ESMO 2020: BREAST CANCER RESEARCH SUMMARY

European Society For Medical Oncology 2020

Every year, the European Society for Medical Oncology (ESMO) hosts its annual conference, bringing together almost 30,000 clinicians, researchers and patients advocates from around 140 countries. These oncology professionals share their latest research and advances in treatments and help to translate the latest science into better patient care.

However, like most events this year, ESMO 2020 had to pivot to an online format, allowing researchers to participate across multiple different time zones to ensure they could hear the latest research results and work towards finding new and better treatments for their patients.

New and exciting breast cancer research was presented, and we have provided a summary of some of the key presentations below:

MonarchE Trial Results: Breakthrough In High Risk HR+ Breast Cancer Patient Treatment

The MonarchE clinical trial results have been described as promising for patients with early stage HR+ breast cancer.

Around 70% of breast cancer patients are diagnosed with hormone receptor positive (HR+) disease. Those with HR+ disease that has spread to the lymph nodes, have a large tumour size when diagnosed or have increased cellular proliferation, are considered to be of high risk of recurrence. These patients were recruited to the MonarchE trial as they had a higher risk of their breast cancer returning in the first two years.

The MonarchE trial found a 25 per cent reduction in recurrence of cancer within the first two years when the CDK 4/6 inhibitor abemaciclib was added to the standard hormone therapy, compared with the hormone therapy alone.

The phase three clinical trial was conducted worldwide and was led by UK researchers. It involved 5,637 patients in 38 countries. Researchers will continue their follow-up assessments to see if the benefit of this treatment continues beyond the two years measured.

SOLAR-1 Trial Results: Survival Benefit For Advanced Breast Cancer Patients With limited Treatment options

Some patients with HR positive, HER2 negative advanced breast cancer could see improved survival thanks to a new drug combination. The SOLAR-1 clinical was open to patients with HR-positive, HER2-negative advanced breast cancer. This analysis focussed on those who had the PI3KCA gene mutation, which was previously shown to benefit most from a PI3K inhibitor, alpelisib. It showed that by giving this group of patients alpelisib with fulvestrant, patients had an overall survival benefit of eight months, compared to a group taking a placebo and fulvestrant.

It is thought that the PI3K pathway (important in cell growth and survival) can become very active in cancer cells because of mutations in the PIK3CA gene, and that this pathway may be important when resistance to CDK4/6 inhibitors and endocrine therapy develops.

About 40% of HR-positive, HER2 negative breast cancers have a PIK3CA mutation. PIK3CA mutations can be found by testing tumour tissue or blood. A blood test is easy to perform, safe, less invasive than a tumour biopsy and can be repeated regularly.

These results are encouraging as they further support the use of alpelisib plus fulvestrant for patients with HR-positive, HER2-negative advanced breast cancer and PI3KCA mutations, a setting in which treatment options are very limited.

It also gives confidence to the Breast Cancer Trials CAPTURE study that is currently open to patients in Australia. The CAPTURE clinical trial will check approximately 400 patients with ER+, HER2 negative breast cancer via a blood test to see if they have the PIK3CA gene mutation in ctDNA. Those participants who have a confirmed PIK3CA gene mutation (approximately 140 (35%)) will be randomised 1:1 to receive alpelisib and fulvestrant (Arm A) or the standard treatment capecitabine (Arm B).

IMpassion 031: Encouraging News For Early Triple Negative Breast Cancer Patients

Data presented at ESMO 2020 from the IMpassion 130 clinical trial is encouraging for patients with early stage triple negative breast cancer.

The IMpassion 031 clinical trial found that neoadjuvant (pre-surgery) treatment with the immunotherapy drug, PD-L1 inhibitor atezolizumab, was associated with a significantly greater pathological complete response rate (no cancer cells left after treatment) when combined with standard chemotherapy. The patients receiving the trial treatment had a pathological complete response rate of 57.6%, compared with 41.1% for those on chemotherapy alone, in previously untreated patients with early triple negative breast cancer.

IMpassion 031 is a phase three clinical trial that enrolled those with stage two or three triple negative breast cancer. Patients received neoadjuvant atezolizumab or placebo plus nab-paclitaxel followed by standard dose-dense chemotherapy with doxorubicin/cyclophosphamide, prior to surgery. Atezolizumab or placebo was continued after surgery to complete one year of therapy.

Research into triple negative breast cancer is important, as this tumour type is typically associated with earlier recurrence and metastatic spread compared to other forms of breast cancer.

IMpassion 131: Results For Metastatic Triple Negative Patients Not As Encouraging As IMpassion 130 Results

Adding atezolizumab to paclitaxel does not improve progression-free survival or overall survival in patients with locally advanced or metastatic triple negative breast cancer, according to results from the Impassion 131 clinical trial presented at ESMO 2020.

The results of Impassion 131 showed that there was no significant difference between the atezolizumab and placebo arms in their response rates. The findings are in contrast to the IMpassion 031 study above, which enrolled patients with early stage breast cancer rather than metastatic, used nab-paclitaxel instead of paclitaxel. The researchers who led this study have said the potential reasons for such a difference between the two trials requires “further exploration.”

HER2CLIMB: Drug Shown To Improve Survival And Quality Of Life For Patients With HER2-Positive Metastatic Breast Cancer

Results from the HER2CLIMB clinical trial presented a ESMO 2020 has shown that the addition of the drug tucatinib (Tukysa) to trastuzumab (Herceptin) and capecitabine (Xeloda) significant improved progression-free survival and overall survival in patients with HER2-positive metastatic breast cancer, with and without brain metastases.

The results showed that, taken together, this treatment regimen improves survival for this group of patients but also maintains quality of life. In this total cohort of patients on the trial, the risk of death was reduced by 34%. The primary end point of progression free survival by blinded independent central review was assessed in the first 480 patients enrolled. Overall, risk of progression or death was reduced by 46%. In patients with brain metastases, risk of progression or death was reduced by 52%.