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In an update of the PREDIX-HER2 trial, trastuzumab emtansine (T-DM1) remained equivalent to standard neoadjuvant chemotherapy plus dual-targeted HER2 therapy in producing pathologic complete remissions (pCRs) among patients with HER2-positive, metastatic breast cancer.
The new data also suggest tumor-infiltrating lymphocytes (TILs) and dramatic improvements in PET-CT scans can predict favorable outcomes in both treatment groups. Though these findings will be useful for research purposes, they likely won’t influence routine clinical practice.
Thomas Hatschek, MD, PhD, of Karolinska Institutet in Stockholm, presented the updated results from PREDIX-HER2 during the European Society for Medical Oncology: Breast Cancer virtual meeting.
PREDIX-HER2 included patients with HER2-positive breast cancer and tumor size greater than 20 mm or lymph node metastases.
Patients received neoadjuvant therapy (NAT) with docetaxel and trastuzumab plus pertuzumab (DTP) or T-DM1 every 3 weeks for a planned total of six courses. The protocol permitted switching to the competing treatment for progression, lack of response, or drug-related severe toxicity.
Postoperatively, all patients received triweekly epirubicin plus cyclophosphamide – four courses for the T-DM1 arm and two courses for the DTP arm. All patients then received triweekly adjuvant trastuzumab for 11 courses. The 62% of patients whose tumors were hormone receptor (HR)–positive received standard endocrine therapy postoperatively.
Updated results, predictors of pCR
At the 2019 ASCO annual meeting, PREDIX-HER2 investigators reported that, when compared with DTP, T-DM1 produced the same likelihood of pCR with less toxicity (ASCO 2019, Abstract 501). Updated data presented at ESMO Breast Cancer 2020 showed similar results.
The pCR rate was 45.5% in the DTP arm and 43.9% in the T-DM1 arm (P = .824). pCR rates were higher for HR-negative tumors – 63.6% in the DTP arm and 59% in the T-DM1 arm – than for HR-positive tumors – 36.4% in the DTP arm and 33.9% in the TDM-1 arm.
Three patients had disease progression with T-DM1, and none progressed with DTP. However, almost twice as many patients switched from DTP to T-DM1, compared with the other sequence.
Dr. Hatschek reported that the presence of at least 10% TILs predicted pCR in both treatment groups. Among patients who achieved a pCR, 52.2% had at least 10% TILs in baseline biopsies, and 30.4% had less than 10% TILs.
In addition, a decrease of FDG maximum standardized uptake value by more than 75% on protocol-required PET-CT scans was highly predictive of pCR. Among patients who achieved a pCR, 70.3% had a maximum standardized uptake value decrease of more than 75%, and 22.5% had a decrease of 75% or less.
At median follow-up of 28.5 months, event-free survival was similar between the treatment arms. Overall, there were 13 cases of progression, relapse, contralateral breast cancer, distant metastases, or death from any cause. There were five such events in the DTP arm and eight in the TDM-1 arm.
Dr. Hatschek concluded that neoadjuvant T-DM1 may be as effective as standard NAT in all clinical subgroups evaluated. Both TILs and PET-CT showed the potential to predict pCR and merit further study in the NAT setting.
An imperfect surrogate
By definition, a surrogate is “one appointed to act in place of another.” In the case of PREDIX-HER2 and most other NAT studies in HER2-positive breast cancer patients, pCR is a surrogate for the endpoint about which doctors and patients really care – cancer-free survival.
As such, pCR is not a perfect surrogate. Reproducibly, pCR has been highly predictive of disease-free survival and overall survival, especially in the HR-negative subset of HER2-positive patients.
However, despite improvements with dual targeting of HER2 in the TRYPHAENA trial (Eur J Cancer. 2018;89:27-35) and the use of T-DM1 for patients failing to achieve pCR in the immediately practice-changing KATHERINE trial (N Engl J Med. 2019;380:617-28), eventual relapse is seen in 10%-20% of patients in various clinical-pathologic subgroups.
