Health stocks closed the week on a relatively dull note, with light news and a few analyst tweaks.

The Nasdaq and Amex biotechnology indices were off 0.5% and by 0.6%, respectively, slightly worse off than the greater markets.

After the market closed Thursday, activist investor Carl Icahn continued his correspondence with

Bristol-Myers Squibb

(BMY) - Get Bristol-Myers Squibb Company Report

CEO James Cornelius, the latest in their exchange regarding Bristol's rejected $60-a-share bid for

ImClone Systems

(IMCL)

. Icahn, who earlier in the week announced that a new bidder had offered $70 a share, said that should Bristol submit a new offer, he would respond accordingly.

ImClone shares closed down $1.13, or 1.7%, at $65.80, while Bristol traded up 41 cents, or 1.9%, to $22.23.

Elsewhere, Robert W. Baird analyst Thomas Russo upgraded

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Gilead Sciences

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to outperform from neutral, noting that prescription trends suggest an in-line or better quarter shaping up. Also, Deutsche Bank analyst Mark Schoenebaum said in a note this week that the street could be underestimating the company's long-term profit margin potential.

Nonetheless, shares were off by 92 cents, or 1.9%, at $48.12.

A few analyst actions, RBC Capital Markets upped its price target for

Micromet

( MITI) to $8 from $4.50. The stock was up 75 cents, or 14%, at $6.07.

Also Jeffries and Co. upped its target for

Allergan

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to $65 from $59. The stock was off by 79 cents, or 1.3%, at $59.74.