Alpelisib plus fulvestrant for PIK3CA-mutated, hormone receptor-positive, human epidermal growth factor receptor-2-negative advanced breast cancer: final overall survival results from SOLAR-1

BACKGROUND

Activation of the phosphatidylinositol-3-kinase (PI3K) pathway via PIK3CA mutations occurs in 28%-46% of hormone receptor-positive (HR+), human epidermal growth factor receptor-2-negative (HER2-) advanced breast cancers (ABCs) and is associated with poor prognosis. The SOLAR-1 trial showed that the addition of alpelisib to fulvestrant treatment provided statistically significant and clinically meaningful progression-free survival (PFS) benefit in PIK3CA-mutated, HR+, HER2- ABC.

PATIENTS AND METHODS

Men and postmenopausal women with HR+, HER2- ABC whose disease progressed on or after aromatase inhibitor (AI) were randomized 1 : 1 to receive alpelisib (300 mg/day) plus fulvestrant (500 mg every 28 days and once on day 15) or placebo plus fulvestrant. Overall survival (OS) in the PIK3CA-mutant cohort was evaluated by Kaplan-Meier methodology and a one-sided stratified log-rank test was carried out with an O'Brien-Fleming efficacy boundary of P ≤ 0.0161.

RESULTS

In the PIK3CA-mutated cohort (n = 341), median OS [95% confidence interval (CI)] was 39.3 months (34.1-44.9) for alpelisib-fulvestrant and 31.4 months (26.8-41.3) for placebo-fulvestrant [hazard ratio (HR) = 0.86 (95% CI, 0.64-1.15; P = 0.15)]. OS results did not cross the prespecified efficacy boundary. Median OS (95% CI) in patients with lung and/or liver metastases was 37.2 months (28.7-43.6) and 22.8 months (19.0-26.8) in the alpelisib-fulvestrant and placebo-fulvestrant arms, respectively [HR = 0.68 (0.46-1.00)]. Median times to chemotherapy (95% CI) for the alpelisib-fulvestrant and placebo-fulvestrant arms were 23.3 months (15.2-28.4) and 14.8 months (10.5-22.6), respectively [HR = 0.72 (0.54-0.95)]. No new safety signals were observed with longer follow-up.

CONCLUSIONS

Although the analysis did not cross the prespecified boundary for statistical significance, there was a 7.9-month numeric improvement in median OS when alpelisib was added to fulvestrant treatment of patients with PIK3CA-mutated, HR+, HER2- ABC. Overall, these results further support the statistically significant prolongation of PFS observed with alpelisib plus fulvestrant in this population, which has a poor prognosis due to a PIK3CA mutation. CLINICALTRIALS.

GOV ID

NCT02437318.

Capivasertib, an AKT Kinase Inhibitor, as Monotherapy or in Combination with Fulvestrant in Patients with AKT1 E17K-Mutant, ER-Positive Metastatic Breast Cancer

PURPOSE

The activating mutation AKT1 E17K occurs in approximately 7% of estrogen receptor-positive (ER+) metastatic breast cancer (MBC). We report, from a multipart, first-in-human, phase I study (NCT01226316), tolerability and activity of capivasertib, an oral AKT inhibitor, as monotherapy or combined with fulvestrant in expansion cohorts of patients with AKT1 E17K-mutant ER+ MBC.

PATIENTS AND METHODS

Patients with an AKT1 E17K mutation, detected by local (next-generation sequencing) or central (plasma-based BEAMing) testing, received capivasertib 480 mg twice daily, 4 days on, 3 days off, weekly or 400 mg twice daily combined with fulvestrant at the labeled dose. Study endpoints included safety, objective response rate (ORR; RECIST v1.1), progression-free survival (PFS), and clinical benefit rate at 24 weeks (CBR24). Biomarker analyses were conducted in the combination cohort.

RESULTS

From October 2013 to August 2018, 63 heavily pretreated patients received capivasertib (20 monotherapy, 43 combination). ORR was 20% with monotherapy, and within the combination cohort was 36% in fulvestrant-pretreated and 20% in fulvestrant-naïve patients, although the latter group may have had more aggressive disease at baseline. AKT1 E17K mutations were detectable in plasma by BEAMing (95%, 41/43), droplet digital PCR (80%, 33/41), and next-generation sequencing (76%, 31/41). A ≥50% decrease in AKT1 E17K at cycle 2 day 1 was associated with improved PFS. Combination therapy appeared more tolerable than monotherapy [most frequent grade ≥3 adverse events: rash (9% vs. 20%), hyperglycemia (5% vs. 30%), diarrhea (5% vs. 10%)].

CONCLUSIONS

Capivasertib demonstrated clinically meaningful activity in heavily pretreated patients with AKT1 E17K-mutant ER+ MBC, including those with prior disease progression on fulvestrant. Tolerability and activity appeared improved by the combination.

Phase III study to evaluate patient's preference of subcutaneous versus intravenous trastuzumab in HER2-positive metastatic breast cancer patients: Results from the ChangHER study (GEICAM/2012-07)

OBJECTIVE

We compared patients' preferences for intravenous (IV-t) versus subcutaneous (SC-t) trastuzumab administration.

METHODS

Phase III, open-label, multicentre study in HER2-positive metastatic breast cancer. Patients were receiving IV-t for at least 4 months without progression. Randomisation was 1:1 to administer 2 cycles of SC-t with vial followed by 2 cycles with single injection device (SID) or the reverse sequence (600mg SC-t every 3 weeks for 4 cycles).

PRIMARY OBJECTIVE

patients' preference for IV-t versus SC-t; secondary objectives: patients' preference for vial versus SID, healthcare professional (HCP) preference and safety.

RESULTS

We randomised 166 patients in 26 sites. Median number of previous lines of chemotherapy and/or endocrine therapy was 1 (1-7). Median duration of prior IV-t was 1.8 years (0.3-14). Of the159 patients completing the questionnaires, 86.2% preferred SC-t, 6.9% preferred IV-t, and 6.9% had no preference. Patients preferred SID (59.2%) over vial (26.3%). Most (87.2%) HCP preferred SC-t of whom 51.3% and 28.2% preferred SID and vial respectively. Related adverse events included G1-2 injection site reactions in 18 patients (10.8%), G1 pain in 8 (4.8%), G1-2 allergic reaction in 2 (1.2%), one G3 heart failure and 1 G2 ejection fraction decrease.

CONCLUSIONS

SC-t is preferred with no safety impact.

Time course and management of key adverse events during the randomized phase III SOLAR-1 study of PI3K inhibitor alpelisib plus fulvestrant in patients with HR-positive advanced breast cancer

BACKGROUND

Alpelisib (α-selective phosphatidylinositol 3-kinase inhibitor) plus fulvestrant is approved in multiple countries for men and postmenopausal women with PIK3CA-mutated, hormone receptor-positive, human epidermal growth factor receptor 2-negative advanced breast cancer following progression on or after endocrine therapy. A detailed understanding of alpelisib's safety profile should inform adverse event (AE) management and enhance patient care.

PATIENTS AND METHODS

AEs in the phase III SOLAR-1 trial were assessed in patients with and without PIK3CA mutations. The impact of protocol-specified AE-management recommendations was evaluated, including an amendment to optimize hyperglycemia and rash management.

RESULTS

Patients were randomly assigned to receive fulvestrant plus alpelisib (n = 284) or placebo (n = 287). The most common grade 3/4 AEs with alpelisib were hyperglycemia (grade 3, 32.7%; grade 4, 3.9%), rash (grade 3, 9.9%), and diarrhea (grade 3, 6.7%). Median time to onset of grade ≥3 toxicity was 15 days (hyperglycemia, based on fasting plasma glucose), 13 days (rash), and 139 days (diarrhea). Metformin alone or in combination with other antidiabetic agents was used by most patients (87.1%) with hyperglycemia. Preventive anti-rash medication resulted in lower incidence (any grade, 26.7% versus 64.1%) and severity of rash (grade 3, 11.6% versus 22.7%) versus no preventative medication. Discontinuations due to grade ≥3 AEs were lower following more-detailed AE management guidelines (7.9% versus 18.1% previously). Patients with PIK3CA mutations had a median alpelisib dose intensity of 248 mg/day. Median progression-free survival with alpelisib was 12.5 and 9.6 months for alpelisib dose intensities of ≥248 mg/day and <248 mg/day, respectively, compared with 5.8 months with placebo.

