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Voluntary licensing of hepatitis C drugs has led to more people on treatment

Keith Alcorn
28 August 2019

Voluntary licensing of hepatitis C treatments to generic drug manufacturers for sale in lower- and middle-income countries has increased the number of people treated by approximately 70 per thousand people diagnosed with hepatitis C, according to a study carried out by researchers at Imperial College, London.

The results were published in The Lancet Global Health in July.

Pharmaceutical companies who own patents on medicines – originator companies – can grant voluntary licences to generic manufacturers to sell versions of the patented medicine in certain countries. These licences can be granted directly by the company or negotiated through the Medicines Patent Pool, a body which holds patents of medicines on behalf of manufacturers.

Voluntary licenses for hepatitis C direct-acting antivirals were first granted by Gilead Sciences in 2014 for sofosbuvir and ledipasvir. The licences covered 91 countries. An additional licence for velpatasvir was granted by Gilead in 2015. In 2015 Bristol-Myers Squibb authorised the Medicines Patent Pool to grant licences for its direct-acting antiviral daclatasvir that cover 112 lower- and middle-income countries.

Advocates for improved access to medicines have argued that voluntary licences enable more people with hepatitis C to be treated, but it has been difficult to assess how much difference the licences make to treatment access. Government resources and rates of diagnosis might also affect the number of people who receive hepatitis C treatment, even when affordable medicines are available.

To assess the impact of voluntary licences, Bryony Simmons and colleagues at Imperial College, London, used an innovative method called a 'difference in differences' analysis to estimate the average effect of voluntary licences. They compared the average number of people treated per thousand people with hepatitis C between countries affected by voluntary licensing and those outside the agreements and adjusted these figures to take into account national health expenditure (public and private), health system indicators such as life expectancy and under 5-mortality, age distribution, GDP per capita and urban population. These factors are more likely to be present in countries that qualify for voluntary licensing agreements but will vary between countries.

The study looked at 35 lower- and middle-income countries with treatment data for the period 2004-2016. Nineteen countries were covered by voluntary licensing agreements, 16 were not, and these countries formed the control group. Treatment data were judged to be of medium quality or high quality for 75% of the countries included in the analysis.

The number of people treated for hepatitis C varied little from year to year prior to 2014 and then began to increase.

The analysis found that the availability of hepatitis C treatment under voluntary licensing increased the uptake of treatment by 69.3 people per 1000 persons diagnosed with hepatitis C (95% CI 46.7-91.9).

Voluntary licensing had its greatest effect in the second year after introduction (perhaps reflecting the time it takes for a national treatment programme to be set up, and for generic manufacturers to obtain approval for new products).

The researchers did not have access to data that showed prices paid for drugs, or which products were procured, so they cannot show a direct relationship between the availability of generic direct-acting antivirals and an increased uptake of treatment. But they conclude that voluntary licensing has been associated with an increase in the uptake of treatment and that longer-term follow-up is needed to investigate whether the effect of voluntary licensing increases over time.


Simmons B, Cooke GS, Miraldo M. Effect of voluntary licences for hepatitis C medicines on access to treatment: a difference-in-differences analysis. Lancet Global Health, 7: e1189-96, 2019. DOI: