What do many kids like most about the coming of a new year? The fireworks. Investors don't mind seeing some fireworks in their portfolios with a new year starting, either.

Three Motley Fool contributors think they have found stocks that could provide a big bang for growth investors. Here's why they believe Novo Nordisk (NVO -0.32%), Summit Therapeutics (SMMT -5.55%), and Viking Therapeutics (VKTX -3.56%) could be monster winners for 2025.

Novo Nordisk could be due for a big comeback in 2025

David Jagielski (Novo Nordisk): It's been a tough 2024 for drugmaker Novo Nordisk. Entering this week, its shares were down 14% as the company behind the popular diabetes drug Ozempic has been generating good growth, but that hasn't been enough to win over investors.

To make things worse, the company recently unveiled results from a trial involving weight loss treatment CagriSema. In a late-stage trial, the drug helped participants lose an average of 22.7% of their weight, versus the 25% that was expected.

The stock fell by around 20% on the news in what looked to be a gross overreaction about what may still be the top weight loss drug in the future. The company already has an approved weight loss treatment in Wegovy, which shares the same active ingredient (semaglutide) with Ozempic.

CagriSema's trial results were by no means awful, but the market has already responded in a big (negative) way. The sell-off in the stock has pushed it near its 52-week low, and it's now trading at 22 times next year's estimated future earnings (based on analyst estimates).

Given its low valuation and the seeming overreaction in the markets to the recent trial results, this is a stock that could generate monster gains next year as a rebound could be in the cards.

Novo Nordisk has been investing in additional capacity to help meet the surging demand for its weight loss and diabetes treatments, and its results have been great in recent quarters. The business has been growing its operating profit by 21% through the first nine months of this year. And with a lot more growth still ahead for the business, investors should be careful not to overlook Novo Nordisk -- the healthcare stock could have plenty of upside next year.

A potential blockbuster on the way

Keith Speights (Summit Therapeutics): 2024 has been a fantastic year for Summit Therapeutics with its stock delivering an explosive 7x gain. I think the new year will bring more good fortune for this up-and-coming drugmaker.

Summit expects to announce top-line results in mid-2025 from a phase 3 study evaluating ivonescimab in combination with chemotherapy as a second-line treatment for advanced non-small cell lung cancer (NSCLC).

The U.S. Food and Drug Administration (FDA) has already granted Fast Track Designation to the therapy for this indication. This means the approval process could be expedited and guarantees the FDA will work closely with Summit on advancing ivonescimab.

To be sure, there's a degree of risk associated with any clinical trial. However, Summit's chances of success with this late-stage study appear to be great.

Why? The company's partner, Chinese pharmaceutical company Akeso, reported spectacular results from its phase 3 study of ivonescimab earlier this year as a first-line treatment for NSCLC. Patients receiving the drug experienced significantly increased progression-free survival rates than patients receiving Merck's Keytruda immunotherapy.

It's important to note that Keytruda ranked as the world's top-selling drug last year with sales of $25 billion. With ivonescimab outperforming Keytruda in Akeso's late-stage study, I predict Summit will have a blockbuster drug on its hands in the not-too-distant future.

And Summit won't be content with the second-line NSCLC indication. The company is evaluating ivonescimab in combination with chemotherapy in a late-stage study as a first-line NSCLC therapy. It also plans to initiate another phase 3 study of the drug as a monotherapy in the first-line NSCLC setting.

Lightning can strike the same place twice

Prosper Junior Bakiny (Viking Therapeutics): Can a stock deliver monster returns two years in a row? Under the right conditions, the answer is yes.

Consider Viking Therapeutics, a mid-cap biotech that soared this year following excellent phase 2 results for its investigational weight loss medicine, VK2735. The company should make progress on this program next year, when it will probably start a phase 3 study.

It is also working on an investigational medicine for metabolic dysfunction-associated steatohepatitis, which should also enter pivotal trials in 2025.

And Viking has more promising early-stage candidates, and progress from those could be what jolts the stock price. Its oral formulation of VK2735 is a good example.

Billion-dollar weight loss medicines like Zepbound and Wegovy are administered via injection. An oral formulation would be a welcome sight for many patients. Although several drugmakers are working on this project, Viking has more upside potential than the large leading pharmaceutical companies, while smaller ones haven't shown the kinds of results it has so far.

And the company is still working on promising anti-obesity programs. It recently reported encouraging pre-clinical results from a brand-new clinical compound. Viking is looking to establish itself as a leader in this therapeutic area, which happens to be the hottest and one of the fastest-growing in the industry. And it has shown more promise in the field than most other companies, even those with far more resources than it has.

So, Viking Therapeutics' shares could once again soar next year. And the stock could also deliver strong performance in the next half-decade.