A judge refused yesterday to block sales of Pfizer’s inhalable in sulin product Exubera, saying the public’s need for a “new and less invasive treatment for diabetes” outweighed Danish drugmaker Novo Nordisk’s claims that Pfizer is infringing on its patents.

U.S. District Judge Leonard Sand in New York said Novo’s at tempts to show irreparable harm for both its current market standing and for future sales of its own inhalable insulin were speculative.

Sand wrote that stopping “the release of a new and less invasive treatment for diabetes would quite obviously be contrary to the public interest, particularly in the interval between now and trial.”

Novo Nordisk, whose U.S. operations are based in Princeton, sued Pfizer earlier this year, saying Exubera infringes on its inventions and would do irreparable harm to its reputation and its sales.

At a recent hearing, Stephanie Wheeler, a lawyer for Novo Nordisk, told Sand that Exubera violates Novo Nordisk’s patents covering insulin delivery to the lungs. Novo Nordisk expects to produce its own inhalable insulin product by 2011.

She said Novo Nordisk, which shares nearly half of the market for Americans who require insulin in jections to control diabetes, could suffer irreparable damages because studies show as many as 89 percent of people who rely on injections would switch to an inhaled drug if they could.

After Sand ruled yesterday, Wheeler said she had no immediate comment. A message left with a company spokesman was not immediately returned.

Pfizer, the world’s largest maker of prescription medicine, began marketing the drug through some diabetes specialists in July and plans a wider launch of the product through more general practitioners early next year. Approximately 21 million Americans suffer from diabetes.

Vanessa Aristide, a Pfizer spokeswoman, said yesterday patients who take insulin injections can take Exubera.

“If they choose to change from injections to Exubera, it’s as effective,” Aristide said.