Updated overall survival from the MONALEESA-3 trial in postmenopausal women with HR+/HER2- advanced breast cancer receiving first-line ribociclib plus fulvestrant

BACKGROUND

The phase III MONALEESA-3 trial included first- (1L) and second-line (2L) patients and demonstrated a significant overall survival (OS) benefit for ribociclib + fulvestrant in patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative (HR+/HER2-) advanced breast cancer (ABC) in the final protocol-specified and exploratory (longer follow-up) OS analyses. At the time of these analyses, the full OS benefit of 1L ribociclib was not completely characterized because the median OS (mOS) was not reached. As CDK4/6 inhibitor (CDK4/6i) + endocrine therapy (ET) is now a preferred option for 1L HR+/HER2- ABC, we report an exploratory analysis (median follow-up, 70.8 months; 14.5 months longer than the prior analysis) to fully elucidate the OS benefit in the MONALEESA-3 1L population.

METHODS

Postmenopausal patients with HR+/HER2- ABC were randomized 2:1 to 1L/2L fulvestrant + ribociclib or placebo. OS in 1L patients (de novo disease or relapse > 12 months from completion of [neo]adjuvant ET) was assessed by Cox proportional hazards model and Kaplan-Meier methods. Progression-free survival 2 (PFS2) and chemotherapy-free survival (CFS) were analyzed. MONALEESA-3 is registered with ClinicalTrials.gov (NCT02422615).

RESULTS

At data cutoff (January 12, 2022; median follow-up time, 70.8 months), mOS was 67.6 versus 51.8 months with 1L ribociclib versus placebo (hazard ratio (HR) 0.67; 95% CI 0.50-0.90); 16.5% and 8.6% of ribociclib and placebo patients, respectively, were still receiving treatment. PFS2 (HR 0.64) and CFS (HR 0.62) favored ribociclib versus placebo. Among those who discontinued treatment, 16.7% and 35.0% on ribociclib or placebo, respectively, received a subsequent CDK4/6i. No new safety signals were observed.

CONCLUSIONS

This analysis of MONALEESA-3 reports the longest mOS thus far (67.6 months) for 1L patients in a phase III ABC trial. These results in a 1L population show that the OS benefit of ribociclib was maintained through extended follow-up, further supporting its use in HR+/HER2- ABC.

Ribociclib plus fulvestrant for postmenopausal women with hormone receptor-positive, human epidermal growth factor receptor 2-negative advanced breast cancer in the phase III randomized MONALEESA-3 trial: updated overall survival

BACKGROUND

Ribociclib plus fulvestrant demonstrated significant progression-free survival (PFS) and overall survival (OS) benefits in patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative (HR+/HER2-) advanced breast cancer (ABC). Here we present a new landmark in survival follow-up for a phase III cyclin-dependent kinases 4 and 6 inhibitor clinical trial in patients with ABC (median, 56.3 months).

PATIENTS AND METHODS

This phase III, randomized, double-blind, placebo-controlled trial was conducted at 174 sites (30 countries). Patients were men and postmenopausal women (age ≥18 years) with histologically/cytologically confirmed HR+/HER2- ABC. Patients could have received ≤1 line of endocrine therapy (ET) but no chemotherapy for ABC. Patients, assigned 2:1, were stratified by the presence/absence of liver/lung metastases and previous ET. Patients received intramuscular fulvestrant (500 mg, day 1 of each 28-day cycle plus day 15 of cycle 1) with oral ribociclib (600 mg/day, 3 weeks on, 1 week off) or placebo. Efficacy analyses were by intention to treat. Safety was assessed in patients receiving ≥1 dose study treatment. OS was a secondary endpoint. MONALEESA-3 is registered with ClinicalTrials.gov (NCT02422615; no longer enrolling).

RESULTS

Between 18 June 2015 and 10 June 2016, 726 patients were randomly assigned (484, ribociclib; 242, placebo). At data cut-off (30 October 2020), median OS (mOS) was 53.7 months (ribociclib) versus 41.5 months (placebo) [hazard ratio (HR), 0.73; 95% confidence interval (CI) 0.59-0.90]. Subgroup analyses were consistent with overall population. In the first-line setting, most patients in the ribociclib arm (∼60%) lived longer than median follow-up; mOS was 51.8 months in the placebo arm (HR, 0.64; 95% CI 0.46-0.88). In the second-line setting, mOS was 39.7 months (ribociclib) versus 33.7 months (placebo) (HR, 0.78; 95% CI 0.59-1.04). No apparent drug-drug interaction between ribociclib and fulvestrant or new safety signals were observed.

CONCLUSIONS

This analysis reported extended OS follow-up in MONALEESA-3. mOS was ∼12 months longer in patients with HR+/HER2- ABC treated with ribociclib plus fulvestrant compared with fulvestrant monotherapy.