In PREDIX-HER2, the pCR rate for node-positive patients was considerably lower with T-DM1 than with DTP (54.1% vs. 38%), noted Valentina Guarneri, MD, of the University of Padova (Italy), in her discussion of the trial at ESMO Breast Cancer 2020.
Patients with larger initial tumor size and multiple involved axillary nodes at diagnosis remain at increased risk of death because of cancer relapse.
Central nervous system relapse remains a vexing problem. Among patients with triple-positive breast cancer, relapses may occur late, despite pCR.
Patients whose tumors transform from HER2 positive to HER2 negative with NAT, seen in approximately 8% of cases in the KATHERINE trial (ESMO Breast Cancer 2020, Abstract 96O), may be another poor-risk group.
Clinical implications
PREDIX-HER2 is an important study. At the early time point of 2.4 years (especially early since most patients were HR-positive), if pCR is achieved, event-free survival is excellent with T-DM1 or an aggressive multiagent cytotoxic combination plus dual HER2 targeting followed by anthracyclines.
It is ideal to have clinical-pathologic tests to distinguish those patients destined to achieve the surrogate endpoint of pCR from those who will not achieve it.
Despite linkage of TILs to improved outcome for triple-negative and HER2-enriched molecular subtypes (Lancet Oncol. 2018 Jan;19[1]:40-50), analysis of TILs is not standard practice in HER2-positive breast cancer in community settings. Optimal cutoffs are not well established, and TILs have not been linked to the choice of particular treatment options.
Currently, PET-CT scans are not part of National Comprehensive Cancer Network guidelines for pretreatment evaluation, except in patients for whom there is clinical suspicion of distant disease.
For those reasons, the main results of PREDIX-HER2 remain research tools that will focus our attention on the clinical-pathologic correlations Dr. Hatschek highlighted, but the results should have no influence on routine clinical practice at this time.
PREDIX-HER2 was funded by the Swedish Cancer Society, Radiumhemmet of Karolinska Institutet, Region Stockholm, and Roche Sweden. Dr. Hatschek disclosed relationships with Roche Sweden, Pfizer Sweden, and Pierre Fabre Sweden. Dr. Guarneri disclosed relationships with Roche, Novartis, and Eli Lilly.
Dr. Lyss was a community-based medical oncologist and clinical researcher for more than 35 years before his recent retirement. His clinical and research interests were focused on breast and lung cancers as well as expanding clinical trial access to medically underserved populations. He is based in St. Louis. He has no conflicts of interest.
SOURCE: Hatschek T et al. ESMO Breast Cancer 2020, Abstract 97O.
In an update of the PREDIX-HER2 trial, trastuzumab emtansine (T-DM1) remained equivalent to standard neoadjuvant chemotherapy plus dual-targeted HER2 therapy in producing pathologic complete remissions (pCRs) among patients with HER2-positive, metastatic breast cancer.
The new data also suggest tumor-infiltrating lymphocytes (TILs) and dramatic improvements in PET-CT scans can predict favorable outcomes in both treatment groups. Though these findings will be useful for research purposes, they likely won’t influence routine clinical practice.
Thomas Hatschek, MD, PhD, of Karolinska Institutet in Stockholm, presented the updated results from PREDIX-HER2 during the European Society for Medical Oncology: Breast Cancer virtual meeting.
PREDIX-HER2 included patients with HER2-positive breast cancer and tumor size greater than 20 mm or lymph node metastases.
Patients received neoadjuvant therapy (NAT) with docetaxel and trastuzumab plus pertuzumab (DTP) or T-DM1 every 3 weeks for a planned total of six courses. The protocol permitted switching to the competing treatment for progression, lack of response, or drug-related severe toxicity.
Postoperatively, all patients received triweekly epirubicin plus cyclophosphamide – four courses for the T-DM1 arm and two courses for the DTP arm. All patients then received triweekly adjuvant trastuzumab for 11 courses. The 62% of patients whose tumors were hormone receptor (HR)–positive received standard endocrine therapy postoperatively.
