Gilead Sciences (NASDAQ: GILD) agreed over the weekend to acquire Immunomedics (NASDAQ: IMMU) in a deal worth $21 billion. The drugmaker will pay $15 billion in cash and $6 billion in newly issued debt.

Gilead agreed to pay $88 per share in cash, which is a premium of over 100% given in mind Friday’s closing price of $41.93. Understandably, IMMU stock is up 106% in premarket, trading at $87.20.

The deal, approved by both the Gilead and Immunomedics Boards of Directors, is expected to close before the end of the year.

“The agreement will provide Gilead with TrodelvyTM (sacituzumab govitecan-hziy), a first-in-class Trop-2 directed antibody-drug conjugate (ADC) that was granted accelerated approval by the U.S. Food and Drug Administration (FDA) in April for the treatment of adult patients with metastatic triple-negative breast cancer (mTNBC) who have received at least two prior therapies for metastatic disease,” two companies said in a statement.

The obvious target for Gilead is Trodelvy, which is an FDA-approved treatment for metastatic triple-negative breast cancer.

“This acquisition represents significant progress in Gilead’s work to build a strong and diverse oncology portfolio. Trodelvy is an approved, transformational medicine for a form of cancer that is particularly challenging to treat. We will now continue to explore its potential to treat many other types of cancer, both as a monotherapy and in combination with other treatments,” said Daniel O’Day, Chairman and Chief Executive Officer, Gilead Sciences.

Some analysts were less thrilled than Gilead about the deal. Although positive on what IMMU will add, Baird’s Brian Skorney is “less than thrilled about the price”.

“While Trodelvy looks like a fine product, we think this deal looks more like Kite than Pharmasset and see it being an uphill climb to reach a positive ROI,” writes Skorney in a note to clients.

Skorney reminds that Gilead management said it has around $40 billion available to conduct major acquisitions, prior to IMMU transaction. Therefore, there is around $20 billion left to execute bigger deals going forward.

“We note that management reiterated their commitment to maintaining and growing the dividend, however, we can not help but imagine that a miss on a transaction this large wouldn't have a negative impact on the company's long-term capacity to execute buybacks”.

Skorney reiteretes a “Neutral” rating on GILD with a price target of $70 per share.

Similarly, Raymond James’ analyst Steven Seedhouse is less worried about the price and more about Gilead’s remdesivir sales.

“This feels like a good move, offering something to believe in for GILD, which was lacking,” he said in today’s note to clients.

“Our positive view of the deal is not enough for us to upgrade the stock though, since the implied >$3B remdesivir sales baked into 2020 guidance looks improbable, particularly since health systems are already declining a quarter of remdesivir allocations and hospitals only purchasing 2/3rds of that, and generally not using in moderate cases despite recent EUA expansion”.

Seedhouse maintains a “Market Perform” rating on GILD.