Association of triple positivity with prognostic parameters and overall survival in a population-based study of 6,122 HER2-positive breast cancer patients: analysis of real-world clinical practice based on a research database

Triple-positive breast cancer (TPBC), i.e. HER2-positive (HER2+) and hormone receptors-positive breast cancer, is a specific subgroup of breast cancers. TPBC biology is characterized by strong mutual interactions between signaling pathways stimulated by estrogens and HER2 amplification. The present study aims to carry out a population-based analysis of treatment outcomes in a cohort of hormone receptor (HR) positive and negative breast cancer patients who were treated with anti-HER2 therapy in the Czech Republic. The BREAST research database was used as the data source for this retrospective analysis. The database covers approximately 95% of breast cancer patients treated with targeted therapies in the Czech Republic. The analysis included 6,122 HER2-positive patients. The patients were divided into two groups, based on estrogen receptor (ER) or progesterone receptor (PR) positivity: hormone receptor negative (HR-) patients had both ER- and PR-negative tumors (n=2,518), unlike positive (HR+) patients (n=3,604). HR+ patients were more often diagnosed premenopausal at the time of diagnosis, presented more often at stage I or II and their tumors were less commonly poorly differentiated. The overall survival (OS) was significantly higher in subgroups of HR+ patients according to treatment setting. When evaluated by stages, significantly higher OS was observed in HR+ patients diagnosed at stages II, III, and IV and regardless of tumor grade.

Abstract PD1-11: nextMONARCH 1: Phase 2 study of abemaciclib plus tamoxifen or abemaciclib alone in HR+, HER2- advanced breast cancer

Background

Abemaciclib is a selective CDK4 & 6 inhibitor approved on a continuous dosing schedule for HR+, HER2- advanced breast cancer (ABC) as monotherapy (MONARCH 1) and in combination with endocrine therapy (ET). A previous Phase 1b (NCT01394016) cohort of HR+ ABC patients (pts) demonstrated efficacy of abemaciclib monotherapy (150mg and 200mg Q12H starting dose); given the small sample size and nonrandomized design the impact of the starting dose was unclear. nextMONARCH 1 (NCT02747004) evaluated abemaciclib in 2 monotherapy arms, in a randomized setting. Abemaciclib has been associated with dose-dependent early onset diarrhea that is well managed with antidiarrheal therapy. nextMONARCH 1 also explored the 200mg Q12H abemaciclib dose in combination with prophylactic loperamide to reduce incidence/severity of diarrhea and dose adjustments. A third arm evaluated abemaciclib + tamoxifen as a strategy to overcome endocrine resistance.

Methods

nextMONARCH 1 is a multicenter, randomized, open-label, Phase 2 study of abemaciclib or abemaciclib + tamoxifen in women with HR+, HER2- ABC who have progressed on or after prior ET and previously received chemotherapy. Pts were stratified by presence of liver metastases and prior use of tamoxifen in the advanced setting. Randomization was 1:1:1 to abemaciclib 150mg Q12H + daily tamoxifen 20mg (Arm A) or abemaciclib 150mg Q12H (Arm B); or abemaciclib 200mg Q12H + prophylactic loperamide (Arm C). Key eligibilities were ≥2 chemotherapy regimens (1-2 administered in metastatic setting), measurable disease and no prior treatment with CDK4 & 6 inhibitors. Primary objective was progression free survival (PFS). Key secondary objectives included objective response rate (ORR), dclinical benefit rate (CBR), and safety. PFS analysis tested superiority of Arm A to C at ∼110 events across the 2 arms assuming a hazard ratio (HR) of 0.667 to achieve ∼80% power. Arm B would be considered non-inferior to Arm C if the observed PFS HR is <1.2.

Results

234 pts were randomized to Arms A (n=78), B (n=79) and C (n=77). 166 PFS events have been observed (A: 57; B: 54; C: 55). Median PFS was 9.1 months in Arm A, 6.5 in Arm B and 7.4 in Arm C (A vs C: HR=.815, 95% CI, .556-1.193, p=.293; B vs C: HR=1.045, 95% CI, .711-1.535 p=.811). Investigator-assessed ORR was 34.6%, 24.1% and 32.5% (confirmed ORR: 25.6%, 19.0%, 28.6%) and CBR was 61.5%, 49.4% and 51.9% in Arms A, B and C, respectively. Prophylactic loperamide reduced the incidence and severity of diarrhea (C: 62.3%, Gr 3: 7.8%) compared to MONARCH 1 (90.2%, Gr 3: 19.7%, Dickler et al. 2017) resulting in similar rates of diarrhea with 150mg abemaciclib without prophylaxis (A: 53.8%, Gr 3: 1.3%; B: 67.1%, Gr 3: 3.8%). The adverse event profile across arms was generally consistent with other breast studies of abemaciclib.

