One thing will always catch my eye when looking for biotech companies: product. That might seem obvious at first, because all these companies are clearly working on life-changing or even life-saving therapies. But I can't help favoring those with strong, late-stage pipelines and at least one promising or successful drug on the market.

If the company isn't profitable, revenue growth can help me look beyond and imagine future profitability. And if the company is profitable and valuation isn't exorbitant, even better. Here are three biotech stocks that fit the bill, making great buys right now.

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1. Exelixis

Exelixis (NASDAQ:EXEL) specializes in difficult-to-treat cancers and has worked to bring four products to market so far. One is sold as part of a collaboration with Roche's (OTC:RHHBY) Genentech, and Daiichi Sankyo (OTC:DSNKY) of Japan sells another. But here, I'll focus on the company's lead molecule, cabozantinib. Exelixis already sells cabozantinib as Cabometyx for advanced kidney cancer and liver cancer, and as Cometriq for medullary thyroid cancer that has spread.

Annual revenue has been climbing since 2016, the year Cabometyx was approved. The company said it is the No. 1 tyrosine kinase inhibitor prescribed for renal cell carcinoma. Tyrosine kinases play a role in normal cell operations, but in cancer, they support tumor growth and disease progression such as metastasis. In the most recent quarter, revenue from the company's cabozantinib products climbed 8% to $193.9 million from the year-earlier period.

But what is most exciting lies ahead. Cabozantinib is involved in about 70 clinical development programs, from phase 1 to phase 3, in lung, gynecologic, pediatric, and other cancers. And in the latest earnings call, Exelixis said its work in the clinic may lead to four new indications for the molecule next year. The company also said it plans on filing as many as three investigational new drug (IND) applications with the U.S. Food and Drug Administration (FDA) alone or as part of collaborations. The FDA studies an IND to make sure a drug candidate is safe enough to be tested in humans.

Exelixis has been profitable since 2017, and the stock is trading at about 25 times trailing 12-month earnings. With more indications likely on the horizon for cabozantinib, this looks like a good deal to me.

2. Seattle Genetics

Seattle Genetics (NASDAQ:SGEN) also develops cancer treatments, and the company received two FDA approvals in recent months: Padcev in December and Tukysa in April. In its first full quarter on the market, Padcev, for locally advanced or metastatic urothelial cancer -- the most common type of bladder cancer -- generated $34.5 million in sales. Tukysa, to be combined with trastuzumab and capecitabine, treats patients with advanced unresectable (meaning surgery can't be used) or metastatic HER2-positive breast cancer.

Again, what lies ahead is compelling. In May, Switzerland approved Tukysa, and Seattle Genetics is ramping up its European team in anticipation of a possible approval from the European Medicines Agency. We can also expect more from Padcev. Seattle Genetics is studying Padcev combined with Merck's (NYSE:MRK) Keytruda as a first-line treatment for advanced urothelial cancer, and discussions with the FDA indicate the drug may benefit from an accelerated pathway to approval.

Hodgkin's treatment Adcetris, the company's first marketed drug, posted a 22% sales gain in the most recent quarter. Seattle Genetics, along with partner Takeda (NYSE:TAK), aims for more approvals for use of the drug as a first treatment in the disease.

Seattle Genetics isn't profitable, as expenses to fund the pipeline and to fund sales of its three products add up. But I'm happy to see the company investing in those crucial areas and expect this to pay off in the long run.

3. Gilead Sciences

Gilead Sciences (NASDAQ:GILD) has been center stage these past few months as the FDA granted emergency use authorization to its coronavirus treatment, remdesivir. Worldwide, there are about 20 ongoing recruiting or active clinical trials of remdesivir, which is administered intravenously. And Gilead said on June 22 that it was getting ready to begin trials of an inhaled version of the drug.

Gilead is still in the process of donating its initial supply of remdesivir. Once that runs out, the company will begin charging for the drug, but it hasn't yet set a price. Gilead will have to find the right balance -- a price that's fair to patients, while adding enough revenue to satisfy investors.

Without knowing the price of remdesivir or how the crisis will develop over the coming months, I wouldn't invest in a company based on a coronavirus program alone. My main reasons for optimism regarding Gilead are a possible new drug approval that may happen at any moment and a strong HIV program. Gilead is awaiting word from the FDA on filgotinib for rheumatoid arthritis, and the company says filgotinib has the potential for approval in five indications over the coming four years. As for HIV, blockbuster Biktarvy's first-quarter sales more than doubled to $1.7 billion.

Though annual revenue has been on the decline or stable over the past few years due to a drop in the company's hepatitis C drug sales, Biktarvy and filgotinib should fuel new growth in the coming years. So, today, paying 19 times trailing 12-month earnings for the potential of this biotech stock sounds good to me.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.