CONCLUSIONS

Hyperglycemia and rash occurred early during alpelisib treatment, while diarrhea occurred at a later time point. Early identification, prevention, and intervention, including concomitant medications and alpelisib dose modifications, resulted in less severe toxicities. Reductions in treatment discontinuations and improved progression-free survival at higher alpelisib dose intensities support the need for optimal AE management. CLINICALTRIALS.

GOV ID

NCT02437318.

Abstract P6-18-17: Ribociclib + letrozole in patients with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2–) advanced breast cancer (aBC) with no prior endocrine therapy (ET) for ABC: CompLEEment-1 trial, preliminary results from Spanish population

Background: The phase III Monaleesa-2, Monaleesa-3 and Monaleesa-7 trials have shown significantly improved PFS for the combination ribociclib + ET vs ET + placebo in pre-, peri-, and postmenopausal women with HR+/HER2–, first and second line aBC. The Compleement-1 trial is a phase IIIb, single-arm, open-label, international study to assess the safety and efficacy of ribociclib + letrozole in men and women who have not received prior ET for HR+, HER2– ABC [J Clin Oncol 36, 2018 (suppl; abstr 1056)].

Methods: 526 patients with HR+, HER2– ABC, ≤1 line of prior CT, and no prior ET for aBC were enrolled in the Compleement-1trial in Spain from April 2017 to January 2018. Patients received ribociclib (600 mg/day, 3 weeks on/1 week off) + letrozole (2.5 mg/day); men and premenopausal women received concomitant goserelin (3.6 mg subcutaneous implant every 28 days). The primary objective was safety and tolerability. Here we report on a sub-analysis from the Spanish population of Compleement-1 trial including baseline characteristics and early safety results for the first patients enrolled who completed at least 56 days of follow-up or discontinued before the cut-off date (3rd Oct 2017).

Results: One hundred fifty four patients constituted the analytical cohort for this sub-analysis. Demographics and baseline characteristics: median age was 52 years (range 24-82); 1% of patients were male, 31.8% female pre-menopausal and 67.5% female post-menopausal; 44.2% vs 38.3% of patients had visceral disease vs bone only disease; 49.9% patients had ≥2 metastatic sites; and 34.4% of patients presented as de novo stage IV. The median exposure for study treatment was 1.8 months (range 0.8-1.8). The grade 3/4 events reported &gt;1% included neutropenia (50%), increased GGT levels (3.2%), leukopenia (1.3%), and increased ALT (1.3%). QTcF prolongation &gt;480ms based on ECG data was reported in 1.2% patients. Median dose intensity for ribociclib was 600mg/day (range 476.5-600); 11% of patients required one dose reduction (8.4% due to AEs), 59.7% had at least one dose interruption (57.1% due to AEs) and 9.7% were permanently discontinued (4.5% due to AEs).

Conclusions: Preliminary safety results from this Compleement-1 sub-analysis including Spanish population are consistent with previous data presented from Monaleesa-2, Monaleesa-3, Monaleesa-7 and Compleement-1. These data support the predictable and manageable safety profile of ribociclib in combination with letrozole. Clinical trial information: NCT02941926

Citation Format: Salvador J, Ciruelos EM, Prat A, Jiménez-Rodríguez B, de la Cruz L, Martínez N, Villanueva Vázquez R, de Toro R, Antón A, Moreno F, Alvarez I, Gavila J, Quiroga V, Vicente E, de la Haba J, González-Santiago S, Díaz N, Barnadas A, Cantos Sánchez de Ibargüen B, Delgado JI, Bellet M, Gimeno A, Sanz S, Martin M. Ribociclib + letrozole in patients with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2–) advanced breast cancer (aBC) with no prior endocrine therapy (ET) for ABC: CompLEEment-1 trial, preliminary results from Spanish population [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 P6-18-17.

Abstract GS4-02: Randomized comparison of adjuvant aromatase inhibitor exemestane (E) plus ovarian function suppression (OFS) vs tamoxifen (T) plus OFS in premenopausal women with hormone receptor positive (HR+) early breast cancer (BC): Update of the combined TEXT and SOFT trials

Background: The combined results of TEXT and SOFT, after 5.7 years median follow-up, found adjuvant E+OFS significantly improved disease-free survival (DFS) vs T+OFS in premenopausal women with HR+ BC (Pagani et al, NEJM 2014). Follow-up was immature for overall survival (OS). We report a planned update with visit cut-off of 31Dec16 after 9 years median follow-up.

Methods: TEXT and SOFT enrolled premenopausal women with HR+ early BC from Nov 2003 to Apr 2011 (2660 TEXT, 3047 SOFT in the intention-to-treat populations). TEXT randomized women within 12wk of surgery to 5 yrs E+OFS vs T+OFS; chemotherapy (CT) was optional and concurrent with OFS. SOFT randomized women to 5 yrs E+OFS vs T+OFS vs T alone, within 12wk of surgery if no CT planned, or within 8mo of completing (neo)adjuvant CT after premenopausal status was (re-)established. OFS was by choice of 5yr GnRH agonist triptorelin, oophorectomy or ovarian irradiation. Both trials were stratified by CT use. The primary endpoint was DFS: randomization until invasive local, regional, distant recurrence or contralateral breast; invasive second malignancy; death. Secondary endpoints included invasive breast cancer-free interval (BCFI), distant recurrence-free interval (DRFI) and OS. Stratified Cox models estimated hazard ratios; Kaplan-Meier method estimated 8yr endpoint rates. NCT00066703/NCT00066690.

Results: DFS for patients assigned E+OFS (n=2346) continued to be significantly improved over T+OFS (n=2344): 8yr DFS was 86.8% vs. 82.8%. The 8yr BCFI was improved by 4.1% (89.3% vs 85.2%) and 8yr DRFI by 2.1% (91.8% vs 89.7%). There was no difference in OS in patients assigned E+OFS vs T+OFS: 93.4% vs 93.3% OS at 8yrs. For 1996 women without CT there have been 45 deaths, with 98% OS at 8yrs with both treatments.

EndpointN. EventsHazard Ratio (95% CI) E+OFS vs T+OFSDFS7200.77 (0.67-0.90); P&lt;0.001BCFI6000.74 (0.63-0.87)DRFI4330.80 (0.65-0.96)OS3200.98 (0.79-1.22)

Overall toxicity was not significantly worse with E+OFS than with T+OFS (32% vs 31% grade 3-4 targeted AEs). Hot flashes, musculoskeletal symptoms and hypertension were the most frequent targeted grade 3-4 AEs. Overall, 15% of patients stopped all protocol-assigned treatment early. Patients assigned E+OFS had increased risk of assigned oral endocrine therapy cessation (25% vs 19% for patients assigned T+OFS by 4yrs) but not of triptorelin cessation (18% vs 19% by 4yrs, respectively).

Conclusions: After 9 yrs median follow-up, adjuvant E+OFS, as compared with T+OFS, shows a sustained reduction of the risk of recurrence but did not improve overall survival. As in postmenopausal women, oncologists need to consider potential absolute benefits and properly select patients at sufficient risk for recurrence for whom E+OFS seems indicated. Follow-up continues, which will further clarify the effect of E+OFS for safety, late recurrence and overall survival.

