Matija Kvasina

Matija Kvasina (born 4 December 1981) is a Croatian racing cyclist, who most recently rode for UCI Continental team.

He finished 56th in the road race and 38th in the road time trial at the 2008 Summer Olympics in Beijing.

Born in Nova Gradiška, Kvasina was named by as part of their squad for the 2016 season.

In 2016, he won the overall title at the Tour of Croatia.

Kvasina tested positive for an experimental drug known as Molidustat (BAY-85-3934), during two tests taken during the 2017 Flèche du Sud - a race in which he won.

Molidustat represents a class of drugs that act on the same physiological pathways and enzyme cascades as those which are activated during altitude training.

Oxygen deprivation has the effect of stimulating the body's production of erythropoietin (EPO) - Molidustat imitates this.

In 2017, Kvasina was given a four-year doping suspension after a positive drugs test at that year's Flèche du Sud.

Kvasina was subsequently kicked out of the 2017 Tour of Austria.

In oxygen poor environments the human body manufactures a protein called hypoxia-inducible factor (HIF), which initiates and drives the processes which allow the body to adapt to those low-oxygen conditions.

Typically this involves increasing the concentrations of naturally made EPO, mobilising iron and an increase in the rate of red blood cell production.

Under normal oxygen environmental conditions, HIF is kept in check (its actions are inhibited) by an enzyme called prolyl hydroxylase (PH).

Moldustat stops PH from blocking HIF, thus, increasing both the concentrations of EPO and red blood cells in the body, imitating altitude training.