Twenty years ago, no targeted treatments existed for breast cancers with high levels of a protein called HER2 (HER2-positive, or HER2+). The significance of HER2 in breast cancer had only been recognized in 1987, when excessive levels of the protein were identified in about 20% of breast cancers. Oncologists realized that high levels of HER2 mark a type of cancer with a poor prognosis, as compared to the predominant type of breast cancer: estrogen receptor-positive, HER2 negative (HER2-).
The possibility of targeting HER2 to treat cancer was fulfilled in 1998, when the U.S. Food and Drug Administration (FDA) approved Herceptin (generic name trastuzumab), for treatment of metastatic HER2+ breast cancer. Made by Genentech, Herceptin is a type of drug known as a humanized antibody, meaning that it mimics an immune system attack on tumor cells, specifically those with high levels of HER2. Now, 20 years later, it is easier to appreciate the significance of this drug, which literally changed the lives of many HER2+ breast cancer patients, and continues to do so today. Continue reading…
“The FDA granted orphan drug designation to tucatinib for the treatment of patients with breast cancer whose disease metastasized to the brain, according to the drug’s manufacturer.
“Tucatinib (ONT-380, Cascadian Therapeutics) is an investigational, orally bioavailable, potent tyrosine kinase inhibitor that is highly selective for HER-2 without significant inhibition of EGFR, which has been associated with significant toxicities.”
“A phase I trial found that the HER2 inhibitor ONT-380 had a lower incidence of certain adverse events associated with this class of agent and notable anti-tumor activity in heavily pretreated patients with HER2-positive metastatic breast cancer (MBC).
” ‘Though existing targeted therapies are improving outcomes in patients with HER2-positive MBC, disease resistance does eventually develop in most patients,’ wrote study authors led by Stacy Moulder, MD, of the MD Anderson Cancer Center in Houston. Also, some agents preclude combination with other regimens due to off-target effects such as skin rash and diarrhea.”
University of Colorado Cancer Center | Jan 10, 2017
“Phase 1 clinical trial data published this week in the journal Clinical Cancer Research show early promise of the investigational anti-cancer agent tucatinib (formerly ONT-380) against HER2+ breast cancer. The 50 women treated had progressed despite a median 5 previous treatment regimens. Twenty-seven percent of these heavily pretreated patients saw clinical benefit from the drug, with at least ‘stable disease’ at 24 or more weeks after the start of treatment. These data have led to two subsequent Phase Ib studies, resulting in tucatinib earning FDA fast-track status and the expansion of this study once meant only to demonstrate drug safety into the “pivotal” trial that will determine approval.”
“Breast cancer patients sometimes end up dying when their tumors spread all the way to the brain. Some very good drugs already exist for patients with breast cancer, especially ones with tumors that overexpress the HER2 marker, but that success has raised a new question: Can drugmakers take another step, and fight those deadly brain metastases that get people in the end?
“Seattle-based Cascadian Therapeutics is testing that idea this week with researchers gathered at the San Antonio Breast Cancer Symposium. Cascadian is reporting today that patients who got conventional capecitabine and trastuzumab, plus an experimental small-molecule drug, tucatinib (aka ONT-380), lived a median of 7.8 months without their tumors getting worse. About 61% of patients on that triple-drug combo saw tumors shrink. It’s an impressive result, given that these patients were especially ill when they enrolled in the study, having already received a median of three prior rounds of HER2-targeted therapy. The data are also holding up over time: a snapshot of the data from June showed patients living a median of 6.3 months without their tumors spreading.”
Erika P. Hamilton, MD, associate director, Breast Cancer and Gynecologic Cancer Research Program, principal investigator, Sarah Cannon Research Institute, on ONT-380 for HER2-positive breast cancer and the treatment’s ability to cross the blood-brain barrier. Hamilton says the reason ONT-380’s ability to cross that barrier is important is because patients with HER2-positive breast cancer have a predilection to develop brain metastases.
She added that ONT-380 was proven to be effective when combined with capecitabine (Xeloda) and trastuzumab (Herceptin), though sometimes a combination of all three proved most useful. ONT-380 is a HER2-specific inhibitor and showed promising results when tested in patients with HER2-positive breast cancer who had previously received trastuzumab and T-DM1.
“Promising clinical trial results presented at the American Society for Clinical Oncology (ASCO) Annual Meeting 2015 show activity of the investigational anti-cancer agent ONT-380 against HER2+ breast cancer, in one case specifically against brain metastases and in another case in overall survival of heavily pretreated HER2+ breast cancer patients.
” ‘I am thrilled to have been able to offer this therapy to a patient in her early 40s. She didn’t have any other great treatment options that we would have expected to have any meaningful impact, especially on her brain. Now she’s been on the study over a year. The mets in her body are gone and the brain lesion has shrunk down to a little nubbin. She’s living a normal life, fretting about the family business and how the kids are doing – normal stuff,’ says Virginia Borges, MD, MMSc, director of the Breast Cancer Research Program and Young Women’s Breast Cancer Translational Program at the University of Colorado Cancer Center and one of the study’s authors.
“Both sets of results being presented are from ongoing phase 1b clinical trials of ONT-380, one in combination with the drug TDM-1, and the other in combination with capecitabine and/or trastuzumab. Women on these studies include those whose disease had progressed after at least two previous rounds of therapy (sometimes including previous drugs used to target HER2).”
The gist: A new targeted drug for HER2-positive, metastatic breast cancer has shown some early promise in clinical trials, and testing will continue to see whether it might be a good treatment option for patients. The drug is called ONT-380 (aka ARRY-380). In one trial, it is being tested in combination with the drug Kadcyla. In another trial, it is being combined with Xeloda (aka capecitabine) and/or Herceptin (aka trastuzumab). Both trials are testing ONT-380 in patients who have already tried other treatments.
“Oncothyreon Inc. (ONTY) today announced that positive preliminary data from two ongoing Phase 1b trials of ONT-380 (ARRY-380), an orally active, reversible and selective small molecule HER2 inhibitor, will be presented at the San Antonio Breast Cancer Symposium…
“ONT-380 was well-tolerated in both studies and in all combinations tested. The most common adverse events included nausea and vomiting, diarrhea, fatigue and elevated liver function tests. Most adverse events were grade 1 or 2 in severity. Elevated liver function tests were more common in patients also receiving Kadcyla. No grade 3 diarrhea was seen in either trial; anti-diarrheal prophylaxis was not a study requirement…
” ‘The preliminary signs of efficacy in both of these trials are encouraging for the further development of ONT-380,” said Stacy Moulder, M.D., Associate Professor, Breast Medical Oncology, University of Texas MD Anderson Cancer Center. “These patients were heavily pre-treated, with the majority already having a history of CNS metastases. Nevertheless, meaningful responses and prolonged stable disease have been observed and many patients currently remain on study. Importantly, ONT-380 has been well-tolerated, with a toxicity profile that facilitates its combination with other agents.”
” ‘We are continuing to enroll patients in both of these Phase 1b trials,’ said Diana Hausman, M.D., Chief Medical Officer of Oncothyreon. ‘We are currently testing an increased dose level of ONT-380 of 350 mg twice daily in both trials. We are also enrolling cohorts of patients in both trials with CNS metastases from HER2+ breast cancer that are either asymptomatic and untreated or progressive following treatment to better define the potential role of ONT-380 in treating patients with this serious unmet medical need.’ ”