Citation Format: Pagani O, Regan MM, Fleming GF, Walley BA, Colleoni M, Láng I, Gomez HL, Tondini C, Burstein HJ, Goetz MP, Ciruelos EM, Stearns V, Debled M, Martino S, Geyer Jr CE, Pinotti G, Coates AS, Goldhirsch A, Gelber RD, Francis PA. Randomized comparison of adjuvant aromatase inhibitor exemestane (E) plus ovarian function suppression (OFS) vs tamoxifen (T) plus OFS in premenopausal women with hormone receptor positive (HR+) early breast cancer (BC): Update of the combined TEXT and SOFT trials [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 GS4-02.

Abstract GS4-03: Randomized comparison of adjuvant tamoxifen (T) plus ovarian function suppression (OFS) versus tamoxifen in premenopausal women with hormone receptor-positive (HR+) early breast cancer (BC): Update of the SOFT trial

Background: The primary results of SOFT at 5.6 years median follow-up found adding OFS to T did not provide a significant benefit in the overall study population of premenopausal women with HR+ BC (Francis et al, NEJM 2015). For those women at sufficient risk for recurrence to warrant adjuvant chemotherapy (CT) and who remained premenopausal, the addition of OFS improved disease outcomes. Follow-up was immature for overall survival (OS). We report a planned update with visit cut-off of 31Dec16 after 8 yrs median follow-up.

Methods: SOFT randomized premenopausal women with HR+ BC from Nov 2003 to Jan 2011 to 5 yrs of T vs T+OFS vs Exemestane(E)+OFS. OFS was by choice of GnRH agonist triptorelin, oophorectomy or ovarian irradiation. SOFT was stratified by the use of prior CT; 47% received no CT and 53% remained premenopausal after prior CT, determined by premenopausal estradiol level within 8 months of CT completion. The primary endpoint was invasive disease-free survival (DFS; randomization until invasive local, regional, distant recurrence or contralateral breast; invasive second malignancy; death). Secondary endpoints included invasive breast cancer-free interval (BCFI), distant recurrence-free interval (DRFI) and OS. NCT00066690.

Results: DFS for patients assigned T+OFS (n=1015) was significantly improved over T (n=1018; HR=0.76 [95%CI 0.62-0.93]) and 8yr DFS was 83.2% vs 78.9%, respectively; BCFI and DRFI results were supportive (see Table). Hazard ratios for these 3 endpoints showed no heterogeneity by use of prior CT. For patients with prior CT, 8yr DFS was 76.7% with T+OFS vs 71.4% with T (Δ=5.3%); in those without CT, 8yr DFS was 90.6% vs 87.4% (Δ=3.2%). E+OFS (n=1014) improved outcomes relative to T (Table); 8yr DFS for E+OFS was 85.9% (80.4% with use of prior CT and 92.5% for those without CT). OS was improved with T+OFS vs T (8yr OS 93.3% vs 91.5%). 8yr OS was 92.1% with E+OFS. 201/225 deaths occurred in women with prior CT. For women without CT there have been 10, 5 and 9 deaths in the T+OFS, T and E+OFS groups (total n=1419), respectively, only half of these deaths after breast cancer event.

N. EventsHazard Ratio (95% CI)Endpoint(3 arms)T+OFS vs TE+OFS vs TDFS5180.76 (0.62-0.93) P=0.0090.65 (0.53-0.81)BCFI4370.76 (0.61-0.95)0.64 (0.51-0.81)DRFI3060.86 (0.66-1.13)0.73 (0.55-0.96)OS2250.67 (0.48-0.92)0.85 (0.62-1.15)

Overall toxicity was worse with T+ OFS than with T, including 32% vs 25% grade 3+ targeted AEs. Early cessation of tamoxifen occurred for 19% assigned T+OFS and 22% of women assigned T; the cumulative incidence of early cessation of triptorelin on the T+OFS arm was 23% by 4yrs. Early cessation of exemestane occurred for 28% and of triptorelin for 21% by 4yrs on the E+OFS arm.

Conclusions: With additional follow-up to a median of 8yrs, SOFT further supports the value of OFS for some premenopausal women. Follow-up continues, which will further clarify the safety and the benefit of OFS for late recurrence and overall survival. Oncologists appear to be able to select a low risk group (no chemotherapy) for whom treatment escalation is unlikely to improve survival.

Citation Format: Fleming G, Francis PA, Láng I, Ciruelos EM, Bellet M, Bonnefoi HR, Climent MA, Pavesi L, Burstein HJ, Martino S, Davidson NE, Geyer Jr CE, Walley BA, Coleman RE, Kerbrat P, Buchholz S, Ingle JN, Rabaglio-Poretti M, Colleoni M, Regan MM. Randomized comparison of adjuvant tamoxifen (T) plus ovarian function suppression (OFS) versus tamoxifen in premenopausal women with hormone receptor-positive (HR+) early breast cancer (BC): Update of the SOFT trial [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 GS4-03.

A phase II study of combined ridaforolimus and dalotuzumab compared with exemestane in patients with estrogen receptor-positive breast cancer

PURPOSE

Combining the mTOR inhibitor ridaforolimus and the anti-IGFR antibody dalotuzumab demonstrated antitumor activity, including partial responses, in estrogen receptor (ER)-positive advanced breast cancer, especially in high proliferation tumors (Ki67 > 15%).

METHODS

This randomized, multicenter, international, phase II study enrolled postmenopausal women with advanced ER-positive breast cancer previously treated with a nonsteroidal aromatase inhibitor (NCT01234857). Patients were randomized to either oral ridaforolimus 30 mg daily for 5 of 7 days (once daily [qd] × 5 days/week) plus intravenous dalotuzumab 10 mg/kg/week or oral exemestane 25 mg/day, and stratified by Ki67 status. Due to a high incidence of stomatitis in the ridaforolimus-dalotuzumab group, two sequential, nonrandomized, reduced-dose cohorts were explored with ridaforolimus 20 and 10 mg qd × 5 days/week. The primary endpoint was progression-free survival (PFS).

RESULTS

Median PFS was 21.4 weeks for ridaforolimus 30 mg qd × 5 days/week plus dalotuzumab 10 mg/kg (n = 29) and 24.3 weeks for exemestane (n = 33; hazard ratio = 1.00; P = 0.5). Overall survival and objective response rates were similar between treatment arms. The incidence of drug-related, nonserious, and serious adverse events was higher with ridaforolimus/dalotuzumab (any ridaforolimus dose) than with exemestane. Lowering the ridaforolimus dose reduced the incidence of grade 3 stomatitis, but overall toxicity remained higher than acceptable at all doses without improved efficacy.

CONCLUSIONS

The combination of ridaforolimus plus dalotuzumab was no more effective than exemestane in patients with advanced ER-positive breast cancer, and the incidence of adverse events was higher. Therefore, the combination is not being further pursued.

Phase I study of the combination of balixafortide (CXCR4 inhibitor) and eribulin in HER2-negative metastatic breast cancer (MBC) patients (pts)

2555

Background: Balixafortide (POL6326) is a cyclic peptide and a potent, selective antagonist of the chemokine receptor CXCR4. Evidence suggests that CXCR4 inhibition interferes with the tumor-protective microenvironment and sensitizes tumor cells to chemotherapy. The combination of balixafortide (B) and eribulin (E) was safe with early signs of efficacy in the dose escalation part of this study. Methods: The expanded cohort of thisopen label phase I study was designed to assess the anti-tumor activity, safety and pharmacokinetics of the addition of the recommended phase 2 dose (RP2D) of B to E in pts with MBC and with any CXCR4 expression level at the tumor site. Patients received E (1.4 mg/m2) on days 2 and 9, flanked by B (5.5 mg/kg) on days 1-3, and 8-10 of 21-day cycles. Results: 24 pts with relapsed MBC (median age 59 [33-82]) were enrolled in the expanded cohort. Median number of prior chemotherapies for MBC was 2 (range 1-3). 20/24 (83%) pts were ER and/or PR positive; 3/24 (13%) pts had TNBC. Objective response rate (ORR) was 33%. 8/24 (33%) pts achieved a partial response and 4/24 (17%) pts had meaningful (≥ 6 months) stable disease for a Clinical Benefit Ratio of 50%. Median duration of treatment was 15.3 weeks (range 5-40) with 11 pts still on treatment. The most common Gr 3-4 adverse events were neutropenia (9/24, 38%) and leucopenia (3/24, 13%); 2 pts had febrile neutropenia and 1 patient died from sepsis. 15/24 (63%) pts experienced histamine-like infusion reactions related to B that were manageable with anti-histamines. Conclusions: The therapeutic activity of this treatment regimen appears promising with an ORR of 33% in patients with advanced MBC. B (5.5 mg/kg) can be combined safely with E (1.4 mg/m2) and the safety profile resembles E monotherapy as previously reported. This is the first study of the treatment combination of E with B in relapsed MBC pts. Further confirmatory studies are being considered. Clinical trial information: NCT01837095.

