The company says that people who received 18 months of infusions with its drug, Gammagard, fared no better than others given infusions of a dummy solution.

Gammagard is immune globulin, natural antibodies culled from donated blood. Researchers thought these antibodies might help remove amyloid, the sticky plaque that clogs patients' brains, sapping memory and ability to think.

Patients with moderate disease and those with a gene that raises risk of Alzheimer's who were taking the higher of two doses in the study seemed to benefit, although the study was not big enough to say for sure.

"The study missed its primary endpoints, however we remain interested by the prespecified sub-group analyses" in groups that seemed to benefit, Ludwig Hantson, president of Baxter's BioScience business, said in a statement.

Gammagard is already sold to treat some blood disorders, and the results of the Alzheimer's study do not affect those uses. About 35 million people worldwide have dementia, and Alzheimer's is the most common type. In the U.S., about 5 million have Alzheimer's. Current medicines such as Aricept and Namenda just temporarily ease symptoms. There is no known cure.

Excitement about Gammagard grew last summer, when researchers reported at a medical conference that the drug had stabilized Alzheimer's disease for as much as three years in four patients who had been receiving the highest dose of it for three years in the study. People typically go from diagnosis to death in about eight years, so to be stable for so long was considered remarkable.

The new results on the full group of study participants are disappointing, said the study's leader, Dr. Norman Relkin, head of a memory disorders program at New York-Presbyterian Hospital/Weill Cornell Medical Center.

"The bar was set very high" for the drug to show improvement, and "there does appear to be a signal" that it helped the two-thirds of patients in the study who had the apoE4 gene that raises the risk of developing Alzheimer's, as well as those with moderate versus mild disease, Relkin said.

No new side effects were seen in the study. About 5 percent of patients on the drug had a rash and decreases in hemoglobin, which carries oxygen in the blood. There were 17 serious reactions, 12 in the drug group and five in the placebo group.

Full results will be presented in July at an Alzheimer's conference in Boston.

Meanwhile, other studies are under way to test drugs earlier in the course of the disease. An experimental drug, Eli Lilly & Co.'s solanezumab, showed some promise in that setting in an earlier study.

Shares of Baxter fell $2.53, or 3.6 percent, to $67.78 in morning trading.

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Marilynn Marchione can be followed at http://twitter.com/MMarchioneAP

Klum will be the fourth judge on the talent show created by British entertainment mogul Simon Cowell. She joins comedian Howie Mandel, radio "shock jock" Howard Stern and former Spice Girl Mel B on the show hosted by Nick Cannon.

"Excited 2 join @HowardStern @howiemandel @OfficialMelB & @NickCannon on @nbcagt as new judge! Will be so fun," Klum tweeted.

Broadcaster NBC said Klum, 39, adds a discerning taste to the jury panel.

"As we look to develop an act that will get the world's attention, we and the contestants will benefit from Heidi's international sensibility and understanding of what works in today's global entertainment industry," NBC president of alternative programming, Paul Telegdy, said in a statement.

NBC said last month that Mel B would replace Sharon Osbourne, who quit the show after her son Jack was dropped from another reality show by the network.

German-born Klum was due to join the other judges for the nationwide auditions set to start on Monday in New Orleans. The show is open to singers, dancer, magicians and other performers with a top prize of $1 million.

NBC is betting that Klum and Mel B will boost falling audiences for the summer show, which experienced record low numbers during the finale in September with less than 11 million viewers.

Klum is also the host on Bravo's fashion-design competition "Project Runway" as well as model competition "Germany's Next Top Model" in her native country.

Bravo is a division of NBCUniversal, which is owned by Comcast Corp.

(Reporting by Patricia Reaney; Editing by Eric Kelsey and Mohammad Zargham)

(Reuters) - The U.S. government filed court documents Tuesday laying out its case against cyclist Lance Armstrong, who is accused of defrauding the Postal Service by taking millions of dollars in sponsorship money while flouting professional cycling rules by doping.

The U.S. Department of Justice said in February it would join a whistleblower lawsuit brought in 2010 by Armstrong's former teammate, Floyd Landis, and on Tuesday filed its formal complaint.

