NEW YORK (AP) -- Shares of Dynavax Technologies Corp. tumbled Wednesday after the company reported a setback in a late-stage trial of its hepatitis B vaccine Heplisav.Dynavax said Heplisav worked better than an older vaccine, GlaxoSmithKline's Engerix-B. However the vaccine did not meet one of its "consistency" goals, which measures the stability of the vaccine over time. The company said one production lot of Heplisav had a higher concentration of antibodies than the other two lots after eight weeks. Later in the study, all three lots had similar consistency.The stock lost 59 cents, or 18.7 percent, to $2.57 in afternoon trading.Wedbush analyst Duane Nash said the consistency problem should be solvable, but he said investors may be unsettled until the Food and Drug Administration offers its response to Dynavax's study data.In the trial, 2,449 health adults were given either Heplisav or Engerix-B. The patients who received Heplisav received one dose at the start of the trial and another one month later, while the Engerix-B patients received a third dose six months after the start of the trial. Dynavax said the Heplisav patients had a 90 percent seroprotection rate eight weeks after their last dose. That was better than the 70 percent protection rate for the Engerix-B patients.The Berkeley, Calif., company also reported a smaller second-quarter loss as its revenue climbed and costs decreased. Dynavax said it lost $10.6 million, or 9 cents per share. A year ago the company lost $28 million, or 34 cents per share, as it wrote down $11 million in costs related to a stock offering. Its revenue rose to $7.3 million from $2.2 million after it received a $6 million payment from partner GlaxoSmithKline PLC.Analysts expected the company to post a loss of 11 cents per share and $3.5 million in revenue, according to FactSet.Dynavax's revenue from collaborations rose to $6.4 million from $1.3 million a year ago. Most of that revenue came from GlaxoSmithKline, its partner on a potential lupus drug. Dynavax started an early-stage study of the drug candidate, called DV1179, in April.The company received $18.7 million from investment fund Aspire Capital, which bought more stock in Dynavax during the quarter.