The healthcare sector is a hotbed of innovation, and those companies that genuinely break new ground are often handsomely rewarded, along with their shareholders. Investors looking to earn outsized returns over long periods (which describes most investors) would do well to consider shares of innovative companies such as CRISPR Therapeutics (CRSP -0.64%), Sarepta Therapeutics (SRPT 1.64%), and DexCom (DXCM 1.18%).

Let's find out why these three revolutionary stocks are worth buying.

1. CRISPR Therapeutics

Gene-editing specialist CRISPR Therapeutics currently has no products on the market. But the company's candidates all use the CRISPR (hence its name) gene-editing technique that earned the researchers who pioneered it a Nobel Prize for their trouble. So far, this groundbreaking technology hasn't led to any approvals.

However, the U.S. Food and Drug Administration (FDA) and its counterpart agency in Europe are currently considering exa-cel for approval in treating sickle cell disease (SCD) and transfusion-dependent beta-thalassemia (TDT). These two rare blood diseases have proved difficult to treat. But exa-cel, discovered by CRISPR Therapeutics and developed in collaboration with Vertex Pharmaceuticals, represents significant progress in these areas -- it could be a one-time curative option for both.

If it earns approval, CRISPR Therapeutics' stock should rise, literally and figuratively, given the addressable market at exa-cel's disposal. The first U.S. approval could land by Dec. 8. Being a clinical-stage biotech, CRISPR Therapeutics doesn't generate much revenue. It also isn't profitable. But at this stage, investors shouldn't focus on that.

Having proven its innovative capabilities with exa-cel, the company should generate enough money from this success to make solid headway with the more than half a dozen products in its pipeline, still using the Nobel Prize-winning technique that helped it develop exa-cel. CRISPR Therapeutics qualifies as a revolutionary stock and could deliver excellent returns to patient investors.

2. Sarepta Therapeutics

Sarepta Therapeutics is a biotech company focusing much of its effort on targeting just one illness: Duchenne muscular dystrophy (DMD), a progressive genetic disease accompanied by symptoms such as muscle degeneration. Treatments have been hard to come by, but Sarepta has produced four of them. It earned its latest FDA approval in June for arguably its most important product yet.

Called Elevidys, it is the first gene therapy for DMD approved by the agency. While Sarepta's other products help manage symptoms of DMD, Elevidys treats the underlying cause of the disease at the genetic level. Sarepta developed it in collaboration with Roche, and the two companies expect peak annual sales of $4 billion for Elevidys.

Sarepta Therapeutics is already delivering solid top-line growth. In the second quarter, the company's revenue was $261.2 million, almost 12% higher than the prior-year quarter. The biotech does remain unprofitable, although it's improving on that front. Its second-quarter net loss per share of $0.27 was much better than the $2.65 reported in the year-ago period.

With a new source of revenue under its belt, things should continue to improve. Sarepta Therapeutics has more DMD products in development and is targeting other rare diseases. The company has more than 40 programs in its pipeline. The focus on DMD alone could be highly lucrative -- Vertex Pharmaceuticals has found incredible success in becoming the leader in the cystic fibrosis market.

Whether within DMD or beyond it, though, Sarepta Therapeutics' ability to generate new groundbreaking therapies is an excellent sign for investors.

3. DexCom

DexCom is a leader in the market for continuous glucose monitors (CGMs). This technology offers diabetecs a better way to perform the crucial task of keeping track of their blood-sugar levels. Blood glucose meters (BGMs) have been the most popular options but are limited. BGMs are manual devices that use painful finger sticks and can only read blood glucose levels at a specific time.

CGMs are automatic, work constantly, and do away with the need for finger sticks. DexCom has been one of the pioneers of CGM technology -- and results have been moving in the right direction. For the second quarter, revenue came in at $871.3 million, 25% higher than in the prior-year period, and adjusted net income doubled to $0.34 per share.

Although it has been progressing in the CGM market for a while, DexCom still has plenty of room for more growth. Armed with two new devices -- the G7, the latest in its flagship G series of CGM options, and the DexCom One -- the company plans to continue making headway in countries where CGM penetration is low, which is almost everywhere. DexCom has been expanding its reach internationally and recently entered Latin America -- specifically Argentina -- for the first time.

Diabetes is a global health crisis affecting some 422 million people. While DexCom doesn't do business all over the world, it ended 2022 with an installed base of just 1.7 million. There should be millions more who are ready to make the switch to CGM -- and DexCom will be one of the primary companies positioned to help them.