Privately owned German drugmaker Boehringer Ingelheim is talking to AbbVie of the US about a partnership in oncology potentially worth billions of dollars, the news agency Bloomberg has reported, citing people familiar with the discussions.

The talks are said to be at an advanced stage with a deal possibly to be announced this week. Neither firm has commented as yet.

Last year, AbbVie took a significant step toward establishing itself as an important player in cancer therapy with its $21 billion acquisition of Pharmacyclics. It beat out competitors such as Johnson & Johnson to gain access to the company's flagship asset, Imbruvica (ibrutinib), which it describes as "a highly effective treatment for hematologic malignancies.”

The US drugmaker also has oncology partnerships with Roche and BristolMyers Squibb for individual cancer drugs.

Boehringer thus far has focused on treatments for lung cancer, marketing its drug Giotrif for non-small cell lung cancer and Vargatef for patients in the advanced stages of the disease, when chemotherapy and other treatments have failed. It is also researching new treatments for lung and intestinal tumors and working on other indications.