Researchers in Southampton have achieved a significant breakthrough in treating mesothelioma, an aggressive asbestos-linked cancer, by successfully using a PARP inhibitor to slow disease progression for the first time.
The clinical trial, known as NERO, demonstrated that patients receiving the PARP inhibitor niraparib experienced a 27% reduction in the risk of cancer progression or death compared to those on standard treatments. This resulted in delaying the worsening of mesothelioma by an average of 1.5 months, with some patients seeing substantially longer periods of disease control.
"We have shown for the first time that this kind of drug can improve progression-free survival for mesothelioma patients compared with their usual treatment in the NHS," said Professor Gareth Griffiths, director of the Southampton Clinical Trials Unit and co-lead of the trial. "This gives enormous hope to those patients and their families."
Understanding Mesothelioma and the Treatment Challenge
Mesothelioma is a rare but highly aggressive cancer that forms in the lining of the lungs or abdomen. It is strongly linked to asbestos exposure, with patients typically developing the disease decades after breathing in or ingesting asbestos fibers. The prognosis is generally poor, with only 5% of diagnosed patients surviving five years or more.
Traditional treatment options have been limited, creating an urgent need for new therapeutic approaches for patients who have exhausted standard care protocols.
The NERO Trial: Mechanism and Design
The NERO trial investigated PARP inhibitors, a class of drugs that work by blocking the repair of damaged DNA in cancer cells, ultimately causing these cells to die. PARP inhibitors have previously shown efficacy in treating certain types of breast and ovarian cancers.
Conducted at 11 hospitals across the UK, the trial enrolled 88 patients whose mesothelioma had progressed despite previous treatments. The study was run by researchers at the University of Leicester and the Cancer Research UK Southampton Clinical Trials Unit, with funding from the charity Asthma + Lung UK.
Patient Experience: A Case of Remarkable Response
James Fox from Dorset exemplifies the potential impact of this treatment. Diagnosed with mesothelioma in 2018 and given less than a year to live, Fox joined the trial after other treatment options failed. As an architect exposed to asbestos in the 1970s and 1980s, he developed the disease decades later.
"I've had seven really good years and been able to enjoy life almost to the full so that's wonderful," Fox reported. "So far it's been almost a miracle in my case."
He described his improvement as "dramatic" and attributes his survival directly to the drug: "It must be the drug that's been keeping me fit and alive, so I'm very grateful for that."
Clinical Implications and Future Research
This breakthrough represents what Professor Griffiths calls "a significant step forward" in mesothelioma treatment. The positive results provide a foundation for further research into how PARP inhibitor treatments could be tailored and enhanced to produce even better responses in more patients.
For patients who have exhausted traditional treatment options, this development offers new hope and potentially more time with loved ones. The success of niraparib in this context also suggests that other PARP inhibitors might be effective against mesothelioma, opening additional avenues for research.
Expanding the Role of PARP Inhibitors
The NERO trial builds on previous research suggesting mesothelioma might respond to PARP inhibitors, but provides the first definitive evidence that these drugs can improve clinical outcomes for patients.
This finding is particularly significant given the limited treatment landscape for mesothelioma and may lead to new standard care protocols for patients who have progressed on first-line therapies.
Researchers are now looking to understand which patients might benefit most from PARP inhibitor therapy and whether combining these drugs with other treatments could further improve outcomes.
