Genentech( DNA) and Biogen Idec (BIIB) - Get Report both fell after the Food and Drug Administration warned doctors of a serious side effect of their drug Rituxan. The letter informed doctors that two patients taking the drug for lupus died from a rare brain disease. Genentech's shares were down 18 cents to $80.78 after a more dramatic drop earlier in the day, while Biogen Idec's shares sank $1.33 to $48.90.

Memory Pharmaceuticals

( MEMY) fell 17 cents, or 7%, to $2.27 after the company said it sold shares in the second installment of a previously announced private placement. The latest sale generated proceeds of $5.5 million for the company.

GenVec

(GNVC)

jumped 36% after the company announced positive early results from a trial on its proposed pancreatic cancer drug. Preliminary trial results showed that overall survival rates more than doubled when GenVec's drug, TNFerade, was added to a standard treatment for the disease. The company says that after one year, the survival rate was 70.5% in the group receiving the drug vs. 28% in the group receiving standard care alone. The stock most recently traded at $2.55, up 69 cents.

Geron

(GERN) - Get Report

says one of its experimental drugs may benefit breast cancer patients undergoing radiation. Early trial results showed that the drug GRN163L helped sensitize patients to radiation as a part of cancer therapy. Shares were up 20 cents, or 2.2%, to $9.

Among other health stocks winners on Tuesday were

Polydex Pharmaceuticals

(POLXF)

, gaining 4.4% to $6.85;

Keryx Biopharmaceuticals

(KERX) - Get Report

, rising 6.2% to $14.51;

SkyePharma

( SKYE), 1.3% higher to $4.81;

SuperGen

( SUPG), up 3.7% to $5.05; and

Neurogen

(NRGN)

, gaining 4.6% to $5.98.

Among the losers were

AstraZeneca

(AZN) - Get Report

, down 3.3% to $53.76;

BioCryst Pharmaceuticals

(BCRX) - Get Report

, off 1.3% to $12.02;

Abraxis Bioscience

( ABBI), falling 3.2% to $28.32;

Par Pharmaceutical

( PRX) 2% lower to $20.70; and

Cardiome Pharma

(CRME)

, down 5.1% to $10.95.