Adjuvant ovarian function suppression and tamoxifen in premenopausal breast cancer patients: A meta-analysis

BACKGROUND

The benefit of adding ovarian function suppression (OFS) to tamoxifen in the adjuvant treatment of premenopausal women with breast cancer is uncertain. We conducted a meta-analysis of randomized controlled trials that addressed this question.

METHODS

Systematic search of PubMed, the web of science, and the meeting library of ASCO, ESMO, and SABCS was conducted using the following keywords: tamoxifen, ovarian suppression, and breast cancer. Eligible studies were those recruiting patients with breast cancer randomized to receive adjuvant tamoxifen and OFS versus tamoxifen alone. Pooled hazard ratio [HR]) for disease-free (DFS) and overall survival (OS) with 95% confidence interval (CI) were calculated using the fixed effect model.

RESULTS

We searched a total of 845 records, of which 5 clinical trials, including 7557 patients, were eligible for our analysis. Adding OFS to tamoxifen improved DFS with pooled HR: 0.88 (95% CI: 0.80-0.96, P= 0.004) and OS (pooled HR: 0.87 {95% CI: 0.77-0.98, P= 0.02}) compared to tamoxifen alone. The benefit of the addition of OFS to tamoxifen was mostly observed in patients younger than 40 years where the pooled HRs of DFS was 0.76 (95% CI: 0.63-0.91; P= 0.004), and in those who received adjuvant chemotherapy with pooled HRs of DFS 0.80 (95% CI: 0.65-0.99, P= 0.042). There was an increase in the incidence of all grade musculoskeletal symptoms and high-grade hot flushes with the addition of OFS with risk ratios of 1.12 (95% CI: 1.07-1.17, P< 0.001) and 2.14 (95% CI: 1.01-4.51, P= 0.047) respectively.

CONCLUSION

Our analysis indicates that the addition of OFS to tamoxifen improves DFS and OS. This strategy could be considered in patients in which tamoxifen alone is not deemed sufficient or in case of poor tolerance to OFS with aromatase inhibitors.

Estimation of historical control rate for a single arm de-escalation study - Application to the POSITIVE trial

BACKGROUND

Although randomized controlled clinical trials are optimal to evaluate the effect of an experimental therapy, single-arm trials are required whenever randomization is unethical or not feasible, such as de-escalation studies. We propose using prospectively identified historical controls to place results of single-arm, de-escalation trials into context.

METHODS

POSITIVE is a prospective, single-arm study in young women with hormone-receptor-positive early breast cancer to determine if temporarily interrupting adjuvant endocrine therapy in order to become pregnant increases the risk of a breast cancer event. After 272 women enrolled in POSITIVE, we identified a cohort of 1499 SOFT/TEXT patients potentially eligible to enroll in POSITIVE who did not interrupt endocrine therapy. Method I used the SOFT/TEXT cohort to calculate annualized hazard rates by a piecewise exponential model. Method II used the SOFT/TEXT cohort to group-match SOFT/TEXT patients to POSITIVE patients; sample sets of SOFT/TEXT patients were randomly drawn 5000 times to obtain sets having patient, disease, and treatment characteristics more balanced with POSITIVE participants.

RESULTS

Compared with SOFT/TEXT, POSITIVE participants were younger, less likely to be overweight/obese, had fewer positive nodes, and fewer received aromatase inhibitor or chemotherapy. The estimated 3-year breast cancer free interval event rates were 9.5% (95% CI: 7.9%,11.1%) for Method I and 9.4% (95% CI: 7.8%,10.9%) for Method II, compared with 5.8% initially assumed when POSITIVE was designed.

CONCLUSION

External control datasets should be identified before launching single-arm, de-escalation trials and methods applied during their conduct to provide context for interim monitoring and interpretation of the final analysis.

ESO-ESMO 4th International Consensus Guidelines for Breast Cancer in Young Women (BCY4)

The 4th International Consensus Conference for Breast Cancer in Young Women (BCY4) took place in October 2018, in Lugano, Switzerland, organized by the European School of Oncology (ESO) and the European Society of Medical Oncology (ESMO). Consensus recommendations for the management of breast cancer in young women were updated from BCY3 with incorporation of new evidence to inform the guidelines. Areas of research priorities were also identified. This article summarizes the ESO-ESMO international consensus recommendations, which are also endorsed by the European Society of Breast Specialists (EUSOMA).

Fertility preservation in patients with BRCA mutation

Evidence suggests a likely negative impact of deleterious BRCA mutations on female fertility. Hence, different studies have aimed to address the reproductive potential and performance of fertility preservation strategies in BRCA-mutated breast cancer patients with a prime focus on their safety and efficacy. However, several uncertainties exist in many domains of this field. The aim of the current paper is to overview the reproductive potential and fertility preservation options in breast and ovarian cancer patients harbouring a BRCA mutation. We also discuss pre-implantation genetic testing in an attempt to help physicians during oncofertility counselling of these patients.

