Perjeta Maker Announces Positive Results in Phase III Trial

A press release says people lived longer without cancer coming back while on pertuzumab (Perjeta), but the full study findings will not be released until summer
Breast Cancer News
March 16, 2017
Eric Fitzsimmons
Reviewed By: 
Hyman B. Muss, MD

The pharmaceutical company Genentech announced that results from a phase III trialinfo-icon showed people with early-stageinfo-icon, HER2-positive breast cancer lived longer without recurrenceinfo-icon when its medicineinfo-icon pertuzumabinfo-icon (Perjeta) was added to treatment with trastuzumabinfo-icon (Herceptininfo-icon) and chemotherapyinfo-icon.

The company said these results were statistically significantinfo-icon, meaning they most likely didn’t happen by chance, but how important the results are will not be known until they are reviewed by the Food and Drug Administrationinfo-icon and the full study findings are presented later this year.


About one out of five cases of breast cancer is HER2-positive, meaning the cancer has too much of a proteininfo-icon called human epidermal growth factor receptor 2info-icon. HER2-positive breast cancers can be harder to treat than other subtypes, but outcomes improved with the use of trastuzumab, a treatment that targets HER2 receptors. Herceptin was approved for use in treating the disease in 1998.

Recently pertuzumab, another targeted therapyinfo-icon, has been showing it, too, could improve outcomes for people with HER2-positive disease. The CLEOPATRA study found that pertuzumab could lengthen life in people with metastaticinfo-icon breast cancer. Results from this and other earlier trials have led the FDAinfo-icon to grant pertuzumab accelerated approval. This is a process that allows promising treatments to become available to the public faster, based on positive early results.

Pertuzumab, like trastuzumab, targets HER2 receptors but at a different part of the protein. Because of this, researchers are interested in whether the two treatments would work better when given together.


The APHINITY study was a phase III, randomized trial to study pertuzumab’s effect on invasive disease-free survival, or the time a person goes without having a recurrence or dying of any cause, when people were given treatment with pertuzumab and trastuzumab compared to trastuzumab alone. It was a double-blind study, so neither the doctor nor the person being treated knew if they were getting pertuzumab or a placeboinfo-icon. The study enrolled 4,805 people with early-stage, HER2-positive breast cancer. The people in the study could go on to get radiation therapyinfo-icon or hormonal therapyinfo-icon, if recommended, after the year of chemotherapy and targeted therapy.


The group taking pertuzumab lived longer than the group that took trastuzumab alone. The company’s announcement said the results were statistically significant, but the data behind that claim will not be seen until the full study is released later in the year.

The announcement said the side effects seen in the study were those already expected with pertuzumab.

What This Means for You

If you have HER2-positive breast cancer, the news that better treatment could be coming is exciting, but it’s important to understand the effects of a medicine. HER2-positive breast cancers are known to be more aggressiveinfo-icon than other types of breast cancer, but new targeted therapies like pertuzumab have helped improve outcomes in certain cases. The FDA has signaled how important this treatment may be by giving it accelerated approval. But how pertuzumab is prescribed will depend on the results of this and future studies.

The recent announcement says the results of the APHINITY study are positive, but what the results could mean for HER2-positive breast cancer treatment will not be known until the data is released. The full results will show how much adding pertuzumab to treatment will really help a person with HER2-positive breast cancer.

Your doctors can answer questions about your specific treatment. If you are interested in trying a new treatment and helping new medicines reach people with cancer, ask about enrolling in a clinical trialinfo-icon

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