Novo Nordisk, the Danish pharmaceuticals group, on Tuesday announced a DKr1.3bn ($260m) charge as it became the second significant drug company to abandon plans for an inhaled version of insulin for diabetics.

The company said it was cancelling the development of its AERx inhaled insulin system, currently in late-stage clinical trials, but would continue research in alternative inhaled systems.

Lars Rebien Sørensen, chief executive, said: "We have concluded that fast-acting inhaled insulin in the form it is known today is unlikely to offer significant clinical or convenience benefits over injections of modern insulin with pen devices."

His action follows the decision last autumn by US drugmaker Pfizer (NYSE: PFE - News) to withdraw Exubera, its equivalent product, in the wake of disappointing sales after less than two years on the market.

The move by Novo Nordisk will put fresh pressure on two other US companies developing in­haled insulins, Eli Lilly with AIR, which is set to launch soon, and MannKind with its Technosphere product currently in the test phase.

Exubera was once heralded as an important advance in boosting convenience for users. It was seen by some analysts as a potential source of more than $1bn in revenues for Pfizer, helping compensate for patent expiries on existing blockbusters.

Instead, Pfizer was forced to write off $2.8bn and sell the rights back to Nektar Therapeutics (NASDAQ: NKTR - News) , the original developer, after poor sales that were blamed on scepticism, limited evidence of benefit and an inhaler that was bulky and required adaptation by doctors and patients.