Phase III Randomized Study of Ribociclib and Fulvestrant in Hormone Receptor–Positive, Human Epidermal Growth Factor Receptor 2–Negative Advanced Breast Cancer: MONALEESA-3

Purpose

This phase III study evaluated ribociclib plus fulvestrant in patients with hormone receptor–positive/human epidermal growth factor receptor 2–negative advanced breast cancer who were treatment naïve or had received up to one line of prior endocrine therapy in the advanced setting.

Patients and Methods

Patients were randomly assigned at a two-to-one ratio to ribociclib plus fulvestrant or placebo plus fulvestrant. The primary end point was locally assessed progression-free survival. Secondary end points included overall survival, overall response rate, and safety.

Results

A total of 484 postmenopausal women were randomly assigned to ribociclib plus fulvestrant, and 242 were assigned to placebo plus fulvestrant. Median progression-free survival was significantly improved with ribociclib plus fulvestrant versus placebo plus fulvestrant: 20.5 months (95% CI, 18.5 to 23.5 months) versus 12.8 months (95% CI, 10.9 to 16.3 months), respectively (hazard ratio, 0.593; 95% CI, 0.480 to 0.732; P < .001). Consistent treatment effects were observed in patients who were treatment naïve in the advanced setting (hazard ratio, 0.577; 95% CI, 0.415 to 0.802), as well as in patients who had received up to one line of prior endocrine therapy for advanced disease (hazard ratio, 0.565; 95% CI, 0.428 to 0.744). Among patients with measurable disease, the overall response rate was 40.9% for the ribociclib plus fulvestrant arm and 28.7% for placebo plus fulvestrant. Grade 3 adverse events reported in ≥ 10% of patients in either arm (ribociclib plus fulvestrant v placebo plus fulvestrant) were neutropenia (46.6% v 0%) and leukopenia (13.5% v 0%); the only grade 4 event reported in ≥ 5% of patients was neutropenia (6.8% v 0%).

Conclusion

Ribociclib plus fulvestrant might represent a new first- or second-line treatment option in hormone receptor–positive/human epidermal growth factor receptor 2–negative advanced breast cancer.

Second cancers in Hodgkin's lymphoma long-term survivals: A 60-year single institutional experience with real-life cohort of 871 patients

BACKGROUND AND PURPOSE

Appropriate surveillance guidelines for patients after successful treatment of Hodgkin's lymphoma (HL) are needed to reduce mortality of iatrogenic secondary cancers (SC). This large single institutional retrospective study analyses the risk of SC in HL patients treated outside of clinical trials over past decades.

MATERIAL AND METHODS

Consecutive series of HL patients were analysed with median follow-up 12 years. Standardised incidence ratio (SIR) and absolute excess risk (AER) were calculated for site-specific risk of SC.

RESULTS

In total of 871 patients (491 men; median age 34 years), chemotherapy alone, radiotherapy alone, and combined treatment underwent 36%, 40%, and 24% patients. 154 SC were found with significantly increased SIR = 2.9 and AER = 80.8 for all cancers except of nonmelanoma-skin cancer. SC-related death occurred in 71 patients (15% of those who died, 8% of whole cohort). The most common SC were lung (17.5% of all malignancies, SIR = 3.2), breast carcinoma (15.6%, SIR = 4.4), and haematological malignancy (non-Hodgkin's lymphoma SIR = 13.1; leukaemia SIR = 5.8). For SC within radiation field, the highest AER was in breast (AER = 46.9), colorectal (AER = 22.8), and lung cancer (AER = 17).

CONCLUSIONS

Patients with HL are generally at great risk of developing SC, which is significantly increased especially by the use of radiotherapy. We suggested special follow-up schema for patients after initial HL treatment suitable for daily real-world clinical practice. The system depends on gender, form of HL treatment and especially the form of radiation therapy in terms of location of radiation fields.

Abstract P5-21-18: Subsequent treatment for postmenopausal women with hormone receptor-positive, HER2-negative advanced breast cancer who received ribociclib + letrozole vs placebo + letrozole in the phase III MONALEESA-2 study

Background: In the Phase III MONALEESA-2 study (NCT01958021), ribociclib (RIB; cyclin-dependent kinase 4/6 inhibitor [CDK4/6i]) + letrozole (LET) significantly prolonged progression-free survival (PFS) vs placebo (PBO) + LET in postmenopausal women with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2–) advanced breast cancer (ABC). The optimal treatment sequence following first-line CDK4/6i-based therapy is not yet known. Here we report the subsequent therapies received following discontinuation from MONALEESA-2.

Methods: The MONALEESA-2 study enrolled 668 patients (pts) with HR+, HER2– ABC. Pts were randomized 1:1 to receive RIB (600 mg/day; 3-weeks-on/1-week-off) + LET (2.5 mg/day; continuous) or PBO + LET. Following discontinuation of MONALEESA-2 study treatment, pts were followed for information regarding post-study treatment, including type and duration of therapy.

