Blood cancers

Waldenström macroglobulinaemia guidelines highlight lack of treatment options in Australia


Australia’s first guidelines for the treatment of Waldenström macroglobulinaemia (WM) highlights that Australia still trails behind other countries when it comes to being able to offer the newer targeted therapies for the condition.

Clinical haematologist, Associate Professor Dipti Talaulikar, from the Myeloma Australia Medical and Scientific Advisory Group who helped develop the guidelines, said while there are already several international guidelines for the treatment of the rare cancer many of those recommendations cannot be applied in Australia because of the limited availability of WM-specific drugs.

Speaking to the limbic, Professor Talaulikar said poor access to novel drugs in Australia means that clinicians must either apply to pharmaceutical companies for compassionate access to the drugs or cross referpatients to tertiary centres where WM trials are being carried out.

It’s a practice that is being ‘strongly encouraged’ as part of the new Australian recommendations. According to Dr Talaulikar international guidelines have a greater emphasis on treatment regimens with newer anti cancer drugs like bortezomib and ibrutinib, which are not currently listed on the PBS for WM.

“Australian clinicians need to navigate local restrictions to decide what a reasonable alternative treatment might be based on the drugs that are available to us locally so we hope that these recommendation will help to fill that gap,” she told the limbic.

She added that other drugs, which have recently been PBS listed for WM in Australia, have restrictions on their use in some patients.

She said clinicians needed to be aware of this fact when planning a treatment strategy.

“Bendamustine has recently been approved on the PBS for WM however it is only available for front-line treatment and cannot be accessed through the PBS for follow up treatment or when patients relapse,” she advised.

Rituximab has been PBS-listed in the relapsed or refractory setting, and access has been recently expanded for CD20-positive low-grade lymphomas in the frontline setting.

The guidelines also cover pre and post treatment monitoring and response assessment, which is crucial, Dr Talaulikar said especially in the case of immunoglobulin M (IgM) flares – which is common in patients on rituximab.

“IgM levels are known to rise when patients are treated with rituximab – at higher IgM levels, this can cause clinical complications such as hyperviscosity which may warrant plasmapheresis.”

The phenomenon is particularly common in patients receiving rituximab monotherapy and usually occurs in the first 8 weeks of initiating treatment.

However, Dr Talaulikar noted that the condition, which can lead to intracerebral bleeding and cause neuropathy to worsen, should not be classified as a lack of response to treatment unless there are other signs of disease progression.

Meanwhile, advances in diagnosis have also been covered by the guidelines, with clinicians being advised to test for the newly found MYD88 L265P mutation, reported to occur in more than 90% of WM cases.

Testing for the mutation will help differentiate the condition from other low grade B lymphomas and identify patients who may benefit from specific therapies.

“This is a very exciting time with WM – we are actually moving to a chemotherapy free state, we’re trying to understand the molecular pathogenesis of the disease and use targeted therapies that block those signalling pathways,” said Professor Talaulikar.

“We still haven’t reached that stage yet but were looking at long term remissions at the very least and down the line – maybe even cure.”

 

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