CORALLEEN: A phase 2 clinical trial of chemotherapy or letrozole plus ribociclib as neoadjuvant treatment for postmenopausal patients with luminal B/HER2-negative breast cancer

TPS594

Background: Dysregulation of cyclin D-CDK4/6-Rb pathway is associated with endocrine resistance in hormone receptor–positive (HR+) breast cancer. Recently, a CDK4/6 inhibitor has shown unprecedented efficacy in metastatic disease, leading to its regulatory approval. Several others are currently in clinical development for the management of HR+ breast cancer in the early and advanced settings. However, it is vital to gain insights into the molecular and biological effects of this class of agents and could identify patients who can benefit the most, delaying or avoiding the use of chemotherapy.The neoadjuvant setting provides an ideal scenario to carry out these investigations. Hence, we propose to conduct an exploratory study to evaluate the biological effects and the efficacy of ribociclib in patients with primary luminal B tumors.We hypothesize that the combination of ribociclib plus letrozole may offer clinical benefit in the preoperative setting. Methods: This is a parallel, multicenter, two-arm, randomized exploratory study in postmenopausal women with primary operable HR+/HER2-negative Luminal B breast cancer designed to evaluate the clinical benefit of ribociclib plus letrozole. Eligibility includes stage I-III operable breast cancer, Luminal B by PAM50, ECOG 0-1. They will be randomized 1:1 to receive either six 28-days cycles of ribociclib (600mg; 3-weeks-on/1-week-off) plus daily letrozole (2.5mg) or chemotherapy: four cycles of AC (doxorubicin 60 mg/m2, cyclophosphamide 600 mg/m2 every 21 days) followed by weekly paclitaxel during 12 weeks. Baseline, Day 15 on-treatment, and surgical specimens will be collected for molecular characterization and evaluation of response (decrease in Ki67, change to ROR low disease) The primary endpoint is the rate of Residual Cancer Burden (RCB) per MD Anderson Cancer Center procedures. A rate of RCB 0 and 1 score at surgery, with a rank between 20% to 25% with 47 evaluable patients by group of treatment will offer a precision between 11.5% and 12.4%, respectively (95%CI). Ninety-four patients will be enrolled in 20 sites across Spain.

A phase 3 study of alpelisib (ALP) plus fulvestrant (FUL) in men and postmenopausal women with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) ABC progressing on or after aromatase inhibitor (AI) therapy: SOLAR-1

TPS1111

Background: Patients (pts) with HR+ breast cancer (BC) often havedysregulatedphosphatidylinositol 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) pathway, which further leads to resistance to endocrine therapy (ET). In a phase 1 study, alpelisib (BYL719), a PI3Kα-specific inhibitor in combination with fulvestrant (FUL) has demonstrated antitumor activity in pts with estrogen receptor-positive, HER2– advanced BC (ABC) with PIK3CA-altered tumors. SOLAR-1 (NCT02437318) aims to assess the efficacy of ALP + FUL in PIK3CA-mutant and non-mutant tumors in HR+, HER2– ABC setting. Methods: SOLAR-1 is a phase 3, randomized, double-blind study conducted in men and postmenopausal women with HR+, HER2– ABC. Pts are randomly (1:1) allocated to oral alpelisib/placebo (300 mg qd) and intramuscular FUL (500 mg) until disease progression or treatment (tx) discontinuation. Stratification factors are presence of liver and/or lung metastases and prior use of CDK4/6 inhibitors. The eligibility criteria for the targeted BC patient population are shown in the Table. The primary endpoint is progression-free survival (PFS; RECIST v1.1; local assessment), while overall survival (OS) is a key secondary endpoint in the PIK3CA-mutant cohort. Other secondary endpoints are PFS and OS in the PIK3CA non-mutant cohort, the association between PFS and baseline PIK3CAstatus in ctDNA, overall response rate, clinical benefit rate, and safety. Recruitment of the planned 560 pts is currently ongoing. Clinical trial information: NCT02437318. [Table: see text]

Abstract OT2-01-04: SOLAR-1: A phase III study of alpelisib and fulvestrant in men and postmenopausal women with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2–) advanced breast cancer (BC) progressing on or after aromatase inhibitor (AI) therapy

Background: The phosphatidylinositol 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) pathway is often dysregulated in HR+ BC and is associated with resistance to endocrine therapy (ET). Alpelisib (BYL719; PI3Kα-specific inhibitor) and fulvestrant showed signs of antitumor activity in patients (pts) with estrogen receptor-positive (ER+), HER2– advanced BC (phase I), especially in PIK3CA-altered tumors (Janku et al. SABCS 2014, PD5-5).

Methods: SOLAR-1 (NCT02437318) is a phase III, randomized, double-blind study in men and postmenopausal women with HR+, HER2– advanced BC. Pts are assigned to 1 of 2 cohorts based on PIK3CA tumor status (mutant vs non-mutant), and randomized 1:1 to oral alpelisib/placebo (300 mg once daily) and intramuscular fulvestrant (500 mg on Day 1 and 15 of Cycle 1; Day 1 of Cycles ≥2 [28-day cycles]) until disease progression or discontinuation. Randomization is stratified by presence of liver and/or lung metastases and prior CDK4/6 inhibitor therapy. Key inclusion criteria: recurrence or progression on or after AI therapy, ≥1 measurable lesion (RECIST v1.1) or predominantly lytic bone lesion, and ECOG performance status ≤1. Key exclusion criteria: symptomatic visceral disease or disease burden precluding ET, acute pancreatitis ≤1 year prior to screening or history of chronic pancreatitis, and prior therapy with fulvestrant, chemotherapy (except [neo]adjuvant), or PI3K/AKT/mTOR inhibitors.

The primary and key secondary endpoints are progression-free survival (PFS; RECIST v1.1; local assessment) and overall survival (OS), respectively, in the PIK3CA-mutant cohort. Other secondary endpoints include PFS and OS in the PIK3CA non-mutant cohort, PFS (Blinded Independent Central Review; RECIST v1.1), the association between PFS and baseline PIK3CA status in circulating tumor DNA, overall response rate, clinical benefit rate, safety, and pharmacokinetics. The primary endpoint will be analyzed by a stratified log-rank test at one-sided 2% level of significance.

Recruitment of the planned 560 pts is ongoing.

Citation Format: Andre F, Kaufman B, Juric D, Ciruelos EM, Iwata H, Mayer IA, Rugo HS, Conte P, Liobl S, Rubovszky G, Inoue K, Tesch H, Lu Y-S, Ryvo L, Longin A-S, Mills D, Wilke C, Germa C, Campone M. SOLAR-1: A phase III study of alpelisib and fulvestrant in men and postmenopausal women with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2–) advanced breast cancer (BC) progressing on or after aromatase inhibitor (AI) therapy [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 OT2-01-04.

Abstract P4-07-09: Differential expression of microRNAs (miRNAs) in HER2 negative breast cancer (BC)

Background:

MiRNAs are non-coding single-stranded RNAs that control gene expression by directing their target mRNAs for degradation and/or posttranscriptional repression. Compared to mRNA signatures, miRNAs have better and stronger biomarker properties with 20 times more power in biomarker studies as compared to mRNAs (when comparing 20,000 mRNAs to ~ 1,000 miRNAs). Global downregulation of miRNAs has emerged as a common theme in human breast tumors and has been shown to contribute to oncogenesis

Hormone receptor (HR) status is one of the most important factors influencing BC outcome. Several data indicate the extensive alterations in miRNAs regulation upon estrogen pathway and suggest the utility of considering miRNAs expression in the understanding the development of cancer disease, invasiveness, metastasis and treatment failure.

