Over the past decade, biotech giant Vertex Pharmaceuticals (VRTX 0.35%) has made a fortune thanks to its monopoly in treatments for cystic fibrosis (CF). This rare disease causes digestive problems and affects patients' internal organs. The drugmaker has also delivered market-crushing returns over this period. 

Despite its success in CF that continues today, Vertex has sought to diversify its lineup of medicines -- and the company seems very close to accomplishing this goal. Let's look at its next likely launch and why it makes the stock an even more attractive pick for biotech investors.

Expect a hefty price tag for this therapy

Vertex Pharmaceuticals has been developing exa-cel, a therapy for sickle cell disease (SCD) and transfusion-dependent beta-thalassemia (TDT), in collaboration with CRISPR Therapeutics. These two companies' efforts seem to be about to pay off because they have filed for approval for the medicine in Europe and are in the process of doing so in the U.S.

Exa-cel is a gene-editing therapy that could be a one-time curative option for these otherwise lifelong illnesses that cause incredible hardship to patients. That's not to mention how expensive the standards of care typically are for both diseases; by Vertex Pharmaceuticals' estimates, SCD patients spend between $4 million and $6 million on disease-related costs throughout their lifetimes, and these options don't rid them of their condition.

Given it is a gene-editing therapy, exa-cel will likely be expensive although it may be well worth the cost. Vertex and CRISPR have already started commercialization efforts to support exa-cel's launch. The two partners will initially target a market of 32,000 SCD and TDT patients in the U.S. and Europe.

Assuming a $2 million price tag for exa-cel, which is well within the range of gene-editing therapies, they could be looking at a market of $64 billion. Vertex and CRISPR Therapeutics are unlikely to capture this entire space by themselves because they may have to contend with competing biotech companies in these markets. One of them is Bluebird Bio, whose gene-editing therapy Zyntenglo earned approval last year as a TDT treatment (Zyntenglo costs $2.8 million). Bluebird is also working on an SCD treatment called lovo-cel.

However, Bluebird does not have the kinds of funds Vertex Pharmaceuticals has to support the launch of its products. So Vertex and CRISPR Therapeutics are well-positioned to capture a significant portion of the markets they are targeting. 

Beyond exa-cel, Vertex's future looks bright

Vertex recently discussed its goal to launch five new products in the next five years. Executives call it their "five-in-five" goal.

The next most advanced, non-CF product the company is working on is VX-548, a potential therapy for acute and neuropathic pain that is currently undergoing a phase 3 study.The biotech estimates it to be a $4 billion market in acute pain alone. Naturally, Vertex hasn't stopped its efforts in CF, where it estimates that there are more than 20,000 (out of 88,000) patients who are eligible for its products but have yet to start treatment.

The company is also working on medicines that could address the remaining 5,000 who aren't eligible for any therapy it currently markets. Overall, Vertex could be looking at a potential target market in excess of $80 billion across all of the treatments for which it could earn approval in the next half decade.

Vertex Pharmaceuticals' forward price-to-earnings ratio of 20, although higher than the biotech industry's average of about 15, is well deserved given its long-term prospects. Even at current levels, the stock remains a solid buy.