Abstract OT1-04-02: POSITIVE: A study evaluating pregnancy, disease outcome and safety of interrupting endocrine therapy for premenopausal women with endocrine responsive breast cancer who desire pregnancy (IBCSG 48-14/big 8-13)

Background: Young patients with breast cancer (BC) are often diagnosed before completing their families. The best available retrospective evidence suggests that pregnancy after BC does not negatively impact disease outcomes overall and in patients with endocrine responsive disease, and is safe for the offspring. However, given also the possibility of extended adjuvant endocrine therapy (ET) (5-10 years), it is not feasible for many of these women to delay pregnancy until completion of therapy. Prospectively evaluating the safety of temporary interruption of ET to allow conception is an unmet, patient-oriented, medical need.

Trial Design: Young patients with endocrine responsive early BC who desire pregnancy will interrupt ET for up to 2 yrs to attempt child-bearing. As resumption of menses and conception depends on many factors (e.g. patient’s age and adjuvant treatment received), the 2-yr interruption period is approximate, intended to include treatment wash-out (3 mos), conception (~3-6 mos), delivery (~9 mos), and breast feeding (~6 mos). Patients will be strongly advised to resume ET as soon as pregnancy attempts/deliveries are concluded, and to complete the planned 5-10 yrs of ET.

Major Eligibility Criteria

- Histologically-proven stage I-III endocrine-responsive BC.

- Patient’s wish to become pregnant.

- Age ≥ 18 and ≤ 42 years at enrollment.

- Adjuvant ET (selective estrogen receptor modulator [SERM] alone, GnRH analogue plus SERM or aromatase inhibitor) for ≥18 months but ≤30 months, stopped within 1 month prior to enrollment.

- Premenopausal status at BC diagnosis.

Specific Aims

1. To assess the risk of BC relapse associated with temporary interruption of ET to permit pregnancy.

2. To evaluate pregnancy success rate and offspring outcome.

Statistical Methods: With 500 pts enrolled and followed for a median of 3 years, the statistical design is based on the 95% CI for the 3-year BC recurrence rate. Interim monitoring assumes a 2% BC recurrence risk/yr with continuous ET and a recommendation to stop the study early if the BC risk exceeds 4%/yr with ET interruption.

Translational Research will evaluate fertility, pregnancy and BC biology determinants (e.g. ovarian function, uterine evaluation and circulating tumor DNA). Fresh frozen paraffin embedded tissue of the primary tumour will be collected to evaluate parameters related to the biology of BC in young women. All material will be banked centrally.

Psycho-oncological Companion Study (POCS) will evaluate fertility concerns, psychological well-being and decisional conflict. It is mandatory in North America and open to interested centers elsewhere.

Accrual: Target: 500; Actual: 421 (30 June 2019)

Psycho-oncological Companion Study Accrual: Target: ~200; Actual: 196 (30 June 2019)

Contact Information: POSITIVE is conducted and sponsored by the International Breast Cancer Study Group. The Alliance for Clinical Trials in Oncology is the US sponsor for NCTN. Contact Monica Ruggeri, IBCSG Coordinating Center, monica.ruggeri@ibcsg.org, or Trial Coordinators at ibcsg48_positive@fstrf.org.

Citation Format: Olivia Pagani, Ann H Partridge, Fedro A Peccatori, Hatem A Azim, Chikako Shimizu, Cristina Saura, Ellen Warner, Anna B Sætersdal, Judith R Kroep, Monica Ruggeri, Richard D Gelber. POSITIVE: A study evaluating pregnancy, disease outcome and safety of interrupting endocrine therapy for premenopausal women with endocrine responsive breast cancer who desire pregnancy (IBCSG 48-14/big 8-13) [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr OT1-04-02.

Understanding the benefits and challenges of first-line cyclin-dependent kinases 4 and 6 inhibitors in advanced breast cancer among postmenopausal women

Endocrine therapy (ET) has been regarded for many years as the standard treatment for patients with hormone receptor-positive (ER+), HER2-negative (HER2-) advanced breast cancer (ABC) without visceral crisis. However, the efficacy of single-agent ET is constrained by the development of resistance, attributed to alterations in several intracellular signaling pathways, including those related to cell cycle dysregulation. The cyclin-dependent kinases 4 and 6 (CDK4/6) are principal regulators of cell cycle progression from the G1-phase into the DNA synthesis (S)-phase. In vitro inhibition of CDK4/6 activity has potent antiproliferative properties against luminal breast cancer cell lines, which are enhanced when combined with traditional ET. This has led to a substantial interest in targeting this pathway to overcome endocrine resistance in the clinic. Three selective CDK4/6 inhibitors (palbociclib, ribociclib, and abemaciclib) have been approved as first-line therapy in combination with an aromatase inhibitor, or fulvestrant in the case of ribociclib in patients with ER+/HER2- ABC. To date, there is no clue as to which subgroup of patients might benefit most from these combinations. Here, we outline some of the established approaches to overcome endocrine resistance, with special emphasis on the unique mechanism of action of CDK4/6 inhibitors.

