Abstract PD13-01: PD13-01 Elacestrant in postmenopausal women with estrogen receptor positive and HER2-negative early breast cancer: primary efficacy and safety analysis of the preoperative, window of opportunity SOLTI-1905-ELIPSE trial

Introduction Elacestrant is the first oral, non-steroidal, selective estrogen receptor degrader (SERD) to demonstrate improved efficacy compared to standard of care endocrine treatment, with greater relative benefit in ESR1-mutated tumors, and manageable safety profile in pretreated patients with metastatic breast cancer (BC) (Bidard F.C., JCO 2022). SOLTI ELIPSE trial (NCT04797728) is a prospective, multicenter, window of opportunity trial designed to assess whether a short-course of preoperative elacestrant may suppress tumor proliferation in postmenopausal women with estrogen receptor positive (ER+)/HER2-negative early BC (Vidal M., SABCS 2021). Here, we present the results of the primary efficacy and safety study analysis. Methods Eligible patients with operable, untreated ER+/HER2-negative BC that were T1c (≥1.5 cm)-T3 by ultrasound, clinically or radiologically N0 and had a locally assessed Ki67 ≥10%, received elacestrant 400 mg once a day continuously for a total of 4 weeks. At the study treatment completion, patients were treated according to local practice. Centralized assessment of post-treatment (D28) Ki67 from surgical specimen or tumor biopsy was required for the primary endpoint evaluation. Primary efficacy endpoint was complete cell cycle arrest (CCCA), defined as Ki67≤2.7%, at D28. Ki67 geometric relative change, variation in tumor infiltrating lymphocytes (TILs), switch in PAM50 subtypes and differential expression of 192 genes from baseline (D1) to D28 was also explored. Adverse events (AEs) were graded according to CTCAE v5.0. Results Between April 2021 and February 2022, 24 patients were enrolled and 22 were evaluable for the primary endpoint. Baseline characteristics were: mean age 69 years (range 50-81); ductal histology 74%; T1c 61%; T2 39%; grade 1-2 83%; median local Ki67 20% (10-70). Baseline PAM50 subtypes distribution was: Luminal A (n=12), Luminal B (n=8), Basal-like (n=1), Normal-like (n=1). At D28, CCCA was achieved in the 27% (n=6) of the patients. Fourteen patients (64%) had D28 Ki67 ≤10%. Paired centralized Ki67 was available in 19 patients. A statistically significant 41% (95% CI, -24 to -58) Ki67 relative reduction (rr) from D1 was observed (p=0.007). CCCA rate was 31% and 17% in patients with D1 Ki67 < 20% (n=13) and D1 Ki67 ≥20% (n=6), respectively. Ki67 varied consistently in both Ki67 < 20% (rr=-38%; 95% CI, -16 to -60) and Ki67 ≥20% (rr=-46%; 95% CI, -20 to -72) groups. Overall, elacestrant was associated with a shift towards a more endocrine sensitive and less proliferative phenotype based on PAM50 gene signatures. CCCA occurred in 45% of Luminal A tumors, whereas no CCCA was observed among Luminal B tumors. Levels of TILs were significantly higher at D28 (mean difference, +3.73; p=0.004). Elacestrant induced high expression of immune-response genes including IGJ, GZMB, CD4, CD8a and suppressed proliferation (e.g., UBE2T, MYBL2, BIRC5, MK67) and estrogen-signaling (e.g., ESR1, PGR, CCND1, BRCA2) genes (false discovery rate 5%). These changes in gene expression were observed both in tumors with D28 Ki67≤2.7% and in those with D28 Ki67 >10%. Overall, 87% of the patients reported any grade AEs. Treatment-related AE occurred in 1 patient (grade 3 cutaneous rash) and led to treatment discontinuation. Most frequently reported AEs (all grade 1) were hot flush (n=6), dyspepsia (n=2), anemia (n=2) and constipation (n=2). No serious AEs were reported. Conclusions In untreated ER+/HER2-negative early BC a short-course preoperative treatment with elacestrant was associated with relevant biological and molecular response and with manageable safety profile. Globally, these findings support further exploration of this highly potent, novel oral SERD in early BC.

