A multinational drug company that has put a $2.1m price tag on a new drug for a muscle-wasting disease that affects children is to offer 100 free doses a year through a global lottery.

Parents of children with spinal muscular atrophy (SMA) and campaigners are disturbed both by the price and the random draw, which they say will be emotionally devastating for families while helping only a tiny proportion of the 60,000 or so children diagnosed each year.

Lucy Frost, whose eight-year-old son George has the disease and who is a trustee of TreatSMA in the UK, said the fortnightly draw would be very hard on families.

“SMA is still the biggest killer of children under two. Imagine parents putting a child in a draw every two weeks to see if their life can be saved. It will have a huge emotional impact,” she said. “As a mother of a child with SMA, I think it could have been done much better.”

The drug, Zolgensma, was developed by AveXis, which is owned by Novartis, one of the wealthiest drug companies in the world. It is designed to add a functional copy of a gene that is missing in babies born with SMA. It is not a cure.

There is only limited data on its safety. It was approved by the Food and Drug Administration (FDA) in the US after trials in just 68 children. The company says it now has information on more than 100 more children who have been treated.

The FDA ruled that the company must follow up on every child given the drug for 25 years. But that will not happen with children given free treatment through the lottery in countries that have not yet approved the drug.

“One of our concerns about the programme is that they are not going to monitor the patients long-term,” said Kacper Rucinski, also a trustee at TreatSMA and a board member of SMA Europe. “They will just supply the drug. Everything else is the responsibility of the treating community.”

Novartis did not consult with families or doctors before announcing the lottery, he said. “They did not involve us or invite key clinicians from around the world. Not one was kept in the loop.”

He said no account would be taken of the severity of the child’s disease or the speed at which it was progressing.

SMA affects the nerves in the spinal cord controlling movement. Patients face muscle weakness, progressive loss of movement and difficulty breathing and swallowing. Those with the most severe forms often die before the age of two.

Families fought a successful campaign for access to the first drug that targeted the underlying causes, Spinraza (generic name nusinersen), which is now available on the NHS.

Zolgensma had very good results in the early trials, although a six-month old child in London died. After an investigation, the company said the drug was not to blame. The gene therapy may have contributed to some of the reasons the child was taken to hospital, such as abnormal liver function and low blood pressure, but Novartis said those side-effects had long been known about.

“We had been concerned about the potential … that Zolgensma might have been causing brain inflammation,” the AveXis chief executive, Dave Lennon, said at the time. “In this case, the original diagnosis and that association hasn’t held true.”

In September the company said two senior executives had been sacked over the falsification of data from the animal studies that take place before human trials. A spokesman said it had been fully explained to the FDA and had not affected the filing for the licence in the US. “It is not clear why it was being done. There was no impact on the medicine itself,” Lennon said.

The European Medicines Agency is deciding whether to license the drug in Europe, including in the UK. The National Institute for Health and Care Excellence would then assess it and decide whether it is cost-effective for the UK, with the final price negotiation up to the NHS in England, Scotland, Wales and Northern Ireland.

Novartis claims it has fairly priced the drug because it is a one-off. It calculated the price as half the cost of 10 years of the current therapy, Spinraza. “We’re bringing in something that is a significant discount on the existing standard of care,” said a spokesman. Spinraza costs $750,000 in the first year and $375,000 after that in the US, but its manufacturer, Biogen, has agreed a substantial discount with the NHS.

A spokesman for AveXis said they were working hard to increase supply of the drug and “design sustainable and ethical solutions” to the issue of access.

“AveXis designed a programme anchored in principles of fairness, clinical need and global accessibility to best determine the equitable global distribution of a finite number of doses that doesn’t favour one child or country over another,” he said.