Results: At data cut-off (January 2, 2017), the median duration of follow-up was 26.4 months. Median PFS was 25.3 vs 16.0 months in the RIB + LET vs PBO + LET arms (hazard ratio=0.568; 95% confidence interval [CI]: 0.457–0.704; p=9.63x10–8). 203 (60.8%) vs 246 (73.7%) pts had discontinued RIB + LET vs PBO + LET. The median time to end of treatment was 20.3 months in the RIB + LET arm vs 13.7 months in the PBO + LET arm. First subsequent antineoplastic treatment was reported for 172/203 (84.7%) vs 212/246 (86.2%) pts who received RIB + LET vs PBO + LET; second subsequent therapy was reported for 45/203 (22.2%) vs 68/246 (27.6%) pts. The median time to first subsequent therapy (from randomization to the first post-study dose of therapy) was 24.2 (95% CI: 20.9–27.6) vs 16.7 (95% CI: 14.8–19.3) months in pts who received RIB + LET vs PBO + LET; median time to initiation of second subsequent therapy was not reached in either arm. The most common type of first subsequent therapy was single-agent hormonal therapy in 90 (44.3%) vs 87 (35.4%) pts who discontinued RIB + LET vs PBO + LET; chemotherapy was the most common second subsequent therapy in 20 (9.9%) vs 36 (14.6%) pts. Chemotherapy alone was the first subsequent treatment after MONALEESA-2 discontinuation in 32 (15.8%) vs 55 (22.4%) pts treated with RIB + LET vs PBO + LET.

Conclusions: RIB + LET significantly prolongs PFS and delays the start of subsequent lines of therapy vs PBO + LET in pts with HR+, HER2– ABC. The most common first subsequent therapy following discontinuation of RIB + LET or PBO + LET was single-agent hormonal therapy, and fewer pts treated with RIB + LET received subsequent chemotherapy compared with those who received PBO + LET.

Citation Format: Blackwell KL, Paluch-Shimon S, Campone M, Conte P, Petrakova K, Favret A, Blau S, Beck JT, Miller M, Sutradhar S, Monaco M, Burris HA. Subsequent treatment for postmenopausal women with hormone receptor-positive, HER2-negative advanced breast cancer who received ribociclib + letrozole vs placebo + letrozole in the phase III MONALEESA-2 study [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-21-18.

Abstract PD4-06: First-line ribociclib + letrozole in hormone receptor-positive, HER2-negative advanced breast cancer: Efficacy by baseline circulating tumor DNA alterations in MONALEESA-2

Background: The addition of first-line ribociclib (RIB; cyclin-dependent kinase 4/6 inhibitor) to letrozole (LET) significantly improved progression-free survival (PFS) compared with placebo (PBO) + LET in patients (pts) with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2–) advanced breast cancer (ABC) in the Phase III MONALEESA-2 study. Identifying biomarkers that predict response to treatment remains a key challenge in pts with HR+ ABC. Here we analyze results from MONALEESA-2 by molecular alterations detected in circulating tumor DNA (ctDNA) at baseline, including PIK3CA mutations and other alterations considered to be important in HR+ ABC.

Methods: Postmenopausal women (N=668) with HR+, HER2– ABC who had not received any prior therapy for ABC were randomized 1:1 to RIB (600 mg/day; 3-weeks-on/1-week-off) + LET (2.5 mg/day; continuous) or PBO + LET. The primary endpoint was PFS. Biomarker analysis of the ctDNA mutation profile was an exploratory endpoint. Plasma samples for ctDNA analysis were collected at baseline and end of treatment. ctDNA was analyzed using next-generation sequencing with a targeted panel of ˜550 genes.

Results: Baseline ctDNA was successfully sequenced in 494 pts (RIB + LET: n=212; PBO + LET: n=215); 67 (14%) of 494 pts were removed from the analysis due to limited tumor DNA in circulation. 427 (86%) pts had ≥1 alteration, including 1,573 mutations, 513 short insertions/deletions, 166 amplifications, and 8 translocations. Alterations (frequency) were commonly observed in the following genes: PIK3CA (33%), TP53 (12%), ZNF703/FGFR1 (5%), and ESR1 (4%), and in genes involved in receptor tyrosine kinase (RTK) signaling (12%). RIB + LET treatment benefit was consistent in pts with wild-type (WT) and altered PIK3CA, and in pts with WT and altered TP53 (Table). RIB + LET improved PFS regardless of RTK or ZNF703/FGFR1 alterations. However, there was a weak trend for increased benefit in pts with WT vs altered RTK genes and in pts with WT vs altered ZNF703/FGFR1 genes. These results should be interpreted with caution due to the small number of pts with these alterations. There were too few ESR1 alterations for firm conclusions to be drawn.

 Events, n/NMedian PFS, months Gene(s)RIB + LETPBO + LETRIB + LETPBO + LETHazard ratio (95% confidence interval)PIK3CAWT54/14393/14229.614.70.44 (0.31–0.62)Altered40/6955/7319.212.70.53 (0.35–0.81)TP53WT72/180129/19427.614.70.44 (0.33–0.59)Altered22/3219/2110.25.50.43 (0.23–0.83)ZNF703/FGFR1WT88/202139/20524.814.60.47 (0.36–0.62)Altered6/109/1010.611.40.73 (0.23–2.29)RTKWT81/189128/18724.814.40.46 (0.35–0.61)Altered13/2320/2821.311.40.72 (0.34–1.53)

Conclusions: Consistent RIB + LET treatment benefit was observed compared with PBO + LET, irrespective of the status of baseline ctDNA biomarkers.

