The Basel-based firm said its net sales over the last six months had fallen six percent to $24.6 billion, but grew four percent in local currencies.
Novartis, the world's largest pharmaceutical company in tems of sales, said in a statement that its outlook for its core business remained unchanged, with 2015 sales expected to grow in the mid-single digits.
The Swiss firm in March agreed to a massive asset swap with Britain's GlaxoSmithKline, and said Tuesday that implementation of the deal remains on track.
Under the deal GSK acquired Novartis's global human vaccines business while the two firms tied up their global consumer health operation under GSK control.
In return, GSK sold its oncology business to Novartis for $16 billion.
Earlier this month, US authorities launched a court action seeking $3.3 billion in fines from Novartis, on allegations it paid kickbacks to boost drug sales.
The filing notes that Novartis maintains it offered legal rebates to pharmacies it worked with.
"We are committed to creating a culture of integrity at Novartis and demonstrating ethical leadership, and have taken concrete steps to increase transparency and strengthen our ethical business practices," the Swiss firm said on Tuesday.