FDA Approves Tukysa Combination for HER2-Positive Breast Cancer

On October 7, 2026, the U.S. Food and Drug Administration approved Tukysa (tucatinib) in combination with trastuzumab and pertuzumab as a maintenance treatment for adults with unresectable locally advanced or metastatic HER2-positive breast cancer following induction therapy.

The FDA decision allows the use of this three-drug regimen for patients whose cancer cannot be surgically removed or has spread. The approval follows clinical trial results evaluating the combination’s effectiveness and safety in this patient group.

Pfizer announced the regulatory approval in a press release on the same day. The company highlighted the supporting data from the Phase 3 HER2CLIMB-05 clinical trial, which compared the new combination to standard therapy.

In the HER2CLIMB-05 trial, patients receiving Tukysa with trastuzumab and pertuzumab experienced a longer median progression-free survival than those given placebo with trastuzumab and pertuzumab. The trial also measured the risk of disease progression or death between the two groups.

What the numbers show

• Median progression-free survival was 24.9 months with the Tukysa regimen.
• Median progression-free survival was 16.3 months with placebo regimen.
• The trial showed a 35.9% reduction in risk of progression or death with Tukysa.

The HER2CLIMB-05 trial reported a hazard ratio of 0.64 for disease progression or death, with a 95% confidence interval of 0.51 to 0.80 and a p-value less than 0.0001. These results indicate a lower risk for patients treated with the Tukysa combination compared to those on the placebo regimen.

According to Pfizer, the safety profile observed in the trial was generally consistent with prior Tukysa data. The company stated that increased liver toxicity was noted, but most of these events were asymptomatic and could be managed by adjusting or stopping the medication.

This FDA approval provides an additional maintenance treatment option for adults with advanced HER2-positive breast cancer after initial therapy. The decision was based on data from a randomized clinical trial assessing both efficacy and safety outcomes for the combination therapy.

* This article is based on publicly available information at the time of writing.