Dose-Ranging and Cohort-Expansion Study of Monalizumab (IPH2201) in Patients with Advanced Gynecologic Malignancies: A Trial of the Canadian Cancer Trials Group (CCTG): IND221

PURPOSE

Monalizumab binds CD94/NKG2A, preventing HLA-E inhibition of tumor lymphocytes. A dose-ranging/cohort expansion trial of monalizumab for recurrent gynecologic malignancies was conducted to determine the recommended phase II dose (RP2D) and to explore clinical activity, pharmacokinetics, pharmacodynamics, safety, and immunogenicity.

PATIENTS AND METHODS

Participants (and part 2 expansion cohorts) included (i) platinum-sensitive ovarian, (ii) platinum-resistant ovarian, (iii) squamous cervical (CX), and (iv) epithelial endometrial (END) carcinomas. Part 1 assessed monalizumab at 1, 4, or 10 mg/kg every 2 weeks. In part 2, ≥4 patients/cohort underwent pre- and on-treatment tumor biopsies. Preset criteria determined cohort expansion.

RESULTS

A total of 58 participants were evaluable. The RP2D was 10 mg/kg i.v. every 2 weeks. Dose proportionality and 100% NKG2A saturation were observed. Related adverse events were mild: headache, abdominal pain, fatigue, nausea, and vomiting. Grade 3 related adverse events were nausea (1), vomiting (1), dehydration (1), fatigue (2), anorexia (1), dyspnea (1), and proctitis (1). Dose-limiting toxicities were not observed. Hematologic and biochemical changes were mild and not dose related. Best response was SD: part 1, 7 of 18 (39%) [3.4 months (1.4-5.5)], and part 2, 7 of 39 (18%) [1.7 months (CX) to 14.8 months (END)]. Neither a predictive biomarker for SD nor evidence of pharmacodynamic effects was identified. There was a trend to significance between a reduction in lymphocyte HLA-E total score and pharmacodynamics.

CONCLUSIONS

Monalizumab 10 mg/kg i.v. every 2 week is well tolerated in patients with pretreated gynecologic cancers. Short-term disease stabilization was observed. Future studies should assess combinations with other agents, including immunotherapeutics.

IPH4102, a first-in-class anti-KIR3DL2 monoclonal antibody, in patients with relapsed or refractory cutaneous T-cell lymphoma: an international, first-in-human, open-label, phase 1 trial

BACKGROUND

IPH4102 is a first-in-class monoclonal antibody targeting KIR3DL2, a cell surface protein that is expressed in cutaneous T-cell lymphoma, and predominantly in its leukaemic form, Sézary syndrome. We aimed to assess the safety and activity of IPH4102 in cutaneous T-cell lymphoma.

METHODS

We did an international, first-in-human, open-label, phase 1 clinical trial with dose-escalation and cohort-expansion parts in five academic hospitals in the USA, France, the UK, and the Netherlands. Eligible patients had histologically confirmed relapsed or refractory primary cutaneous T-cell lymphoma, an Eastern Cooperative Oncology group performance score of 2 or less, were aged 18 years or older, and had received at least two previous systemic therapies. Ten dose levels of IPH4102, administered as an intravenous infusion, ranging from 0·0001 mg/kg to 10 mg/kg, were assessed using an accelerated 3 + 3 design. The primary endpoint was the occurrence of dose-limiting toxicities during the first 2 weeks of treatment, defined as toxicity grade 3 or worse lasting for 8 or more days, except for lymphopenia. Global overall response by cutaneous T-cell lymphoma subtype was a secondary endpoint. Safety and activity analyses were done in the per-protocol population. The study is ongoing and recruitment is complete. This trial is registered with ClinicalTrials.gov, number NCT02593045.

FINDINGS

Between Nov 4, 2015, and Nov 20, 2017, 44 patients were enrolled. 35 (80%) patients had Sézary syndrome, eight (18%) had mycosis fungoides, and one (2%) had primary cutaneous T-cell lymphoma, not otherwise specified. In the dose-escalation part, no dose limiting toxicity was reported and the trial's safety committee recommended a flat dose of 750 mg for the cohort-expansion, corresponding to the maximum administered dose. The most common adverse events were peripheral oedema (12 [27%] of 44 patients) and fatigue (nine [20%]), all of which were grade 1-2. Lymphopenia was the most common grade 3 or worse adverse event (three [7%]). One patient developed possibly treatment-related fulminant hepatitis 6 weeks after IPH4102 discontinuation and subsequently died. However, the patient had evidence of human herpes virus-6B infection. Median follow-up was 14·1 months (IQR 11·3-20·5). A confirmed global overall response was achieved in 16 (36·4% [95% CI 23·8-51·1]) of 44 patients, and of those, 15 responses were observed in 35 patients with Sézary syndrome (43% [28·0-59·1]).