Armstrong has been stripped of his seven Tour de France titles and was banned for life from cycling in 2012 after accusations he had cheated for years. In January, he said the accusations were true in an interview with television host Oprah Winfrey.

Armstrong and his teammates from Tailwind Sports were paid $40 million by the Postal Service from 1998 to 2004, according to the suit. Armstrong's salary during that time, excluding bonuses, was $17.9 million, according to the complaint.

The government is suing under the False Claims Act and can recoup up to three times the amount it lost as a result of the fraud. The complaint also alleges breach of contract, unjust enrichment and fraud.

An attorney for Armstrong said the complaint was opportunistic and insincere.

"The U.S. Postal Service benefited tremendously from its sponsorship of the cycling team. The USPS was never the victim of fraud," said attorney Elliot Peters in a statement. "Lance Armstrong rode his heart out for the USPS team, and gave the brand tremendous exposure during the sponsorship years."

The complaint echoes Landis' claims that Armstrong and others defrauded the U.S. government by falsely denying the doping accusations and continuing their sponsorship relationship with the Postal Service.

When the government believes a suit has merit, it may take over the litigation. The individuals, or whistleblowers, get a portion of the proceeds if the case is successful.

The U.S. complaint accuses Armstrong of using at least one prohibited substance or method in connection with every Tour de France between 1999 and 2005. "Moreover, he knew that his teammates were engaged in similar doping practices, and he actively encouraged and facilitated those practices," the complaint said.

"(T)he United Stated suffered damage in that it did not receive the value of the services for which it bargained," the complaint said.

A lawyer for Landis, Paul Scott, said in statement that he was "pleased to see the United States take this important step toward recovering taxpayer dollars lost to fraud."

The case is U.S. ex rel Landis v. Tailwind Sports Corp, U.S. District Court for the District of Columbia, No. 10-976.

(Reporting by Jessica Dye in New York; Additional reporting by Mark Hosenball; Editing by Lisa Shumaker)

PITTSBURGH (AP) -- THE CHANGE: The U.S. Environmental Protection Agency recently dramatically lowered its estimates of how much of a potent greenhouse gas leaks during gas drilling operations, from 214 million metric tons for 2010 to 144 million metric tons, a change of more than 30 percent.

THE DISPUTE: There's a split between leading environmental groups over whether the boom in natural gas drilling, or fracking, will help or hurt efforts to fight climate change. That's because while natural gas is a far cleaner burning fuel than coal, the methane in the gas is also a potent greenhouse gas. If too much methane leaks into the atmosphere, that negates the benefits over coal.

THE REACTION: Environmentalist Michael Shellenberger said the EPA revisions are "great news" and "kind of an earthquake." But 350.org founder Bill McKibben said the news doesn't change the fact that natural gas is still a fossil fuel that emits some greenhouse gas.

Tommy Haas won ugly, becoming the oldest man to beat a No. 1-ranked player in 30 years.

Eight days shy of his 35th birthday, tour veteran Haas defeated three-time champion Novak Djokovic in the fourth round of the Sony Open, 6-2, 6-4. The upset Tuesday night snapped Djokovic's 14-match winning streak at Key Biscayne, where he won the tournament the past two years.

"This is crazy," Haas said. "Playing against someone like Novak and coming out on top at this time of my career, it's unbelievable."

As for Haas' outfit: "Yeah, I'm pretty pathetic I think when it comes to color matching," he said. "Sometimes I look at myself in the mirror before I go out and I'm like, 'Geez, what was I thinking?' I guess if I maybe had a clothing contract it would be different."

The top-ranked Djokovic has lost two of his past four matches after winning 22 in a row, including the Australian Open for his sixth Grand Slam title.

"All the credit to Tommy," Djokovic said. "He played a great match and he was the better player, no question about it."

Haas improved to 2-14 against No. 1-ranked players. His only other win came against Andre Agassi in 1999.

The oldest player in the top 50, Haas is making his 13th appearance at Key Biscayne and advanced the tournament's quarterfinals for the first time. His opponent Wednesday will be No. 11 Gilles Simon, who rallied past No. 7 Janko Tipsarevic, 5-7, 6-2, 6-2.

