The Correctional Service of Canada spent more than $100 million over three-and-a-half years to provide inmates with prescription drugs, including revolutionary but expensive biologic medications that some Canadians living with serious illnesses struggle to afford.

Documents obtained by CTV News through the Access to Information Act show that the drug bill for incarcerated offenders is driven largely by spending on new medications that can effectively cure hepatitis C.

The service also spent $2.1 million between January 2015 and August 2018 on biologic drugs such as Remicade, Humira and Enbrel that have revolutionized treatment for people with serious autoimmune disorders, including arthritis and psoriasis and disabling inflammatory bowel diseases Crohn’s and ulcerative colitis.

Ongoing treatments with biologic drugs can cost as much as $20,000 annually. Patients who require them must navigate a patchwork of private insurance plans, provincial drug coverage and, in some cases, compassionate care programs provided by the drug-makers themselves.

Access to the provincial coverage for biologics varies by province, type of illness and with the severity of the disease.

Offenders in federal prisons -- those serving sentences of two years or longer -- are provided biologic drugs at no charge.

The Correctional Service of Canada says it is mandated under the Corrections and Conditional Release Act to provide every inmate with essential health care, including medications.

“Requests for all medications, including biologics, are made by a CSC physician after diagnosis and assessment of the offender,” the service said in a written statement.

“With respect to biologic medications, as these medications are listed as benefits with criteria, certain diagnosis criteria for coverage is required.”

While prisoners can get free drugs, some patients must fight with provincial health administrators for full coverage or partially fund their own medication.

The family of 21-year-old college student Tristin Ozard says they had to remortgage their home and use a line-of-credit to pay for Remicade treatments that the British Columbia’s provincial plan stopped fully covering when he turned 18.

The Victoria, B.C., college student’s disease responds best to a double dosage of Remicade, leaving his family paying $7,800 every second month while the provincial plan covers the other dose. BC PharmaCare would provide coverage for Tristin with a less-expensive ”biosimilar” of Remicade that Tristin’s family worries may not work for him.

The Ozards have had to raise money to pay for Tristan’s Remicade with a GoFundMe fundraising campaign, but those contributions have made only a small dent in the family’s drug bill.

"It's hard because you can't provide for your own family and that doesn't feel good,” said Ozard’s mother, Melissa.

Though they could get the medication through a compassionate care program run by a drug-maker, Melissa Ozard says she wasn’t willing to provide access to her son’s full medical file that the application required.

She says she’d rather fight BC PharmaCare in court to make it easier for other patients to get the brand-name version of Remicade in future.

While most Canadians can usually get coverage for biologics, some still fall through the cracks, depending on where they live and the severity of their disease.

"Certain provinces do a better job than others,” said Arthritis Society CEO Janet Yale.

“Young or old, employed, unemployed, incarcerated or not, people should have access to their medicines no matter what."

The discrepancy between the coverage provided federal inmates and patients like Ozard illustrates what critics have long-decried as a major gap in Canada’s health care system -- that care from doctors and hospitals is paid for but essential drugs are not always.

"I think Canadians would think it's unfair prisoners are getting expensive drugs paid for when many people are struggling and going bankrupt just trying to care for their loved ones,” said Conservative Party health critic Marilyn Gladu.

The federal government last year appointed former Ontario health minister Eric Hoskins to lead an advisory committee studying the feasibility of launching a national pharmacare program. His report is due in March.

The bulk of the Correctional Service of Canada’s drug spending goes towards a new class of drugs that can effectively cure hepatitis C, which is transmitted by exposure to infected blood and so also carries a low risk of sexual transmission. It’s a potentially fatal liver disease that is common among offenders.

Since 2015, the service has spent $77 million on drugs such as Harvoni and Epclusa, which typically cost about $80,000 for a full course of treatment, though the government may be able to negotiate a lower price.

The Canadian Liver Foundation says this is money well-spent as the ongoing costs of older hepatitis C drugs like interferon will usually exceed the one-time costs of the new medication over a typical patient’s lifetime.

The assertive approach to combating hepatitis C has reduced the prevalence rate in Canadian prisons from 31.6 per cent in 2007 to 7.8 per cent by 2017, the service says.

Canadians in most provinces and territories can obtain provincial coverage for these hepatitis C drugs.

With files from Mackenzie Gray, CTV News national producer