As far too many of us know, a diagnosis of breast cancer is shattering, frightening, overwhelming … a maelstrom of one emotion after another. And while trying to come to terms with this life-altering diagnosis, many of us have found that we’re confronting a new language where pathologic terms and molecular subclasses, the biology and behavior of our breast cancer, are driving our treatment options, our choices, our prognoses.
Shortly before I learned that I had breast cancer in 2007, patients diagnosed with what is known as HER2+ breast cancer were told that their cancers were very aggressive and that their prognoses were poor. Normally, the protein known as “HER2,” a receptor on breast cells, helps to control breast cell growth, division, and repair. But in those with HER2+ breast cancer, more than the two copies of the HER2 gene may be present, leading to overproduction of the receptors on the cell’s surface, HER2+ overexpression, and uncontrolled breast cell division and growth. The day that I finally gained the courage to read my pathology report after my surgery, I was aware of this–that HER2+ breast cancers were considered more aggressive, tended to grow and spread more rapidly, and were less responsive to certain therapies when compared to other breast cancer subtypes. And though I already knew that my tumor was found to be estrogen-receptor positive (ER+), I didn’t yet know my HER2/neu status. Either that conversation with my surgeons had taken place during the drug-induced haze immediately following my surgery, or it hadn’t happened yet.
As I turned the pages of my pathology report, I registered that the estrogen receptors were 62%–and that a higher percentage would have been considered “better,” but that this was still considered “good” prognostically. When I saw 0% for progesterone receptors, I recognized that that actually wasn’t so “good”: after all, it was labeled right there on the report as of “unfavorable prognostic significance.” But it was the next line that I was most nervous about: and there it was, my HER2/neu status … and it was “Negative.”
When I saw this, I did feel something akin to relief—though as I learned not long after, there is nothing clear-cut about breast cancer. On that January afternoon in 2007, should my tumor’s HER2 status have been positive, I actually would have been in a much better position than women diagnosed just a few short years before my own diagnosis. The fact was that recent advances had offered a critical new treatment option for patients with HER2+ breast cancer. Just 2 months before, in November of 2006, trastuzumab (Herceptin®), a targeted biologic therapy, had been approved in the postsurgical (adjuvant) setting for early-stage HER2+ breast cancer (BC). I was correct in my understanding that HER2+ disease is a particularly aggressive form of BC—and that because of the aggressiveness of breast cancers that overexpress the HER2 protein, patients with HER2+ disease have an increased risk of recurrence and decreased survival compared to those with HER2-negative disease. But the development and approval of trastuzumab was truly a dramatic breakthrough for the treatment of HER2+ BC, both in reducing recurrence risk for those with early disease and increasing overall survival for patients with metastatic disease. In fact, when the combined results of the adjuvant BC trials were presented during the American Society of Clinical Oncology (ASCO)’s 2005 Annual Meeting, the audience greeted the news with thunderous applause and a prolonged standing ovation.
Those who jumped to their feet when hearing the news about trastuzumab recognized this targeted therapy for the critical breakthrough that it was, one that has since changed the natural history of early HER2+ BC. And yet …
Though trastuzumab and other targeted therapies since approved for breast cancer–and other cancers– have led to remarkable improvements in response to treatment and survival for some, resistance to targeted treatment, both intrinsic and acquired, has limited efficacy for others and is now a clear, sobering reality. The upsetting truth: studies have also reported that depending on tumor characteristics and stage, 17 to 40% of patients treated with trastuzumab regiments for early-stage HER2+ BC go on to develop recurrences within 5 years. Said another way, despite the fact that trastuzumab heralded a new era in the treatment of HER2+ BC, there remains a critical unmet medical need for preventing recurrence after treatment for early-stage HER2+ disease—and for preventing the approximately 6,000 to 8,000 deaths due to HER2+ metastatic disease every year in this country. Accordingly, there also remains a need to expedite the development, study, and approval of safe, highly effective therapies for patients with high-risk early breast cancer. And it is for this reason that the FDA released a draft guideline in May 2012 outlining an Accelerated Approval pathway for presurgical (neoadjuvant) treatments in breast cancer.
But why then the title above, “A Historic Moment”? Last month, on Thursday, September 12th , the FDA convened its Oncologic Drugs Advisory Committee (ODAC), asking ODAC for the first time to consider Accelerated Approval for an oncologic agent in the neoadjuvant setting, based on a primary endpoint known as “pathologic complete response” (pCR).” Pathologic complete response is proposed as a “surrogate endpoint” of tumor response that should be strongly correlated with more traditional endpoints, such as disease-free survival or overall survival. In other words, if approved, this would be the first neoadjuvant regimen formally approved by the FDA for any type of cancer.
