Drugmaker Shire Plc. may be close to clinching a much sought-after merger with U.S. based Baxalta Inc. in a cash and stock deal valued at $32 billion, excluding debt, Bloomberg reported Saturday, citing sources. The two drugmakers may announce a deal as soon as this week, the report added.

While final details of the deal are still being negotiated, the new offer by Shire could value Baxalta at $46.50 to $48 per share, two sources told Bloomberg. An agreement would successfully end Shire's six-month pursuit of Baxalta.

Baxalta had turned down Shire’s initial all-stock offer in July valued at $30.6 billion -- based on Shire’s stock price at the time -- as the offer excluded any cash payment. Shire said at the time that an all-stock transaction would keep the merger tax-free and offered to buy back shares after the merger to return some cash to Baxalta shareholders.

In December, Reuters reported that Shire’s deal makers had added enough cash to its previous bid for talks to advance, citing sources close to the matter.

If a deal succeeds, the combined company would generate $20 billion in sales by 2020, according to Shire. The drug maker has focused on buying pharmaceutical companies which make treatments for rare diseases. Shire acquired Dyax Inc. for $5.9 billion in November and NPS Pharmaceuticals Inc. for $5 billion in February last year.

Deerfield, Illinois-based Baxalta -- spun off from Baxter International Inc. in July -- produces biotech treatments for rare blood conditions, cancers and immune system disorders. Rare disease treatments and the companies that make them have seen a high amount of interest from investors due to their potential to create high-priced products as well as market exclusivity along with tax breaks offered by regulators.

Baxalta could also enjoy a lower tax rate if it is taken over by Dublin-based Shire. The U.S. drugmaker projected a tax rate of 23 percent in 2016, but a merger would yield an effective tax rate of 16 percent to 17 percent, Shire said.

Irish companies pay taxes at a rate of about 12.5 percent, while the U.S., at almost 40 percent in some states, has the highest corporate tax rate of any industrialized country.