Updated results, predictors of pCR
At the 2019 ASCO annual meeting, PREDIX-HER2 investigators reported that, when compared with DTP, T-DM1 produced the same likelihood of pCR with less toxicity (ASCO 2019, Abstract 501). Updated data presented at ESMO Breast Cancer 2020 showed similar results.
The pCR rate was 45.5% in the DTP arm and 43.9% in the T-DM1 arm (P = .824). pCR rates were higher for HR-negative tumors – 63.6% in the DTP arm and 59% in the T-DM1 arm – than for HR-positive tumors – 36.4% in the DTP arm and 33.9% in the TDM-1 arm.
Three patients had disease progression with T-DM1, and none progressed with DTP. However, almost twice as many patients switched from DTP to T-DM1, compared with the other sequence.
Dr. Hatschek reported that the presence of at least 10% TILs predicted pCR in both treatment groups. Among patients who achieved a pCR, 52.2% had at least 10% TILs in baseline biopsies, and 30.4% had less than 10% TILs.
In addition, a decrease of FDG maximum standardized uptake value by more than 75% on protocol-required PET-CT scans was highly predictive of pCR. Among patients who achieved a pCR, 70.3% had a maximum standardized uptake value decrease of more than 75%, and 22.5% had a decrease of 75% or less.
At median follow-up of 28.5 months, event-free survival was similar between the treatment arms. Overall, there were 13 cases of progression, relapse, contralateral breast cancer, distant metastases, or death from any cause. There were five such events in the DTP arm and eight in the TDM-1 arm.
Dr. Hatschek concluded that neoadjuvant T-DM1 may be as effective as standard NAT in all clinical subgroups evaluated. Both TILs and PET-CT showed the potential to predict pCR and merit further study in the NAT setting.
An imperfect surrogate
By definition, a surrogate is “one appointed to act in place of another.” In the case of PREDIX-HER2 and most other NAT studies in HER2-positive breast cancer patients, pCR is a surrogate for the endpoint about which doctors and patients really care – cancer-free survival.
As such, pCR is not a perfect surrogate. Reproducibly, pCR has been highly predictive of disease-free survival and overall survival, especially in the HR-negative subset of HER2-positive patients.
However, despite improvements with dual targeting of HER2 in the TRYPHAENA trial (Eur J Cancer. 2018;89:27-35) and the use of T-DM1 for patients failing to achieve pCR in the immediately practice-changing KATHERINE trial (N Engl J Med. 2019;380:617-28), eventual relapse is seen in 10%-20% of patients in various clinical-pathologic subgroups.
In PREDIX-HER2, the pCR rate for node-positive patients was considerably lower with T-DM1 than with DTP (54.1% vs. 38%), noted Valentina Guarneri, MD, of the University of Padova (Italy), in her discussion of the trial at ESMO Breast Cancer 2020.
Patients with larger initial tumor size and multiple involved axillary nodes at diagnosis remain at increased risk of death because of cancer relapse.
Central nervous system relapse remains a vexing problem. Among patients with triple-positive breast cancer, relapses may occur late, despite pCR.
Patients whose tumors transform from HER2 positive to HER2 negative with NAT, seen in approximately 8% of cases in the KATHERINE trial (ESMO Breast Cancer 2020, Abstract 96O), may be another poor-risk group.
Clinical implications
PREDIX-HER2 is an important study. At the early time point of 2.4 years (especially early since most patients were HR-positive), if pCR is achieved, event-free survival is excellent with T-DM1 or an aggressive multiagent cytotoxic combination plus dual HER2 targeting followed by anthracyclines.
It is ideal to have clinical-pathologic tests to distinguish those patients destined to achieve the surrogate endpoint of pCR from those who will not achieve it.
