At a time in history when vaccines are once again claiming their potential, a disease has been waiting for its 40 years: AIDS, an infection caused by the human immunodeficiency virus (HIV).
Currently, the Janssen company is promoting the Mosaic trial , a large-scale phase III study that evaluates the efficacy of a vaccine scheme against this pathogen in men who have sex with men and transgender people, and in which six Spanish hospitals participate. .
Mosaico aims to recruit 3,800 people in eight countries in North America, South America and Europe, in approximately 55 clinical spaces. “The objective is to know if the administration of the four doses planned in the research prevents infection in people at risk of acquiring it,” says Miguel Górgolas, head of the Department of Infectious Diseases at the Fundación Jiménez Díaz University Hospital in Madrid and head of the Mosaico program in this hospital.
The immunization under test is officially called Ad26.Mos4.HIV and is made up of a virus known as adenovirus type 26 and bivalent gp140, in turn made up of two proteins called clade C gp140 and mosaic gp140. “In Ad26, the genes that code for a protein important for viral invasion have been incorporated. In this case, a mosaic of the protein variations observed in the different viral strains is included; hence the name of the study ”, explains Dr. Górgolas.
“Four doses of the first vaccine are administered in a year, in addition to a second formulation that is administered together with the last two doses. It is made up of the specific protein of the virus and incorporates aluminum as an immunity promoter ”, adds Górgolas.
Mosaico is taking place in Argentina, Brazil, Mexico, Peru, Italy, Poland, the United States and Spain. Here, the Barcelona hospitals Germans Trials i Pujol and the Vall d’Hebron University Hospital are participating; the Reina Sofía Hospital in Córdoba; the Fundación Jiménez Díaz University Hospital and the San Carlos Clinic, both in Madrid; and the General University Hospital of Valencia.
Meanwhile, it recently suspended the clinical trial of the phase 2b HIV vaccine, known as the Imbokodo study, for not showing sufficient protection against infection in a population of young women in sub-Saharan Africa at high risk of contracting HIV. The scheme of the compounds used in Mosaico differs slightly from that used in Imbokodo, since it incorporates a second component in the protein vaccine.
“ The results of Imbokodo are bad news for Mosaico. However, the study population is different and, in Africa, a subtype of HIV predominates that does not prevail in Western Europe, with which the immune response may be different ”, explains Vicente Estrada Pérez, head of the Infectious Diseases Unit of the Hospital Clínico San Carlos and coordinator of the trial at this hospital. “Also, the vaccine is slightly different. Mosaic has an antigenic determinant that is believed to be the most immunogenic. In other words, with a greater capacity to stimulate the production of antibodies ”, adds the expert.