INTERPRETATION

IPH4102 is safe and shows encouraging clinical activity in patients with relapsed or refractory cutaneous T-cell lymphoma, particularly those with Sézary syndrome. If confirmed in future trials, IPH4102 could become a novel treatment option for these patients. A multi-cohort, phase 2 trial (TELLOMAK) is underway to confirm the activity in patients with Sézary syndrome and explore the role of IPH4102 in other subtypes of T-cell lymphomas that express KIR3DL2.

FUNDING

Innate Pharma.

Safety of pregnancy following breast cancer (BC) in patients (pts) carrying a BRCA mutation (mBRCA): Results of an international cohort study

11506

Background: Very limited data are available on the safety of pregnancy and reproductive outcomes in mBRCA pts with prior BC history. We report the results of the largest study to date addressing these questions. Methods: This international, multicenter, hospital-based, retrospective cohort study included consecutive pts with invasive early BC (stage I-III) diagnosed between Jan-2000 and Dec-2012 at the age of ≤40 years and carrying a deleterious germline mBRCA. Primary endpoints were pregnancy rate and disease-free survival (DFS); overall survival (OS) and pregnancy outcomes were secondary endpoints. To account for guarantee-time bias, we performed two survival analyses: 1) Case-control approach matching pregnant and non-pregnant (1:3) pts for classic prognostic factors (each non-pregnant control had a disease-free interval ≥ than the time elapsing between BC diagnosis and date of pregnancy of the matched pregnant case); 2) Extended Cox model with time-varying covariates including all pts. Results: 1,252 mBRCA BC pts (811 mBRCA1, 430 mBRCA2, 11 mBRCA1&2) were included from 30 centers worldwide, of whom 195 pts had a pregnancy (pregnancy rate = 16% [95% CI 14-18]) after a median 4.5 years (range 3.1-6.7 years) following BC diagnosis. Pregnant pts were younger and had more ER-negative tumors (all p < 0.01). 16 (8.2%) and 20 (10.3%) pts had an induced and spontaneous abortion, respectively. Among the 150 (76.9%) pts who conceived (n = 170 babies), pregnancy complications and congenital anomalies were described in 13 (11.6%) and 2 (1.8%) cases, respectively. Median follow-up was 8.3 years (range 8.1-8.7 years). In the case-control analysis, pregnant pts had better DFS (HR 0.71; 95% CI 0.51-0.99; p = 0.045), with no difference in OS (HR 0.86; 95% CI 0.44-1.67; p = 0.65). Subgroup analysis suggested that the superior outcome was restricted to mBRCA1 pregnant pts (p-interaction < 0.01). Similar results were obtained in the second supportive analysis. Conclusions: Pregnancy following BC is safe in mBRCA pts, particularly mBRCA1, with no detrimental impact on maternal prognosis or fetal outcomes . These findings are of paramount importance for fertility counseling in young mBRCA BC pts.

Reproductive potential and performance of fertility preservation strategies in BRCA-mutated breast cancer patients

Background

Preclinical evidence suggests a possible negative impact of deleterious BRCA mutations on female fertility. However, limited and rather conflicting clinical data are available. This study assessed the reproductive potential and performance of fertility preservation strategies in BRCA-mutated breast cancer patients.

Patients and methods

This was a retrospective analysis of two prospective studies investigating oocyte cryopreservation and ovarian tissue cryopreservation in newly diagnosed early breast cancer patients. In the current analysis, baseline anti-Mullerian hormone (AMH) and performance of cryopreservation strategies were compared between patients with or without germline deleterious BRCA mutations.

Results

Out of 156 patients included, 101 had known BRCA status of whom 29 (18.6%) were BRCA-mutated and 72 (46.1%) had no mutation. Median age in the entire cohort was 31 years [interquartile range (IQR) 28-33). Median AMH levels were 1.8 μg/l (IQR 1.0-2.7) and 2.6 µg/l (IQR 1.5-4.1) in the BRCA-positive and BRCA-negative cohorts, respectively (P = 0.109). Among patients who underwent oocyte cryopreservation (N = 29), women in the BRCA-positive cohort tended to retrieve (6.5 versus 9; P = 0.145) and to cryopreserve (3.5 versus 6; P = 0.121) less oocytes than those in the BRCA-negative cohort. Poor response rate (i.e. retrieval of ≤4 oocytes) was 40.0% and 11.1% in the BRCA-positive and BRCA-negative cohorts, respectively (P = 0.147). Among patients who underwent ovarian tissue cryopreservation (N = 72), women in the BRCA-positive cohort tended to have a numerically lower number of oocytes per fragment (0.08 versus 0.14; P = 0.193) and per square millimeter (0.33 versus 0.78; P = 0.153) than those in the BRCA-negative cohort. Two BRCA-mutated patients were transplanted after chemotherapy and one delivered at term a healthy baby. No difference between BRCA1- and BRCA2-mutated patients was observed in any of the above-mentioned outcomes.