Our aim was to identify differential expression miRNAs in HER2 negative BC. We previously reported a set of miRNAs deregulated in HR+/HER2- BC vs. Triple negative BC (TNBC). In this work we have validate these differences in a new cohort of BC patients.

Methods:

Total RNA was extracted samples extracted from primary breast cancer FFPE tissue. MicroRNAs expression was analyzed by RT-qPCR using TaqMan Arrays from Applied Biosystems. Normalization was performed using de DCt method with two housekeeping miRNAs identified previously identified using NorMean. MicroRNA expression values in each group were compared by the Mann Whitney test.

Results:

121 patients with early HER2 negative BC were included in the present study. All patients showed absence of nodal involvement at the time of diagnosis. The median age at diagnosis was 56 years, 89 cases (74%) had positive estrogen receptor and 53 cases (44%) grade 3. miR-20a, miR-19a, miR-106a, miR-18a and miR-135b expression were significantly higher in TNBC samples, whereas miR-190b, miR-375, miR-449a, miR-342, miR-149, miR-193b, miR-214, miR-30a*and miR-30e* were significantly more expressed in ER+/HER2- samples. No significant differences were found in miR-139-5p expression between both groups.

Conclusions:

We have validated fourteen miRNAs that are differentially expressed between ER+/HER2- and TNBC breast cancer subtypes. Altered expression of miRNAs could be a potential therapeutic tool and promising biomarker in personalized treatment.

Citation Format: Pascual T, Gámez-Pozo A, Camara-Jurado M, Manso LM, Pérez-Campos A, Trilla L, Fresno-Vara JA, Ciruelos EM. Differential expression of microRNAs (miRNAs) in HER2 negative breast cancer (BC) [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 P4-07-09.

Abstract P4-21-16: Phase III trial to evaluate patient´s preference for subcutaneous versus intravenous trastuzumab administration in patients with HER2 positive advanced breast cancer (ABC) under IV trastuzumab (IV-t) treatment for at least 4 months. ChangHER-SC study (GEICAM/2012-07)

Background: Patients with HER2-positive ABC, receive anti-HER2 treatment for several months or even years. IV-t is administered weekly or 3-weekly, mandating patients to visit the hospital on a regular basis to receive infusions. This has inconveniences for patients and increase treatment costs. Subcutaneous administration could improve convenience of trastuzumab therapy. This study was designed to evaluate patient's preference for IV-t or SC trastuzumab (SC-t) in ABC patients.

Methods:This is a phase III, open label, multicenter study inpatients with HER2 positive ABC, receiving IV-t for at least 4 months and without evidence of disease progression. Patients received 600 mg of SC-t, either from a vial or from a single injection device (SID), every 3 weeks for 4 cycles. Before starting SC-t, patients received an additional IV-t cycle. Patients were randomized 1:1 to arm A, receiving 2 cycles of SC-t with vial followed by 2 cycles with SID or arm B, receiving the opposite sequence. After cycle 4, patients decided to continue with IV-t or SC-t till disease progression. Stratification criteria were the associated therapy (Chemotherapy, Hormone-therapy or none) and its administration route (IV, oral or none). Patients completed a questionnaire of experiences and preferences at three time points: before starting SC-t, after cycle 2 and after cycle 4. Health Care Professionals completed a satisfaction questionnaire every 5 patients. The primary objective was to evaluate patient´s preference for IV-t or SC-t (after cycle 2) and, secondary objectives were, to evaluate patient´s preference between the two SC-t administrations (vial or SID) after cycle 4, Health Care Professional satisfaction, associated costs of the administration options (Time and Motion pharmacoeconomic study) and safety.

Results: From September-13 to July-15, 166 patients were randomized (81 arm A, 85 arm B) in 26 Spanish sites from GEICAM. Median age was 60 years (35-93), 88% of patients were postmenopausal and 123 and 42 had an ECOG PS of 0 and 1, respectively. The median duration of prior IV-t for ABC was 1.8 years (range: 0.3-14). Patients received a median of 2 previous lines of Chemotherapy and/or Hormone-therapy (range: 1-9). Twenty patients were receiving pertuzumab at inclusion. According to patient questionnaires completed after cycle 2, 137 patients preferred the SC-t (66 arm A, 71 arm B), 11 the IV-t (6 arm A, 5 arm B), 11 didn't have a preference (4 arm A, 7 arm B), and 7 didn't answer (3 progressed, 2 withdrew participation before cycle 2 and 2 unknown reason). Three of the 11 patients choosing IV-t were receiving IV treatment as accompanying therapy; after cycle 4 five of these 11 patients finally continued with SC-t, 5 with IV-t and 1 progressed. From the 11 patients without any preference 7 received SC-t, 2 receive IV-t and 2 progressed; from the 137 patients preferring SC-t, 125 actually received it, 3 received IV-t and 9 progressed.

Conclusions: Our study shows that 82.5% of patients preferred the SC-t over the IV-t. Treatment choice was not influenced by the accompanying therapy.

Citation Format: Ciruelos EM, Montaño Á, Rodríguez CA, González-Flores E, Lluch A, Garrigós L, Quiroga V, Antón A, Malón D, Chacón JI, Velasco M, Gonzalez-Cortijo L, Jolis L, Pascual T, Amigo Y, Casas M, Cámara MC, Carrasco E, Casas A. Phase III trial to evaluate patient´s preference for subcutaneous versus intravenous trastuzumab administration in patients with HER2 positive advanced breast cancer (ABC) under IV trastuzumab (IV-t) treatment for at least 4 months. ChangHER-SC study (GEICAM/2012-07) [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 P4-21-16.

Safety of everolimus plus exemestane in patients with hormone-receptor-positive, HER2-negative locally advanced or metastatic breast cancer progressing on prior non-steroidal aromatase inhibitors: primary results of a phase IIIb, open-label, single-arm, expanded-access multicenter trial (BALLET)

BACKGROUND

This European phase IIIb, expanded-access multicenter trial evaluated the safety of EVE plus EXE in a patient population similar to BOLERO-2.

PATIENTS AND METHODS

Post-menopausal women aged ≥18 years with hormone receptor-positive, human epidermal growth factor-receptor-2-negative advanced breast cancer (ABC) recurring/progressing during/after prior non-steroidal aromatase inhibitors were enrolled. The primary objective was safety of EVE plus EXE based on frequency of adverse events (AEs), and serious AEs (SAEs). The secondary objective was to evaluate AEs of grade 3/4 severity.

RESULTS

The median treatment duration was 5.1 months [95% confidence interval (CI) 4.8-5.6] for EVE and 5.3 months (95% CI 4.8-5.6) for EXE. Overall, 2131 patients were included in the analysis; 81.8% of patients experienced EVE- or EXE-related or EVE/EXE-related AEs (investigator assessed); 27.2% were of grade 3/4 severity. The most frequently reported non-hematologic AEs were (overall %, % EVE-related) stomatitis (52.8%; 50.8%) and asthenia (22.8%; 14.6%). The most frequently reported hematologic AEs were (overall %, % EVE-related) anemia (14.4%; 8.1%) and thrombocytopenia (5.9%; 4.6%). AE-related treatment discontinuations were higher in elderly (≥70 years) versus non-elderly patients (23.8% versus 13.0%). The incidence of EVE-related AEs in both elderly and non-elderly patients appeared to be lower in first-line ABC versus later lines. The incidence of AEs (including stomatitis/pneumonitis) was independent of BMI status (post hoc analysis). Overall, 8.5% of patients experienced at least one EVE-related SAE. Of the 121 on-treatment deaths (5.7%), 66 (3.1%) deaths were due to disease progression and 46 (2.2%) due to AEs; 4 deaths were suspected to be EVE-related.

