6. Keytruda

Driven by trial win after trial win, Keytruda has rapidly expanded into a range of new indications. (Merck)

6. Keytruda
Merck & Co.
2018 U.S. sales: $4.15 billion
Used for: melanoma, non-small cell lung cancer, head and neck cancer, Hodgkin lymphoma, primary mediastinal B-cell lymphoma, bladder cancer, stomach cancer, cervical cancer, liver cancer, Merkel cell carcinoma, kidney cancer 

In a heated contest with Bristol-Myers Squibb’s Opdivo—and, to a lesser extent, checkpoint inhibitors from Roche, Pfizer and Merck KGaA, and AstraZeneca—Merck’s Keytruda has proven itself the more nimble I-O competitor. And now it's seriously threatening its biggest rival in the U.S. market. In 2018, Keytruda secured $4.2 billion in U.S. sales, an 80% increase that easily bests any other drug on the year’s top 20 sellers list.

Driven by trial win after trial win, Keytruda has rapidly expanded into a range of new indications that broadened its reach, jacked up sales and heaped pressure on Opdivo’s previously significant lead in the market. Keytruda started off its landmark 2018 with an FDA “breakthrough therapy” nod in January as a potential treatment for patients with advanced or metastatic kidney cancer. That sped-up review approval led to an FDA approval in April 2019.

The drug followed that up with major clinical trial wins in lung cancer and melanoma, and FDA nods for cervical cancer and non-Hodgkin lymphoma in the span of two days in June. The next big win—and a sign that Opdivo’s time on top was coming to a close—was the FDA’s speedy approval for Keytruda in non-small cell lung cancer in August.

Merck finished 2018 with FDA nods for liver cancer and esophageal cancer.

If early 2019 numbers are any indication, Keytruda will surpass Opdivo in annual U.S. sales this year. The Merck drug slightly outpaced BMS' blockbuster with $1.28 billion in sales, compared with Opdivo's $1.12 billion.

6. Keytruda