New York — On Thursday, Bristol-Myers Squibb significantly raised its full-year earnings forecast, even as first-quarter sales of some medicines fell short of expectations and sent shares of the US pharmaceutical firm down more than 1%.

Sales of immuno-oncology drug Opdivo, by far the company’s most important growth driver, surged 34% to $1.51bn, beating analysts’ estimates of $1.28bn.

"Eliquis and Opdivo were very strong," SunTrust Robinson Humphrey analyst John Boris said, but added: "There was weakness across several of its franchises," noting sales shortfalls of cancer drugs Sprycel for leukaemia and Bristol’s older immunotherapy, Yervoy.

The hepatitis C franchise all but disappeared with sales of just $3m, while Wall Street was looking for about $56m. That stood in sharp contrast to AbbVie’s hepatitis C drugs, which blew past analysts’ forecasts on Thursday.

Bristol-Myers shares were down 1.5% at $50.98, while AbbVie’s were up 4.1% at $95.70, on Thursday.

Excluding special items, Bristol-Myers said it earned 94 US cents per share, topping analysts’ average expectations by 9c, according to Thomson Reuters I/B/E/S.

The company increased its 2018 earnings forecast by well over 9c per share as it now sees a lower than previously anticipated tax rate and reported reduced research and other expenses.

Bristol-Myers now expects 2018 earnings of $3.35 to $3.45 per share, up from its prior view of $3.15 to $3.30 and well ahead of average Wall Street estimates of $3.26 per share. It expects mid-single digit sales growth after previously forecasting low-to mid-single percentage growth.

Sales of Eliquis, the blood clot preventer Bristol shares with Pfizer, jumped 37% to $1.5bn, exceeding analysts’ estimates of $1.34bn.

Yervoy sales dropped 25% to $249m, missing Wall Street estimates by about $32m. It could see a rebound if its use in combination with Opdivo increases. The pairing recently won US approval to treat advanced kidney cancer.

Sprycel sales fell 5% to $438m.

Revenue for the quarter rose 5% to $5.2bn with help from favourable foreign exchange rates, but was about 1% below Wall Street consensus.

The company said net profit for the quarter slipped to $1.5bn, or 91c per share, from $1.52bn, or 94c a share, a year ago.

Helped by the new US tax law, Bristol-Myers projected an effective 2018 tax rate of 17% to 18%, below its previous estimate of about 20%.