At their next meeting in July 2016, the Pharmaceutical Benefits Advisory Committee (PBAC) will be considering a potential new medication for relapsing remitting MS, daclizumab (marketing name Zinbryta), for reimbursement on the pharmaceutical benefits scheme (PBS). The PBAC are inviting submission from organisations and members of the public in relation to all drugs that are being considered at their July 2016 meeting.
The PBAC is required to consider a number of factors when making recommendations, including the clinical efficacy and cost-effectiveness of a treatment, relative to other medicines, and the cost to the government of a new listing.
Daclizumab is also undergoing parallel consideration by the Therapeutic Goods Administration (TGA) for registration in Australia as a drug for the treatment of relapsing remitting MS. It will require a positive assessment by both TGA and PBAC if it is to be made available for prescription in Australia. Daclizumab was recently approved for use by the European Medicines Agency (EMA).
Daclizumab is already in use clinically for the prevention of kidney transplant rejection and has been under investigation as a treatment for relapsing remitting MS for some time. It is a monoclonal antibody (a type of antibody that recognises a single specific target) that blocks the activity of interleukin-2, a chemical messenger of the immune system. It interferes with the activation and growth of immune cells. Daclizumab is given as an injection under the skin once a month.
The TGA and PBAC will be mainly considering the results of two phase III clinical trials of daclizumab, known as SELECT and DECIDE, in their assessment of the drug.
The ‘SELECT’ study was a randomised controlled trial in which 208 patients with relapsing remitting MS received 150mg of daclizumab, 209 patients received 300mg of daclizumab and 204 patients were given placebo (dummy injections) for one year. Relapses were reduced by around 50% in both groups receiving daclizumab and there was also a reduction in the number of patients who had progression of disability that was confirmed after a 3 month period. The number of gadolinium enhancing lesions seen on magnetic resonance imaging (MRI) scans, which is a sign of active inflammation, was also reduced by 69% and 78% in the people who received 150mg or 300mg of daclizumab respectively. Daclizumab did not appear to have any effect on the rate of brain shrinkage (atrophy).
In the ‘DECIDE’ study, a 150mg dose of daclizumab administered under the skin every 4 weeks was given to 919 people with relapsing remitting MS and compared with weekly injections of interferon β-1a given to 922 patients. People in the daclizumab group had an overall 45% reduction in annualised relapse rate compared with interferon and a 54% reduction in new or enlarging lesions on MRI scans. No significant difference was seen in the effect of daclizumab on disability progression in this trial in comparison with interferon.
The most common side effects with daclizumab seen in both clinical trials were elevations of liver enzymes and liver injury, skin reactions such as eczema and rashes, infections, gastrointestinal disorders, and depression. 2% of people in the daclizumab groups in the SELECT trial experienced serious adverse events, predominantly infections.
MS Research Australia welcomes the availability of further affordable treatment options for people with relapsing remitting MS that have undergone rigorous clinical testing, as this increases the opportunity for people with MS and their doctors to find effective therapies suited to their individual circumstances.
For people wishing to make a submission to the PBAC regarding daclizumab, more information can be found here. The closing date for comments is 7 June 2016.