Positive jobs news and positive rumors out of China are lifting stock markets today, as the U.S. Labor Department reports adjusted nonfarm payrolls grew by 177,000 jobs in April, and CNBC reports that China may be "evaluating the possibility of starting trade negotiations" that could abbreviate a trade war with the U.S.

Within the pharmaceuticals industry in particular, shares of Eli Lilly (LLY 3.74%), Novo Nordisk (NVO 4.79%), and Viking Therapeutics (VKTX 4.77%) are all looking to close out the week strong. As of 10:30 a.m. ET, Lilly stock is gaining 2.8%, Viking is up 3.5%, and Novo Nordisk stock is doing best of all -- up 5.8%.

Image source: Getty Images.

And why are big pharma stocks doing particularly well today? Let's ask Novo Nordisk...and JPMorgan, too.

Novo Nordisk's news...

You've probably heard how, earlier this week, Novo Nordisk inked a deal with Hims & Hers Health (HIMS 9.40%) that will permit the latter to distribute the former's blockbuster Wegovy weight-loss drug, right? Well, it turns out Hims wasn't the only drug distributor Novo was talking with.

Yesterday CVS Health (CVS -2.19%) announced that it will make Novo's Wegovy available to customers for a "more affordable price" than it charges for rival GLP-1 drug Zepbound (from Eli Lilly). CNBC predicts this will "significantly expand access to Novo Nordisk's blockbuster weight loss drug." It could also hamstring Lilly's efforts to take over the GLP-1 drug market and limit the benefits Viking might gain from bringing its own VK2735 weight loss drug to market.

...and what JPMorgan had to say about it

So great news for Novo Nordisk stock, and bad news for Lilly and Viking, right? Well, not so fast.

In a note covered by TheFly.com this morning, investment bank JPMorgan doesn't dispute that this news is good for Novo. However, the bank does believe that the sell-off of Lilly stock on the news (Lilly shares were down 12% yesterday, although part of that was due to earnings) is "overdone." In JPMorgan's view, CVS's move "will likely impact only a small portion of Eli Lilly's Zepbound business," and the bank therefore believes Lilly stock will still outperform the market.

Investment banks Cantor Fitzgerald and Leerink are likewise doubling down on their support for Lilly stock today, according to reports on StreetInsider.com.

The big picture on Novo Nordisk, Eli Lilly, and Viking Therapeutics stocks

I've said many times that from a valuation perspective, there's a lot less risk involved in buying Novo Nordisk stock at 19 times trailing earnings than in betting on Lilly to outperform from its present P/E ratio of nearly 65 times earnings. And a whole lot less risk in it than in buying still-unprofitable Viking.

What I think is perhaps most important to keep in mind, though, is the big picture in this space, and the big picture is this:

CVS is offering lower prices on Wegovy. Lilly is likely to cut prices at least somewhat to preserve its market share from the new threat, maybe cutting prices through a partner like Novo is doing, or maybe simply cutting its prices at the point of manufacture. Viking, once its own drug is ready for market, won't be able to charge as much, either. Any way you cut it, therefore, prices are coming down, and a price war is brewing in this space.

As more and more companies vie to enter the GLP-1 market (not just Viking; Roche and Pfizer are still trying to find their own ways in), and as the incumbents Novo and Lilly increase their own production, thus bringing more supply to market, the long-term story is that GLP-1 prices will erode, and profit margins will get thinner across all players.

How should an investor play this trend? My opinion remains the same:

Buy the cheapest GLP-1 stock, and you'll have less to lose. And right now, the cheapest GLP-1 stock is Novo Nordisk's.