Sam Querrey lasted only 50 minutes in the fourth round and lost to Tomas Berdych, 6-1, 6-1. Querrey was playing his first tournament as the No. 1 American on the ATP Tour, and his elimination means that for the first time, the 28-year-old tournament will have no U.S. men in the quarterfinals.

The shutout is the latest sign of declining fortunes for American tennis.

"I guess you could say it's been somewhat of the norm the last couple of years," Querrey said. "It's not like we had guys in the quarters week in, week out."

American results on the women's side have been better lately, thanks mostly to No. 1-ranked Serena Williams. The five-time Key Biscayne champion advanced to Thursday's semifinals and tied the women's record for career victories in the tournament by beating No. 5-seeded Li Na 6-3, 7-6 (5).

Williams' opponent in the semifinals Thursday will be defending champion Agnieszka Radwanska, who hit a desperation shot behind her back for a winner en route to a win over No. 30 Kirsten Flipkens, 4-6, 6-4, 6-2.

With temperatures in the 50s for the final match of the night, Djokovic appeared out of sorts from the start. During his second service game he became annoyed at fans shouting as he was about to serve.

"It's definitely the worst match I have played in a long time," Djokovic said. "I just didn't feel good on the court. Conditions were really much, much different from what I have played in previous matches. Balls didn't bounce at all. He has a quite flat shots. He used the variety really well. It was very cold, and I just didn't find a better solution to come back."

Djokovic hit consecutive forehand errors to lose serve and fall behind 3-2, the start of a stretch where Haas won six consecutive games. The German hit three spectacular winners to break again for a 5-2 lead, and Djokovic double-faulted to lose serve once more in the opening game of the second set.

Djokovic broke for the only time to reach 3-all, but lost his serve again. Haas closed out the victory with a forehand winner, then shared a warm exchange at the net with a gracious Djokovic, who gave the crowd a wave as he left the court.

Haas didn't look his age from the start, and not just because he played with his cap on backward. He played patiently from the baseline, mixing the pace of his shots to win a succession of long rallies, and he repeatedly whacked winners when Djokovic tried to force the issue by coming forward.

"I'm just really happy and proud that tonight, against such a great player who has been dominating the sport the past couple of years, I really took advantage of the opportunities I got," Haas said. "I think I played extremely well."

While Williams continues to dominate the WTA Tour, no American man has reached the past five Grand Slam quarterfinals. The outlook wasn't helped by the retirement of Andy Roddick, whose 2003 U.S. Open championship is the most recent major title by a U.S. male.

Querrey was playing his first tournament as the top American, and he managed his best showing in eight appearances at Key Biscayne, aided by a walkover in the third round.

His serve and forehand let him down against Berdych, however. The 6-foot-6 Querrey came into tournament second on the tour in aces this year, but he had only four against Berdych, and made only 39 percent of his first serves.

"Just one of those awful days," Querrey said. "The more you miss, the harder it gets to get the ball in. It just kept getting worse."

No. 2 Andy Murray, the champion in 2009 and runner-up last year, beat No. 16 Andreas Seppi 6-2, 6-4. His opponent Wednesday will be No. 9 Marin Cilic, who defeated No. 6 Jo-Wilfried Tsonga 7-5, 7-6 (4).

No. 8 Richard Gasquet hit 17 aces, including three in the final tiebreaker, defeated No. 10 Nicolas Almagro 6-7 (3), 7-5, 7-6 (3). Gasquet will next face No. 4 Berdych.

No. 3 David Ferrer beat No. 13 Kei Nishikori 6-4, 6-2. Ferrer's opponent Wednesday will be unseeded Jurgen Melzer, who rallied past Albert Ramos, 2-6, 6-3, 6-3.

The company said on Tuesday it earned $2.75 billion, or 38 cents per share, in the first quarter. That compared with $1.79 billion, or 24 cents per share, in the year-earlier period, when Pfizer took charges to boost productivity and address legal matters.

Excluding special items, Pfizer earned 54 cents per share. Analysts, on average, expected 55 cents per share.

Global revenue fell 9 percent to $13.5 billion, below Wall Street expectations of $13.99 billion, hurt by wholesaler purchasing patterns that led to lower demand for its Prevnar vaccines against pneumococcal bacteria.