CONCLUSIONS

This is the largest ever reported safety dataset on a general patient population presenting ABC treated with EVE plus EXE and included a sizeable elderly subset. Although the patients were more heavily pretreated, the safety profile of EVE plus EXE in BALLET was consistent with BOLERO-2.

CLINICAL TRIAL REGISTRATION

EudraCT Number: 2012-000073-23.

Abstract P4-13-10: Stomatitis following everolimus (EVE) plus exemestane (EXE) in patients with hormone receptor-positive (HR+), HER2– advanced breast cancer (ABC) in the BALLET trial (CRAD001YIC04)

Background

Stomatitis is the most common adverse event (AE) associated with mTOR inhibitors, including EVE. In the pivotal BOLERO-2 trial, stomatitis was reported for 59% vs 12% (Gr3, 8% vs &lt;1%) of pts with HR+, HER2– ABC who received EVE + EXE vs EXE alone. Of the limited real world evidence available, the BRAWO trial showed a stomatitis incidence of 39.8% (Gr3, 3.4%) in a similar pt population. Additional data are warranted to better understand the stomatitis incidence and time-course in order to minimize treatment discontinuations.

Methods

BALLET is a Phase 3b, European, multi-center, open-label, single-arm, expanded-access study that evaluated safety of EVE (10 mg/d) and EXE (25 mg/d) in 2131 postmenopausal women with HR+, HER2– ABC that progressed on prior NSAI treatment. Primary endpoint was safety; secondary endpoint was characterization of grade 3/4 AEs. In this exploratory analysis, we split the pts in two groups based on having experienced at least one all grade stomatitis event in the first 8 wks (cut-off chosen based on reports that 89.4% of stomatitis events occurred within 8 wks of EVE initiation [Rugo, ASCO 2014]) vs none.

Results

This subgroup analysis included 919 pts with stomatitis (43.1% of the full population). Baseline pt characteristics were comparable to the overall study population, except for more comorbidity (cardiovascular and metabolic disorder) in stomatitis subset. Pts with stomatitis had a longer EVE treatment duration vs pts who didn't (5.8 mo [95%CI, 5.0-6.2] vs 4.7 mo [95%CI, 4.4-5.3]; hazard ratio, 1.121 [95%CI, 0.97-1.28] censored by pts who switched to commercial drug). The relative risk of initial onset of stomatitis at 6 wks was ∼40%; median time to onset was 28 days. Majority of stomatitis events were of grade 1/2 severity (80%); grade 3/4 stomatitis was reported for 20% of pts. Most frequent reasons for treatment discontinuation in pts with stomatitis were reimbursement (37.6%), disease progression (35.0%), and AEs (16.2%). Most frequent AEs which led to treatment discontinuation in these pts were stomatitis in 3.7% (Grade 3/4, 2%), pneumonitis in 2.9% (Grade 3/4, 1.3%) and asthenia in 1.8% (Grade 3/4, 1%). Median EVE relative dose intensity in pts with stomatitis was 0.92. In the stomatitis subset, dose interruptions and reductions were required for 66.7% and 37.6% of pts, respectively; most frequent reasons for dose adjustments were AEs (65.9%) which included stomatitis (46.8%), asthenia (6.3%), and pneumonitis (5.3%). Median time to first dose modification in pts with stomatitis was 30 days; median duration of dose interruptions was 16 days. On-treatment deaths (4.4%) were due to progressive disease (2.1%), AEs (1.7%), and other reasons (0.5%).

Conclusions

These results confirmed the stomatitis time-course observed previously and that the majority of these events are of low grade. Stomatitis was the most common cause of dose reductions and interruptions due to AEs and was manageable with dose adjustments; there was a positive association between stomatitis and longer treatment duration. Therefore, proactive management, diligent monitoring and appropriate dose modifications, are recommended to keep pts on treatment.

Citation Format: Ciruelos EM, Jerusalem G, Generali D, Lang I, Gavila JG, Michelotti A, Tjan-Heijnn VCG, Mariani G, Conte P, Beliera A, Camozzi M, Lorizzo K, Martin M. Stomatitis following everolimus (EVE) plus exemestane (EXE) in patients with hormone receptor-positive (HR+), HER2– advanced breast cancer (ABC) in the BALLET trial (CRAD001YIC04). [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-13-10.

Abstract P3-07-40: Pharmacogenetic study of exemestane and everolimus in metastatic breast cancer patients progressing on prior non-steroidal aromatase inhibitors

Background: Activation of the mTOR pathway has been observed in patients (pts) with metastatic breast cancer (MBC) progressing on endocrine therapy. BOLERO-2 trial demonstrated a significant increase in progression free survival (PFS) obtained with everolimus (EVE) and exemestane (EXE) versus EXE alone in pts refractory to a prior non-steroidal aromatase inhibitors (NSAI). However, there is large interindividual variability in toxicity and efficacy profiles of EXE-EVE treatment. Single Nucleotide Polymorphisms (SNPs) have been proposed to explain some of these differences. The objective of this study was to perform a pharmacogenetic analysis to identify SNPs associated with EVE toxicity and activity.

Methods: This is a prospective unicentric clinical trial for postmenopausal pts with hormone receptor-positive, HER2 negative, MBC progressing on prior NSAI, treated with EXE-EVE.

Blood samples were obtained from all pts, and 12 SNPs in key genes involved in EXE pharmacokinetics (ABCB1, CYP2C8, CYP3A4, CYP3A5) and pharmacodynamics (AKT1, AKT2, FGFR4, PHLPP2, PIK3R1, RAPTOR) were genotyped. EVE pharmacokinetics data was available for a subset of 37 pts. The association between the SNPs and EVE pharmacokinetic parameters were analyzed using U-Mann-Whitney test. A selection of clinically relevant toxicities (non-infectious pneumonitis (NIP), mucositis, hyperglycemia and hematological) was analyzed using binary logistic regression. Cox regression was used to analyze the association of SNPs with time to treatment modifications (reduction or interruption) due to toxicity, PFS and OS.

Results: 90 patients with median age of 62 yrs were included. At data cut off, a total of 77 pts had discontinued treatment. Major reasons for discontinuation were: disease progression (80%), adverse events (17%) and death (2%). Number of prior chemotherapy lines: 0; 50%, 1;18%, 2;10%, ≥3; 22%. 76% of pts experienced at least one adverse event related to EVE.

CYP3A4 rs35599367 (CYP3A4*22 allele) heterozygous pts had higher EVE concentration in blood compared to wild type pts (P=0.019), in agreement with previous data.

Regarding EVE toxicities, ABCB1 SNP rs1045642 showed a higher risk of mucositis (HR=2.3, 95%CI=1.1-4.8, P=0.031; multivariable analysis), and PIK3R1 rs10515074 variant was inversely associated with hyperglycemia (HR=0.24, 95%CI=0.1-0.8, P=0.016; multivariable analysis). RAPTOR rs9906827 protected for NIP (HR=0.38, 95%CI=0.2-0.9, P=0.024; multivariable analysis). When analyzing the time to treatment modification due to any toxicity, we observed a trend for FGFR4 rs351855 and RAPTOR rs9906827 (HR=0.59, 95%CI=0.3-1.0, P=0.06 and HR=0.71, 95%CI=0.5-1.1, P=0.12; respectively, in multivariable analysis).

Regarding activity, RAPTOR rs9906827 was also associated with longer PFS (dominant model HR=0.48, 95%CI=0.3-0.8, P=0.006; multivariable analysis). No SNP was significantly associated with OS.

Conclusions: We found altered EVE pharmacokinetics for CYP3A4*22 carriers and protection for NIP and longer PFS for RAPTOR rs9906827. This study supports prospective trials for genetic testing prior to EXE-EVE therapy to stratify patients according to toxicity and efficacy risk profiles.

