Shares of Novo Nordisk (NVO 2.48%) are falling this week, down 33% as of 3:27 p.m. ET on Friday. The drop comes as the S&P 500 lost 2.4%, and the Nasdaq-100 lost 2.2%. The Danish pharmaceutical giant's stock was hit after it released disappointing earnings showing that sales of its blockbuster GLP-1 drugs remain weaker than hoped.

Novo Nordisk disappoints

Novo Nordisk was forced to cut guidance for its top-line sales, driven primarily by lagging sales of its GLP-1 drugs, Ozempic and Wegovy. The company says it now expects full-year sales growth of 8% to 14%, down significantly from its earlier range of 13% to 21%. Its guidance for operating profit was cut as well, from between 16% and 24% to between 10% and 16%.

Wegovy and Ozempic have been absolute blockbusters for the company, propelling Novo to the most valuable company in Europe before competition from "compounders" -- companies that market their own tailor-made versions using its active ingredients -- impacted sales.

A person injects a GLP-1.

Image source: Getty Images.

Is this a buying opportunity?

I think Novo does have significant issues it must overcome, but I think these fears are overblown. For long-term investors, this seems like a great time to buy in. The company's stock is trading at one of its lowest price-to-earnings ratios (P/E) in nearly 30 years and the lowest in at least five years. This seems like an opportunity to me.