Pharmaceutical companies have reported strong Q1 growth by their oncology drugs, based on earnings reports from Johnson & Johnson, Bristol-Myers Squibb, Bayer, Novartis and AbbVie.

A report from IQVIA, released this week, found that pharma is investing the most in research and development in oncology, which is proving again to be one of the highest-selling and fastest-growing areas of the business.

Bristol-Myers Squibb’s immunotherapy blockbuster, Opdivo, saw a 19% increase globally in Q1 compared to last year, bringing sales up to $1.8 billion. The company’s other CAR-T cancer therapy, Yervoy also saw a significant increase in sales, jumping 54% to $384 million.

Sales of BMS’s blood thinner, Eliquis, surpassed Opdivo, with $1.9 billion in sales globally, jumping 28%, with an even stronger sales increase of 36% in the U.S. to $1.2 billion.

Bayer’s oncology drugs also reported double-digit sales growth. Its preventive cancer treatment, Stivarga, had the strongest increase at 34.5%, bringing it up to $108 million in sales worldwide. Similar drug Nexavar reported $204 million in sales, an 11.4% increase. Bayer’s best-selling drug is its blood thinner, Xarelto, which reached more than $1 billion in sales in Q1.

Johnson & Johnson reported an overall loss in Q1, partially due to legal expenses. However, half of its oncology drugs saw double-digit increases last quarter, though the oncology unit overall only grew 3% in the U.S. Its immunology group, which includes treatments for autoimmune diseases like Stelara, Remicade and Tremfya, was the biggest earner. The whole franchise brought in nearly $2.2 billion globally in Q1, up 8%.

Another immunology blockbuster, AbbVie’s Humira, had a more difficult Q1. It is AbbVie’s best seller by far, but saw a decline in sales last quarter by 5.6% globally. The drop was even sharper in international markets, where sales fell nearly 28%.

With threats to Humira’s patent looming and generic competition to the drug expected within the next five years, AbbVie is focusing on its other franchises. Its oncology unit, specifically focused on blood cancers, saw strong growth. Sales of its main cancer drug, Imbruvica, increased 33% in the U.S. to $829 million.

Oncology was also the biggest seller for Novartis. Sales from its oncology unit increased slightly in Q1 to $3.3 billion, but several of its top-selling, older cancer drugs, including Tasigna, Sandostatin and Afinitor, reported decreased sales. Novartis’s immunotherapy cancer treatment Kymriah, approved last May, picked up the pace with sales reaching $45 million last quarter.

Merck and Pfizer, which make cancer blockbusters Keytruda and Ibrance, respectively, will report their Q1 earnings next Tuesday.