Blackstone Group LP has emerged as the frontrunner in the auction for Allscripts Healthcare Solutions Inc , but the two sides remain far apart on valuation and a deal is highly uncertain, people familiar with the matter said.

The New York-based buyout firm has prevailed over rival private equity suitors Carlyle Group LP and TPG Capital LP in the race to buy Allscripts, the healthcare technology company with a market value of $2.1 billion, three people said this week.

Although still in the running, Blackstone remains skeptical about the prospects of a deal given the high premium sought by Allscripts and other challenges facing the company, the people said.

Sources told Reuters earlier this month that Blackstone, Carlyle and TPG made second-round bids for Allscripts, after the company reported third-quarter earnings.

The people asked not to be identified because the matter is not public. Allscripts, TPG, Blackstone and Carlyle declined to comment.

(Reporting by Soyoung Kim and Greg Roumeliotis in New York; editing by Matthew Lewis)