During this September 12th ODAC Panel, I had the privilege of serving as the Patient Representative as a temporary full voting member. The question before the committee specifically concerned Accelerated Approval of the anti-HER2 therapy pertuzumab (Perjeta) in combination with trastuzumab (Herceptin) and docetaxel (Taxotere) for patients with HER2+ breast cancer in the neoadjuvant setting. Like trastuzumab, pertuzumab is a monoclonal antibody that targets the HER2 receptor, yet it binds to a different part of the HER2 molecule and therefore does not compete with trastuzumab. Pertuzumab prevents the pairing (called “dimerization”) of HER2 with other HER receptors (HER1, HER3, and HER4), serving to block the signaling pathways within the cell that lead to tumor growth. When pertuzumab is combined with trastuzumab, it therefore provides a “dual” or more complete blockage of the HER pathway.
Approving an oncologic agent as a neoadjuvant therapy in early-stage disease would be historic since traditionally, new breast cancer drugs have first been approved in the setting of metastatic disease. Typically, approval for the treatment of early-stage BC then follows several years later based on the results of very large randomized postsurgical (adjuvant) trials with thousands of patients and prolonged follow-up. If successful, neoadjuvant trials may therefore enable more rapid assessment of drug efficacy and expedite the approval of treatments for early breast cancer.
During this ODAC panel, the comprehensive discussion focused on several critical topics, including:
* the remaining unmet medical need for high-risk early HER2+ breast cancer and the far too many patients who have their cancer return as metastatic disease
* considerations regarding the use of pathologic complete response (pCR) as a primary endpoint in the neoadjuvant setting
* potential long-term toxicities associated with the neoadjuvant use of pertuzumab
* the need for very clear labeling to provide clear guidelines on proper patient selection (due to some data suggesting increased risk of cardiotoxicity) and the safest, most effective use of pertuzumab
* the unique circumstances concerning pertuzumab, including its earlier approval as a first-line treatment for metastatic HER2+ BC based on statistically significant improvement in overall survival and its well-studied mechanism of action with the HER2 pathway and safety signals
* the need to consider the totality of the evidence concerning this agent
* the ongoing, now fully accrued APHINITY Phase III adjuvant trial that, if successful, could support conversion of accelerated approval to regular approval
On this last topic, many ODAC panel members stressed a critical point to the sponsor: that if the results of the APHINITY adjuvant trial are in fact negative, Genentech should voluntarily remove the drug for the neoadjuvant treatment of early-stage breast cancer
During the public hearing portion of the session, many members of the public, including advocates, breast cancer survivors, and nonprofit advocacy organization leadership eloquently stressed the need for earlier, evidence-based treatment options and for treatments that may potentially prevent early high-risk HER2+ BC from later recurring, while also expressing the need for caution, urging Genentech to establish registries to follow those who receive pertuzumab specifically in the neoadjuvant setting for potential late toxicities.
Our panel ultimately voted 13-0 with one abstention in support of pertuzumab in combination with trastuzumab and doxetaxel for patients with HER2+ BC in the neoadjuvant setting. And just a few weeks later, on September 30th, the FDA went on to approve pertuzumab in this setting, indeed making it the first FDA-approved pre-surgical breast cancer drug.
As stated by Dr. Mikkael Sekeres, ODAC Committee Chair, “This is a historic moment as we have voted to support the first approval of a drug for the neoadjuvant treatment of breast cancer: pertuzumab. In doing so, we are supporting the rapid movement of a highly active drug for metastatic breast cancer to the first-line setting, with the hope that women with earlier stages of breast cancer will live longer and better. We do this with some words of advice to Genentech. All eyes will be on the confirmatory APHINITY trial and on you to verify this initial signal of efficacy and to confirm the bandwidth of safety that we have seen so far. If these are not confirmed we urge you to avoid a repeat performance of Avastin and voluntarily remove this drug from the market.”
Upon announcing the approval of pertuzumab, Dr. Richard Pazdur, director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research, said in an FDA statement, “We are seeing a significant shift in the treatment paradigm for early stage breast cancer. By making effective therapies available to high-risk patients in the earliest disease setting, we may delay or prevent cancer recurrences.’’
All eyes will indeed be on the large adjuvant APHINITY trial, with the hope that this was ultimately a critical first step in truly expediting the approval and availability of safe, highly effective treatments for patients with high-risk early BC and in significantly decreasing the risk of developing metastatic disease.
For patients with HER2+ breast cancer, whether newly diagnosed or long-term survivors, the HER2 Support Group provides information, resources, and support at http://her2support.org/.
The FDA’s Meeting Materials for the September 12, 2013 Meeting of the Oncologic Drugs Advisory Committee (ODAC) are available on the FDA’s website at http://tinyurl.com/bdsgot2
In addition, if you are interested in learning more about the FDA’s Patient Representative Program, visit http://www.fda.gov/forconsumers/byaudience/forpatientadvocates/patientinvolvement/ucm123858.htm.
Please note: The views expressed on these pages are mine alone and do not represent those of any other party.