"The thrill of victory and the agony of defeat."

That phrase became well-known years ago thanks to sportscaster Jim McKay. And it pretty much sums up the different trajectories for CRISPR Therapeutics (CRSP 0.34%) and Pfizer (PFE 0.55%) in 2023. CRISPR Therapeutics has enjoyed the thrill of victory, while Pfizer has experienced the agony of defeat.

But which of these two biopharmaceutical stocks is the better pick for a new bull market? Motley Fool contributors Adria Cimino and Keith Speights make the arguments for CRISPR Therapeutics and Pfizer, respectively.

The case for CRISPR Therapeutics

Adria Cimino (CRISPR Therapeutics): CRISPR Therapeutics has advanced more than 50% this year, but this biotech stock may continue to climb -- especially in a market favoring growth. The gene-editing specialist just won U.S. regulatory approval for its very first product: Casgevy, a treatment for sickle cell disease. Regulators are set to decide on Casgevy for a second blood disorder, beta thalassemia, in March.

Investors anticipated this approval, thanks to promising clinical trial data, and you could argue that a regulatory nod was priced into the shares well before the decision. But that doesn't mean the opportunity for gains is over. That's because CRISPR Therapeutics' growth as a commercial-stage company is just getting started.

Casgevy sales will provide the biotech's first product revenue, and the therapy has the potential to become a blockbuster. Meanwhile, CRISPR Therapeutics is developing other candidates, using the same gene-editing technology.

By cutting DNA at a certain location and letting a natural repair process take over, the company edits the genome -- correcting faulty genes responsible for disease. As a result, the technology produces what could be functional cures for diseases, meaning each potential product could be a game changer both for patients and for the company. And the recent regulatory approval shows us that authorities are ready to vote in favor of this technology, another green light for CRISPR Therapeutics.

Casgevy sales and positive trial results from candidates both should offer CRISPR Therapeutics plenty of catalysts for share performance well into the future. And investors, looking for growth in a bull market, may flock to this company as its revenue increases and other potential products progress through the pipeline.

Considering all of this, CRISPR Therapeutics makes a top bull-market buy, and a stock you'll want to hold onto over time, as the company works to bring other exciting products to market.

The case for Pfizer

Keith Speights (Pfizer): I can sum up the year for Pfizer in just three letters: U-G-H. The big drugmaker's sales, profits, and share price have declined sharply. The main culprit is the continued slump for Pfizer's COVID-19 vaccine Comirnaty and oral antiviral drug Paxlovid.

Pfizer's guidance for 2024 didn't provide any reason to be encouraged about the near-term prospects for Comirnaty and Paxlovid. So why would this stock potentially be a smart pick for investors in a new bull market? I can think of three primary reasons.

First, Pfizer stock is now dirt cheap. Its forward earnings multiple is a super-low 9.8. There's no way to compare this valuation with CRISPR Therapeutics, by the way. CRISPR Therapeutics isn't profitable yet, while Pfizer raked in nearly $5.5 billion in profits during the first nine months of 2023.

Second, forward-looking investors should recognize that Pfizer is likely to return to solid revenue and earnings growth once sales for Comirnaty and Paxlovid bottom out. The company has multiple growth drivers, including its new vaccine for respiratory syncytial virus (RSV) Abrysvo, migraine drug Nurtec, and its Vyndaqel family of products for rare heart diseases. The acquisition of Seagen should also help fuel growth.

Third, Pfizer's share price doesn't have to move much higher for the stock to deliver market-beating total returns. That's because Pfizer's dividend yield currently stands at around 6%.

No, Pfizer won't generate sizzling growth anytime soon. But the stock just might be a better choice for a new bull market than many investors might think.

Better buy?

Which of these two stocks is the better buy in a new bull market will largely depend on your investing style. Income investors will obviously like Pfizer more since CRISPR Therapeutics doesn't pay a dividend. Value investors will also probably prefer Pfizer.

On the other hand, growth investors are more likely to choose CRISPR Therapeutics. With its first approved product on the market in 2024, look for the company's revenue to increase significantly.