** RBC starts coverage on Belgian pharma company Argenx ARGX.BR with "outperform", citing a growing top-line and expanding margins, and especially its Vyvgart medicine
** The drug is showing a lot of potential, it says, noting increased usage, more convenient dosing methods, a lack of disruptive competition, and geographical expansion
** RBC does not think Argenx's valuation at about 20x last years sales should be a problem on Vyvgart acceleration and sticks a PT of $850 on the company, a 29% upside to current prices
** "Overall, we can't think of many Biotech companies with ~$2b top-line that may quadruple by the end of the decade and that may result in $10b+ in cumulative operating cash flows and give plenty of optionality to fuel the next leg of growth," RBC says
** Out of 19 analysts that cover Argenx SE, 19 rate the stock "strong buy" or "buy"
(Reporting by Jakob Van Calster)
((jakob.vancalster@thomsonreuters.com;))