Conclusions

nextMONARCH 1 confirmed single-agent activity of abemaciclib in heavily pretreated pts with HR+, HER2- ABC. Efficacy of abemaciclib monotherapy at 150mg was similar to 200mg. Combining tamoxifen with abemaciclib did not demonstrate a statistically significant improvement in PFS compared to abemaciclib monotherapy. Addition of prophylactic loperamide to abemaciclib 200mg resulted in diarrhea similar to 150mg without prophylaxis.

Citation Format: Hamilton E, Cortes J, Dieras V, Ozyilkan O, Chen S-C, Petrakova K, Manikhas A, Jerusalem G, Hegg R, Lu Y, Bear MM, Johnston EL, Martin M. nextMONARCH 1: Phase 2 study of abemaciclib plus tamoxifen or abemaciclib alone in HR+, HER2- advanced breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD1-11.

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.

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.

A phase III study (EMBRACE) of eribulin mesylate versus treatment of physician's choice in patients with locally recurrent or metastatic breast cancer previously treated with an anthracycline and a taxane

CRA1004^

Background: Eribulin mesylate (E7389; E) is a nontaxane microtubule dynamics inhibitor with a novel mode of action. This study is the first to compare overall survival (OS) with this new chemotherapeutic (CT) agent to real-life choices in heavily pretreated patients (pts) with metastatic breast cancer (MBC).

Methods: Women with locally recurrent or MBC were enrolled in this phase III open-label, randomized, multicenter study. Pts had received 2-5 prior CT (≥2 for advanced disease), including an anthracycline and a taxane, unless contraindicated. Pts were randomized 2:1 to E 1.4 mg/m2 2-5 min IV bolus on days 1 and 8 of a 21-day cycle or treatment of physician's choice (TPC). TPC was any monotherapy (cytotoxic, hormonal, biologic) or supportive care only. The primary endpoint was OS; secondary endpoints were objective response rate (ORR), and progression-free survival (PFS) by independent review, and duration of response (DOR). Safety and tolerability were assessed. Data are from the final analysis after 422 deaths.

Results: 762 pts were treated (508 E, 254 TPC). Median age was 55.2 (range 27-85), 16% were HER2-positive, 19% triple-negative, 73% received prior capecitabine, median no. of prior CT was 4. Median OS was 13.1 months (mo) for E vs. 10.7 mo for TPC, p=0.04 (primary analysis, stratified log rank test; HR 0.81; 95% CI 0.66, 0.99). Median PFS was 3.7 mo for E and 2.3 mo for TPC p=0.09 (HR 0.85; 95% CI 0.70, 1.03). ORR was 12% (0.4% complete response [CR], 11.5% partial response [PR]) for E and 5% (0 CR; 5% PR) for TPC, p=0.005. Median DOR was 4.1 mo for E (56 responders) vs. 6.7 mo for TPC (11 responders). Grade [G] 3/4 treatment-related adverse events (AEs) of interest for E were asthenia/fatigue (7.6%), neutropenia (44%), peripheral neuropathy (8.4%). 10% of pts experienced treatment-related serious AEs (12% E, 7% TPC).

Conclusions: The study met its primary endpoint with a significant improvement in OS by a median of 2.5 mo with E vs. TPC. E demonstrated a manageable tolerability profile, acceptable for a CT agent used as monotherapy in this late-line setting.

[Table: see text]

In compliance with the guidelines established by the ASCO Conflict of Interest Policy (J Clin Oncol. 2006 Jan 20;24[3]:519-521) and the Accreditation Council for Continuing Medical Education (ACCME), ASCO strives to promote balance, independence, objectivity, and scientific rigor through disclosure of financial and other interests, and identification and management of potential conflicts. According to the ASCO Conflict of Interest Policy, the following financial and other relationships must be disclosed: employment or leadership position, consultant or advisory role, stock ownership, honoraria, research funding, expert testimony, and other remuneration (J Clin Oncol. 2006 Jan 20;24[3]:520). The ASCO Conflict of Interest Policy disclosure requirements apply to all authors who submit abstracts to the Annual Meeting.

For clinical trials that began accrual on or after April 29, 2004, ASCO's Policy places some restrictions on the financial relationships of principal investigators (J Clin Oncol. 2006 Jan 20;24[3]:521). If a principal investigator holds any restricted relationships, his or her abstract will be ineligible for placement in the 2010 Annual Meeting unless the ASCO Ethics Committee grants an exception. Among the circumstances that might justify an exception are that the principal investigator (1) is a widely acknowledged expert in a particular therapeutic area; (2) is the inventor of a unique technology or treatment being evaluated in the clinical trial; or (3) is involved in international clinical oncology research and has acted consistently with recognized international standards of ethics in the conduct of clinical research. NIH-sponsored trials are exempt from the Policy restrictions. Abstracts for which authors requested and have been granted an exception in accordance with ASCO's Policy are designated with a caret symbol (^) in the Annual Meeting Proceedings.

