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Alliance Ready for Advanced Tests of 'Liquid Air'

Health: Substance is meant to get oxygen to patients unable to breathe on their own. Final OK is years away.

September 02, 1997|From Reuters

"Liquid air" sounds like a contradiction in terms, but a San Diego-based company has developed just such a substance and believes it could solve the problem of getting oxygen to patients unable to breathe on their own.

Alliance Pharmaceutical Corp. says it is ready to start advanced human trials of its LiquiVent substance, which looks just like water but is rich in oxygen.

The company has already put the substance to the ultimate test in laboratory mice. In one demonstration recorded on video, it submerged a mouse in a container of the clear liquid. The mouse inhaled the water-like substance and lived.

In people, LiquiVent is delivered more gradually, trickled into the lungs of those who need the assistance of a ventilator to breathe. The hope is that LiquiVent can shorten the time patients must remain on ventilators and be more gentle on the lungs than regular oxygen.

Each year, some 700,000 people in the United States go on ventilators for lung damage resulting from pneumonia, inhalation of toxic gases, near-drownings and a condition known as acute respiratory distress syndrome (ARDS), which often strikes infants.

Preliminary tests of LiquiVent on these patients show that, like the mouse, they can absorb the liquid into their lungs.

Although the product shows promise, it must undergo years of further study before reaching the market. Even under a best-case scenario, such a product would normally not receive Food and Drug Administration approval before early next century.

"People often call it liquid oxygen, but that isn't entirely accurate. It is a liquid that carries oxygen," said a spokeswoman for Alliance Pharmaceutical, which is developing LiquiVent in a partnership with Hoechst Marion Roussel, a division of German company Hoechst.

The base component of Liqui-Vent, a chemical known as Perflubron, can dissolve 20 times as much oxygen as water. As it delivers oxygen to the lungs, it also removes carbon dioxide.

Despite LiquiVent's properties, Alliance has had some problems demonstrating that it has clear benefits for all patients. In one recent trial in children with ARDS, those receiving LiquiVent responded similarly to those in the control group, who were not given the substance.

Since most people who go on ventilators are seriously, often critically, ill, a large portion of them die even after receiving oxygen, statistics show. In such patients with multiple ailments, it is sometimes impossible to determine the precise cause of death or demonstrate that a treatment they received might have offered them some relief before they died.

Alliance said it determined its last trial was flawed.

"It's way, way too early to say this is a clinically important advance," said Dr. Richard Albert, chief of medicine at the Denver Health and Medical Center and a specialist in pulmonary and critical care.

Albert said LiquiVent has not yet been tested on enough patients to ease concerns over potential dangers, such as the effects of the chemical, which he said can remain in the lungs for years after treatment.

Alliance, however, says it remains committed to its product.

Ventilators are cumbersome machines that work by forcing oxygen into the lungs under high pressure, which can damage the alveoli, or air sacs, that have collapsed. Prolonged use of a ventilator can be more deadly than the initial illness. Patients with acute lung injury who are on a ventilator for more than four days have a mortality rate of 40%.

"Even though it is a lifesaving machine, the longer a patient remains on a ventilator, the more damage their lungs sustain," said Gordon Schooley, vice president of clinical research at Alliance.

Preliminary trials in adult patients showed that LiquiVent enabled the patients to get off a ventilator five days sooner than with conventional treatment, Alliance said.

After the company announced last week that it was moving forward with trials of LiquiVent, at least two industry analysts issued recommendations for the company's stock, based on expectations that the product could come onto the market within three or four years.

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