Fourth-quarter revenue for Amgen (NASDAQ:AMGN) slipped 1% year over year to $6.2 billion as the company faced competition from biosimilar and generic competition for its older medications. Adjusted earnings per share increased 6% year over year, boosted by the company's repurchase of 40.2 million shares for $7.6 billion during 2019.

Sales of Parsabiv, which helps patients on hemodialysis, jumped 49% year over year. Cholesterol-lowering Repatha saw sales increase 26% year over year as Amgen parlayed data from an outcomes study showing the drug reduces cardiovascular events. Sales of osteoporosis treatment Prolia and immune thrombocytopenia treatment Nplate both increased 15% year over year. Psoriasis and psoriatic arthritis treatment Otezla, which Amgen acquired to facilitate Bristol-Myers Squibb's (NYSE:BMY) closing of its deal with Celgene, added $178 million in revenue during the five weeks or so that Amgen owned the drug during the quarter.

Doctor talking to a patient

Image source: Getty Images.

While Amgen fights biosimilars to its branded drugs, it's also launching biosimilars of its own, including Avsola, a biosimilar to Johnson & Johnson's (NYSE:JNJ) Remicade that gained Food and Drug Administration approval in December. The drugmaker also has a biosimilar to Biogen's (NASDAQ:BIIB) and Roche's (OTC:RHHBY) Rituxan that was submitted to the FDA in December.

Management guided for 2020 revenue of $25.0 billion to $25.6 billion, up 8.2% at the midpoint. Adjusted earnings per share are expected to fall in the $14.85 to $15.60 range, higher than the $14.82 Amgen recorded last year, but up just 2.7% at the midpoint, suggesting that the company plans to increase spending faster than revenue this year.