Gilead CEO Daniel O’Day came armed with some impressive numbers at Fortune’s virtual Brainstorm Health conference on April 28. Not just with regard to the company’s efforts to fight the coronavirus pandemic, but in its resilience during the outbreak in therapeutic areas ranging from HIV to cancer.

“Today, one out of two [COVID] patients in the hospital are receiving remdesivir,” said the longtime pharmaceutical industry veteran in an interview with MSNBC anchor and NBC News senior business correspondent Stephanie Ruhle at Brainstorm Health. Remdesivir, which goes by the brand name Veklury, was the first drug to receive Food and Drug Administration (FDA) emergency authorization last year and was given official FDA approval in October 2020.

That approval has clearly had an effect on remdesivir’s market reach. But it’s not the only area where Gilead is thriving, according to O’Day. “Three out of four HIV patients around the world are on a Gilead medicine,” he said.

From COVID to HIV to cancer drugs, Gilead’s success in the past year highlights the secret sauce, and the agonizing uncertainty, of drug development: Foundations laid far in the past may not bear fruit for more than a decade. That’s how long Gilead had been working on remdesivir as an antiviral before shifting its focus toward treating COVID patients.

That’s also why Gilead didn’t slow its work on other important and potentially lifesaving therapies during a year when many companies felt pressure to drop everything else and focus exclusively on COVID. For instance, even beyond its titanic presence in the HIV treatment market, the company has been branching out into oncology drugs.

“That’s actually the thing I’m most proud of, being part of Gilead and the life sciences industry,” said O’Day. “We had to divide and conquer…We made amazing strides last year in cancer medicines.”

Case in point: Just weeks ago, the FDA granted Gilead’s Trodelvy official approval in certain patients with advanced or metastatic triple-negative breast cancer.