NEW YORK (TheStreet) -- Shares of Medivation (MDVN) were jumping 19.77% to $80.43 on heavy trading volume Monday morning after Pfizer (PFE) said it would acquire the drug maker for $14 billion.

"I think it's very healthy for the group, which has been as we know a very tough group to own," TheStreet's Jim Cramer said of biopharma stocks on CNBC's "Squawk on the Street" this morning.

"This company has one drug that's $2 billion," Cramer noted, referring to Medivation's prostate-cancer drug Xtandi, which generates about $2 billion in yearly sales.

"Pfizer needs an anti-cancer franchise to be able to extend what is a pretty good book of business," Cramer added.

Medivation has "a major cancer franchise that I think gets slotted right into Pfizer, which needs growth," Cramer commented.

"I think this is all about the old days when you saw these companies that really developed drugs and once they got to the point where the drugs were working, companies come in and buy them," Cramer stated.

In April, Sanofi (SNY) offered to pay $9.3 billion to purchase Medivation, then raised its bid to $10 billion in July.

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"Sanofi, we thought they had locked it up," Cramer said, "But does it matter? Sanofi has a war chest. They're going to do something."

About 26.42 million of Medivation's shares traded so far today vs. its average volume of 1.67 million shares per day.

Shares of Pfizer were edging up in mid-morning trading today.

Separately, TheStreet Ratings Team has a "Hold" rating with a score of C on Medivation stock.

The primary factors that have impacted the rating are mixed. The company's strengths can be seen in multiple areas, such as its solid stock price performance, robust revenue growth and largely solid financial position with reasonable debt levels by most measures.

But the team also finds weaknesses including feeble growth in the company's earnings per share, deteriorating net income and disappointing return on equity.

Recently, TheStreet Ratings objectively rated this stock according to its "risk-adjusted" total return prospect over a 12-month investment horizon. Not based on the news in any given day, the rating may differ from Jim Cramer's view or that of this articles's author.

You can view the full analysis from the report here: MDVN

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