A prisoners’ rights group in Massachusetts has filed a class action lawsuit against the state’s Department of Corrections, alleging that prisons and jails throughout the system are withholding hepatitis C virus (HCV) treatment from inmates living with the disease, MassLive.com reports.

The complaint, recently filed at the U.S. District Court in Boston by attorneys for the National Lawyers Guild and Prisoners’ Legal Services, claims that over the last year, the state has been actively reducing the number of patients receiving hep C treatment. The suit also claims that prisons within the state’s correctional system have purposely delayed HCV evaluations for their inmates to avoid being responsible for their treatment.

According to recent Department of Corrections (DOC) statistics obtained by Prisoners’ Legal Services, more than 1,500 prisoners in Massachusetts are HCV positive, but only three inmates are being treated for the virus. Prosecutors also noted that in the beginning of 2015, the state’s prison system spent an average of $35,000 a month on hep C treatment—a significant cut from the average $86,000 a month the state spent on HCV five years prior, in 2009.

The Massachusetts DOC noted that a course of the latest generation of hep C treatments costs prisons between $40,000 and $84,000 per inmate. However, the department would not comment directly on the allegations.

In response, legal advocates argue that the DOC knew that expensive new hep C medications like Sovaldi (sofosbuvir), Viekira Pak (ombitasvir/paritaprevir/ritonavir, dasabuvir) and Harvoni (ledipasvir/sofosbuvir) were coming and should have budgeted accordingly.

Treating HCV among inmates is not just an issue in Massachusetts—prisoners in Minnesota recently sued their DOC for failing to provide hep C drugs. For more information, click here.