The biotechnology industry is comprised of hundreds of companies that fuse biology and technology to develop drugs and related products for the treatment of diseases and medical conditions. Today's biotechnology industry includes companies that make medical devices and diagnostics, as well as biofuels, biomaterials, pollution controls, and more. Among the largest companies in the industry are pharmaceutical companies like Vertex Pharmaceuticals Inc. (VRTX) and Gilead Sciences Inc. (GILD). Gilead's investigational compound named remdesivir is seen as having the potential to treat COVID-19.  These companies generally focus on creating and testing new drug compounds for medical use, and must go through lengthy trial and approval processes for their products. This means investors often must wait for months or even years before knowing whether a potential drug therapy is usable or profitable.

In spite of the many challenges facing biotechnology companies, a number of enterprises have risen to the top of the list. Below, we take a look at the 10 biggest as measured by 12-month trailing (TTM) revenue. This list is limited to companies which are publicly traded in the U.S. or Canada, either directly or through ADRs. Some foreign companies may report semiannually, and so may have longer lag times. All figures are as of March 25, 2020 and all data is provided by YCharts.

Novo Nordisk A/S (NVO)

  • Revenue (TTM): $18.3 billion
  • Net Income (TTM): $5.8 billion
  • Market Cap: $118.6 billion
  • 1-Year Trailing Total Return: 0.5%
  • Exchange: New York Stock Exchange

Novo Nordisk is a multinational biotech company headquartered in Denmark with production facilities in seven countries and affiliates or offices in 80 countries. The company's primary focus is diabetes care, hemophilia care, growth hormone therapy, and hormone replacement therapy. The company makes several drugs under various brand names including Levemir, NovoLog, Novolin R, NovoSeven, NovoEight, and Victoza.

Regeneron Pharmaceuticals Inc. (REGN)

  • Revenue (TTM): $7.9 billion
  • Net Income (TTM): $2.1 billion
  • Market Cap: $49.5 billion
  • 1-Year Trailing Total Return: 14.7%
  • Exchange: Nasdaq

Biopharmaceutical company Regeneron develops and markets drug treatments for patients with eye disease, cancer, cardiovascular diseases, allergic and inflammatory issues, and infectious diseases. Through its Regeneron Genetics Center, the company aims to conduct one of the largest gene sequencing operations worldwide.

Alexion Pharmaceuticals Inc. (ALXN)

  • Revenue (TTM): $5.0 billion
  • Net Income (TTM): $2.4 billion
  • Market Cap: $19.0 billion
  • 1-Year Trailing Total Return: -34.1%
  • Exchange: Nasdaq

Alexion is a biopharmaceutical company that develops and markets immunoregulatory drugs for the treatment of cardiovascular and autoimmune diseases. Through its drug therapies, Alexion aims to provide patients with compounds that selectively target portions of the immune system which may allow diseases to proliferate.

Vertex Pharmaceuticals Inc. (VRTX)

  • Revenue (TTM): $4.2 billion
  • Net Income (TTM): $1.2 billion
  • Market Cap: $57.9 billion
  • 1-Year Trailing Total Return: 22.9%
  • Exchange: Nasdaq

Biopharmaceutical company Vertex focuses on creating and marketing drug treatments for patients suffering from cancer, cystic fibrosis, autoimmune diseases, and neurological disorders, among others.

Jazz Pharmaceuticals PLC (JAZZ)

  • Revenue (TTM): $2.2 billion
  • Net Income (TTM): $0.5 billion
  • Market Cap: $5.4 billion
  • 1-Year Trailing Total Return: -30.0%
  • Exchange: Nasdaq

Irish biopharmaceutical company Jazz Pharmaceuticals creates and commercializes drug products designed to address issues related to narcolepsy, psychiatry, pain management, and oncology. On March 25, the company announced FDA approval of its drug JZP-258 for the treatment of cataplexy or excessive daytime sleepiness.

Incyte Corp. (INCY)

  • Revenue (TTM): $2.2 billion
  • Net Income (TTM): $0.5 billion
  • Market Cap: $14.6 billion
  • 1-Year Trailing Total Return: -21.0%
  • Exchange: Nasdaq

Focusing on small molecule drugs for use in oncology primarily, Incyte is a biopharmaceutical company responsible for discovering, developing, and marketing drug therapies. The company is best known for its drug Jakafi, a treatment for myelofibrosis.

Biomarin Pharmaceutical Inc. (BMRN)

  • Revenue (TTM): $1.7 billion
  • Net Income (TTM): -$0.02 billion
  • Market Cap: $14.4 billion
  • 1-Year Trailing Total Return: -9.3%
  • Exchange: Nasdaq

A maker of therapeutic enzyme products, Biomarin Pharmaceutical develops drug treatments for lysosomal storage diseases as well as serious burns. The company also provides diagnostic and analytic services for carbohydrate biology applications.

United Therapeutics Corp. (UTHR)

  • Revenue (TTM): $1.4 billion
  • Net Income (TTM): -$0.1 billion
  • Market Cap: $3.9 billion
  • 1-Year Trailing Total Return: -27.1%
  • Exchange: Nasdaq

United Therapeutics primarily develops drug treatments for pulmonary hypertension, peripheral vascular disease, and other vascular conditions. Among the company's most popular medicines are Remodulin, Orenitram, Unituxin, and Tyvaso.

Alkermes PLC (ALKS)

  • Revenue (TTM): $1.2 billion
  • Net Income (TTM): $-0.2 billion
  • Market Cap: $2.2 billion
  • 1-Year Trailing Total Return: -58.6%
  • Exchange: Nasdaq

Alkermes is an Irish biopharmaceutical company. This firm creates treatments for central nervous system disorders including depression, schizophrenia, and addiction. It also focuses on treatments for diabetes.

Ionis Pharmaceuticals Inc. (IONS)

  • Revenue (TTM): $1.1 billion
  • Net Income (TTM): $0.3 billion
  • Market Cap: $6.2 billion
  • 1-Year Trailing Total Return: -43.2%
  • Exchange: Nasdaq

Biotechnology company Ionis discovers and develops RNA-based therapeutic products. Its three primary, commercially-available medicines include WAYLIVRA, Spinraza, and Tegsedi. It also has drug treatments in various stages of development to treat Huntington's disease, ALS, and cardiovascular disease.