Updated from 2:37 p.m. EDT with new stock prices

Biotech stocks hit a high for the week as investors applauded an acquisition and showed the same enthusiasm that graced the broader markets.

The Amex biotechnology index surged 35.83, or 4.8%, to 780.83, with some notable support from component

Millennium Pharmaceuticals

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( MLNM), which rose nearly 50%.

Millennium Pharmaceuticals said Thursday that it will be acquired by Japan's largest drugmaker, Takeda Pharmaceuticals, in

a deal worth $8.8 billion

-- the largest overseas acquisition by a Japanese drugmaker to date. Takeda is paying $25 a share, or a 53% premium to Millennium's closing price of $16.35 a share on Wednesday. Shares rose $7.99, or 48.9%, to $24.34.

Other stocks helping the BTK were

Amgen

(AMGN) - Get Report

, up 5.8%, and

OSI Pharmaceuticals

( OSIP), up 5%.

Bellwether biotechs

Biogen

(BIIB) - Get Report

and

Celgene

(CELG) - Get Report

each cleared more than 2.6% on Thursday.

Pharma stocks were also green, particularly

Wyeth

( WYE) and

Bristol-Myers Squibb

(BMY) - Get Report

, which added 4.2% and 2.7%, respectively.

In a follow-up to previous day's news,

MannKind

(MNKD) - Get Report

responded to the inhaled insulin drama that arose Wednesday when

Pfizer

(PFE) - Get Report

and

Nektar Therapuetics

(NKTR) - Get Report

announced a higher rate of lung cancer found in patients who took Exubera in clinical trials.

"To date with our product, we have seen no adverse effects on the measures of pulmonary function that have been reported to occur with Exubera," the company wrote in the release. "We are working closely with the DSMB and regulatory agencies in order to understand the implications of the Exubera data."

But, given the market sentiment, the company said it will suspend partnership discussions. "At this time, we believe that we will be unable to achieve an appropriate valuation for Technosphere Insulin until phase 3 data are available that confirm our belief in the safety and efficacy of Technosphere Insulin."

MannKind shares nudged up 18 cents, or 7.7%, to $2.53 on Thursday after plummeting nearly 60% on Wednesday. (Nektar shares also edged back up a little -- gaining 12 cents, or 2.2%.)

In Wall Street news, JMP Securities upped its price target for

Vertex Pharmaceuticals

(VRTX) - Get Report

to $30 from $25, and RBC Capital Markets hiked its target for

Gilead

(GILD) - Get Report

to $58 from $50.

Vertex was trading down 20 cents, or 0.8%, at $26.29, while Gilead was up $1.06, or 2.1%, at $52.09.