Heartburn medication Nexium ate up the majority of Medicare Part D’s branded drug spend in 2013, according to the Centers for Medicare and Medicaid Services. The just-released data shows the government spent $2.56 billion to cover 8.19 billion prescriptions of AstraZeneca’s Nexium. GlaxoSmithKline’s respiratory medication Advair Diskus was the second most-prescribed branded medication. It racked up a bill of $2.26 billion. The Washington Post pointed out that although generics make up the bulk of the program’s prescriptions, most of the government’s drug spend goes toward branded drugs.

Nine Republican senators pressed the FDA to finalize all biosimilar guidance in a letter sent to acting FDA Commissioner Dr. Stephen Ostroff, reported BioCentury. The lawmakers, including Sens. Orrin Hatch (R-Utah) and Pat Roberts (R-Kan.), are members of the Senate Committee on Health, Education, Labor and Pensions. The FDA finalized three biosimilar guidance documents earlier this week. The regulator still has to finalize guidance around issues that include interchangeability and naming.

Gilead Sciences’ first-quarter profits just about doubled, with the company reporting $4.3 billion in net income for the first three months of this year. Revenues jumped 52% to $7.6 billion, reported Reuters. The results topped Wall Street expectations, and Gilead’s CEO told investors that the drugmaker is ready to jump into the M&A rush, something it has avoided since buying Pharmasset in 2011.

Pfizer is rumored to be vying to buy the rare-disease drug manufacturer Sobi, Reuters reported. Sobi, also known as the Swedish Orphan Biovitrum, is valued at around $4.3 billion; the firm manufactures the drug substance in Pfizer’s hemophilia treatment ReFacto AF.

The FDA approved GlaxoSmithKline’s Breo Ellipta for adult asthma but the regulator declined to approve it for children. The approval aligned with an earlier advisory panel vote in which members voted 16-4 for adult use but 19-1 against use among younger patients, Reuters reported. The drug was already approved to treat COPD.