For more information about the ASCO Conflict of Interest Policy and the exceptions process, please visit www.asco.org/conflictofinterest .

Genetic testing and prevention of hereditary cancer at the MMCI--over 10 years of experience

Hereditary cancer syndromes are frequently seen in young cancer patients and patients with a positive family history. Genetic testing is important for the identification of high-risk individuals, and for the early introduction of specialized preventive care or prophylactic surgeries. High-risk tumour suppressor genes (BRCA1 and BRCA2) and DNA repair genes (MLH1, MSH2 and MSH6) are responsible for a substantial part of hereditary breast, ovarian and colorectal cancer. Other hereditary cancers are seen less frequently, but genetic testing has increased for many other site-specific cancers and complex syndromes. Genetic centres and molecular genetic laboratories are located mostly within university or regional hospitals. Some genetic centres are private. It is highly recommended (Czech Society for Medical Genetics) that all laboratories are accredited according to ISO 15,189 and that genetic testing of hereditary cancer syndromes is indicated by medical geneticists. The indication criteria and prevention strategies were published in Supplement 22 of Clinical Oncology 2009 (in Czech). Preventive care for high-risk individuals is organized by thirteen Oncology Centres, which provide most of the oncology care in the Czech Republic. Genetic testing and preventive care for high-risk individuals and mutation carriers is covered by health insurance. The molecular genetic laboratory at the MMCI provides molecular genetic testing of BRCA1, BRCA2, CHEK2 for hereditary breast/ovarian cancer, MLH1, MSH2, MSH6 for Lynch syndrome,TP53 for Li-Fraumeni syndrome, CDKN2A for familial malignant melanoma syndrome and CDH1 gene for hereditary diffuse gastric cancer. Other syndromes are tested in specialized laboratories elsewhere.The use of genetic testing is increasing because of more frequent referrals from oncologists and other specialists and the increasing variety of genes tested. However, in some patients the testing is not recommended and other family members are dying because of the late diagnosis of hereditary syndrome. Greater awareness of the importance of genetic testing in oncology is needed.

Factors, Predicting Failure of Adjuvant Hormonotherapy of Breast Carcinoma. A Study in Tamoxifen Treated Patients

Background: The latest clinical trials indicate better performance of aromatase inhibitors, compared to tamoxifen, in adjuvant hormonotherapy of breast carcinoma. The identification of molecular markers, predicting resistance to tamoxifen, could help to identify patients, which are most likely to benefit from aromatase inhibitors in up-front adjuvant hormonotherapy.Material and methods: Tissue microarrays were constructed from archival paraffin blocks of primary tumors of 179 patients with estrogen receptor positive operable breast carcinoma in stage I-III, subsequently treated with tamoxifen for five years or until relapse, with at least 7 years follow up available. The amplifications of Her-2 and cyclin D1 genes were evaluated by fluorescence in-situ hybridization. The level of progesterone receptor (PR) and Ki67 were estimated by immunohistochemistry.Results: 54 of above patients recurred during follow up. In univariate analysis of disease free survival, the presence of more than three nodal metastases (RR=4,5 p<0,001), grade 3 (RR=2,3 p=0,035), cyclin D1 (RR=3,06 p<0,001) and Her-2 (RR=3,06 p<0,001) amplifications were identified as significant risk factors, together with the negativity of PR (RR=2,1 p=0,013). In multivariate analysis, only clinical stage III (RR=2,6 p=0,003), cyclin D1 (RR=2,7 p=0,001) and Her-2 (RR=2,1 p=0,014) amplifications proved significant. In 77 patients who received adjuvant chemotherapy no statistically significant risk factor was identified. In multivariate analysis of 102 patients without adjuvant chemotherapy only stage III (RR=6,9 p=0,001) and Her-2 amplification (RR=4,5 p=0,001) were confirmed.Discussion: The advanced clinical stage, cyclin D1 and Her-2 gene amplifications represent factors, predicting the failure of adjuvant tamoxifen treatment, but their predictive value is much lower in patients receiving adjuvant chemotherapy. This fact indicates, they can reflect the common biological aggressiveness of tumor and need not to be tamoxifen specific.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6031.

[Therapeutic approaches for breast carcinoma]

With increasing incidence of breast cancer its prevalence also increases. Improvement of therapeutic approaches recently introduced led to improved treatment outcomes. The introduction of taxanes into the adjuvant treatment prolongs the overall survival (OS) of the patients. Third generation of aromatase inhibitors appear better than tamoxifen in the adjuvant treatment of postmenopausal women. New anticancer drugs in combination with bevacizumab and trastuzumab have brought new possibilities in treatment of patients with metastatic breast cancer: their use apparently increases the rate of treatment response and overall survival.