Citation Format: Hortobagyi GN, Stemmer S, Campone M, Sonke GS, Arteaga CL, Paluch-Shimon S, Petrakova K, Villanueva C, Nusch A, Grischke E-M, Chan A, Jakobsen E, Marschner N, Hart LL, Alba E, Ohnstand HO, Blau S, Yardley DA, Solovieff N, Su F, Germa C, Yap Y-S. First-line ribociclib + letrozole in hormone receptor-positive, HER2-negative advanced breast cancer: Efficacy by baseline circulating tumor DNA alterations in MONALEESA-2 [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr PD4-06.

Abstract P5-21-31: Treatment patterns and outcomes of pertuzumab in combination with trastuzumab and docetaxel as first-line treatment of metastatic HER-2 positive breast cancer : Comparison of Czech clinical registry and CLEOPATRA trial data

Key words: pertuzumab, HER-2 positive, breast cancer

Background: The present retrospective analysis was conducted to evaluate efficacy of pertuzumab, a monoclonal antibody, used in combination with trastuzumab and docetaxel as first-line therapy for metastatic HER-2 positive breast cancer in real-world clinical practice. The database of the Czech Clinical Registry of cancer patients treated with pertuzumab was used.

Materials and methods: Data of patients included in the national registry were analyzed and the outcomes were compared with the results of the Phase III CLEOPATRA trial (Baselga et al 2012). The registry is estimated to cover at least 95% of patients treated with the regimen outside of clinical trials.

Results: : A total of 182 patients (mean age 56.5 years) were included in the present analysis. Patients had performance status of 0 (61.0%) or 1 (39%), 64.6% were postmenopausal, 62,6% had visceral disease and 36.8% received neo/adjuvant trastuzumab. The median progression-free survival of 21.2 months (95% CI 12.2–NR [not reached]) for patients included in the registry was longer, compared to 18.5 months reported in the CLEOPATRA trial, although the difference did not reach statistical significance (p=0.13). Best response was evaluable in 79.7% of patients. The overall response and disease control rates were 57.2% and 98.6%, respectively. Median overall survival has not been reached; the survival at 18 months was 86.6% (95% CI 75.7%-92.9%). Pertuzumab with trastuzumab and docetaxel was well tolerated with adverse events (AEs) attributed to pertuzumab reported in 8 patients. No AEs were life- threatening.

Conclusion: Pertuzumab in combination with trastuzumab and docetaxel is an effective and well-tolerated first-line therapy for patients with metastatic HER-2 positive breast cancer in real-world clinical practice setting. The PFS observed was consistent with data of CLEOPATRA trial.

Citation Format: Studentova H, Petrakova K, Tesarova P, Buchler T, Chloupkova R, Hejduk K, Melichar B. Treatment patterns and outcomes of pertuzumab in combination with trastuzumab and docetaxel as first-line treatment of metastatic HER-2 positive breast cancer : Comparison of Czech clinical registry and CLEOPATRA trial data [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-21-31.

Pazopanib for Metastatic Renal Cell Carcinoma: A Registry-based Analysis of 426 Patients

BACKGROUND

Pazopanib is approved for the first-line treatment of patients with metastatic renal cell carcinoma (mRCC). The present study was a retrospective registry-based analysis of 426 patients with mRCC treated with pazopanib as first-line targeted therapy.

PATIENTS AND METHODS

The data were obtained from the Renal Cell Carcinoma Information system registry. Patient baseline parameters, treatment course and outcomes, and toxicity were analysed.

RESULTS

Median progression-free and overall survival were 12.9 (95% confidence interval(CI)=11.0-14.8) months and 33.2 (95% CI=29.9-36.4) months, respectively. Overall response rate and disease control rate were 25.1% and 57.4%, respectively. Adverse events led to discontinuation of treatment in 37 (12.1%) patients.

CONCLUSION

The results confirm that pazopanib is an effective and safe first-line targeted treatment in patients with mRCC. Both the International mRCC Database Consortium and the Memorial Sloan Kettering models were valid predictors of prognosis and nephrectomy was associated with improved survival.

Ribociclib plus letrozole versus letrozole alone in patients with de novo HR+, HER2- advanced breast cancer in the randomized MONALEESA-2 trial

PURPOSE

Determine the efficacy and safety of first-line ribociclib plus letrozole in patients with de novo advanced breast cancer.

METHODS

Postmenopausal women with HR+ , HER2- advanced breast cancer and no prior systemic therapy for advanced disease were enrolled in the Phase III MONALEESA-2 trial (NCT01958021). Patients were randomized to ribociclib (600 mg/day; 3 weeks-on/1 week-off) plus letrozole (2.5 mg/day; continuous) or placebo plus letrozole until disease progression, unacceptable toxicity, death, or treatment discontinuation. The primary endpoint was investigator-assessed progression-free survival; predefined subgroup analysis evaluated progression-free survival in patients with de novo advanced breast cancer. Secondary endpoints included safety and overall response rate.

