On June 28, the U.S. Food and Drug Administration (FDA) approved Gilead Sciences’ Epclusa (sofosbuvir/velpatasvir), the first hepatitis C virus (HCV) regimen to treat all six major genotypes of the virus. For most people seeking treatment Epclusa does not promise higher cure rates, since by and large such rates were already very high with previously available regimens. But for some categories of those living with the virus, the new fixed-dose, once-daily combination tablet does offer a higher cure rate, a shortened treatment length, a simplified regimen or the ability to avoid use of ribavirin, which can cause anemia.
In crafting Epclusa, Gilead stuck with its blockbuster standby sofosbuvir, which goes by the brand name Sovaldi and which revolutionized hep C care when it was approved in December 2013. Gilead initially paired the NS5B polymerase inhibitor sofosbuvir with the NS5A inhibitor ledipasvir in Harvoni (ledipasvir/sofosbuvir), which was approved in October 2014. Next the pharmaceutical giant essentially took the ledipasvir component out of Harvoni and swapped in the pangenotypic (meaning it combats all genotypes) NS5A inhibitor velpatasvir to create Epclusa.
Together, Sovaldi and Harvoni have vastly dominated the hep C drug market, while AbbVie’s Viekira Pak (ombitasvir/paritaprevir/ritonavir; dasabuvir) and Technivie (ombitasvir/ paritaprevir/ritonavir), Bristol-Myers Squibb’s (BMS) Daklinza (daclatasvir) and Merck’s Zepatier (elbasvir/grazoprevir) have taken up the remaining fraction of hep C drug sales.
Andrew H. Talal, MD, MPH, a professor of medicine and hepatologist at University at Buffalo, State University of New York, who recently received an award from the Patient-Centered Outcomes Research Institute to research providing hep C treatment through telemedicine, doesn’t see Epclusa pushing Harvoni into obscurity. “I think that [Epclusa] fills two voids,” he says, “one is genotype 2 and 3 as an alternative to [Daklinza] and [Sovaldi], as well as in decompensated cirrhotics. I think those are the two areas where this drug will have its greatest impact.”
The FDA approval indicates 12 weeks of Epclusa across the board, and requires the use of ribavirin only for those with the most advanced liver disease, specifically decompensated cirrhosis classified as Child-Pugh level B or C. This is the first time the FDA has approved a hep C treatment for decompensated cirrhotics with genotypes 5 and 6. Previously, the recommended treatment for those with genotype 3 and compensated cirrhosis, the more mild form of the liver disease, was 24 weeks of Daklinza and Sovaldi with ribavirin.
Avoiding ribavirin is no small thing, according to Daniel Fierer, MD, an associate professor of medicine and infectious disease specialist at Mount Sinai Hospital in New York City. “Ribavirin was a lot more toxic than we thought it was because we were giving [patients with hep C] interferon and I blamed most of the side effects on interferon,” he says. It wasn’t until he saw the level of side effects reported by his patients taking ribavirin but not interferon that he appreciated the former drug’s true apparent level of toxicity.
Epclusa’s indication for genotypes 2 and 3 is likely bad news for BMS, since Daklinza, paired with Sovaldi, has found a niche as a treatment for those genotypes. The two-drug pairing comes with a high price tag, given that the wholesale cost of a 12-week regimen is $63,000 for Daklinza and $84,000 for Sovaldi. And for some with those genotypes and advanced liver disease, 24 weeks of both drugs is recommended, which doubles the wholesale cost.
The pricing of pharmaceuticals is a mysterious game, in which companies set what is known as the wholesale acquisition cost, or WAC, at one level and then typically make secret arrangements with insurers to pay a discounted price. So it is difficult to gauge how much the drugs actually cost insurers. Gilead’s wholesale cost for Epclusa is $74,760, a bit less expensive than Technivie’s $76,653, and more expensive than Zepatier’s $54,600. Harvoni is much more expensive at $94,500; however, that’s the price for a 12-week regimen, and a considerable proportion of those with genotype 1 of hep C can likely take just eight weeks, which costs $63,000.
“I was pleasantly surprised with the WAC [of Epclusa],” says Michael Ninburg, executive director of the Hepatitis Education Project in Seattle. “Now they certainly did their homework. As to how that would affect sales of Harvoni and [Sovaldi] remains to be seen—and what the difference is going to be after discounts for these new drugs.”
In major advanced trials of Epclusa, those with genotypes 1 through 6 who did not have cirrhosis or who had compensated cirrhosis had, overall, a 98 percent rate of sustained virologic response 12 weeks after completing therapy (SVR12, considered a cure). This was a similar cure rate to the 94 to 99 percent rates seen in advanced trials of Harvoni among those with genotype 1, with or without compensated cirrhosis. Trials of Harvoni including people with genotypes 4, 5 and 6, with or without compensated cirrhosis, yielded respective cure rates of 93 percent, 93 percent and 96 percent.
For those with genotypes 1 through 6 who had decompensated cirrhosis (Child-Pugh B), 12 weeks of Epclusa and ribavirin offered a 94 percent cure rate in an advanced trial. Trials of 12 weeks of Harvoni and ribavirin among people with genotype 1 and decompensated cirrhosis saw an 87 percent cure rate for those with Child-Pugh B and an 88 percent cure rate with Child-Pugh C cirrhosis. A trial of 12 weeks of Sovaldi and Daklinza plus ribavirin among those with genotype 1 and decompensated cirrhosis yielded respective cure rates of 92 percent and 50 percent for those with Child-Pugh B and C cirrhosis.
While advances for individuals with genotypes 2 and 3 are significant, those two genotypes are actually relatively uncommon in the United States, which potentially limits Epclusa’s role as a game changer here.
“For me, that’s one of the big questions: What is Gilead going to do around access to these drugs outside of Europe, the U.S. and Japan,” says Ninburg, referring to wealthy nations where genotypes 2 and 3 are more rare.
In North America, an estimated 76 percent of the hep C population has genotype 1; 12 percent has genotype 2; 10 percent has genotype 3; 1 percent has genotype 4; and less than 1 percent each have genotype 5 or 6. Genotype 3 is predominant in South Asia, including India and Pakistan, while genotype 2 is the most common genotype in several Western African nations. There are also considerable numbers of people with genotypes 2 and 3 in China and genotype 2 in Russia; each country has a large hep C population.
A major advance that Epclusa has to offer the global epidemic is the chance for a one-size-fits-all regimen that does not require genotype testing, which is prohibitively expensive in some parts of the world.
“For developing countries where genotyping is not easily accessible, pangenotypic regimens like Epclusa will be particularly useful once we have a point-of-care test for [hep C viral load]—a test that would make both confirmatory and genotype tests unnecessary,” says Ninburg. “Hopefully we’ll start to see the first such tests in the next couple of years.”