Citation Format: Pascual-Martínez T, Apellániz-Ruiz M, Pernaut C, Cueto-Felgueroso C, Villalba P, Alvarez C, Manso L, Rodriguez-Antona C, Ciruelos EM. Pharmacogenetic study of exemestane and everolimus in metastatic breast cancer patients progressing on prior non-steroidal aromatase inhibitors. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-07-40.

Abstract P5-19-02: Everolimus in combination with exemestane in hormone receptor-positive locally advanced or metastatic breast cancer (BC) patients progressing on prior non-steroidal AI (NSAIs): Ballet study (CRAD001YIC04)

Background:

Despite progress, a large number of breast cancer patients experience metastatic relapse and death.

Hyperactivation of the mTOR pathway has been observed in patients (pts) with BC progressing on endocrine therapy. The BOLERO-2* trial demonstrated significant doubling of PFS obtained via dual blockade with everolimus (EVE) and exemestane (EXE), versus EXE alone in pts refractory to NSAIs.

Methods:

BALLET is a European multi-center open-label, single-arm, expanded-access study to evaluate the safety of EVE (10 mg/day) and EXE (25 mg/day) in postmenopausal women with hormone receptor-positive HER2 negative locally advanced or metastatic BC progressing on prior NSAIs. Study treatment continued until disease progression, unacceptable toxicity, death, drug locally reimbursed, discontinuation from the study for any other reason or last patient last visit (June 30th, 2014), whichever occurred first. Here we report an ad hoc-analysis that includes all pts recruited from May 12th 2012 till Dec 31st 2013 with cut-off date March 17th 2014 (final database will be available on October 31st 2014).

Results:

2.133 pts were recruited in 269 sites across 14 European countries. Baseline characteristics were median age: 64 yrs; PS (ECOG) 0/1/2: 64%/30%/3%; median time from first diagnosis: 8 yrs; Stage IV pts: 99%. At the data cut off, a total of 1795 pts (84%) had discontinued the treatment. Reasons for discontinuation were: disease progression (38%), drug reimbursement (35%), adverse events (15 %), consent withdrawn (4%), death (1.5%) and others (6.5%). EVE and EXE were administered as first line treatment in 10% of pts, as second line in 23%, as third line in 22% and as fourth line or beyond in 45% of pts. 74% of pts received more than 1 line of chemotherapy in the metastatic setting. 80% of pts experienced at least one adverse event (AE) referred by the investigators as related to EVE [45% stomatitis, 7% non-infectious pneumonitis (NIP)]. The most frequent grade 3-4 drug related AEs were stomatitis (8.9%), asthenia (3.2%), GGT increase (2.4%), hyperglycemia (2.4%), and NIP (1.8%).The median time to onset of stomatitis and NIP was 3-4 weeks and 2-3 months respectively.

Conclusions:

These results confirm that the combination of EVE + EXE is a tolerable treatment in a real world setting even in pts more heavily pretreated by chemotherapy compared to BOLERO 2. The better understanding of side effects leading to treatment discontinuation in this large European study where investigators frequently administered the drug for the first time, will allow defining priority actions for better management of side effects including patient education and early interventions.

Longer follow up with mature data (expected in October 2014) will give additional information on the safety profile, stratified by line of treatment.

* Everolimus in Postmenopausal Hormone- Receptor–Positive Advanced Breast Cancer. J. Baselga et al, NEJM 2012.

Citation Format: Guy Jerusalem, Gabriella Mariani, Eva M Ciruelos, Miguel Martin, Vivianne CG Tjan-Heijnen, Patrick Neven, Joaquin Gavila Gregori, Andrea Michelotti, Filippo Montemurro, Istvan Lang, Josef Mardiak, Bjoem Naume, Maura Camozzi, Katia Lorizzo, Dariusz Brenski, Pierfranco Conte. Everolimus in combination with exemestane in hormone receptor-positive locally advanced or metastatic breast cancer (BC) patients progressing on prior non-steroidal AI (NSAIs): Ballet study (CRAD001YIC04) [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 P5-19-02.

Abstract S3-08: Randomized comparison of adjuvant tamoxifen (T) plus ovarian function suppression (OFS) versus tamoxifen in premenopausal women with hormone receptor-positive (HR+) early breast cancer (BC): Analysis of the SOFT trial

Background It is uncertain if the addition of OFS to adjuvant endocrine therapy with T improves outcomes in premenopausal HR+ BC. The SOFT trial was designed to determine the value of OFS in women who remain premenopausal and are treated with T (OFS question) and also to test whether an AI improves outcome in premenopausal women with HR+ BC treated with OFS (AI question). In the combined analysis of the TEXT and SOFT trials (AI question), the group treated with the AI exemestane+OFS had a significantly better disease-free survival (DFS) than those with T+OFS. This abstract presents the results of the OFS question (n=2,045).

Patients and Methods Between November 2003 and January 2011, the SOFT phase 3 trial randomized 3066 premenopausal women with HR+ BC to 5 years of adjuvant endocrine therapy with exemestane+OFS versus T+OFS versus T alone, with OFS initiated by choice of GnRH agonist triptorelin, oophorectomy or ovarian irradiation. Prior chemotherapy was allowed, provided women had confirmed premenopausal estradiol levels within 8 months of completing chemotherapy. The primary end point was DFS which included invasive local, regional, distant and contralateral breast events, second non-breast malignancies and deaths without prior cancer. Because of a lower-than expected overall event rate and to ensure results within a reasonable time-frame, a protocol amendment in 2011 changed the originally event-driven analysis plan. The amendment (1) designated the comparison of T+OFS versus T alone as the primary analysis for SOFT (n=2045), recognizing that the statistical power for the original three pairwise comparisons would be substantially reduced and (2) specified that the primary analysis of T+OFS versus T be undertaken when median follow-up was at least 5 years. The comparison would be tested at the 2-sided 0.05 level with no interim analysis. Based on the projected number of events at the lower rates, the estimated power to detect hazard ratios of 0.75, 0.70, and 0.66 for the comparison would be 52%, 69%, and 80%.

Results The SOFT trial completed planned patient enrollment with an international collaboration involving 426 centres from BIG and NABCG led by the International Breast Cancer Study Group (IBCSG). Numbers of patients randomized, randomization strata, and pt age are summarized in the Table. The database lock for the primary analysis of the OFS question will occur in September 2014 and the final analysis will be completed by October 15, 2014.

SOFT Patients (%)Tamoxifen alone1021 (33%)Tamoxifen+OFS1024 (33%)Exemestane+OFS1021 (33%)*  Prior Chemotherapy54%Lymph node positive35%Median age (% &lt; 40 years)43 years (30%)*Patients randomized to Exemestane+OFS are not part of the current analysis

Conclusions We will present the primary analysis of outcomes and toxicities by treatment for women randomized to receive T+OFS versus T and address the value of OFS in addition to T as adjuvant endocrine therapy for premenopausal women with HR+ BC.

Citation Format: Aron Goldhirsch, Richard D Gelber, Prudence A Francis, Meredith M Regan, Gini F Fleming, Istvan Lang, Eva M Ciruelos, Meritxell Bellet, Herve Bonnefoi, Miguel A Climent, Lorenzo Pavesi, Harold J Burstein, Silvana Martino, Nancy E Davidson, Charles E Geyer Jr, Barbara A Walley, Robert E Coleman, Pierre Kerbrat, Manuela Rabaglio-Poretti, Alan S Coates. Randomized comparison of adjuvant tamoxifen (T) plus ovarian function suppression (OFS) versus tamoxifen in premenopausal women with hormone receptor-positive (HR+) early breast cancer (BC): Analysis of the SOFT trial [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 S3-08.

The Long-HER study: clinical and molecular analysis of patients with HER2+ advanced breast cancer who become long-term survivors with trastuzumab-based therapy

Background

Trastuzumab improves survival outcomes in patients with HER2+ metastatic breast cancer. The Long-Her study was designed to identify clinical and molecular markers that could differentiate long-term survivors from patients having early progression after trastuzumab treatment.

