Everolimus/exemestane improves PFS of ER+/HER2– breast cancer vs. everolimus alone

CHICAGO – For women with estrogen receptor–positive breast cancer resistant to endocrine therapy, the combination of everolimus and exemestane had better efficacy than did everolimus alone, but single-agent capecitabine appeared to offer benefit comparable to that of the combination therapy, results of the BOLERO-6 trial suggest.

Among 309 postmenopausal women with ER-positive, HER2-negative advanced breast cancer, the combination of everolimus (Afinitor) and exemestane (Aromasin and generics) was associated with a 26% improvement in progression-free survival (PFS) compared with everolimus alone, reported Guy Jerusalem, MD, PhD, of Liege University, Belgium.

There was also, however, a numerical but not statistically significant difference in PFS favoring capecitabine (Xeloda and generics) “which may be attributed to various baseline characteristics favoring capecitabine, and potential informative censoring,” he said at the annual meeting of the American Society of Clinical Oncology.

“We have noted in BOLERO-6 a better-than-expected outcome in median progression-free survival of capecitabine compared with the previously reported 4.1 to 7.9 months median progression-free survival,” he said.

BOLERO-6, results of which were published online June 3 in JAMA Oncology, was a postmarketing study by the sponsors to fulfill commitments to both the Food and Drug Administration and the European Medicines Agency to estimate the treatment benefit with combined everolimus and exemestane vs. monotherapy with everolimus or capecitabine in patients with ER-positive, HER2-negative breast cancer that progressed during nonsteroidal aromatase inhibitor therapy.

Patients from 83 centers in 18 countries were enrolled in the open label, phase 2 study and randomly assigned to receive oral everolimus 10 mg daily with oral exemestane 25 mg daily, everolimus at the same dose alone, or oral capecitabine 1,250 mg/m² twice daily for 2 weeks on, 1 week off.

The trial was not powered for statistical comparisons between arms, but was instead designed with the primary objective of estimated investigator-assessed PFS for the combination vs. everolimus alone.

At baseline, more patients assigned to capecitabine vs. everolimus-containing regimens were younger than 65, white, had an Eastern Cooperative Oncology Group status of 0 (fully active), and had bone-only metastases. In addition, fewer patients in the capecitabine arm had three or more metastatic sites, Dr. Jerusalem noted,

For the primary analysis, the median PFS with everolimus/exemestane was 8.4 months, compared with 6.8 months for everolimus alone. The estimated hazard ratio (HR) for PFS with everolimus/exemestane vs. everolimus alone was 0.74 (90% confidence interval [CI], 0.57-0.97)

In contrast, median PFS with capecitabine was 9.6 months, with a nonsignificant hazard ratio of 1.26 for the combination (90% CI, 0.96-1.66).

A stratified multivariate Cox regression model controlling for baseline difference and known prognostic factor yielded an HR for PFS of 1.15 (90% CI, 0.86-1.52) for the combination.

Censoring of patients was more frequent in the capecitabine arm (33% vs. 23% in the combination arm), which included 20% of patients on capecitabine who were censored for starting on a new antineoplastic therapy vs. 9% of patients on everolimus/exemestane.

The median time to treatment failure was 5.8 months with the combination, vs. 4.2 months with everolimus alone (HR, 0.66, 90% CI, 0.52-0.4), and 6.2 months with capecitabine alone (HR, 1.03, 90% CI, 0.81-1.31).

Median overall survival was 23.1 months in the combination arm, 29.3 months in the everolimus arm, and 25.6 months in the capecitabine arm. There were no statistically significant differences in overall survival among the groups.

Grade 3 or greater adverse events were more frequent in the combination vs. everolimus arms, and comparable between the combination and capecitabine arms, Dr. Jerusalem said.

Serious adverse events of any grade were more frequent in the combination arm than in the other two arms, but there were no significant differences in discontinuations due to adverse events

“The results of the present study suggest that mTOR inhibitor and endocrine therapy combinations remain important for aromatase inhibitor–refractory disease. Safety and PFS with everolimus plus exemestane in this study were consistent with BOLERO-2 and are now supported by real-world evidence,” the investigators wrote.

“The take home from the BOLERO-6 trial is that the progression-free survival for the combination of everolimus and exemestane is superior to everolimus alone, and is in line with data from the BOLERO-2 trial, and also the PrE0102 study, demonstrating the consistent activity of mTOR inhibition in combination with endocrine therapy in the aromatase inhibitor resistance setting, and this supports our use of the combination in the endocrine resistant patients,” said Cynthia X. Ma, MD, PhD, of Washington University, St. Louis, the invited discussant.

Novartis funded the study. Dr Jerusalem received research funding from Novartis and Roche; honoraria from Novartis, Roche, Pfizer, Lilly, Celgene, Amgen, BMS, and Puma Technology; and nonfinancial support from Novartis, Roche, Pfizer, Lilly, Amgen, and BMS. Dr. Ma reported consulting/advising, travel expenses, and institutional research funding from Novartis and others.

