WASHINGTON (AP) - A federal appeals court Tuesday reversed a lower-court ruling that would have provided an experimental drug to a Minnesota teen suffering from a rare, fatal form of muscular dystrophy.

The U.S. Court of Appeals for the 3rd Circuit in Philadelphia dealt a blow to 17-year-old Jacob Gunvalson, who is afflicted with Duchenne muscular dystrophy.

The court ruled that U.S. District Judge Hon. William Martini in Newark erred in his August ruling that PTC Therapeutics of South Plainfield, N.J., must provide the drug to Gunvalson. That decision had been stayed pending the company's appeal.

"I just think it's really unfair that these drug companies get all these benefits from the federal government," said Jacob's mother, Cheri Gunvalson. "And then they're allowing boys to fall through the cracks and die." She said she would not give up her fight, but was uncertain what the next step would be.

In its ruling, the appeals court said it was "sympathetic to the plight of Jacob and his family. Similarly, we are moved by the Gunvalsons' heroic efforts on behalf of their son and others afflicted with this devastating disease." But the court said it was limited by the law.

The ruling said that the lower court "abused its discretion" in ordering PTC to supply the drug to Gunvalson. The Gunvalsons, who live in Gonvick, Minn., about 220 miles northwest of Minneapolis, maintained that the company led them to believe that Jacob could participate in a clinical trial of the drug, which is being investigated as a possible treatment - and that the company then went back on its word.

The company countered that no promises were made, and that allowing Jacob to join the clinical trial would not be safe and would set a bad precedent that could hinder research.

In its ruling Tuesday, the appeals court said that comments made by PTC officers "fail as a clear and definite promise" because they didn't promise anything conclusive about Jacob's participation in future trials or his access to PTC124. The appeals court remanded the case back to the district court.

In a statement, PTC president and CEO Stuart Peltz called the ruling "important not just for PTC124 but for the future of the clinical-trial process for all experimental drugs for rare disease.

"We continue to believe our approach to the development of PTC124 is in the best interests of all boys suffering from this rare disease," the statement continued. "The sooner we can complete the required clinical trials and get this drug approved, the sooner all who suffer from the type of Duchenne muscular dystrophy addressed by PTC124 may benefit."

Former Minnesota Attorney General Mike Hatch, who is representing the Gunvalsons at no charge, called the ruling "a surprise, a huge disappointment, a real tragedy."

He said the legal team was weighing its options, including a request for a rehearing or pursuing a trial at the district court level.

"The Court of Appeals really dealt a very bad blow to Jacob's life, and I for the life of me don't understand it," Hatch said. The family had sought a "compassionate use exception," such as a single-patient study.

"What's the point of a compassionate-use exception if companies won't use them?" he asked.

Cheri Gunvalson helped persuade Congress to significantly boost spending to find a cure for the disease. In 2001, she teamed with the late Sen. Paul Wellstone, D-Minn., for passage of the MD CARE Act, which increased federal funding to study the disease. The legislation established several "centers of excellence" - since renamed "Wellstone Centers" - for muscular-dystrophy research.

Typically, those who suffer from Duchenne muscular dystrophy die in their 20s because of weakness in their heart and lung muscles. Gunvalson uses a wheelchair because the disease has left him unable to walk. There is no known cure, but the Gunvalsons believe the experimental drug holds hope.

Cheri Gunvalson said she still hadn't told her son about the ruling.

"I have to figure out what to say to him," she said. "I have to figure out when to do it and how to say it. I'm just a mother who doesn't want to watch her son continually deteriorate."