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.