SOURCE: Jerusalem G et al. ASCO 2018 Abstract 1005

CHICAGO – For women with estrogen receptor–positive breast cancer resistant to endocrine therapy, the combination of everolimus and exemestane had better efficacy than did everolimus alone, but single-agent capecitabine appeared to offer benefit comparable to that of the combination therapy, results of the BOLERO-6 trial suggest.

Among 309 postmenopausal women with ER-positive, HER2-negative advanced breast cancer, the combination of everolimus (Afinitor) and exemestane (Aromasin and generics) was associated with a 26% improvement in progression-free survival (PFS) compared with everolimus alone, reported Guy Jerusalem, MD, PhD, of Liege University, Belgium.

There was also, however, a numerical but not statistically significant difference in PFS favoring capecitabine (Xeloda and generics) “which may be attributed to various baseline characteristics favoring capecitabine, and potential informative censoring,” he said at the annual meeting of the American Society of Clinical Oncology.

“We have noted in BOLERO-6 a better-than-expected outcome in median progression-free survival of capecitabine compared with the previously reported 4.1 to 7.9 months median progression-free survival,” he said.

BOLERO-6, results of which were published online June 3 in JAMA Oncology, was a postmarketing study by the sponsors to fulfill commitments to both the Food and Drug Administration and the European Medicines Agency to estimate the treatment benefit with combined everolimus and exemestane vs. monotherapy with everolimus or capecitabine in patients with ER-positive, HER2-negative breast cancer that progressed during nonsteroidal aromatase inhibitor therapy.

Patients from 83 centers in 18 countries were enrolled in the open label, phase 2 study and randomly assigned to receive oral everolimus 10 mg daily with oral exemestane 25 mg daily, everolimus at the same dose alone, or oral capecitabine 1,250 mg/m² twice daily for 2 weeks on, 1 week off.

The trial was not powered for statistical comparisons between arms, but was instead designed with the primary objective of estimated investigator-assessed PFS for the combination vs. everolimus alone.

At baseline, more patients assigned to capecitabine vs. everolimus-containing regimens were younger than 65, white, had an Eastern Cooperative Oncology Group status of 0 (fully active), and had bone-only metastases. In addition, fewer patients in the capecitabine arm had three or more metastatic sites, Dr. Jerusalem noted,

For the primary analysis, the median PFS with everolimus/exemestane was 8.4 months, compared with 6.8 months for everolimus alone. The estimated hazard ratio (HR) for PFS with everolimus/exemestane vs. everolimus alone was 0.74 (90% confidence interval [CI], 0.57-0.97)

In contrast, median PFS with capecitabine was 9.6 months, with a nonsignificant hazard ratio of 1.26 for the combination (90% CI, 0.96-1.66).

A stratified multivariate Cox regression model controlling for baseline difference and known prognostic factor yielded an HR for PFS of 1.15 (90% CI, 0.86-1.52) for the combination.

Censoring of patients was more frequent in the capecitabine arm (33% vs. 23% in the combination arm), which included 20% of patients on capecitabine who were censored for starting on a new antineoplastic therapy vs. 9% of patients on everolimus/exemestane.

The median time to treatment failure was 5.8 months with the combination, vs. 4.2 months with everolimus alone (HR, 0.66, 90% CI, 0.52-0.4), and 6.2 months with capecitabine alone (HR, 1.03, 90% CI, 0.81-1.31).

Median overall survival was 23.1 months in the combination arm, 29.3 months in the everolimus arm, and 25.6 months in the capecitabine arm. There were no statistically significant differences in overall survival among the groups.

Grade 3 or greater adverse events were more frequent in the combination vs. everolimus arms, and comparable between the combination and capecitabine arms, Dr. Jerusalem said.

Serious adverse events of any grade were more frequent in the combination arm than in the other two arms, but there were no significant differences in discontinuations due to adverse events

“The results of the present study suggest that mTOR inhibitor and endocrine therapy combinations remain important for aromatase inhibitor–refractory disease. Safety and PFS with everolimus plus exemestane in this study were consistent with BOLERO-2 and are now supported by real-world evidence,” the investigators wrote.

“The take home from the BOLERO-6 trial is that the progression-free survival for the combination of everolimus and exemestane is superior to everolimus alone, and is in line with data from the BOLERO-2 trial, and also the PrE0102 study, demonstrating the consistent activity of mTOR inhibition in combination with endocrine therapy in the aromatase inhibitor resistance setting, and this supports our use of the combination in the endocrine resistant patients,” said Cynthia X. Ma, MD, PhD, of Washington University, St. Louis, the invited discussant.

Novartis funded the study. Dr Jerusalem received research funding from Novartis and Roche; honoraria from Novartis, Roche, Pfizer, Lilly, Celgene, Amgen, BMS, and Puma Technology; and nonfinancial support from Novartis, Roche, Pfizer, Lilly, Amgen, and BMS. Dr. Ma reported consulting/advising, travel expenses, and institutional research funding from Novartis and others.

