If you don't have biotech stocks in your investing portfolio, why not? For many people, the answer is that they think biotech stocks are too risky. Although it's true that some biotech stocks are very risky, that's not the case for all of them. And leaving out these stocks means that you're also forfeiting tremendous growth opportunities.

There are several biotech stocks that I think make great candidates for investors who have never bought a biotech stock before. Here's why Celgene (CELG), Regeneron Pharmaceuticals (REGN -0.80%), and Vertex Pharmaceuticals (VRTX 0.10%) stand at the top of the list.

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Celgene

Each of the three biotech stocks on our list are in great shape financially, but Celgene appears to be in the best position. Celgene made nearly $2 billion in earnings last year on revenue of $11.2 billion. The company reported a cash stockpile of $8.9 billion at the end of the first quarter, including cash, cash equivalents, and marketable securities.

Celgene's coffers continue to grow, thanks in large part to its powerhouse blood cancer drug Revlimid. But while Revlimid still generates 64% of the biotech's total revenue, sales for other drugs are growing quickly. Celgene's No. 2 product, multiple myeloma drug Pomalyst, saw sales surge nearly 33% in the first quarter compared with the prior-year period. Otezla, which treats psoriasis and psoriatic arthritis, wasn't too far behind, with year-over-year sales growth of 23.5%.

The company expects to grow adjusted earnings by an average annual rate of 22% over the next few years. Several pipeline candidates will be key to reaching this goal. Celgene thinks it could win regulatory approval for seven drugs by 2020 that have blockbuster sales potential.

Are there risks for Celgene? Sure, but they're less than those facing many biotechs. Revlimid could face competition in the future, although it would be several years away. Promising experimental drugs might not pan out as expected. Still, I think Celgene's solid financial position and deep pipeline makes it one of the best stocks for long-term investors -- regardless of industry.

Regeneron Pharmaceuticals

Regeneron also looks solid financially. The biotech reported earnings of nearly $896 million last year on revenue of $4.9 billion. Regeneron had cash, cash equivalents, and marketable securities of $1.3 billion at the end of March.

Like Celgene, Regeneron depends on one drug for most of its revenue. Eye-disease drug Eylea generates roughly 78% of the biotech's total revenue. Much of the rest of Regeneron's revenue stems from collaborations with Sanofi (SNY -1.56%) and Bayer. Other drugs should become more important to Regeneron in the near future, though. 

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Wall Street analysts project that the biotech will grow earnings by 19% annually over the next five years. Three products (other than Eylea) should especially be important in this anticipated growth. Regeneron and Sanofi won U.S. approval for atopic dermatitis drug Dupixent in March and for rheumatoid arthritis drug Kevzara in late May. In addition, the partners hope for good news from a cardiovascular-outcomes study of Praluent that could help significantly boost sales for the cholesterol drug.

Regeneron's primary risks include pipeline setbacks and the potential that its drugs don't perform on the market as well as expected. There's also the possibility that Amgen could be successful in litigation alleging that Regeneron and Sanofi infringed on its intellectual property rights with the development of Praluent. However, I think the potential rewards that Regeneron offers investors outweigh these risks.

Vertex Pharmaceuticals

Vertex doesn't yet have the track record of Celgene or Regeneron, but the up-and-coming biotech is on its way. In 2016, Vertex reported a net loss of $112 million on revenue of $1.7 billion. However, the biotech posted a profit in the first quarter of 2017 totaling $248 million. It also claimed a nice cash position of $1.4 billion, including cash, cash equivalents, and marketable securities.  

Two cystic fibrosis (CF) drugs are primarily driving Vertex's success -- Orkambi and Kalydeco. Orkambi generated 41% of the company's total revenue in the first quarter, while Kalydeco contributed 26% of total revenue. Most of the rest of Vertex's revenue stemmed from collaborations, including a key deal with Merck KGaA.

Vertex could be poised for a very bright future, with Wall Street analysts projecting average annual earnings growth of nearly 65% over the next few years. Some of that growth will come from higher sales of Orkambi. However, a potentially greater opportunity is with a combination regimen of tezecaftor and Kalydeco in treating CF for which the company plans to submit for approval later this year. 

Like most biotechs, Vertex could experience clinical trial failures and regulatory agency rejections. There's also the potential for new rivals to enter the CF market. Despite these risks, I recently put Vertex on the list of stocks that the smartest investors are buying. I continue to believe that smart investors will want to add this biotech to their portfolios.