Genentech, a developer of medicine, announced September 30 that the U.S. Food and Drug Administration granted accelerated approval of the company’s medicine pertuzumab (Perjeta)—in combination with the targeted medicine trastuzumab (Herceptin) and chemotherapy medicine docetaxel—as neoadjuvant therapy, or pre-surgery treatment, for those with high-risk, HER2-positive, inflammatory, early-stage or locally advanced breast cancer.
Background and Reason for the Accelerated Approval
When a woman is diagnosed with breast cancer and undergoes testing, the tumor is tested for several proteins that have implications for treatment and prognosis. These include the estrogen and progesterone receptors as well as a protein called human epidermal growth factor receptor-2 (HER2); a positive result means too much HER2 is present in the cells, fueling cancer growth.
Anti-HER2 medicines, like trastuzumab (Herceptin) and pertuzumab, are given by vein to block chemical signals that cause cancer cells to grow.
Trastuzumab has been used to treat early-stage breast cancer for about 8 years and advanced breast cancer for about 15 years. Pertuzumab was approved for metastatic disease 1 year ago when data showed a very significant benefit when this medicine was combined with standard chemotherapy to treat HER2-positive metastatic breast cancer.
Before pertuzumab was approved by the FDA in 2012 for use in women with HER2-positive metastatic disease, researchers were studying its effects as a neoadjuvant treatment for women with early-stage or locally-advanced HER2-positive breast cancer in two clinical trials. Breast cancer is considered locally-advanced when it has spread to the skin, chest wall, or nearby lymph nodes, but not to distant organs like the liver.
The phase II NEOSPHERE (Neoadjuvant Study of Pertuzumab and Herceptin in an Early Regimen Evaluation) and TRYPHAENA (Tolerability of Pertuzumab, Herceptin and Anthracyclines in Neoadjuvant breast cancer) studies examined whether pertuzumab was beneficial and safe as neoadjuvant therapy given to women with locally advanced-and early-stage, HER2-positive or inflammatory breast cancers. In both studies, treatment with pertuzumab in combination with other therapies—such as trastuzumab and the chemotherapies docetaxel and anthracycline—led to pathological complete response (pCR), or no evidence of cancer detected at the time of surgery, in significant percentages of women.
In NEOSPHERE, nearly 40 percent of participants taking pertuzumab, Herceptin and docetaxel experienced pCR compared with
- 21.5 percent of those taking Herceptin and docetaxel
- 11.2 percent of those taking pertuzumab and Herceptin
- 17.7 percent of those taking pertuzumab and docetaxel
The pertuzumab regimens in NEOSPHERE and TRYPHAENA were not associated with a significant increase in severe side effects. In TRYPHAENA the primary goal was to assess the cardiac safety of this treatment regimen and no new or unexpected cardiac problems occurred.
The positive findings of both phase II trials, examined together with the safety data from the phase III CLEOPATRA study of pertuzumab for the treatment of HER2-positive metastatic breast cancer, led to the FDA agreeing to perform a priority review of the pertuzumab regimen this past July. The outcome of their review—accelerated approval—means that those with high-risk HER2-positive, inflammatory, locally advanced or early-stage breast cancer will be able to benefit from receipt of this combination therapy.
At this time, a phase III trial, APHINITY, looking at the use of pertuzumab-based combination therapy in women with early-stage breast cancer who have undergone surgery, has been completed. Results of this study are not yet available but are eagerly awaited. Before the FDA’s accelerated approval of the neodadjuvant pertuzumab regimen can be changed to full approval, a complete review of these findings will need to take place.
What This Means for You
If you have been diagnosed with high-risk HER2-positive, inflammatory, locally-advanced or early-stage breast cancer, you now have another treatment option available to you—pertuzumab in combination with trastuzumab and docetaxel, as neoadjuvant therapy.
Although currently available trial data show the clinical benefit and safety of this combination, no study has yet proven this regimen improves survival when given as neoadjuvant treatment. The safety of receiving pertuzumab for greater than six cycles has also not yet been proven in studies with participants diagnosed with early-stage breast cancer.
The use of pertuzumab may be associated with severe side effects, including heart problems and allergic reactions, but these reactions are less common. The benefits of receiving pertuzumab in combination with trastuzumab and docetaxel may outweigh these risks. Talk with your healthcare team to find out whether this treatment is right for you.
Living Beyond Breast Cancer will provide updates on the final review of data from the phase III APHINITY trial as it becomes available.