Pfizer expects full-year 2013 earnings of $2.14 to $2.24 per share, down from its previous forecast of $2.20 to $2.30. It noted that the falling Japanese yen was hurting company sales in that important market.

The stock dropped nearly 5 percent to $29.01 in premarket trading.

(Reporting by Ransdell Pierson; Editing by Lisa Von Ahn and Jeffrey Benkoe)

"Who knew, right?" Psy said as he was presented his Tribeca Disruptive Innovation Award. "Giving me this award in itself is innovation, I think."

Referring to his sudden worldwide fame both on and off the Internet, where his videos have racked up more than one billion views on YouTube, Psy said, "I still cannot believe what happened right now."

"I'm still figuring out the reason for this happening like this," he said, noting that he had been working in music in his native South Korea for over a decade.

The Disruptive Innovation Awards honor those whose ideas have broken the mold to create significant impact.

"In our fourth installment, we are exploring the ever-increasing gap between the rate of technological change and the bumpier, slower-moving cultural adoption and diffusion," said Craig Hatkoff, a festival co-founder and the awards' chief curator.

Wearing a black suit and stylish white dress shirt, Psy, known for his megahit "Gangnam Style" as well as his energetic and flamboyant performances, charmed the audience with self-effacing remarks offered in rather halting English.

"I don't want to say this but, it's kind of embarrassing, but ... maybe, am I handsome?" The audience expressed its approval with cheers and applause.

The awards were presented at New York University, marking a homecoming of sorts for Psy, whose real name is Park Jae-sang.

"I applied to this school in 1996, but I failed. What a success," he said. "Finally, I entered this building this morning."

Other recipients of the Disruptive Innovation Awards included Beck, a conservative television and radio commentator, fashion designer Norma Kamali, Chobani yogurt mogul Hamdi Ulukaya, music and film entrepreneur Peter Shapiro and Forbes Media, in addition to Tharp who received a lifetime achievement award.

(Reporting by Chris Michaud, Editing by Jill Serjeant and Paul Simao)

The TV says Prime Minister Wael al-Halqi was unhurt in the attack in the capital's western neighbourhood of Mazzeh. The TV said Monday's bombing left a number of casualties.

The attack was not the first targeting a high official in the Syrian capital.

On July 18, a blast at the Syrian national security building in Damascus during a meeting of Cabinet ministers killed the defence minister and his deputy, who was President Bashar Assad's brother-in-law. That attack also wounded the interior minister.

PHOENIX (AP) -- Efforts to allow immigrants without legal status to pay lower tuition rates have pitted Arizona Attorney General Tom Horne against higher education leaders.

The Maricopa County Community College District decided Tuesday to uphold a new policy allowing young immigrants participating in the Obama administration's deferred deportation program to pay in-state tuition rates despite warnings from Horne that it violates state law.

"Our position is the same, and that is that we are obeying the law," district spokesman Tom Gariepy said in a phone interview. "We feel pretty confident that our interpretation of the law is correct."

A spokeswoman for Horne said Wednesday he has not made a decision to legally challenge the district's policy at this time, but could move forward as soon as Thursday.

Meanwhile, the Arizona Board of Regents has directed its legal staff to find a way to lower tuition rates for these students without violating state law. A proposal is expected in June. The regents have not reached out to Horne's office for legal guidelines, spokeswoman Sarah Harper said.

"They would definitely be making sure that any options would be within the perimeters of the law," Harper said.

Under state law, immigrants without lawful status do not qualify for public benefits, including in-state tuition rates. But the law doesn't define what constitutes a legal resident.

Gov. Jan Brewer has said youth in the Obama administration program do not have lawful status. Immigrants protected under the new Obama policy must be younger than 30 and must have come to the U.S. before they turned 16. Roughly 80,000 immigrants in Arizona are eligible, according to state estimates.

The Maricopa County Community College District adopted its reduced tuition program in September. Gariepy would not say whether the school is prepared to defend its policy in court.

"We would cross that bridge when we come to it," he said.

At least 13 states allow immigrants who have lived in the country for many years without legal status to pay in-state tuition.