RESULTS

Six hundred and sixty-eight patients were enrolled, of whom 227 patients (34%; ribociclib plus letrozole vs placebo plus letrozole arm: n = 114 vs. n = 113) presented with de novo advanced breast cancer. Median progression-free survival was not reached in the ribociclib plus letrozole arm versus 16.4 months in the placebo plus letrozole arm in patients with de novo advanced breast cancer (hazard ratio 0.45, 95% confidence interval 0.27-0.75). The most common Grade 3/4 adverse events were neutropenia and leukopenia; incidence rates were similar to those observed in the full MONALEESA-2 population. Ribociclib dose interruptions and reductions in patients with de novo disease occurred at similar frequencies to the overall study population.

CONCLUSIONS

Ribociclib plus letrozole improved progression-free survival vs placebo plus letrozole and was well tolerated in postmenopausal women with HR+, HER2- de novo advanced breast cancer.

Updated results from MONALEESA-2, a phase 3 trial of first-line ribociclib + letrozole in hormone receptor-positive (HR+), HER2-negative (HER2–), advanced breast cancer (ABC)

1038

Background: Endocrine therapy (ET) is the basis of first-line (1L) treatment for HR+ ABC. However, ET resistance are almost universal. At the first interim analysis (IA) of MONALEESA-2 (NCT01958021), ribociclib (RIB; cyclin-dependent kinase 4/6 inhibitor) + letrozole (LET) significantly prolonged progression-free survival (PFS) vs placebo (PBO) + LET in patients (pts) with HR+, HER2– ABC.1 Here we report updated efficacy and safety data from MONALEESA-2 with a further ~11 months of follow-up. Methods: Postmenopausal women with no prior therapy for ABC were randomized 1:1 toRIB (600 mg/day, 3-weeks-on/1-week-off) + LET(2.5 mg/day, continuous) vs PBO + LET. The primary endpoint was locally assessed PFS. Secondary endpoints include overall survival (OS; key) and safety. OS significance was defined by a p-value threshold of 3.15 x 10-5. Tumor assessments were performed every 8 weeks for the first 18 months, and every 12 weeks, thereafter. Results: 668 pts were enrolled (334 in each arm). At the second IA for OS (data cut-off Jan 2, 2017), the median duration of follow-up was 26.4 months; 116 deaths and 345 PFS events had occurred. OS data remain immature, with 15.0% vs 19.8% of pt deaths in the RIB + LET vs PBO + LET arm (HR = 0.746; 95% CI: 0.517–1.078; p= 0.059). Updated PFS analyses confirmed continued treatment benefit in the RIB + LET vs PBO + LET arm. The 24-month PFS rates (RIB + LET vs PBO + LET) were 54.7% vs 35.9%. Treatment benefit was consistent across pt subgroups. The most common Grade 3/4 laboratory abnormalities (≥10% of pts; RIB + LET vs PBO + LET) were decreased neutrophils (62.6% vs 1.5%), decreased leukocytes (36.8% vs 1.5%), decreased lymphocytes (16.2% vs 3.9%), and elevated alanine aminotransferase (11.4% vs 1.2%). Conclusion: After 26+ months of follow-up, treatment benefit with 1LRIB + LET persists in postmenopausal women with HR+, HER2– ABC. The study remains immature for OS analysis. The safety profile of RIB + LET remains manageable. 1. Hortobagyi G, et al. N Engl J Med 2016;375:1738–48. Clinical trial information: NCT01958021.

Abstract P4-22-05: First-line ribociclib plus letrozole in patients with de novo HR+, HER2– advanced breast cancer (ABC): A subgroup analysis of the MONALEESA-2 trial

Background: Around 15,000 US patients per year are diagnosed with de novo ABC. Due to the absence of prior systemic treatment for breast cancer, tumors of patients with de novo ABC may exhibit a different disease biology, which could result in different tumor responses compared with patients who have relapsed breast cancer. Ribociclib is an orally bioavailable cyclin-dependent kinase (CDK) 4/6 inhibitor. Results from MONALEESA-2, a double-blind, placebo-controlled, randomized Phase 3 trial (NCT01958021), demonstrated that first-line therapy with ribociclib + letrozole significantly improved progression-free survival (PFS) vs placebo + letrozole in patients with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2–) ABC. Many patients with de novo ABC receive endocrine therapy in the first line and in subsequent lines; here we present results from the MONALEESA-2 study in a subpopulation of patients with de novo ABC.

Methods: Postmenopausal women (N=668) with HR+, HER2– ABC who had no prior systemic therapy for ABC were randomized 1:1 (stratified by liver and/or lung metastases) to receive ribociclib (600 mg/day; 3-weeks-on/1-week-off) + letrozole (2.5 mg/day; continuous) or placebo + letrozole. Patients with de novo ABC were eligible. Additional eligibility criteria included measurable disease or ≥1 predominantly lytic bone lesion, Eastern Cooperative Oncology Group performance status ≤1, and adequate bone marrow/organ function. Prior CDK4/6 inhibitors or systemic therapy for ABC were prohibited. Patients may have received ≤14 days of letrozole or anastrozole for ABC. The primary endpoint was locally assessed PFS; a predefined subgroup analysis evaluated PFS in patients with de novo ABC.

