Vertex Pharmaceuticals (VRTX 0.78%) is known for its blockbuster cystic fibrosis treatments. The company generates billions of dollars in revenue and profit from them annually, and it looks as if that's set to continue for quite some time. The closest potential competitor for Vertex's top-selling product is actually a candidate in its own pipeline.

That may be a good reason to buy shares of this biotech company, but I've got an even better one. Vertex today has six programs that are in mid-to-late-stage clinical trials, and during its recent first-quarter earnings call, management said they represent "multibillion-dollar opportunities."

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One possible cure for two blood diseases

The company's nearest-to-market candidate just so happens to be a potential game-changer. If it is approved, it is designed to be a one-time curative treatment for a pair of inherited blood disorders. Vertex and partner CRISPR Therapeutics are studying the gene-editing candidate -- CTX001 -- in a pivotal trial. So far, results have been positive in both beta-thalassemia and sickle cell disease patients. The companies plan to file for regulatory approval by the end of this year.

Today, there are about 32,000 sickle cell and beta-thalassemia patients in the U.S. and Europe, all of whom could be candidates for the treatment, according to Vertex. The company already is preparing for a potential launch.

CTX001 would represent a significant milestone for Vertex as the company's first marketed product outside of its cystic fibrosis specialty. The biggest worry investors have had about Vertex in recent times is its dependence on the cystic fibrosis business -- even though its leadership position in the indication is solid. Success here could prove that Vertex has what it takes to expand into new areas.

Another potentially key treatment on the horizon is Vertex's candidate for acute pain. What makes that candidate -- VX-548 -- special is that it isn't an opioid. While opioids are effective, use of them may lead to addiction, and there are few other options when potent painkillers are needed. If Vertex is successful in developing an alternative to opioids, it could be a major revenue generator. The company recently reported positive phase 2 data for VX-548, and aims to begin pivotal studies in the second half of the year.

A third candidate that I see as big is VX-800, which targets type 1 diabetes. It's a stem cell-derived treatment to restore the function of pancreatic islet cells, which regulate the body's glucose levels.

Delays on the diabetes treatment candidate

Vertex actually is facing some headwinds here at the moment. The Food and Drug Administration (FDA) placed a clinical hold on the phase 1/2 study of VX-880. The agency said there is "insufficient information" to support an increase to full dosage of the diabetes treatment in the next part of the trial. Vertex's data using a half dose were positive. The study actually treated one patient with a full dose -- and that patient's results were positive too. Vertex now is working with the FDA to address the agency's questions. Considering the data so far, I'm still very optimistic about this type 1 diabetes program, and don't view the pause as a threat to what could be another game-changing product.

Vertex also has several preclinical programs worth keeping an eye on, though any revenues they may generate would start rolling in farther in the future.

One early program that stands out is an mRNA therapy for cystic fibrosis patients who aren't candidates for Vertex's current treatments. That's being developed in partnership with Moderna. Their candidate would instruct the body to make a particular protein these patients lack. Vertex and Moderna plan to ask the FDA for authorization to begin clinical studies in the second half of this year.

All of these elements could be fuel for future earnings increases -- and eventually, improved share performance. Speaking of the shares, they've lost about 17% since they hit a 52-week peak last month. They're now trading at less than 17 times forward earnings estimates, down from more than 20 earlier this year. As such, the stock looks like a bargain considering the potential of the new products that Vertex could bring to market -- both in the next year or so and farther down the road.