In October 2016, the results of the PROTEST study were published in the journal HIV Medicine. This study evaluated the validity of a new technique to determine HIV tropism (its affinity for infecting a particular type of cell) and whether or not to determine maraviroc therapy.
It is known that the drug maraviroc is only indicated in those patients who present a certain tropism. The techniques validated so far to analyze the tropism were phenotypic: the PROTEST study proposed to use a genotypic one.
Phenotypic techniques have the disadvantages of being expensive and laborious. They can only be performed in a laboratory in the United States and only on patients with a viral load above 1,000 copies/mL. PROTEST was intended to demonstrate the validity of a genotypic technique: it is fast, inexpensive, it can be carried out in hospital labs and even practiced in patients with undetectable viral load.
This study was carried out between 2012 and 2015 and involved 25 Spanish hospitals. A total of 175 patients who were willing to switch antiretroviral treatment were selected, mostly to improve lipid parameters such as cholesterol or triglycerides. Of these, 74 initiated treatment with maraviroc based on the favorable results of the genotypic technique employed. Patients were followed for one year, keeping blood samples and measuring viral load, CD4 count, and routine laboratory parameters to see if there was an improvement in pre-change alterations.
Changes in cholesterol and triglycerides were found to be improved after one year of treatment, and liver enzyme levels in the blood were also improved, results which were already anticipated according to previous information available on maraviroc behaviour. Finally, and with respect to the main objective of the study, the conclusion is that the genotypic technique for the determination of tropism is valid to determine the indication of treatment with maraviroc or to opt for another drug.
Further information online.