Results: In total, 227 patients with de novo ABC were enrolled. Patients with de novo ABC were equally distributed with 114 (34%) and 113 (34%) in the ribociclib + letrozole and placebo + letrozole arms, respectively. Median duration of exposure to study treatment in the ribociclib + letrozole vs placebo + letrozole arms was 14.1 vs 12.8 months. Treatment was discontinued in 84 (37%) patients with de novo ABC (ribociclib + letrozole vs placebo + letrozole, n [%]; 34 [30%] vs 50 [44%]). Reasons for treatment discontinuation (ribociclib + letrozole vs placebo + letrozole, n [%]) included disease progression (21 [18%] vs 41 [36%]), patient/physician decision (5 [4%] vs 6 [5%]), and adverse events (6 [5%] vs 3 [3%]). PFS was increased in patients with de novo ABC who received ribociclib + letrozole vs placebo + letrozole (hazard ratio=0.448 [95% confidence interval: 0.267–0.750]). The 12-month PFS event-free probability in patients with de novo ABC was 82% in the ribociclib + letrozole arm vs 66% in the placebo + letrozole arm.

Conclusions: The combination of ribociclib + letrozole significantly improved PFS compared with placebo + letrozole in postmenopausal women with HR+, HER2– de novo ABC at diagnosis and therefore may become an important treatment option in the de novo ABC setting.

Keywords: Advanced breast cancer; CDK4/6 inhibitor; Letrozole; Ribociclib

Citation Format: O'Shaughnessy J, Petrakova K, Sonke GS, André F, Conte P, Arteaga CL, Cameron DA, Hart LL, Villanueva C, Jakobsen EH, Lindquist D, Souami F, Li X, Germa C, Hirawat S, Hortobagyi GN. First-line ribociclib plus letrozole in patients with de novo HR+, HER2– advanced breast cancer (ABC): A subgroup analysis of the MONALEESA-2 trial [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-22-05.

Abstract P4-21-12: Preference of trastuzumab administration route (intravenous or subcutaneous) in patients in the Czech Republic. Cross-sectional study on 429 patients

Background: Trastuzumab is the treatment for HER2-positive breast cancer in the metastatic, adjuvant, and neoadjuvant settings. Trastuzumab is available in intravenous (i.v.) and subcutaneous (s.c.) application form. PrefHer study published in 2013 described patients' preference for use of subcutaneous trastuzumab. Our aim was to find out and describe if any preference exists in real clinical practice in the Czech Republic.

Objectives: To analyse reasons for preference of s.c. or i.v. application of trastuzumab in patients with HER2-positive breast cancer in real clinical setting in the Czech Republic.

Methods: A questionnaire based data collection from patients treated in Comprehensive Cancer Centres between January 2015 and July 2015.

Results: We received 429 questionnaires from patients. Data analysis has been conducted in 301 (70.2%) patients' questionnaires after quality control for questionnaires completeness. Out of the 301 patients there were 151 who had ≥ 11 i.v. applications, 137 patients with 3-10 i.v. applications and 13 patients with only 2 i.v. applications. Majority of patients were treated in adjuvant setting (62.8%, n=189), 21.9% (n=66) received neoadjuvant treatment and 15.3% (n=46) patients were treated for advanced disease. Only 33 patients had experience with ≥ 11 s.c. applications, 222 patients with 3-10 s.c. applications and 46 patients with 2 s.c. applications. Subcutaneous form was given in 74.8% (n=225) in adjuvant setting, in 20.3% (n=61) in advanced setting and in 5.0% (n=15) in neoadjuvant setting. Pain related to trastuzumab application was assessed – 52.2% (n=157) patients stated that s.c. application is less painful, 34.2% (n=103) did not see difference and 13.6% (n=41) patients felt that i.v. form is less painful. When assessing site reactions majority (62.4%, n=184) of patients did not see difference between application forms, 20.0% (n=59) patients preferred s.c. form and 17.6% (n=52) preferred i.v. form. Lower anxiety related to trastuzumab application was reported with s.c. form (46.0%, n=137). Only 6.0% (n=18) patients reported lower anxiety with i.v. application and 48.0% (n=143) did not see any difference. Vast majority (92.7%, n=279) patients described s.c. form as more comfortable, 4.7% (n=14) patients did not see difference and only 2.7% (n=8) described i.v. form as more comfortable. Overall 95.0% (n=286) patients preferred s.c. application form of trastuzumab. The main reasons are time savings (86.7%, n=261) and better comfort (71.8%, n=216). Only 10 patients (3.3%) favoured i.v. application form. The main reason for i.v. preference is lower pain and lower incidence of complications (2.0%, n=6). The remaining 5 patients (1.7%) had no preference of any application form.

Conclusion: Patients treated in Comprehensive Cancer Centres in the Czech Republic prefer subcutaneous application form of trastuzumab. The main reasons for their preference are time savings and better application comfort.

Citation Format: Petrakova K, Melichar B, Bortlicek Z, Hejduk K. Preference of trastuzumab administration route (intravenous or subcutaneous) in patients in the Czech Republic. Cross-sectional study on 429 patients [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-21-12.