Conclusion

A consistent trend for reduced reproductive potential and performance of cryopreservation strategies was observed in BRCA-mutated breast cancer patients. Independent validation of these results is needed.

Abstract P6-18-16: Ribociclib (RIBO) + letrozole (LET) in older patients with hormone receptor-positive (HR+), human epidermal growth factor receptor-2–negative (HER2–) advanced breast cancer (ABC): Preliminary subgroup results from the phase 3b CompLEEment-1 trial

Background: The cyclin-dependent kinase (CDK)4/6 inhibitor RIBO is approved in combination with an aromatase inhibitor (AI) for HR+, HER2– ABC in postmenopausal women with no prior therapy for ABC, based on the MONALEESA-2 trial (Hortobagyi et al. NEJM 2016). Although a high proportion of patients with HR+, HER2– ABC are &gt;65 years of age, older patients are often under-represented in clinical trials. Furthermore, treatment decisions may be complicated by comorbidities, functional status, and concurrent medications. Here, we report early safety results for patients ≥65 years of age enrolled in CompLEEment-1, an open-label, phase 3b trial evaluating RIBO+LET as first-line endocrine-based therapy in an expanded patient population.

Methods: Patients with HR+, HER2– ABC, ≤1 line of prior chemotherapy (CT), and no prior endocrine therapy for ABC received RIBO (600 mg/day, 3 weeks on/1 week off) + LET (2.5 mg/day); men and premenopausal women received concomitant goserelin (3.6-mg subcutaneous implant every 28 days). The primary outcome was safety and tolerability. A pre-planned interim analysis was conducted ˜15 months after first patient first visit.

Results: Of the first 1,008 patients enrolled who completed 56 days of follow-up or discontinued before the data cut-off date, 377 were ≥65 years of age. Of these, 157 (41.6%) were 65-&lt;70 years, 107 (28.4%) were 70-&lt;75 years, and 113 (30%) were ≥75 years. The majority of patients (94.4%) had an Eastern Cooperative Oncology Group performance status ≤1; 33.2% presented with stage IV disease at diagnosis; 9 patients were male. The most common sites of metastasis were bone (70.0%), lung (44.8%), and lymph nodes (29.7%). The most common all-grade adverse events (AEs) were neutropenia (58.4%), nausea (31.8%), and fatigue (24.1%). The most common grade 3/4 AEs were neutropenia (37.7%) and alanine aminotransferase increase (4.2%). QT prolongation events were mild (majority grade 1/2) and occurred in 6.1% of patients (0.5% grade 3/4). Dose reduction or interruption due to AEs occurred in 54.5% of patients; 6.9% of patients had AEs leading to treatment discontinuation. In the overall patient population, the most frequent grade 3/4 AEs were neutropenia (42.8%), leukopenia (3.4%), and increased alanine aminotransferase (2.9%); QT prolongation occurred in 5.4% of patients (0.5% grade 3/4).

Conclusions: Initial safety results from CompLEEment-1, from the first 56 days of follow-up, demonstrate the tolerability of RIBO+LET in older patients, consistent with the overall patient population. NCT02941926.

Citation Format: Ring A, Borstnar S, Ferreira A, Azim HA, Cottu P, Lu J, Martin M, Zamagni C, Beck JT, Zhou K, Wu J, Menon L, De Laurentiis M. Ribociclib (RIBO) + letrozole (LET) in older patients with hormone receptor-positive (HR+), human epidermal growth factor receptor-2–negative (HER2–) advanced breast cancer (ABC): Preliminary subgroup results from the phase 3b CompLEEment-1 trial [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 P6-18-16.

Abstract OT1-01-06: POSITIVE: A study evaluating Pregnancy, disease outcome and safety of interrupting endocrine therapy for premenopausal women with endocrine responsIVE breast cancer who desire pregnancy (IBCSG 48-14/BIG 8-13)

Background

Young patients with breast cancer (BC) are often diagnosed with the disease before completing their families. The best available retrospective evidence suggests that pregnancy after BC does not negatively impact disease outcomes in patients with endocrine responsive BC and is safe for the offspring. However, given the possibility of extended adjuvant endocrine therapy (ET) (5-10 years), it is not feasible for many of these women to delay pregnancy until completion of therapy and thus there is a need to study the safety of interrupting ET to allow pregnancy. To date, no prospective study has been conducted in BC survivors attempting future pregnancy.