SOURCE: Jerusalem G et al. ASCO 2018 Abstract 1005

CHICAGO – For women with estrogen receptor–positive breast cancer resistant to endocrine therapy, the combination of everolimus and exemestane had better efficacy than did everolimus alone, but single-agent capecitabine appeared to offer benefit comparable to that of the combination therapy, results of the BOLERO-6 trial suggest.

Among 309 postmenopausal women with ER-positive, HER2-negative advanced breast cancer, the combination of everolimus (Afinitor) and exemestane (Aromasin and generics) was associated with a 26% improvement in progression-free survival (PFS) compared with everolimus alone, reported Guy Jerusalem, MD, PhD, of Liege University, Belgium.

There was also, however, a numerical but not statistically significant difference in PFS favoring capecitabine (Xeloda and generics) “which may be attributed to various baseline characteristics favoring capecitabine, and potential informative censoring,” he said at the annual meeting of the American Society of Clinical Oncology.

“We have noted in BOLERO-6 a better-than-expected outcome in median progression-free survival of capecitabine compared with the previously reported 4.1 to 7.9 months median progression-free survival,” he said.

BOLERO-6, results of which were published online June 3 in JAMA Oncology, was a postmarketing study by the sponsors to fulfill commitments to both the Food and Drug Administration and the European Medicines Agency to estimate the treatment benefit with combined everolimus and exemestane vs. monotherapy with everolimus or capecitabine in patients with ER-positive, HER2-negative breast cancer that progressed during nonsteroidal aromatase inhibitor therapy.

Patients from 83 centers in 18 countries were enrolled in the open label, phase 2 study and randomly assigned to receive oral everolimus 10 mg daily with oral exemestane 25 mg daily, everolimus at the same dose alone, or oral capecitabine 1,250 mg/m² twice daily for 2 weeks on, 1 week off.

The trial was not powered for statistical comparisons between arms, but was instead designed with the primary objective of estimated investigator-assessed PFS for the combination vs. everolimus alone.

At baseline, more patients assigned to capecitabine vs. everolimus-containing regimens were younger than 65, white, had an Eastern Cooperative Oncology Group status of 0 (fully active), and had bone-only metastases. In addition, fewer patients in the capecitabine arm had three or more metastatic sites, Dr. Jerusalem noted,

For the primary analysis, the median PFS with everolimus/exemestane was 8.4 months, compared with 6.8 months for everolimus alone. The estimated hazard ratio (HR) for PFS with everolimus/exemestane vs. everolimus alone was 0.74 (90% confidence interval [CI], 0.57-0.97)

In contrast, median PFS with capecitabine was 9.6 months, with a nonsignificant hazard ratio of 1.26 for the combination (90% CI, 0.96-1.66).

A stratified multivariate Cox regression model controlling for baseline difference and known prognostic factor yielded an HR for PFS of 1.15 (90% CI, 0.86-1.52) for the combination.

Censoring of patients was more frequent in the capecitabine arm (33% vs. 23% in the combination arm), which included 20% of patients on capecitabine who were censored for starting on a new antineoplastic therapy vs. 9% of patients on everolimus/exemestane.

The median time to treatment failure was 5.8 months with the combination, vs. 4.2 months with everolimus alone (HR, 0.66, 90% CI, 0.52-0.4), and 6.2 months with capecitabine alone (HR, 1.03, 90% CI, 0.81-1.31).

Median overall survival was 23.1 months in the combination arm, 29.3 months in the everolimus arm, and 25.6 months in the capecitabine arm. There were no statistically significant differences in overall survival among the groups.

Grade 3 or greater adverse events were more frequent in the combination vs. everolimus arms, and comparable between the combination and capecitabine arms, Dr. Jerusalem said.

Serious adverse events of any grade were more frequent in the combination arm than in the other two arms, but there were no significant differences in discontinuations due to adverse events

“The results of the present study suggest that mTOR inhibitor and endocrine therapy combinations remain important for aromatase inhibitor–refractory disease. Safety and PFS with everolimus plus exemestane in this study were consistent with BOLERO-2 and are now supported by real-world evidence,” the investigators wrote.

“The take home from the BOLERO-6 trial is that the progression-free survival for the combination of everolimus and exemestane is superior to everolimus alone, and is in line with data from the BOLERO-2 trial, and also the PrE0102 study, demonstrating the consistent activity of mTOR inhibition in combination with endocrine therapy in the aromatase inhibitor resistance setting, and this supports our use of the combination in the endocrine resistant patients,” said Cynthia X. Ma, MD, PhD, of Washington University, St. Louis, the invited discussant.

Novartis funded the study. Dr Jerusalem received research funding from Novartis and Roche; honoraria from Novartis, Roche, Pfizer, Lilly, Celgene, Amgen, BMS, and Puma Technology; and nonfinancial support from Novartis, Roche, Pfizer, Lilly, Amgen, and BMS. Dr. Ma reported consulting/advising, travel expenses, and institutional research funding from Novartis and others.

SOURCE: Jerusalem G et al. ASCO 2018 Abstract 1005