Mergers and acquisitions have been a hot topic throughout the drug industry lately, as companies face slowing sales and rising costs. In fact, deals worth $128 billion have been announced in the sector so far this year, according to Dealogic. This is the highest total since 2009.

As of late, Pfizer Inc.’s $100 billion bid for AstraZeneca is the largest and most recent in a series of proposed big pharma mergers. Pfizer has a new approach to AstraZeneca PLC regarding a takeover valued at almost $100 billion, but the U.K.-listed pharmaceutical firm declined to discuss further.

“The combination of Pfizer and AstraZeneca could further enhance the ability to create value for shareholders of both companies and bring an expanded portfolio of important treatments to patients,” said Pfizer CEO Ian Reed in a statement.

According to Pfizer, it had originally approached AstraZeneca in early January about a merger of the two companies, but these considerations were dismissed later that month. Pfizer’s previous proposal made to the board of AstraZeneca in January included a combination of cash and shares in the combined entity, which represented a value of 76.62 per AstraZeneca share and a premium of 30 percent to AstraZeneca’s closing share price of GBP35.86 on January 3rd. So, the indicative price would value AstraZeneca at about or $98.68 billion. If a transaction is executed, Pfizer said the resulting company would be incorporated in Britain, but headquartered in New York and listed on the NYSE.

“The deal makes sense because the two companies end up quite a bit stronger,” Seamus Fernandez, manager director for Leerink Partners Equity Research, told USA Today. “But at the existing price, this is clearly not going to happen.”

AstraZeneca said that the latest offer “very significantly undervalued AstraZeneca and its prospects.” The company is undergoing a major research and development re-organization to offset expirations of drug patents. It’s also been reducing costs and attempting to boost productivity of research programs.

“We have great respect for AstraZeneca and its proud heritage as an innovation-driven biopharmaceutical business with a rich science-based foundation in both the United Kingdom and Sweden,” said Reed. “In addition, the United Kingdom has created attractive incentives for companies to manufacture products and maintain and protect intellectual property, and we have seen that capital and jobs have followed these types of incentives.”

Pfizer plans to pursue a bid for AstraZeneca, eyeing a tie-up that would create a pharmaceutical giant and fuel a booming year for merger-and-acquisition activity. A pairing of Pfizer and AstraZeneca would create a company with drugs treating most of the major maladies, including diabetes, heart disease and rheumatoid arthritis.

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