Trial Design

Young patients with endocrine responsive early BC who desire pregnancy will interrupt ET for up to 2 yrs to attempt pregnancy. As resumption of menses and conception depends on many factors (e.g. patient's age and adjuvant treatment received), the 2-yr interruption period is approximate, intended to include treatment wash-out (3 mos), conception (˜3-6 mos), delivery (˜9 mos), and breast feeding (˜6 mos). Patients will be strongly advised to resume ET as soon as pregnancy attempts/deliveries are concluded, and to complete the planned 5-10 yrs of ET.

Major Eligibility Criteria

- Histologically-proven stage I-III endocrine-responsive BC.

- Patient's wish to become pregnant.

- Age ≥ 18 and ≤ 42 years at enrollment.

- Adjuvant ET (selective estrogen receptor modulator [SERM] alone, GnRH analogue plus SERM or aromatase inhibitor) for ≥18 months but ≤30 months, stopped within 1 month prior to enrollment.

- Premenopausal status at BC diagnosis.

Specific Aim

To assess the risk of BC relapse associated with the interruption of ET to permit pregnancy, and to evaluate pregnancy success rate and offspring outcome.

Statistical Methods

With 500 pts enrolled and followed for a median of 3 years, the statistical design is based on the 95% CI for the 3-year BC recurrence rate. Interim monitoring assumes a 2% BC recurrence risk/yr with continuous ET and a recommendation to stop the study early if the BC risk exceeds 4%/yr with ET interruption.

Translational Research will investigate various ovarian function and uterine parameters and circulating tumour DNA. Fresh frozen paraffin embedded tissue of the primary tumour will be collected to evaluate parameters related to the biology of BC in young women. All material will be banked centrally.

Psycho-oncological Companion Study (POCS) will evaluate fertility concerns, psychological well-being and decisional conflict. It is mandatory in North America and open to interested centers elsewhere.

Accrual: Target: 500; Actual: 262 (30 June 2018)

Psycho-oncological Companion Study Accrual: Target: 200; Actual: 138 (30 June 2018)

Citation Format: Pagani O, Partridge AH, Peccatori F, Azim HA, Colleoni M, Saura C, Kroep JR, Warner E, Gombos A, Sætersdal AB, Ruggeri M, Gelber RD, Sun Z. POSITIVE: A study evaluating Pregnancy, disease outcome and safety of interrupting endocrine therapy for premenopausal women with endocrine responsIVE breast cancer who desire pregnancy (IBCSG 48-14/BIG 8-13) [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 OT1-01-06.

Knowledge, attitudes and practice of physicians towards fertility and pregnancy-related issues in youngBRCA-mutated breast cancer patients

RESEARCH QUESTION

This study explored the knowledge, attitudes and practice of physicians towards fertility and pregnancy-related issues in young BRCA-mutated breast cancer patients.

DESIGN

Physicians attending two international breast cancer conferences completed a 26-item questionnaire exploring fertility preservation, pregnancy during (BCP) or after breast cancer. A statistical comparison was carried out of the responses exploring the same issues in young breast cancer patients overall or specifically in those with BRCA mutations.

RESULTS

The survey was completed by 273 physicians. Ovarian tissue cryopreservation (33% versus 40%; P = 0.009) and gonadotrophin-releasing hormone analogues during chemotherapy (74% versus 81%; P = 0.001) were less commonly suggested in BRCA-mutated patients than in the overall breast cancer population. 42% of respondents agreed or were neutral on the statement that ovarian stimulation should not be considered safe in BRCA-mutated breast cancer patients. 45% and 30% agreed or were neutral on the statement that pregnancy in breast cancer survivors may increase the risk of recurrence in BRCA-mutated patients or in the overall breast cancer population, respectively (P < 0.001). 15% and 3% disagreed that transplanting the cryopreserved ovarian tissue can be considered safe in BRCA-mutated patients or in the overall breast cancer population, respectively (P < 0.001). 33.3% were against the addition of platinum agents as neoadjuvant chemotherapy in BRCA-mutated patients with BCP.

CONCLUSIONS

Several misconceptions on fertility preservation and pregnancy-related issues in breast cancer patients persist even among physicians directly involved in breast cancer care. Focused research efforts to address these issues in BRCA-mutated breast cancer patients and education to improve physicians' knowledge and adherence to available guidelines are urgently needed.

Pregnancies during and after trastuzumab and/or lapatinib in patients with human epidermal growth factor receptor 2-positive early breast cancer: Analysis from the NeoALTTO (BIG 1-06) and ALTTO (BIG 2-06) trials

BACKGROUND

Limited data exist on the safety of using anti-human epidermal growth factor receptor 2 (HER2) targeted agents during pregnancy. To date, only retrospective studies have assessed the prognosis of patients with a pregnancy after prior early breast cancer, with no data in HER2-positive patients.