Despite linkage of TILs to improved outcome for triple-negative and HER2-enriched molecular subtypes (Lancet Oncol. 2018 Jan;19[1]:40-50), analysis of TILs is not standard practice in HER2-positive breast cancer in community settings. Optimal cutoffs are not well established, and TILs have not been linked to the choice of particular treatment options.
Currently, PET-CT scans are not part of National Comprehensive Cancer Network guidelines for pretreatment evaluation, except in patients for whom there is clinical suspicion of distant disease.
For those reasons, the main results of PREDIX-HER2 remain research tools that will focus our attention on the clinical-pathologic correlations Dr. Hatschek highlighted, but the results should have no influence on routine clinical practice at this time.
PREDIX-HER2 was funded by the Swedish Cancer Society, Radiumhemmet of Karolinska Institutet, Region Stockholm, and Roche Sweden. Dr. Hatschek disclosed relationships with Roche Sweden, Pfizer Sweden, and Pierre Fabre Sweden. Dr. Guarneri disclosed relationships with Roche, Novartis, and Eli Lilly.
Dr. Lyss was a community-based medical oncologist and clinical researcher for more than 35 years before his recent retirement. His clinical and research interests were focused on breast and lung cancers as well as expanding clinical trial access to medically underserved populations. He is based in St. Louis. He has no conflicts of interest.
SOURCE: Hatschek T et al. ESMO Breast Cancer 2020, Abstract 97O.
In an update of the PREDIX-HER2 trial, trastuzumab emtansine (T-DM1) remained equivalent to standard neoadjuvant chemotherapy plus dual-targeted HER2 therapy in producing pathologic complete remissions (pCRs) among patients with HER2-positive, metastatic breast cancer.
The new data also suggest tumor-infiltrating lymphocytes (TILs) and dramatic improvements in PET-CT scans can predict favorable outcomes in both treatment groups. Though these findings will be useful for research purposes, they likely won’t influence routine clinical practice.
Thomas Hatschek, MD, PhD, of Karolinska Institutet in Stockholm, presented the updated results from PREDIX-HER2 during the European Society for Medical Oncology: Breast Cancer virtual meeting.
PREDIX-HER2 included patients with HER2-positive breast cancer and tumor size greater than 20 mm or lymph node metastases.
Patients received neoadjuvant therapy (NAT) with docetaxel and trastuzumab plus pertuzumab (DTP) or T-DM1 every 3 weeks for a planned total of six courses. The protocol permitted switching to the competing treatment for progression, lack of response, or drug-related severe toxicity.
Postoperatively, all patients received triweekly epirubicin plus cyclophosphamide – four courses for the T-DM1 arm and two courses for the DTP arm. All patients then received triweekly adjuvant trastuzumab for 11 courses. The 62% of patients whose tumors were hormone receptor (HR)–positive received standard endocrine therapy postoperatively.
Updated results, predictors of pCR
At the 2019 ASCO annual meeting, PREDIX-HER2 investigators reported that, when compared with DTP, T-DM1 produced the same likelihood of pCR with less toxicity (ASCO 2019, Abstract 501). Updated data presented at ESMO Breast Cancer 2020 showed similar results.
The pCR rate was 45.5% in the DTP arm and 43.9% in the T-DM1 arm (P = .824). pCR rates were higher for HR-negative tumors – 63.6% in the DTP arm and 59% in the T-DM1 arm – than for HR-positive tumors – 36.4% in the DTP arm and 33.9% in the TDM-1 arm.
Three patients had disease progression with T-DM1, and none progressed with DTP. However, almost twice as many patients switched from DTP to T-DM1, compared with the other sequence.
Dr. Hatschek reported that the presence of at least 10% TILs predicted pCR in both treatment groups. Among patients who achieved a pCR, 52.2% had at least 10% TILs in baseline biopsies, and 30.4% had less than 10% TILs.
In addition, a decrease of FDG maximum standardized uptake value by more than 75% on protocol-required PET-CT scans was highly predictive of pCR. Among patients who achieved a pCR, 70.3% had a maximum standardized uptake value decrease of more than 75%, and 22.5% had a decrease of 75% or less.
