“Imagining it 35 years ago was thinking of a miracle. Instead it is reality, a fantastic achievement of science”. So said virologist Roberto Burioni in a tweet. The reference is to the results of a phase 3 study – conducted by the biopharmaceutical giant Gilead – to verify the efficacy of Lenacapavir, a new drug to be used in the prevention of the HIV virus (it is important to point out that the global AIDS epidemic is increasing: in accordance with the update of the 2006 Unaids/WHO report on the AIDS epidemic, it is estimated that 39.5 million people are living with the virus).
Well, none of the 2,134 women who participated contracted HIV during the entire trial period. There was no other drug, in comparison, that proved so effective. “With zero infections and 100 percent efficacy, Lenacapavir administered twice a year has demonstrated its potential as a relevant new tool to help prevent HIV infections,” explains Merdad Parsey, medical director of Gilead (a company founded in 1987 and present in over 35 countries), in a statement.
Clinical trial of the drug
During the phase 3 study (which, AIFA points out on its website, “is needed to determine how effective the drug is, whether it has any additional benefits compared to similar drugs already on the market and what the risk/benefit ratio is”), called “Purpose 1” and conducted in South Africa and Uganda, the drug Lenacapavir was injected twice every twelve months to a group of 2,134 young women (all aged between 16 and 25).
The choice of countries of origin is well thought out: Africa, in fact, remains the most affected country today, especially in the sub-Saharan region. In this sense, “Epicentro ISS”, the epidemiology site of the Istituto Superiore di Sanità, circumscribes that “the updated data of the 2007 report on the AIDS epidemic, presented by the joint United Nations program on HIV/AIDS (UNAIDS) and the WHO, estimate that in 2007 there were 33.2 million people affected by HIV, 2.5 million who had just contracted the virus and 2.1 million patients who died of AIDS”.
The aim of the study is to evaluate the safety and efficacy of Lenacapavir, with a six-monthly injection, for PrEP (or “pre-exposure prophylaxis”, which consists of taking a combination of drugs active against HIV before sexual intercourse) and other previous drugs: the antiretrovirals Truvada, the only drug approved in EU countries, and Descovy, which instead has been given the green light only in the USA, together with Truvada. Both drugs are taken as daily pills (the same way they were administered to the participants in the study), unlike Lenacapavir, which was administered through two injections per year.
Very promising results
Released by Gilead after being evaluated by an independent Data Monitoring Committee, the results of the study showed that Lenacapavir was, by far, the most effective drug among those compared. The only one that, in this phase of clinical trials – we are talking about the penultimate stage that a drug must successfully pass in order to be evaluated by the relevant pharmaceutical authorities: the Food and Drug Administration (USA) and the aforementioned Italian Medicines Agency – has proven suitable for preventing infection in 100 percent of cases.
In fact, only in the group that had received the latter drug (in the formula of two injections every twelve months) no participant contracted the virus. On the other hand, 16 of the 1,068 women in the group treated with Truvada and 39 of the 2,136 participants in the Descovy group contracted HIV during the study. Furthermore, Lenacapavir was generally well tolerated and no new (or significant) problems in terms of safety were identified. Having acquired these results, the DMC recommended that Gilead offer Lenacapavir to all participants in the study.