METHODS

The Neoadjuvant Lapatinib and/or Trastuzumab Treatment Optimization (NeoALTTO) trial and the Adjuvant Lapatinib and/or Trastuzumab Treatment Optimization (ALTTO) trial were randomized phase 3 trials for patients with HER2-positive early breast cancer. In both trials, pregnancy information was prospectively collected. Pregnancy outcomes were compared between patients unintentionally exposed to trastuzumab and/or lapatinib during gestation (the exposed group) and those who became pregnant after trastuzumab and/or lapatinib completion (the unexposed group). In the ALTTO trial, disease-free survival (DFS) was compared between pregnant patients and those aged 40 years or younger without a subsequent pregnancy via an extended Cox model with time-varying covariates to account for a guarantee-time bias.

RESULTS

Ninety-two patients (12 in the exposed group and 80 in the unexposed group) had a pregnancy: 7 in the NeoALTTO trial and 85 in the ALTTO trial. Seven patients (58.3%) in the exposed group and 10 patients (12.5%) in the unexposed group opted for an induced abortion; in the unexposed group, 10 patients (12.5%) had a spontaneous abortion. No pregnancy/delivery complications were reported for the remaining cases, who successfully completed their pregnancy, with the exception of 1 fetus with trisomy 21 (Down syndrome). No significant difference in DFS (adjusted hazard ratio, 1.12; 95% confidence interval, 0.52-2.42) was observed between young patients with a pregnancy (n = 85) and young patients without a pregnancy (n = 1307).

CONCLUSIONS

For patients with HER2-positive early breast cancer, having a pregnancy after treatment completion appears to be safe without compromising fetal outcome or maternal prognosis.

Breast cancer diagnosed during pregnancy is associated with enrichment of non-silent mutations, mismatch repair deficiency signature and mucin mutations

Breast cancer diagnosed during pregnancy (BCP) is a rare and highly challenging disease. To investigate the impact of pregnancy on the biology of breast cancer, we conducted a comparative analysis of a cohort of BCP patients and non-pregnant control patients by integrating gene expression, copy number alterations and whole genome sequencing data. We showed that BCP exhibit unique molecular characteristics including an enrichment of non-silent mutations, a higher frequency of mutations in mucin gene family and an enrichment of mismatch repair deficiency mutational signature. This provides important insights into the biology of BCP and suggests that these features may be implicated in promoting tumor progression during pregnancy. In addition, it provides an unprecedented resource for further understanding the biology of breast cancer in young women and how pregnancy could modulate tumor biology.

Abstract CT101: D-BEYOND: A window of opportunity trial evaluating denosumab, a RANK-ligand (RANKL) inhibitor and its biological effects in young pre-menopausal women diagnosed with early breast cancer

Background

Breast cancer (BC) in young women has unique biology and poor prognosis. Previous reports suggest that they often express RANKL, which was also shown to play a role in mammary tumorigenesis and the etiology of BRCA1/2 related BC. Here, we present the primary results of D-BEYOND, a window of opportunity study investigating the biological activity of the RANKL inhibitor; denosumab in pre-menopausal BC patients.

Methods

D-BEYOND is a prospective, phase IIa, single-arm, multicenter study assessing the effect of denosumab on BC biology in premenopausal women with early BC (NCT01864798). Patients received two subcutaneous injections of denosumab (120mg), one week apart, followed by breast surgery. Blood, tumor and normal adjacent breast tissue were collected at baseline and at surgery. The primary endpoint was geometric mean change in tumor Ki67 assessed by immunohistochemistry (IHC) from baseline to surgery. Absolute Ki67 responders were defined as having &lt;2.7% IHC staining in the post-treatment tumor. Serum levels of soluble RANKL (sRANKL), OPG and C-terminal telopeptide (CTX) were assessed by ELISA. Ki67, RANK and RANKL expression were assessed by IHC. The percentage of tumor infiltrating lymphocytes (TILs) were also evaluated. Pre- and post-treatment values were compared using a paired t-test.

Results

A total of 27 patients were enrolled in the study between October 2013 and July 2016. The median age was 45 years (range 35-51 years). Tumors of 21 patients were hormone receptor positive (77.8%), 4 were HER2 positive (14.8%) and 2 were triple negative (7.4%). No serious adverse events were reported, the most frequent non-serious adverse event being arthralgia (14.8%). After treatment, serum levels of CTX and sRANKL decreased in all patients (P &lt; 0.001) whereas serum levels of OPG increased in 76.9% of patients (P = 0.009, 95% CI 0.56-0.91). There was no significant reduction of Ki67 values from baseline (geometric mean change after treatment; 0.98, 95% CI 0.76-1.26; P = 0.90) and there were no absolute Ki67 responders. Twenty-four pre- and post-treatment tumor pairs were available for RANK/L staining and TILs assessment. There was no significant difference in RANKL and RANK H-score in tumors after treatment (P = 0.842, P = 0.142, respectively) but we observed a decrease of RANKL H-score in 3 tumors (12.5%) and an increase of RANK H-score in 5 tumors (20%). Interestingly, there was a significant increase in the percentage of stromal TILs after treatment (geometric mean change of 2.51, 95% CI 1.58-3.97; P = 0.004). There were 10/24 patients (41.7%) with a change in TILs of at least 10%, all of them having an increase in TILs presence (P = 0.002).