At median follow-up of 28.5 months, event-free survival was similar between the treatment arms. Overall, there were 13 cases of progression, relapse, contralateral breast cancer, distant metastases, or death from any cause. There were five such events in the DTP arm and eight in the TDM-1 arm.
Dr. Hatschek concluded that neoadjuvant T-DM1 may be as effective as standard NAT in all clinical subgroups evaluated. Both TILs and PET-CT showed the potential to predict pCR and merit further study in the NAT setting.
An imperfect surrogate
By definition, a surrogate is “one appointed to act in place of another.” In the case of PREDIX-HER2 and most other NAT studies in HER2-positive breast cancer patients, pCR is a surrogate for the endpoint about which doctors and patients really care – cancer-free survival.
As such, pCR is not a perfect surrogate. Reproducibly, pCR has been highly predictive of disease-free survival and overall survival, especially in the HR-negative subset of HER2-positive patients.
However, despite improvements with dual targeting of HER2 in the TRYPHAENA trial (Eur J Cancer. 2018;89:27-35) and the use of T-DM1 for patients failing to achieve pCR in the immediately practice-changing KATHERINE trial (N Engl J Med. 2019;380:617-28), eventual relapse is seen in 10%-20% of patients in various clinical-pathologic subgroups.
In PREDIX-HER2, the pCR rate for node-positive patients was considerably lower with T-DM1 than with DTP (54.1% vs. 38%), noted Valentina Guarneri, MD, of the University of Padova (Italy), in her discussion of the trial at ESMO Breast Cancer 2020.
Patients with larger initial tumor size and multiple involved axillary nodes at diagnosis remain at increased risk of death because of cancer relapse.
Central nervous system relapse remains a vexing problem. Among patients with triple-positive breast cancer, relapses may occur late, despite pCR.
Patients whose tumors transform from HER2 positive to HER2 negative with NAT, seen in approximately 8% of cases in the KATHERINE trial (ESMO Breast Cancer 2020, Abstract 96O), may be another poor-risk group.
Clinical implications
PREDIX-HER2 is an important study. At the early time point of 2.4 years (especially early since most patients were HR-positive), if pCR is achieved, event-free survival is excellent with T-DM1 or an aggressive multiagent cytotoxic combination plus dual HER2 targeting followed by anthracyclines.
It is ideal to have clinical-pathologic tests to distinguish those patients destined to achieve the surrogate endpoint of pCR from those who will not achieve it.
Despite linkage of TILs to improved outcome for triple-negative and HER2-enriched molecular subtypes (Lancet Oncol. 2018 Jan;19[1]:40-50), analysis of TILs is not standard practice in HER2-positive breast cancer in community settings. Optimal cutoffs are not well established, and TILs have not been linked to the choice of particular treatment options.
Currently, PET-CT scans are not part of National Comprehensive Cancer Network guidelines for pretreatment evaluation, except in patients for whom there is clinical suspicion of distant disease.
For those reasons, the main results of PREDIX-HER2 remain research tools that will focus our attention on the clinical-pathologic correlations Dr. Hatschek highlighted, but the results should have no influence on routine clinical practice at this time.
PREDIX-HER2 was funded by the Swedish Cancer Society, Radiumhemmet of Karolinska Institutet, Region Stockholm, and Roche Sweden. Dr. Hatschek disclosed relationships with Roche Sweden, Pfizer Sweden, and Pierre Fabre Sweden. Dr. Guarneri disclosed relationships with Roche, Novartis, and Eli Lilly.
Dr. Lyss was a community-based medical oncologist and clinical researcher for more than 35 years before his recent retirement. His clinical and research interests were focused on breast and lung cancers as well as expanding clinical trial access to medically underserved populations. He is based in St. Louis. He has no conflicts of interest.
SOURCE: Hatschek T et al. ESMO Breast Cancer 2020, Abstract 97O.
FROM ESMO BREAST CANCER 2020