Drug maker Novartis is taking legal action in Britain to make state-run hospitals use an eye drug that costs about 700 pounds ($1,130) per shot instead of a cheaper one that costs 60 pounds ($97).

In a statement, Novartis said it was calling for a judicial review "as a last resort" because it believed patient safety was being potentially compromised.

According to the U.K.'s health watchdog, Novartis' Lucentis is the only drug recommended to treat the eye problem macular degeneration in the country's state-run National Health Service hospitals.

However, several NHS hospitals have been prescribing the much cheaper Avastin, a cancer drug made by Genentech Inc., a subsidiary of Roche, for the same problem even though it has not been officially approved.

A study published in the New England Journal of Medicine last year showed Avastin worked just as well as Lucentis for treating the eye disorder.

Lucentis and Avastin act on the same biological protein in the body to spur blood vessel growth. In the U.S., eye doctors have often used tiny amounts of Avastin and billed the government for the cost, rather than buying Lucentis.

Most U.K. doctors only prescribe drugs approved by the health watchdog, but have the discretion to use other treatments if they believe they are warranted.

Britain's drug regulator has not approved Avastin for eye diseases, so it has not been considered by the health service's advisory agency, known as NICE, for this use. NICE makes decisions based only on cost-effectiveness and agency officials said they would need help from the drug regulator to decide whether Avastin should be used for patients with macular degeneration.

Last year, four hospitals in southern England decided they would pay for Avastin when it was prescribed by a doctor.

In a statement Tuesday, Novartis AG said it was demanding a judicial review to make the hospitals use Lucentis rather than Avastin.

Novartis said it was concerned patients and clinicians were being pushed to use an unlicensed medicine in order to cut costs. Britain's coalition government has mandated that its National Health Service trim $20 billion ($31 billion) from its budget by 2015 as part of a national austerity drive.

"It is unacceptable to put the safety of patients at risk through the widespread use of an unlicensed treatment when a licensed medicine is available," the pharmaceutical company said. Novartis noted there was "emerging evidence" of safety concerns for using Avastin to treat eye problems.

Patient groups called for an independent analysis to determine which drug should be used. "If Avastin is not as safe as Lucentis, no one should be using it," said Helen Jackman, chief executive of the Macular Disease Society. "If it is as good, perhaps everyone should be using it."

Alexander Klauser, a Roche spokesman, said the company was so far only pursuing studies for Avastin for cancer treatments, rather than eye diseases. "No studies have been done for Avastin and (macular degeneration) and this is not the plan."

Klauser said the company thought Avastin's biggest potential was in cancer treatments and that there is still a large "unmet need" for the drug. He said it was ultimately up to physicians whether to prescribe Lucentis or Avastin.

Meanwhile, others slammed Novartis for its decision to go to the courts.

"Companies like Novartis should not be in the position to block moves to more cost-effective treatments in order to maximize their profits," said John Harris, of the Institute for Science Ethics and Innovation at the University of Manchester, in a statement. He said it was legitimate for health providers to use treatments that were much cheaper than ones that were already licensed.

Genentech developed both Avastin and Lucentis, but Novartis has exclusive rights on Lucentis outside the U.S.