"NPP" code in this case is because the pediatric study was sufficient to qualify as New Clinical Investigation, New Patient Population, which is why it got 3 years exclusivity instead of 6 months (code "PED"). Nonetheless, it is Pediatric Exclusivity, and no, it is not limited to kiddies. But do not lose hope! Maybe IPCI will get lucky, and Purdue will sue. If they can get a quick disposition in court (not entirely impossible given recent Supreme Court inaction), then they would have a successful Paragraph IV patent challenge and thus a FREE PASS around Pediatric Exclusivity (per Hatch-Waxman). Another possibility is approval with a carved-out label like Arymo just got (EGLT down 50% with APPROVAL).
There are entire law firms devoted to this stuff, and they get surprised by the FDA all the time. I know EGLT didn't see it coming. Look it all up for yourself and decide what you think it means. OxyContin has FDA marketing exclusivity until August 13, 2018.