Ribociclib as First-Line Therapy for HR-Positive, Advanced Breast Cancer

BACKGROUND

The inhibition of cyclin-dependent kinases 4 and 6 (CDK4/6) could potentially overcome or delay resistance to endocrine therapy in advanced breast cancer that is positive for hormone receptor (HR) and negative for human epidermal growth factor receptor 2 (HER2).

METHODS

In this randomized, placebo-controlled, phase 3 trial, we evaluated the efficacy and safety of the selective CDK4/6 inhibitor ribociclib combined with letrozole for first-line treatment in 668 postmenopausal women with HR-positive, HER2-negative recurrent or metastatic breast cancer who had not received previous systemic therapy for advanced disease. We randomly assigned the patients to receive either ribociclib (600 mg per day on a 3-weeks-on, 1-week-off schedule) plus letrozole (2.5 mg per day) or placebo plus letrozole. The primary end point was investigator-assessed progression-free survival. Secondary end points included overall survival, overall response rate, and safety. A preplanned interim analysis was performed on January 29, 2016, after 243 patients had disease progression or died. Prespecified criteria for superiority required a hazard ratio of 0.56 or less with P<1.29×10^-5.

RESULTS

The duration of progression-free survival was significantly longer in the ribociclib group than in the placebo group (hazard ratio, 0.56; 95% CI, 0.43 to 0.72; P=3.29×10^-6 for superiority). The median duration of follow-up was 15.3 months. After 18 months, the progression-free survival rate was 63.0% (95% confidence interval [CI], 54.6 to 70.3) in the ribociclib group and 42.2% (95% CI, 34.8 to 49.5) in the placebo group. In patients with measurable disease at baseline, the overall response rate was 52.7% and 37.1%, respectively (P<0.001). Common grade 3 or 4 adverse events that were reported in more than 10% of the patients in either group were neutropenia (59.3% in the ribociclib group vs. 0.9% in the placebo group) and leukopenia (21.0% vs. 0.6%); the rates of discontinuation because of adverse events were 7.5% and 2.1%, respectively.

CONCLUSIONS

Among patients receiving initial systemic treatment for HR-positive, HER2-negative advanced breast cancer, the duration of progression-free survival was significantly longer among those receiving ribociclib plus letrozole than among those receiving placebo plus letrozole, with a higher rate of myelosuppression in the ribociclib group. (Funded by Novartis Pharmaceuticals; ClinicalTrials.gov number, NCT01958021 .).

Pictilisib for oestrogen receptor-positive, aromatase inhibitor-resistant, advanced or metastatic breast cancer (FERGI): a randomised, double-blind, placebo-controlled, phase 2 trial

BACKGROUND

Inhibition of phosphatidylinositol 3-kinase (PI3K) is a promising approach to overcome resistance to endocrine therapy in breast cancer. Pictilisib is an oral inhibitor of multiple PI3K isoforms. The aim of this study is to establish if addition of pictilisib to fulvestrant can improve progression-free survival in oestrogen receptor-positive, endocrine-resistant breast cancer.

METHODS

In this two-part, randomised, double-blind, placebo-controlled, phase 2 study, we recruited postmenopausal women aged 18 years or older with oestrogen receptor-positive, HER2-negative breast cancer resistant to treatment with an aromatase inhibitor in the adjuvant or metastatic setting, from 123 medical centres across 21 countries. Part 1 included patients with or without PIK3CA mutations, whereas part 2 included only patients with PIK3CA mutations. Patients were randomly allocated (1:1 in part 1 and 2:1 in part 2) via a computer-generated hierarchical randomisation algorithm to daily oral pictilisib (340 mg in part 1 and 260 mg in part 2) or placebo starting on day 15 of cycle 1, plus intramuscular fulvestrant 500 mg on day 1 and day 15 of cycle 1 and day 1 of subsequent cycles in both groups. In part 1, we stratified patients by presence or absence of PIK3CA mutation, primary or secondary aromatase inhibitor resistance, and measurable or non-measurable disease. In part 2, we stratified patients by previous aromatase inhibitor treatment for advanced or metastatic disease or relapse during or within 6 months of an aromatase inhibitor treatment in the adjuvant setting and measurable or non-measurable disease. All patients and those administering treatment and assessing outcomes were masked to treatment assignment. The primary endpoint was progression-free survival in the intention-to-treat population for both parts 1 and 2 and also separately in patients with PIK3CA-mutated tumours in part 1. Tumour assessment (physical examination and imaging scans) was investigator-assessed and done at screening and after 8 weeks, 16 weeks, 24 weeks, and 32 weeks of treatment from day 1 of cycle 1 and every 12 weeks thereafter. We assessed safety in as-treated patients who received at least one dose of study medication. This trial is registered with ClinicalTrials.gov, number NCT01437566.

