Humira has been AbbVie's (NYSE:ABBV) main growth driver for many years, but with the rheumatoid arthritis drug facing stiff competition from biosimilars in Europe, many were quick to write AbbVie's obituary.

Because of Humira's declining prospects in international markets, the pharma giant didn't perform well on the stock market last year, with its shares sliding by almost 4%. For context, the pharmaceutical industry -- as measured by the SPDR S&P Pharmaceuticals ETF Index -- was up by almost 25% last year.

However, AbbVie hasn't said its last words yet, and there's likely still some fuel in the company's growth engine, at least if its latest earnings report is any indication. 

AbbVie's fourth-quarter results

On Feb. 7, AbbVie reported its fourth-quarter results, which showed net revenue of $8.7 billion, representing a 4.8% year-over-year increase -- slightly ahead of analyst estimates. Meanwhile, the company's net earnings of $2.8 billion -- and its earnings per share (EPS) of $1.88 -- also came in ahead of consensus estimates. AbbVie reported a net loss of $1.9 billion during the prior-year quarter. As expected, sales of Humira continue to lose steam in international markets.

Doctor giving a thumbs up

Image source: Getty Images.

During the fourth quarter, international sales of Humira were $948 million, representing a 27.3% decline compared to the year-ago period. But the blockbuster drug continues to perform well domestically. U.S. sales of Humira were $3.97 billion, a 9.8% year-over-year increase. Overall, Humira's worldwide sales came in at $4.9 billion and remained flat year over year.

Beyond Humira, some of AbbVie's other products are also performing well. In particular, sales of cancer treatment Imbruvica improved by 28.9% to $1.3 billion. Furthermore, Venclexta -- also a cancer drug -- saw its sales soar by more than 100% year over year to $251 million. AbbVie's oncology lineup performed well overall, recording net sales of $1.5 billion, representing a 37% year-over-year increase. 

Other notable products the company can count on moving forward include moderate to severe plaque psoriasis treatment Skyrizi, which had sales in the fourth quarter of  $216 million, and rheumatoid arthritis drug Rinvoq, with $33 million in sales. AbbVie launched both Skyrizi and Rinvoq last year, and these products could help the company offset Humira's declining international sales.

Management touts Allergan acquisition

AbbVie acquired Allergan (NYSE:AGN) in a cash and stock transaction valued at $63 billion that was announced last year. The move was criticized by many, especially considering the transaction price represented a significant premium over Allergan's share price at the time. However, AbbVie saw an opportunity to decrease its top-line exposure to Humira with Allergan's Botox, a product for which there is unlikely to be many (if any) biosimilars, at least according to AbbVie's CEO Richard Gonzalez.

During the company's fourth-quarter earnings conference call, Gonzalez once again talked about the benefits of AbbVie acquiring Allergan:

Allergan will provide AbbVie with highly valuable on-market assets with leadership positions across additional attractive growth segments, including new growth platforms in aesthetics and CNS neuroscience. The acquisition will further diversify AbbVie's revenue and payer mix, and immediately accelerates the stand-alone scale of our non-HUMIRA business, the AbbVie growth platform, which is expected to drive high-single-digit annual growth revenue over the next decade and beyond.

AbbVie's acquisition of Allergan should close during the first quarter. 

Don't forget about the dividend

As a final incentive to consider buying shares of AbbVie, the company offers investors a juicy dividend yield of 5.4%, and with its annual dividend payout growing by 84% over the past three years, there are likely more dividend increases on the horizon for the pharma giant. And with some of its products still growing in sales and the pending acquisition of Allergan, AbbVie could perform much better this year than it did during 2019.