There is one S&P/ASX 200 Index (ASX: XJO) stock that's going...

There is one S&P/ASX 200 Index (ASX: XJO) stock that's going absolutely gangbusters but is hardly spoken about.Believe it or not, the Neuren Pharmaceuticals Ltd (ASX: NEU) share price has gained 118% in the past year.Just in the past six weeks the healthcare stock has rocketed more than 53%.The analysts at the Elvest Fund are fans, and explained what's going on."Neuren Pharmaceuticals, a leading pharmaceutical company focused on neurodevelopmental disorders, rallied following the release of better than expected quarterly sales results," read their memo to clients."Neuren receives royalty and milestone payments from Nasdaq-listed Acadia Pharmaceuticals Inc (NASDAQ: ACAD) on its Daybue product, the world's first and only approved therapy for Rett Syndrome."But after such a fruitful year, is there much more to come for investors who buy now?Cash reserves, royalty income, development workThe Elvest team is backing Neuren and its pipeline for further gains."The company is currently conducting phase 2 trials of its second drug candidate, NNZ-2591, for a range of disorders," read the memo see ."Phase 2 top-line results are due in December 2023 for the first of these, Phelan McDermid syndrome (PMS)."While many early stage pharmaceutical and biotechnology companies burn cash like there's no tomorrow, the analysts like that this ASX 200 company has both an income stream and development work."With cash reserves of $230 million, a steady stream of high margin royalty income and a promising pipeline of 'orphan drug' designated therapies, Neuren is swiftly emerging as a high quality ASX-listed pharmaceutical."Orphan drug designation provides incentives to encourage development of therapies for rare and serious diseases."Last month Bell Potter also expressed its bullishness for Neuren Pharmaceuticals because of the cash cow that is Daybue."Daybue's implied 4Q23 annualised sales is US$336 million at the guidance midpoint, which all but guarantees NEU will receive the first US$50m sales milestone in CY24."We forecast CY24e DAYBUE sales of ~US$460 million which would result in Neuren receiving US$50 million in royalties plus the US$50 million sales milestone."All five analysts surveyed on CMC Invest currently rate Neuren Pharmaceuticals shares as a buy.o