Citation Format: Maria Vidal, Tomás Pascual, Claudette Falato, Rodrigo Sanchez-Bayona, Montserrat Muñoz, Isaac Cerbrecos, Xavier Gonzalez-Farré, Tomás Cortadellas, Mireia Margelí, Miguel Angel Luna, Christian Siso, Kepa Amillano, Patricia Galván, Fernando Salvador, Alejandra Espinosa, Laia Paré, Esther Sanfeliu, Aleix Prat, Meritxell Bellet Ezquerra. PD13-01 Elacestrant in postmenopausal women with estrogen receptor positive and HER2-negative early breast cancer: primary efficacy and safety analysis of the preoperative, window of opportunity SOLTI-1905-ELIPSE trial [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr PD13-01.

Abstract PD13-10: PD13-10 Impact of Proton Pump Inhibitors (PPI) on Palbociclib (PAL) Outcomes in Hormone Receptor-Positive, HER2-Negative Advanced Breast Cancer (HR+/HER2- ABC): Exploratory Analysis of the PARSIFAL Trial

Background The use of PPI among cancer patients (pts) is quite frequent. PAL is an oral, cyclin-dependent kinase 4 and 6 inhibitor recommended to be taken under fed conditions. PAL showed a reduced solubility when gastric pH is >4.5, a level commonly achieved by PPI. Observational, retrospective studies on concomitant PPI with PAL or ribociclib showed a shorter progression-free survival (PFS) among PPI users than nonusers. In the randomized, phase 2 PARSIFAL trial, PAL plus fulvestrant demonstrated no improvement in PFS and overall survival (OS) versus PAL plus letrozole as frontline treatment in HR+/HER2- ABC pts (Llombart-Cussac et al, JAMA Oncol 2021). Here we assessed the impact of PPI on PAL efficacy and safety in pts included in the PARSIFAL study. Methods Pts with endocrine-sensitive HR+/HER2- ABC and no prior therapy in advanced setting were randomly assigned to receive PAL (hard capsule formulation) plus either fulvestrant or letrozole. Pts with ≥1 PPI received over the entire PAL-based regimen were defined as PPI users, or PPI naïve (N-PPI) if no PPI was administered over the whole study treatment. We carried out two analyses considering early PPI users (E-PPI) –composed by pts who were receiving PPI since the PAL-based regimen initiation– and long-term PPI users (LT-PPI) –composed by pts who received PPI over the entire or ≥⅔ of the PAL-based regimen. PPI users defined as neither E-PPI nor LT-PPI were excluded from the analysis to avoid biases due to the PPI limited exposition. PFS, OS, and safety were compared among groups. Landmark analysis at 3, 6, 12, 18, 24, and 30 months (mo) was used for survival estimates conditional on surviving to certain time points and adjust for immortality bias in comparison between N-PPI and PPI users. Analyses were adjusted by stratification factors and patient characteristics. Results Of 486 pts included in the study, 325 (66.9%) were N-PPI. Among 161 (33.1%) PPI users, 64 (13.2%) were E-PPI and 91 (18.7%) were LT-PPI. Omeprazole was the most prescribed PPI in 80.7% (130 of 161) of PPI users. Median exposition to PPI for PPI users, E-PPI, and LT-PPI was 13.6, 15.9, and 19.4 mo, respectively. Compared with N-PPI, E-PPI and LT-PPI were older (median age, 60.5 vs 66.5 vs 67.0 years, respectively; P< 0.001) and had a worse functional status (ECOG PS of 0, 60.0% vs 34.0% vs 43.0%, respectively; P=0.002). Median follow-up for the whole population was 32 mo. Median PFS was 28.7 mo in N-PPI compared with 23.0 mo in E-PPI (HR 1.5; 95%CI 1.1–2.2; P=0.024) and 23.0 mo in LT-PPI (HR 1.4; 95%CI 1.0–1.9; P=0.035). Both PPI groups had poorer median PFS than N-PPI by landmark analysis at 3 and 12 mo. Subgroup analysis showed a consistent trend regardless of endocrine partner. Three-year OS rate was 81.1% in N-PPI compared with 63.5% in E-PPI (HR 2.2; 95%CI 1.3–3.7; P=0.003) and 62.0% in LT-PPI (HR 2.1; 95%CI 1.4–3.4; P=0.001). Both PPI groups had poorer 3-year OS rate than N-PPI by landmark analysis at 3, 6, 12, and 18 mo. Grade ≥3 hematological adverse events (AEs) occurred in 71.7% (233 of 325 pts) of N-PPI compared with 57.8% (37 of 64 pts; P=0.021) of E-PPI and 54.9% (50 of 91 pts; P=0.003) of LT-PPI. Dose reductions and delays due to hematological AEs were reported in 70.8% (230 of 325 pts) of N-PPI compared with 56.3% (36 of 64 pts; P=0.018) of E-PPI and 52.7% (48 of 91 pts; P=0.002) of LT-PPI. At 3 mo, 45.8% (149 of 325 pts) of N-PPI required a dose reduction or delay due to hematological AEs compared with 39.1% (25 of 64 pts; P=0.42) of E-PPI. Conclusions Early and sustained coadministration of PPI with PAL and endocrine therapy were associated with lower efficacy, hematological toxicities, and dose modifications. Despite the post-hoc nature of the study, these findings suggest pharmacokinetic interactions between PPI and PAL capsules. Further confirmatory studies including the tablet formulation of PAL, which is expected to assure its optimal absorption, are needed.