Conclusion

Short course of denosumab did not reduce tumor proliferation rate. However, it induced a significant increase in TILs. These findings suggest that denosumab may potentiate immunotherapy efficacy, at least in young BC patients. Additional results including immune cell profiling by multiplex IHC and RNA-sequencing of tumor and normal tissues will be presented at the meeting.

Citation Format: Bastien Nguyen, Marion Maetens, Roberto Salgado, David Venet, Peter Vuylsteke, Laura Polastro, Hans Wieldiers, Philippe Simon, Geoff Lindeman, Denis Larsimont, Gert Van den Eynden, Chloe Velghe, Francoise Rothe, Soizic Garaud, Stefan Michiels, Karen Willard-gallo, Hatem A. Azim, Sherene Loi, Martine Piccart, Christos Sotiriou. D-BEYOND: A window of opportunity trial evaluating denosumab, a RANK-ligand (RANKL) inhibitor and its biological effects in young pre-menopausal women diagnosed with early breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr CT101.

Tumor PIK3CA Genotype and Prognosis in Early-Stage Breast Cancer: A Pooled Analysis of Individual Patient Data

Purpose Phosphatidylinositol-4, 5-bisphosphate 3-kinase catalytic subunit alpha ( PIK3CA) mutations are frequently observed in primary breast cancer. We evaluated their prognostic relevance by performing a pooled analysis of individual patient data. Patients and Methods Associations between PIK3CA status and clinicopathologic characteristics were tested by applying Cox regression models adjusted for age, tumor size, nodes, grade, estrogen receptor (ER) status, human epidermal growth factor receptor 2 (HER2) status, treatment, and study. Invasive disease-free survival (IDFS) was the primary end point; distant disease-free survival (DDFS) and overall survival (OS) were also assessed, overall and by breast cancer subtypes. Results Data from 10,319 patients from 19 studies were included (median OS follow-up, 6.9 years); 1,787 patients (17%) received chemotherapy, 4,036 (39%) received endocrine monotherapy, 3,583 (35%) received both, and 913 (9%) received none or their treatment was unknown. PIK3CA mutations occurred in 32% of patients, with significant associations with ER positivity, increasing age, lower grade, and smaller size (all P < .001). Prevalence of PIK3CA mutations was 18%, 22%, and 37% in the ER-negative/HER2-negative, HER2-positive, and ER-positive/HER2-negative subtypes, respectively. In univariable analysis, PIK3CA mutations were associated with better IDFS (HR, 0.77; 95% CI, 0.71 to 0.84; P < .001), with evidence for a stronger effect in the first years of follow-up (0 to 5 years: HR, 0.73; 95% CI, 0.66 to 0.81; P < .001; 5 to 10 years: HR, 0.82; 95% CI, 0.68 to 0.99; P = .037); > 10 years: (HR, 1.15; 95% CI, 0.84 to 1.58; P = .38; P heterogeneity = .02). In multivariable analysis, PIK3CA genotype remained significant for improved IDFS ( P = .043), but not for the DDFS and OS end points. Conclusion In this large pooled analysis, PIK3CA mutations were significantly associated with a better IDFS, DDFS, and OS, but had a lesser prognostic effect after adjustment for other prognostic factors.

Long-term Safety of Pregnancy Following Breast Cancer According to Estrogen Receptor Status

Safety of pregnancy in women with history of estrogen receptor (ER)-positive breast cancer remains controversial. In this multicenter case-control study, 333 patients with pregnancy after breast cancer were matched (1:3) to 874 nonpregnant patients of similar characteristics, adjusting for guaranteed time bias. Survival estimates were calculated using the Kaplan-Meier analysis; groups were compared with the log-rank test. All reported P values were two-sided. At a median follow-up of 7.2 years after pregnancy, no difference in disease-free survival was observed between pregnant and nonpregnant patients with ER-positive (hazard ratio [HR] = 0.94, 95% confidence interval [CI] = 0.70 to 1.26, P = .68) or ER-negative (HR = 0.75, 95% CI = 0.53 to 1.06, P = .10) disease. No overall survival (OS) difference was observed in ER-positive patients (HR = 0.84, 95% CI = 0.60 to 1.18, P = .32); ER-negative patients in the pregnant cohort had better OS (HR = 0.57, 95% CI = 0.36 to 0.90, P = .01). Abortion, time to pregnancy, breastfeeding, and type of adjuvant therapy had no impact on patients' outcomes. This study provides reassuring evidence on the long-term safety of pregnancy in breast cancer survivors, including those with ER-positive disease.