While the overall market plummeted last year, shares of Vertex Pharmaceuticals (VRTX -0.76%) skyrocketed 31%. So far in 2023, the stock is up nearly 20%.

I've shouted from the rooftop for a long time that Vertex is one of the best biotech stocks around. And I'm more convinced of that than ever after a key development last week. Here's why Vertex stock is an even better buy now thanks to AbbVie (ABBV -0.30%).

Throwing in the towel

AbbVie had been evaluating a triple-drug combo targeting cystic fibrosis (CF) in phase 2 testing. Note the use of the past tense in that statement. The company announced in its first-quarter earnings call on April 27, 2023, that it's throwing in the towel on its CF program.

Chief Scientific Officer Tom Hudson said in the Q1 call that AbbVie recently analyzed data from the phase 2 study. He stated bluntly that the triplet combo "did not work."

When asked by an analyst if AbbVie has any other asset in early development that it might move forward, Hudson replied that the company doesn't have any other CF pipeline candidates. He added, "So we don't have other options than to discontinue the CF program."

This wasn't AbbVie's first setback in CF. Last year, the company halted the development of ABBV-119, which it had licensed from Galapagos. Hudson alluded to the failure of the experimental CF drug in his comments.

The only game in town

Vertex remains the only company with approved therapies that target the underlying cause of CF. With AbbVie's decision to shut down its CF program, that leaves only two other drugmakers that have potentially competitive drugs in clinical testing.

Eloxx Pharmaceuticals is conducting a phase 2 study of ELX-02 in treating CF. However, in the company's latest quarterly update, it didn't even mention this study. Instead, Eloxx appears to be focusing much more heavily on the potential for ELX-02 to treat Alport syndrome, a genetic kidney disease.

4D Molecular Therapeutics is only in phase 1 testing with its experimental CF therapy 4D-710. The small drugmaker expects to present interim data from the early stage study at a scientific conference this quarter. But it has a long way to go before having even a possibility of being in a position to compete against Vertex. 

Vertex doesn't lose patent protection for its top CF drug, Trikafta, until 2037. The company isn't resting on its laurels, either. What could be Vertex's most powerful CF therapy yet -- a triple-drug combo featuring vanzacaftor -- is in late-stage testing. This vanzacaftor triplet could also be the company's most profitable CF therapy yet, if approved. Vertex's royalties will be much lower with it compared to its other CF drugs.

Looking beyond CF

The company's prospects beyond CF are even more exciting. Vertex and its partner, CRISPR Therapeutics, hope to soon win approvals in the U.S. and Europe for exa-cel in treating sickle cell disease and transfusion-dependent beta-thalassemia. The gene-editing therapy seems likely to become a megablockbuster.

Vertex expects to wrap up late-stage testing of its non-opioid pain drug VX-548 as soon as late 2023. It could be another multibillion-dollar therapy for the company if approved.

The big biotech is evaluating inaxaplin in a pivotal study targeting APOL1-mediated kidney disease. This indication impacts more patients than CF does. In addition, Vertex's pipeline includes earlier-stage programs focused on rare genetic disease alpha-1 antitrypsin deficiency and type 1 diabetes. 

In the meantime, AbbVie's discontinuation of its CF program makes Vertex's monopoly even stronger. Vertex should be able to continue growing its CF revenue as it rolls out new products, secures additional reimbursements, and wins approvals in younger age groups.

This biotech stock was already a great pick. Now it's an even better one.