April 2019 new listings wrap-up

Aciclovir (AciVision) 3% eye ointment has been listed on the PBS General Schedule (Section 85) for the treatment of herpes simplex keratitis.¹

What is it?²

Aciclovir is an antiviral agent (purine nucleoside analogue) with in-vitro activity against herpes simplex virus (HSV) types I and II.

The relationship between in-vitro activity and clinical response to aciclovir has not been established.

Aciclovir is converted to its active form (aciclovir triphosphate) in HSV-infected cells, where it inhibits viral DNA synthesis. Conversion of aciclovir to active aciclovir is limited in normal cells.

Who is it for?

Aciclovir 3% eye ointment is indicated and recommended for the treatment of herpes simplex keratitis.^2,3

Ocular manifestations of HSV include blepharitis (inflammation of the eyelid margins), lacrimal duct obstruction, conjunctivitis, iritis, retinitis, and keratitis (dendritic ulceration).³

The AciVision brand of aciclovir 3% eye ointment is an alternative option for patients currently using the Zovirax brand of aciclovir 3% eye ointment.

Zovirax is currently listed on the PBS for the same indication as AciVision but it will be deleted from the PBS Schedule on 1 December 2019.^1,4

Safety issues

Patients with known hypersensitivity to aciclovir or valaciclovir should not use aciclovir 3% eye ointment.²

Transient mild stinging immediately after application is a common adverse effect.^2,5

Advise patients to avoid wearing contact lenses when using aciclovir 3% eye ointment.²

The Australian-approved product information for aciclovir 3% (Zovirax) states that it should not be used during pregnancy unless the benefits to the patient clearly outweigh the potential risks to the fetus.²

The Australian Medicines Handbook states that aciclovir (when used for the eye) is safe to use during pregnancy.⁵

Safinamide (Xadago) 50 mg and 100 mg tablets have been listed on the PBS General Schedule for patients with Parkinson disease.¹

What is it?⁶

Safinamide is a highly selective and reversible monoamine oxidase B (MAO-B) inhibitor that increases levels of extracellular dopamine in the brain.

It selectively inhibits MAO-B over MAO-A (1000-fold greater) and also inhibits voltage-gated sodium channels, modulates calcium channels and inhibits glutamate release.

Who is it for?

Safinamide is PBS listed for patients with Parkinson disease, as an adjunctive treatment to a levodopa-decarboxylase inhibitor combination.¹

According to the registered indication, patients are required to be adults with fluctuating idiopathic Parkinson disease symptoms.⁶

There are currently no recommendations on the use of safinamide for Parkinson disease in Australian Therapeutic Guidelines or the Australian Medicines Handbook.^7,8

However, in November 2018, the PBAC previously considered that safinamide should be treated as interchangeable on an individual patient basis with rasagiline, another MOA-B inhibitor.^8,9

Rasagiline is described as having mild effect on symptoms of Parkinson disease and recommended for the management of motor complications as disease progresses (to manage medicine ‘wearing off’).⁸

Safety issues

Safinamide is contraindicated in patients with severe hepatic impairment, albinism, retinal degeneration, uveitis, inherited retinopathy or severe progressive diabetic retinopathy.⁶

Orthostatic hypotension, dyskinesia, headache, insomnia, nausea, vomiting, accidental injury, rash, arthralgia are common adverse effects with MAO-B inhibitors.⁷

When used with levodopa, MAO-B inhibitors may increase dopaminergic adverse effects (such as dyskinesia, hallucinations, nausea and vomiting).⁷

At least 7 days must elapse between discontinuation of safinamide and initiation of another MAO inhibitor (or pethidine).⁶

Sofosbuvir 400 mg + velpatasvir 100 mg + voxilaprevir 100 mg fixed-dose combination (FDC) tablets (Vosevi) have been listed on the PBS General Schedule and Highly Specialised Drugs Program (Section 100) for the treatment of chronic hepatitis C infection.¹

What is it?¹⁰

Sofosbuvir is a nucleotide inhibitor of hepatitis C virus (HCV) NS5B RNA-dependent RNA polymerase, velpatasvir is an HCV NS5A inhibitor and voxilaprevir is an HCV NS3/4A protease inhibitor.

The NS5B RNA-dependent RNA polymerase is required for HCV replication and the HCV NS5A protein is required for HCV RNA replication and assembly of HCV virions.

Sofosbuvir, velpatasvir and voxilaprevir are all pan-genotypic HCV inhibitors.

Who is it for?¹¹

Sofosbuvir + velpatasvir + voxilaprevir FDC is PBS-listed for patients with chronic HCV infection for whom treatment with an NS5A-based treatment regimen has been unsuccessful.

Patients can have any HCV genotype.

Criteria to determine patient eligibility for PBS-subsidised hepatitis C treatment can be found in the General Statement for Drugs for the Treatment of Hepatitis C on the PBS website.¹²

The General Statement makes treatment recommendations according to HCV genotype, treatment history and cirrhotic status.¹²

The PBAC considered that sofosbuvir + velpatasvir + voxilaprevir FDC should be listed under the same conditions as glecaprevir + pibrentasvir FDC (see criteria in the General Statement).

In addition to meeting criteria set out in the General Statement, duration of treatment with sofosbuvir + velpatasvir + voxilaprevir FDC must be limited to a maximum of 12 weeks.

Clinical criteria for sofosbuvir + velpatasvir + voxilaprevir FDC subsidy are the same for its listing on the PBS General Schedule and the Highly Specialised Drugs Program.

Safety issues¹⁰

Use of sofosbuvir + velpatasvir + voxilaprevir FDC with rifampicin or rosuvastatin is contraindicated.

Symptomatic bradycardia has occurred when sofosbuvir is co-administered with amiodarone and other HCV direct-acting antivirals.

There is a potential for drug interactions between sofosbuvir, velpatasvir or voxilaprevir and other medicines.

Potential drug interactions can be checked using the University of Liverpool HEP Drug Interactions checker.

Safety and efficacy have not been established in patients with severe renal impairment or end stage renal disease requiring haemodialysis, and its use is not recommended in patients with moderate or severe hepatic impairment.

The most common side effects with sofosbuvir + velpatasvir + voxilaprevir FDC include headache, tiredness, diarrhea, and nausea.

Patients are required to take sofosbuvir + velpatasvir + voxilaprevir FDC tablets with food.

Other items listed in April 2019 include:

• atazanavir for HIV infection (Highly Specialised Drugs Program, Item 11657M)
• levodopa + carbidopa for Parkinson disease (General Schedule, Items 11663W and 11655K)
• riluzole for amyotrophic lateral sclerosis (General Schedule, Item 11662T).

See the PBS Summary of Changes for a complete list of all additions, deletions and alterations.