More than 6,000 Australians living with multiple sclerosis (MS) are set to save about $54,000 a year on the drug Mavenclad, with the Morrison Government listing the medicine on the Pharmaceutical Benefits Scheme (PBS).

Key points: From January 1 the multiple sclerosis medication will costs $40.30 per script, or $6.50 for concessional patients

From January 1 the multiple sclerosis medication will costs $40.30 per script, or $6.50 for concessional patients The Prime Minister appeared at Kirribilli House in Sydney to make the announcement

The Prime Minister appeared at Kirribilli House in Sydney to make the announcement Clinical trials for the drug showed multiple sclerosis symptoms dissipating within a month

Prime Minister Scott Morrison, whose brother-in-law Gary Warren suffers from the autoimmune disease, announced on Sunday the drug would become a more affordable treatment option for people with relapsing remitting multiple sclerosis (RRMS).

Through the PBS, the Government will subsidise almost the entire cost of Mavenclad and drive its cost down to $40.30 per script, or $6.50 for concessional patients.

Stuart Allen from Melbourne was diagnosed with MS in 2008 and in 2010 became the first person in the world to be prescribed Mavenclad.

Speaking alongside Mr Morrison at a press conference at Kirribilli House, Mr Allen said he had struggled with other drugs but Mavenclad had "made such a massive difference for me".

"It's the difference between working or not working, [and] I love my job," he said.

The Prime Minister described the subsidy as "Christmas, a few days early" for patients with MS.

He said the drug would be available through the PBS from New Year's Day.

Is Mavenclad a wonder drug?

Mavenclad, also known as cladribine, is taken by MS patients in tablet form.

It was submitted to the Pharmaceutical Benefits Advisory Committee (PBAC) for consideration for the PBS in November 2017.

Clinical trial results published in the Multiple Sclerosis Journal last year showed the medicine was linked to fewer relapses, less brain atrophy, slowed progression of the disease and improved quality of life for multiple sclerosis patients.

Taking the drug is also a relatively simple process, according to patients on the treatment.

Stuart Allen, who was diagnosed with multiple sclerosis in 2008, was the first person prescribed Mavenclad. ( ABC News )

In a submission for Mavenclad to be listed on the PBS, an RRMS patient said it involved five days of taking the tablet orally over one month.

Within a month, she noticed her MS symptoms dissipating, and an MRI taken at the three-month mark showed less active lesions in her brain.

Canadian-born Paralympian Carol Cooke, who also began treatment taking Mavenclad in 2010 and spoke at the Kirribilli House announcement, said it changed her life.

"I had no side effects whatsoever. I had been on eight other drugs which caused a lot of side effects," she said.

"You almost forget you have MS, other than little things you live with constantly.

"To not go through relapse makes all the difference in the world."