Updated from 1:39 p.m. EDT

Shares of

Xoma

(XOMA) - Get Report

were among the worst-performing health and pharmaceutical stocks Tuesday after the company said its acne gel showed inconclusive results.

Xoma said the phase II trial showed no discernable dose response and the vehicle response was higher than anticipated. It also said the drug appeared safe and well-tolerated. The company will analyze the data and review the results with dermatology experts, but it does not plan to initiate additional trials with the drug. Shares of Xoma traded down $1.23, or 35.1%, to $2.27.

Quinton Cardiology Systems

(QUIN)

rose after it said that it entered into an agreement to sell

Cardiac Science's

(DFIB)

AED G3-Pro defibrillator. Cardiac Science will manufacture the product and Quinton will sell it under the Burdick brand name to medical offices and hospitals in the U.S. The product will be sold under the CardioVive trade name. Financial terms were not disclosed. Shares of Quinton Cardiology traded up 78 cents, or 10.7%, to $8.06.

Shares of

BriteSmile

(BSML) - Get Report

fell after the company announced the immediate departure of CEO Bruce Fleming. The teeth-whitening systems company said that Tony Pilaro would serve as interim CEO until a full-time replacement is hired. BriteSmile said Fleming's decision to leave the company was based on personal reasons. The company has hired an outside firm to conduct a formal search process for Fleming's replacement. Shares of BriteSmile traded down 71 cents, or 8.3%, to $7.80.

Lifeway Foods

(LWAY) - Get Report

fell after it reported weaker-than-expected second-quarter earnings and sales. The manufacturer of health food products earned 5 cents a share during the second quarter on sales of $4 million. The lone analyst following the company expected earnings of 8 cents a share on sales of $4.2 million. Lifeway said earnings were impacted by a more than 100% increase in milk prices. Shares of Lifeway Foods traded down $1.90, or 17.4%, to $9.05.

Other health care volume movers included

Pfizer

(PFE) - Get Report

, down 2 cents to $31.38;

Teva Pharmaceutical

(TEVA) - Get Report

, up 11 cents to $27.50;

Amgen

(AMGN) - Get Report

, up 21 cents to $55.98;

Johnson & Johnson

(JNJ) - Get Report

, up 45 cents to $56.54;

Elan

(ELN)

, down 54 cents to $20.57; and

Schering-Plough

(SGP)

, down 13 cents to $18.03.