The study, sponsored by the Finnish Breast Cancer Group with support from PHARMAC, found there was a 90.5 per cent disease-free survival rate among study participants who had 12 months of treatment compared to 88 per cent of those who were treated with it for nine weeks.
There was a smaller difference in five-year overall survival: 94.7 per cent in the nine-week arm and 95.9 per cent in the 12-month arm.
The drug has been shown to be effective in treating people with HER2-positive breast cancer but the Synergism Or Longer Duration study was the first to prove a statistically significant benefit over the different treatment periods.
Breast Cancer Foundation NZ chief executive Evangelia Henderson said it was fantastic to see New Zealand was on the right track by funding 12-months of treatment.
“Herceptin has made a huge difference in treating these difficult cancers, but it’s an expensive drug, so it’s important to find out the optimum duration of treatment.”
The 12-month regimen became standard of care here after the National Party made it a campaign pledge in the 2008 election. Before that, women received only nine weeks, a duration that studies had showed to be effective for many people.
The earliest trials of Herceptin mainly involved sequential treatment – chemo first, then Herceptin. But there was a strong suggestion that concurrent treatment might be more effective. In New Zealand patients now have concurrent treatment for the first three months, with Herceptin extended out to 12 months.
However, no one knew whether concurrent treatment was effective enough that the duration of Herceptin could be less than 12 months, saving money and sparing patients from side-effects. The study was designed to address that question.
“We now have a much clearer picture of the benefits of 12 months of Herceptin, and that’s good news for everyone,” Henderson said.