Methods

Data were collected from women with HER2-positive metastatic breast cancer treated with trastuzumab that experienced a response or stable disease during at least 3 years. Patients having a progression in the first year of therapy with trastuzumab were used as a control. Genes related with trastuzumab resistance were identified and investigated for network and gene functional interrelation. Models predicting poor response to trastuzumab were constructed and evaluated. Finally, a mutational status analysis of selected genes was performed in HER2 positive breast cancer samples.

Results

103 patients were registered in the Long-HER study, of whom 71 had obtained a durable complete response. Median age was 58 years. Metastatic disease was diagnosed after a median of 24.7 months since primary diagnosis. Metastases were present in the liver (25%), lungs (25%), bones (23%) and soft tissues (23%), with 20% of patients having multiple locations of metastases. Median duration of response was 55 months. The molecular analysis included 35 patients from the group with complete response and 18 patients in a control poor-response group. Absence of trastuzumab as part of adjuvant therapy was the only clinical factor associated with long-term survival. Gene ontology analysis demonstrated that PI3K pathway was associated with poor response to trastuzumab-based therapy: tumours in the control group usually had four or five alterations in this pathway, whereas tumours in the Long-HER group had two alterations at most.

Conclusions

Trastuzumab may provide a substantial long-term survival benefit in a selected group of patients. Whole genome expression analysis comparing long-term survivors vs. a control group predicted early progression after trastuzumab-based therapy. Multiple alterations in genes related to the PI3K-mTOR pathway seem to be required to confer resistance to this therapy.

Abstract P2-16-04: A phase 2 study of ridaforolimus (RIDA) and dalotuzumab (DALO) in estrogen receptor positive (ER+) breast cancer

Background: Preclinical studies indicate that the dual inhibition of IGFR and mTOR may be additive or synergistic and abrogates the feedback activation of AKT due to rapamycin analog mTOR inhibitors. A phase 1 study of the mTOR inhibitor RIDA and the anti-IGFR antibody DALO demonstrated that the combination was feasible and well-tolerated at doses that were nearly those used for the two single agents. The dose limiting toxicity was stomatitis, similar to RIDA monotherapy. Preliminary signals of anti-tumor activity, including partial responses and prolonged progression free survival (PFS), were observed in ER+ advanced breast cancer (ABC), especially in high proliferation tumors (Ki67 ≥15%). Methods: The trial was a multi-center, international randomized study with PFS as the primary endpoint. Key eligibility included ABC with prior treatment with a non-steroidal aromatase inhibitor. The original phase 2 study design was a two-part, adaptive design intended to first test the combination of RIDA (30 mg by mouth daily for 5 out of every 7 days), -DALO (10 mg/kg IV weekly) against a standard agent, exemestane in Part A. Patients were stratified into high and low proliferation strata based on baseline Ki67. Following a demonstration of PFS benefit of the combination in Part A, Part B was intended to show the PFS benefit of the combination over each single agents by comparing RIDA-DALO to RIDA and DALO. Results: The study was initiated in October 2011. Accrual was suspended after the first 66 patients were randomized due to a higher than expected rate of stomatitis in the RIDA-DALO arm. Preliminary data indicated an overall incidence of any grade stomatitis was 68% (22/33 pts), and of grade 3 stomatitis was 35% (11/33 pts). In an effort to identify a more tolerable regimen, the study was amended to eliminate Part B and to evaluate two sequential reduced dose RIDA-DALO cohorts in a non-randomized design: 20mg and 10mg for 5 out of every 7 days. The dose of DALO was unchanged. Preliminary safety results of overall and grade 3 stomatitis in the 20 mg were 81.5% (22/27 pts) and 37% (10/27 pts), respectively. Although the incidence of overall stomatitis in the 10 mg cohort remained high, 88% (22/25 pts), grade 3 stomatitis was dramatically reduced to 8% (2/25 pts). Conclusion: Preliminary evaluation of safety from this phase 2 study demonstrates that the previously recommended phase 2 dose of RIDA-DALO was not tolerable. However lower doses of RIDA (10 mg) in combination with DALO appeared to be tolerable with markedly reduced rates of grade 3 stomatitis. Final results of efficacy, safety and RNA profiling analysis from the two RIDA-DALO dose cohorts as well as from the randomized portion of the study will be available at the time of the meeting.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-16-04.

Lapatinib with trastuzumab for heavily treated HER2-positive metastatic breast cancer (mBC)

e11561

Background: Trastuzumab and lapatinib show complementary and non-cross resistant mechanisms of anti-HER2 action. Dual HER2 blockade has been preclinically and clinically assessed with encouraging results. Trastuzumab and lapatinib combination is effective in terms of survival in patients with heavily pretreated HER2-positive mBC. We aim to report our experience with lapatinib plus trastuzumab in this setting. Methods: Descriptive retrospective study of trastuzumab plus lapatinib activity in patients with HER2-overexpressing metastatic breast cancer treated in two institutions from 01/2007 to 12/2012. The objective of this analysis is to report the response rate (RR), progression-free survival (PFS) and toxicity. Results: 23 HER2-positive mBC patients previously treated with trastuzumab received trastuzumab plus lapatinib based therapy. 15 patients (65%) received 2 or more previous lines. 17 patients (74%) had visceral disease. Chemotherapy (CT) was added to the dual HER2 blockade treatment in 13 patients (56%) whereas hormonotherapy (HT) was added in 8 patients (35%) and 2 patients (9%) received lapatinib plus trastuzumab without any other agent. Chemotherapeutic drugs most used were: capecitabine (54%) and vinorelbine (15%). RR: partial response 22% (5/23), stable disease 39% (9/23). Median of follow-up was 11 months. PFS in the overall population was 4 months. PFS in patients with CT was 5 months, while PFS in patients with HT was only 2. PFS in hormone receptor positive and negative was 3 and 5 months respectively. The most common toxicities were: diarrhea (48%), anemia (39%), asthenia (39%) and hand-and-foot syndrome (17%). Grade ≥ 3 toxicity was diarrhea (26%) and hand-and-foot syndrome (9%). The incidence of cardiotoxicity was 9% (grade 2). Conclusions: These findings suggest that dual HER2 blockade in combination with CT is feasible and active in heavily pretreated HER2-positive mBC patients. However, further investigation is warranted to demonstrate superiority over sequential blockade with trastuzumab and lapatinib in this setting.

Abstract P5-10-11: Clinical significance of microRNA expression as a prognostic factor in early N+ breast cancer (BC)

Background: microRNAs (miRNAs) are small noncoding RNA molecules that post-transcriptionally regulate gene expression. In the present study, we describe miRNA expression in early node-positive BC and identify a 8-miRNA score that could contribute to prognosis assessment.

Methods: First, microarray analysis was performed using RNA samples extracted from primary breast cancer. The expression of miRNAs was analyzed by RT-qPCR using the TaqMan Arrays from Applied Biosystems. After a suitable normalization of the 677 miRNAs analyzed, 123 presented a good correlation between their levels of expression in frozen tissue and paraffin tissue. A supervised analysis was done in order to identify MIR that could predict relapse.

Results: 172 patients with node-positive chemotherapy-treated early BC were included in the present study. The median age at diagnosis was (53.7) years, 128 cases (74.4%) had positive estrogen receptor, and 163 patients (94,7%) received adjuvant chemotherapy. After a median follow up of 8,1 years, 71p (41.2%) relapsed. Supervised analyses identified 8 microRNAs (has miR-30e, miR-30a, miR-21, miR-210, miR-93, miR-150, miR-99b, miR-572) associated with higher risk of relapse (5 year PFS 50% vs 90%, HR 3.75, 95% CI 2.27–6.19) and with estimated overall survival (median not reached, HR 4.51, 95% CI 2.36–8.61). Interestingly, miRNAs defined 2 prognostic groups (high and low risk) regardless of type of adjuvant chemotherapy (with or without anthracyclines) and histological subtype (luminal A, B or triple negative).