FINDINGS

In part 1, between Sept 27, 2011, and Jan 11, 2013, we randomly allocated 168 patients to the pictilisib (89 [53%]) or placebo (79 [47%]) group. In part 2, between March 18, 2013, and Jan 2, 2014, we randomly allocated 61 patients to the pictilisib (41 [67%]) or placebo (20 [33%]) group. In part 1, we found no difference in median progression-free survival between the pictilisib (6·6 months [95% CI 3·9-9·8]) and placebo (5·1 months [3·6-7·3]) group (hazard ratio [HR] 0·74 [95% CI 0·52-1·06]; p=0·096). We also found no difference when patients were analysed according to presence (pictilisib 6·5 months [95% CI 3·7-9·8] vs placebo 5·1 months [2·6-10·4]; HR 0·73 [95% CI 0·42-1·28]; p=0·268) or absence (5·8 months [3·6-11·1] vs 3·6 months [2·8-7·3]; HR 0·72 [0·42-1·23]; p=0·23) of PIK3CA mutation. In part 2, we also found no difference in progression-free survival between groups (5·4 months [95% CI 3·8-8·3] vs 10·0 months [3·6-13·0]; HR 1·07 [95% CI 0·53-2·18]; p=0·84). In part 1, grade 3 or worse adverse events occurred in 54 (61%) of 89 patients in the pictilisib group and 22 (28%) of 79 in the placebo group. 19 serious adverse events related to pictilisib treatment were reported in 14 (16%) of 89 patients. Only one (1%) of 79 patients reported treatment-related serious adverse events in the placebo group. In part 2, grade 3 or worse adverse events occurred in 15 (36%) of 42 patients in the pictilisib group and seven (37%) of 19 patients in the placebo group. Four serious adverse events related to pictilisib treatment were reported in two (5%) of 42 patients. One treatment-related serious adverse event occurred in one (5%) of 19 patients in the placebo group.

INTERPRETATION

Although addition of pictilisib to fulvestrant did not significantly improve progression-free survival, dosing of pictilisib was limited by toxicity, potentially limiting its efficacy. For future assessment of PI3K inhibition as an approach to overcome resistance to hormonal therapy, inhibitors with greater selectivity than that of pictilisib might be needed to improve tolerability and potentially increase efficacy. No further investigation of pictilisib in this setting is ongoing.

FUNDING

F Hoffmann-La Roche.

Neratinib after trastuzumab-based adjuvant therapy in patients with HER2-positive breast cancer (ExteNET): a multicentre, randomised, double-blind, placebo-controlled, phase 3 trial

BACKGROUND

Neratinib, an irreversible tyrosine-kinase inhibitor of HER1, HER2, and HER4, has clinical activity in patients with HER2-positive metastatic breast cancer. We aimed to investigate the efficacy and safety of 12 months of neratinib after trastuzumab-based adjuvant therapy in patients with early-stage HER2-positive breast cancer.

METHODS

We did this multicentre, randomised, double-blind, placebo-controlled, phase 3 trial at 495 centres in Europe, Asia, Australia, New Zealand, and North and South America. Eligible women (aged ≥18 years, or ≥20 years in Japan) had stage 1-3 HER2-positive breast cancer and had completed neoadjuvant and adjuvant trastuzumab therapy up to 2 years before randomisation. Inclusion criteria were amended on Feb 25, 2010, to include patients with stage 2-3 HER2-positive breast cancer who had completed trastuzumab therapy up to 1 year previously. Patients were randomly assigned (1:1) to receive oral neratinib 240 mg per day or matching placebo. The randomisation sequence was generated with permuted blocks stratified by hormone receptor status (hormone receptor-positive [oestrogen or progesterone receptor-positive or both] vs hormone receptor-negative [oestrogen and progesterone receptor-negative]), nodal status (0, 1-3, or ≥4), and trastuzumab adjuvant regimen (sequentially vs concurrently with chemotherapy), then implemented centrally via an interactive voice and web-response system. Patients, investigators, and trial sponsors were masked to treatment allocation. The primary outcome was invasive disease-free survival, as defined in the original protocol, at 2 years after randomisation. Analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00878709.

FINDINGS

Between July 9, 2009, and Oct 24, 2011, we randomly assigned 2840 women to receive neratinib (n=1420) or placebo (n=1420). Median follow-up time was 24 months (IQR 20-25) in the neratinib group and 24 months (22-25) in the placebo group. At 2 year follow-up, 70 invasive disease-free survival events had occurred in patients in the neratinib group versus 109 events in those in the placebo group (stratified hazard ratio 0·67, 95% CI 0·50-0·91; p=0·0091). The 2-year invasive disease-free survival rate was 93·9% (95% CI 92·4-95·2) in the neratinib group and 91·6% (90·0-93·0) in the placebo group. The most common grade 3-4 adverse events in patients in the neratinib group were diarrhoea (grade 3, n=561 [40%] and grade 4, n=1 [<1%] vs grade 3, n=23 [2%] in the placebo group), vomiting (grade 3, n=47 [3%] vs n=5 [<1%]), and nausea (grade 3, n=26 [2%] vs n=2 [<1%]). QT prolongation occurred in 49 (3%) patients given neratinib and 93 (7%) patients given placebo, and decreases in left ventricular ejection fraction (≥grade 2) in 19 (1%) and 15 (1%) patients, respectively. We recorded serious adverse events in 103 (7%) patients in the neratinib group and 85 (6%) patients in the placebo group. Seven (<1%) deaths (four patients in the neratinib group and three patients in the placebo group) unrelated to disease progression occurred after study drug discontinuation. The causes of death in the neratinib group were unknown (n=2), a second primary brain tumour (n=1), and acute myeloid leukaemia (n=1), and in the placebo group were a brain haemorrhage (n=1), myocardial infarction (n=1), and gastric cancer (n=1). None of the deaths were attributed to study treatment in either group.

