New Delhi: For researchers and clinicians working in the field of infectious diseases, it’s the most exciting news in a long time — a twice-yearly injectable drug, lenacapavir, has been shown to offer 100 percent protection from HIV.
The drug developed by US-based pharma major Gilead Sciences is from a new class of medication called capsid inhibitor, which works by interfering with a protein shell that protects the virus’s genetic material and enzymes needed for replication.
Lenacapavir was approved for medical use in the European Union in August 2022 before being approved by the US Food and Drug Administration (USFDA) four months later, but as of now it is indicated for AIDS patients (HIV-infected individuals who go on to develop AIDS) with limited treatment options.
The drug was tested as a pre-exposure prophylaxis (PrEP) in a large number of African women and is now being tested in other groups who are among the most vulnerable to HIV.
“The results from the drug’s trial as a PrEP are astounding — they have shown its potential to be something between a cure and a vaccine — and will have ramifications for the HIV, AIDS landscape worldwide,” Dr Ishwar Gilada, president emeritus at the AIDS Society of India, told ThePrint.
According to the World Health Organization, globally, 39 million or 3.9 crore people were living with HIV at the end of 2022 and Africa remains the most severely affected, with nearly one in every 25 adults living with HIV and accounting for more than two-thirds of the people living with HIV worldwide.
Although the number of HIV- and AIDS-affected people in India has been declining since the successful implementation of the anti-viral therapy programme at government-run centres, it still has a high burden of the disease.
According to statistics from India’s National AIDS Control Organisation (NACO), the country had an estimated 24.67 lakh people living with HIV as of 2022 — the second highest number in the world after South Africa.
The lenacapavir development, however, offers hope like never before. Another good thing is that adverse events related to the drug are mild — injection site-related discomfort and nausea.
A statement by Gilead Sciences issued last Thursday said the results from a late-stage trial of the drug were so impressive that the independent data monitoring committee, overseeing the trial, recommended that the company stop the blinded phase of the trial, where only half the participants were receiving lenacapavir, and offer it to all volunteers.
How the trial unfolded
The trial — with the first phase named PURPOSE — involved 5,300 women, including those who were pregnant and lactating, and adolescent girls aged 16-25 across 25 sites in South Africa and three sites in Uganda.
As part of the study that started in August 2021, lenacapavir was compared with descovy and truvada — two other drugs used as PrEP for HIV.
Descovy and Truvada are both fixed-dose combinations that have emtricitabine and tenofovir as active pharmaceutical ingredients with the form of tenofovir different in the two drugs. These drugs, however, are to be taken as daily pills.
The interim results of the trial, which are yet to be peer-reviewed, showed that there were zero incident cases of HIV infection among 2,134 women in the lenacapavir group, in comparison to 16 incident cases among 1,068 women in the truvada group and 39 incident cases among 2,136 women in the descovy group.
“Truvada and descovy, too, are very efficient PrEP against HIV but what sets lenacapavir apart is that it’s showing to be 100 percent effective in preventing HIV, and it being available as twice-yearly shots is very convenient,” said Gilada.
“With zero infections and 100 per cent efficacy, twice-yearly lenacapavir has demonstrated its potential as an important new tool to help prevent HIV infections,” Merdad Parsey, chief medical officer, Gilead Sciences, said in a statement.
“We look forward to additional results from the ongoing PURPOSE clinical programme and continuing towards our goal of helping to end the HIV epidemic for everyone, everywhere.”
Gilead expects results in late 2024 or early 2025 from the programme’s other pivotal trial, PURPOSE 2, which is assessing twice-yearly lenacapavir for PrEP among cisgender men who have sex with men, transgender men, transgender women and gender non-binary individuals who have sex with men in Argentina, Brazil, Mexico, Peru, South Africa, Thailand and the US.
The regulatory filing for lenacapavir for PrEP will include the results of both PURPOSE 1 and PURPOSE 2, if positive, in order to ensure the drug for PrEP can be approved for multiple populations and communities most in need of additional HIV prevention options, the company has said.
Access challenge?
One issue that may limit access to lenacapavir, when it is approved as PrEP, is its cost, say experts.
The drug, available under the brand name Sunlenca, costs $40,000 (over Rs 33 lakh) per year in the US. But experts also said that Gilead has a history of making crucial patented drugs accessible to poorer countries, far more than owners of other innovative companies.
“It had provided voluntary licences to several Indian companies to produce remdesivir, an Ebola drug that had initially shown huge promise to treat COVID-19, in order to bring down its cost for low and middle-income countries,” said an official attached with the Organisation of Pharmaceutical Producers of India (OPPI), a network of multi-national drugmakers.
Voluntary licensing allows the production of generic versions of a patented drug, typically in the event of a public health emergency.
Gilada, too, highlighted that Gilead in 2014 had signed voluntary licensing agreements with seven India-based generic pharmaceutical manufacturers to expand access to its chronic hepatitis C medicine, sofosbuvir, and a combination of sofosbuvir and ledipasvir to expand access in developing countries when the disease was emerging as a major threat to public health.
ThePrint reached Gilead over email for comment on pricing and licensing-related information. This report will be updated if and when a response is received.
(Edited by Nida Fatima Siddiqui)
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