** India's Apollo Hospitals APLH.NS climbs 4% to 7,539 rupees
** Hospital chain operator says it will spin-off and separately list its digital health and pharmacy unit within 18 to 21 months
** Analysts say demerger of the business unlocks value for existing investors
** Transaction enables APLH's shareholders to gain a direct shareholding in India's top omnichannel pharmacy chain, Macquarie says
** APLH has set "aggressive" revenue and EBITDA targets for the demerged entity, says Morgan Stanley
** If the new entity is able to meet these targets, it would generate value for shareholders - Morgan Stanley
** Session's gains erase stock's YTD losses
(Reporting by Kashish Tandon in Bengaluru)
((Kashish.tandon@thomsonreuters.com))