A few larger biotechs dumped their smaller co-developers on Thursday, sending shares into the red, while others had fresh relationships and deals to discuss.

Altus Pharmaceuticals

( ALTU) tumbled $3.94, or 40%, to $5.96 Thursday. After the close on Wednesday, the company said that it's regaining the North American commercialization rights to ALTU-238, a once-weekly IV human growth hormone product that uses its drug delivery technology, from

Genentech

( DNA). Altus said it still plans to resume clinical study of the drug, which is in midstage development, in mid-2008.

Genentech was trading up 68 cents, or 1.01%, at 67.97 on Thursday.

Also on the decline on Thursday,

Array BioPharma

(ARRY) - Get Report

, which delivered disappointing news on Wednesday after the closing bell. Array said that AZD6244, an experimental treatment for advanced melanoma, failed to meet its primary goal in a midstage trial. Subsequently, its co-developer

AstraZeneca

(AZN) - Get Report

has opted not to take the drug to late-stage development. Array slid $3, or 27%, to $8.02, and Astra Zeneca was trading down 38 cents, or 0.9%, to $43.94.

Array is a component of the Nasdaq biotechnology index, which was flat most of the day, up just 0.24, or 0.03%, at 834.78 in recent trading.

Also on the clinical side,

Introgen Therapeutics

(INGN) - Get Report

said it will increase the tissue samples in a late stage study for its Advexin. This drug is for head and neck cancer and the effect of the increase will allow the total data reviewed for biomarker analyses to rise by at least 20%, per recommendation by external clinical and regulatory advisers. The company expects to announce top-line phase III data and file regulatory applications for Advexin for head and neck cancer in the first half of 2008.

Introgen's shares fell $1.08, or 24%, to $3.43.

Meanwhile, smaller-cap cancer-drug company

YM BioSciences

( YMI) crept up 9 cents, or 7.4%, to $1.26. The company said that it completed patient accrual in the first of two 50-patient groups in a midstage study on its nimotuzumab in combination with irinotecan for the treatment of colorectal cancer. The company said the safety profile thus far in the trial is consistent with previous trials of nimotuzumab and there hasn't been any evidence of severe side effects that are frequently seen with similar antibodies and small molecules.

Elsewhere,

Flamel Technologies

(FLML)

rose after announcing a partnership with Merck Serono, a division of German company Merck KGaA to study Flamel's Medusa technology for the extended release of a Merck Serono therapeutic protein. Merck Serono will make an upfront payment of $2.9 million and will fund the research and development. Flamel's shares added 63 cents, or 6.74%, to $9.98 on Thursday.

Finally, an update: after previously announcing it planned to divest hepatitis C drug Infergen,

Valeant Pharmaceuticals

(VRX)

announced on Thursday that it will sell the drug to Three Rivers Pharmaceuticals for about $91.3 million. Three Rivers will receive all U.S. and Canadian rights to Infergen, in the deal which is expected to close in the first quarter of 2008. Valeant's shares were trading down 12 cents, or 1.1%, at $11.19