INTERPRETATION

Neratinib for 12 months significantly improved 2-year invasive disease-free survival when given after chemotherapy and trastuzumab-based adjuvant therapy to women with HER2-positive breast cancer. Longer follow-up is needed to ensure that the improvement in breast cancer outcome is maintained.

FUNDING

Wyeth, Pfizer, Puma Biotechnology.

Abstract S2-02: The FERGI phase II study of the PI3K inhibitor pictilisib (GDC-0941) plus fulvestrant vs fulvestrant plus placebo in patients with ER+, aromatase inhibitor (AI)-resistant advanced or metastatic breast cancer – Part I results

Background: Preclinical and clinical data indicate a key role for the PI3-kinase (PI3K) pathway in the pathogenesis of resistance to endocrine therapies in hormone receptor-positive (HR) breast cancer (BC) and suggest that combining PI3K inhibitors with endocrine therapy may partially overcome this resistance. FERGI is the first randomized Phase II study testing pictilisib (GDC-0941), a PI3K inhibitor, in combination with fulvestrant to evaluate this hypothesis in MBC patients with and without PIK3CA-mutant tumors.

Methods: 168 post-menopausal pts with ER-positive, HER2-negative MBC were randomized (1:1) to receive fulvestrant with either pictilisib 340 mg QD (n=89, "combination" arm) or matching placebo (n=79, "control" arm). To be eligible, pts had to have relapsed during or within 6 mos of completing adjuvant AI treatment or have progressed on an AI for MBC. Pts were stratified based on tumor PIK3CA mutation status, resistance to prior AI therapy and presence of measurable disease. The primary endpoint was PFS by investigator assessment in the intent-to-treat (ITT) group and in pts with centrally confirmed PIK3CA-mutant tumors. The primary analysis was based on a 6 mo median duration follow up.

Results: Baseline disease and prior treatment characteristics were similar between study arms. Observed treatment-emergent AEs were consistent with those previously described for single agent pictilisib and fulvestrant (primary toxicities were rash and GI disorders). In the ITT population (84 events) the median PFS (mPFS) was 6.2 mo in the combination arm vs 3.8 months for the control arm (HR, 0.77; 95% CI, 0.50-1.19). For pts with PIK3CA-mutant tumors (37 events), mPFS was 6.2 mo in the combination arm vs 5.1 mo in the control arm (HR, 0.92; 95% CI, 0.48-1.76). For pts without a detectable PIK3CA mutant tumor (43 events), mPFS was 5.8 months in the combination arm vs 3.6 months in the control arm (HR, 0.64; 95% CI, 0.35-1.17). Exploratory post-hoc subgroup analysis suggested improvement in PFS in pts with ER+ and PR+ tumors (centrally confirmed) treated with pictilisib plus fulvestrant. In the ER+/PR+ subgroup (57 events) mPFS was 7.2 mo in the combination arm vs 3.7 mo in the control arm (HR, 0.46; 95% CI, 0.27 to 0.78). This improvement was independent of tumor PIK3CA mutation status. Multivariate analysis suggests that this treatment effect in pts with ER+/PR+ tumors is maintained after adjusting for possible baseline imbalances. A similar analysis on pts with luminal A tumors (per PAM50 analysis) was also consistent with the findings in pts ER+/PR+ disease.

Conclusions: This is the first report of a blinded, randomized clinical study evaluating a PI3K inhibitor in pts with MBC. In the ITT population, the addition of pictilisib to fulvestrant was associated with a mPFS improvement of 3.8 mo to 6.2 mo. Exploratory subgroup analyses suggested in pts with ER+/PR+ tumors are more likely to derive benefit from the addition of pictilisib to fulvestrant irrespective of PIK3CA mutation status, though the subgroup analyses are limited by the sample size. Additional biomarker analyses will be reported.

Citation Format: Ian Krop, Stephen Johnston, Ingrid A Mayer, Maura Dickler, Vinod Ganju, Andres Forero-Torres, Bohuslav Melichar, Serafin Morales, Richard de Boer, Steven Gendreau, Mika Derynck, Mark Lackner, Jill Spoerke, Ru-Fang Yeh, Gallia Levy, Vivian Ng, Carol O'Brien, Heidi Savage, Yuanyuan Xiao, Timothy Wilson, Soo Chin Lee, Katarina Petrakova, Susanne Vallentin, Denise Yardley, Matthew Ellis, Martine Piccart, Edith A Perez, Eric Winer, Peter Schmid. The FERGI phase II study of the PI3K inhibitor pictilisib (GDC-0941) plus fulvestrant vs fulvestrant plus placebo in patients with ER+, aromatase inhibitor (AI)-resistant advanced or metastatic breast cancer – Part I results [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr S2-02.