Introduction of DAAs improved hepatitis C cure rates
The introduction of direct antiviral agents (DAAs) substantially improved sustained virological response (SVR) in patients with hepatitis C virus (HCV), a recent study found.
“SVR rates in our cohort increased steadily from 19.2 percent in 1999 to 36 percent in 2010 before a remarkable increase to 90.5 percent in 2015,” said the researchers. “The number of patients cured in 2015 [n=28,084] represented almost half of all patients cured in the entire 17-year period [n=57,445].”
Researchers obtained the medical records of patients (mean age 56.2 years, 96.8 percent male) in the United States Veterans Affairs (VA) national healthcare system who initiated HCV antiviral treatment regimens between January 1999 and December 2015 (105,369 treatment regimens for 78,947 patients).
In 2010, the final year of the interferon era, 1,313 patients achieved SVR. This rose to 1,273–2,296 in the boceprevir/telaprevir era (DAAs used in combination with interferon and ribavirin, 2011–2013) to 7,377 in the simeprevir/sofosbuvir era (2014). The introduction of ledipasvir/sofosbuvir and paritaprevir/ritonavir/ombitasvir/dasabuvir led to an even bigger increase in annual SVR rate (28,084 in 2015). [Aliment Pharmacol Ther 2017;doi:10.1111/apt.14021]
The improvement in annual SVR rate between 2010 and 2015 appeared to benefit individuals with cirrhosis, decompensated cirrhosis, and hepatocellular carcinoma (HCC) with 52.3-, 48.6-, and 48.5-fold increases, as well as those with genotype 1 HCV (39.1-fold) and older individuals (age >60 years, 80.7-fold) compared with 21.4-fold among all patients.
The increase in funds allocated to the VA between October 2014 and September 2015 to offset DAA costs led to an increase in treatment rates, from 1,135 treatments a month in October 2014 to 3,413 in March 2015. However, the increase in treatment rates coupled with the high cost of DAAs depleted funds in several treatment facilities leading to a decline in treatment rates to 762 treatments a month between March and July 2015. The subsequent allocation of funds extending to September 2015 raised the treatment rates once again to 4,416 and 6,959 in August and September 2015, respectively.
Among the factors cited for the improvement in HCV treatment and cure rates in the final 2 years of the study were the introduction of interferon-free DAAs which “vastly increased the VA population eligible for and willing to undergo antiviral treatment” as well as the increase in funding, said the researchers.
According to the researchers, treatment and cure rates are expected to continue to rise with the allocation of more funding (January 2016) and approval of more DAAs, though they acknowledged that the findings of this study may not extend to all populations.
“The [US Food and Drug Administration] approval of additional antiviral agents including daclatasvir, elbasvir/grazoprevir, and velpatasvir/sofosbuvir will lead to increased treatment and cure rates, particularly for genotype 2- and 3-infected patients who have fewer treatment options and lower SVR rates than genotype 1-infected patients,” they said.
“Considering that HCV infection is the most common cause of cirrhosis and liver cancer in the VA and the US, that the benefits of SVR are long-lasting ... the potential public health benefits of large-scale HCV treatment are great.”
According to Dr Desmond Wai from the Desmond Wai Liver and Gastrointestinal Diseases Centre, Mount Elizabeth Novena Specialist Centre, Singapore, who was not affiliated with the study, DAAs are a game-changer in HCV treatment.
Current DAAs do not require interferon injections or ribavirin intake, and have few adverse effects. They are efficacious with a more than 95 percent chance of cure in most patients, he said.
“With DAAs, most patients can tolerate treatment well, especially those who were previously ineligible or intolerable to interferon-based treatment,” he said, citing that the biggest drawback to DAA use is cost. However, due to the increase in number of approved DAAs, prices have dropped significantly, though they are still considerably high. Furthermore, DAAs are new drugs and therefore, long-term studies are needed to confirm their safety, said Wai.
Another drawback is that SVR from DAAs may not necessarily lower HCC risk. HCV patients who have achieved SVR should still be followed-up regularly, said Wai.