINE 1 may have helped with discontinuations and GI adverse events (not disclosed in topline) but also tainted weight loss efficacy - not meeting Novo's prior guidance of 25%."

BMO Capital analysts noted that the NVO results "are roughly in line with what Lilly has demonstrated for tirzepatide (22.5% and 20.9% respectively at 72 weeks), but fall short of the 25% bar for efficacy many investors were anticipating."

"Flexible dosing resulted in only 57% of patients achieving the highest dose, likely blunting efficacy," they added.