AstraZeneca has approached its rival Gilead Sciences about a potential merger, Bloomberg News reported on Sunday.
Any merger, which would be the biggest healthcare deal on record, would bring together two of the companies leading the pharmaceutical industryâ€™s efforts to develop a vaccine and treatments for Covid-19.
A combination of the two would be valued at about Â£200bn. AstraZeneca, which is valued at Â£110bn, recently overtook Royal Dutch Shell to become the UKâ€™s largest company by market value. Gilead was valued at about $96bn (Â£74bn) at Friday nightâ€™s closing price.
A spokeswoman for AstraZeneca said the company did comment on rumours or speculation. Gilead did not immediately respond to a request for comment.
The two firms and several other drugmakers, including Eli Lilly, Pfizer and Merck, are racing to develop a vaccine and treatments for Covid-19.
More than 6.9 million people are reported to have been infected with the coronavirus globally and 399,025 have died, a Reuters tally showed on Sunday.
Bloomberg said Gilead had discussed the merger idea with advisers, but that no decision had been made on how to proceed and the companies were not in formal talks. Gilead was not interested in selling to or merging with another big pharmaceutical company, and preferred to focus on partnerships and smaller acquisitions, the report said.
AstraZeneca said last week that it had doubled manufacturing capacity for its potential coronavirus vaccine to 2bn doses in two deals involving the Microsoft billionaire Bill Gates that guaranteed early supply to lower income countries.
It is unclear if the vaccine will work, but AstraZenecaâ€™s partnership with Oxford University to develop one is among a handful of initiatives backed by Donald Trumpâ€™s Covid taskforce.
Gilead has also been at the forefront. Its remdesivir antiviral drug is the first to lead to improvement in Covid-19 patients in formal clinical trials.