Enhertu's promise in HER2+ breast cancer

AstraZeneca and Daiichi Sankyo's Enhertu, when combined with Roche's Perjeta, reduced the risk of progression or death by 44% in HER2-positive breast cancer, according to results from the DESTINY-Breast09 study presented at ASCO.

Why it matters: 

This advancement could redefine first-line treatment for metastatic HER2-positive breast cancer, which hasn't seen significant innovation in over a decade.

• The Enhertu-Perjeta combo achieved a median progression-free survival (PFS) of 40.7 months, significantly surpassing the 26.9 months with the standard THP regimen.

• Enhertu is already approved for second-line treatment, making this development crucial for expanding its clinical use.

Study highlights: 

The trial randomized 1157 treatment-naïve patients.

• The Enhertu-Perjeta arm showed a 15.1% complete response rate, nearly double the 8.5% seen with the standard care.

• The monotherapy arm remains blinded until the final PFS analysis.

Clinical implications: 

While overall survival data are still immature, there's a positive trend favoring the Enhertu-Perjeta combo, with a hazard ratio of 0.84.

• The findings suggest a possible new standard of care, potentially impacting treatment protocols worldwide.

Side effects: 

Both treatment groups reported similar rates of serious adverse events, but Enhertu patients experienced more nausea and interstitial lung disease, though most lung issues weren't severe.

What they're saying: 

"The results could establish a new standard of care," said lead author Sara Tolaney.

• ASCO expert Rebecca Dent praised the "impressive" results, highlighting the potential for earlier treatment integration.