Citation Format: Serena Di Cosimo, José Manuel Pérez-García, Meritxell Bellet Ezquerra, Florence Dalenc, Miguel Gil Gil, Manuel Ruiz Borrego, Joaquín Gavilá, Miguel Sampayo-Cordero, Elena Aguirre, Peter Schmid, Frederik Marmé, Joseph Gligorov, Andreas Schneeweiss, Joan Albanell, Pilar Zamora, Duncan Wheatley, Eduardo Martínez De Dueñas, Vicente Carañana, Kepa Amillano, Andrea Malfettone, Javier Cortés, Antonio Llombart-Cussac. PD13-10 Impact of Proton Pump Inhibitors (PPI) on Palbociclib (PAL) Outcomes in Hormone Receptor-Positive, HER2-Negative Advanced Breast Cancer (HR+/HER2- ABC): Exploratory Analysis of the PARSIFAL Trial [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr PD13-10.

Palbociclib with Fulvestrant or Letrozole in Endocrine-Sensitive Patients with HR-Positive/HER2-Negative Advanced Breast Cancer: A Detailed Safety Analysis of the Randomized PARSIFAL Trial

BACKGROUND

Palbociclib has gained a central role in the treatment of hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer (ABC). Despite its manageable toxicity profile, venous thromboembolism (VTE) or interstitial lung disease (ILD)/pneumonitis may infrequently occur. Therefore, we provide a comprehensive summary of the safety and tolerability of the combination of endocrine therapy and palbociclib among patients included in the randomized phase 2 PARSIFAL study.

MATERIALS AND METHODS

Patients with endocrine-sensitive HR+/HER2- ABC and no prior therapy in an advanced setting (n = 486) were randomly assigned 1:1 to receive fulvestrant-palbociclib (FP) or letrozole-palbociclib (LP). Laboratory tests and the incidence of adverse events (AEs) were recorded at baseline and day 1 of each cycle. Progression-free survival (PFS) was estimated for patients with and without VTE.

RESULTS

A total of 483 patients were analyzed. Neutropenia, leukopenia, anemia, asthenia, arthralgia, fatigue, and diarrhea were the most frequent AEs in both groups. Febrile neutropenia occurred in 3 (1.2%) patients of the FP group and in 1 (0.4%) patient in the LP group. Six (2.5%; 0.4% grade 3) patients in the FP group and 6 patients (2.5%; 0.4% grade 3) in the LP group experienced ILD/pneumonitis. Pulmonary embolism was reported in 12 (5.0%) patients in the FP group and 6 (2.5%) patients in the LP group. Advanced age at baseline was the only factor significantly associated with an increased risk of pulmonary embolism (P < .01).

CONCLUSION

The PARSIFAL data confirmed the favorable safety profile of both palbociclib regimens. VTE and ILD/pneumonitis were occasionally reported, and their early detection allowed patients to continue treatment effectively without detriment to efficacy.

CLINICALTRIALS.GOV IDENTIFIER

NCT02491983; https://clinicaltrials.gov/ct2/show/NCT02491983).

SOLTI-1904 ACROPOLI TRIAL: efficacy of spartalizumab monotherapy across tumor-types expressing high levels of PD1 mRNA

Improved selection of cancer patients who are most likely to respond to immune checkpoint inhibitors remains an unmet clinical need. Recently, a positive correlation between levels of PD1 mRNA and clinical outcome in response to PD1 blockade across diverse tumor histologies has been confirmed in several datasets. ACROPOLI is a parallel cohort, non-randomized, phase II study that aims to evaluate the efficacy of the anti-PD1 immune checkpoint inhibitor spartalizumab as monotherapy in metastatic patients with solid tumors that express high levels of PD1 (cohort 1; n = 111). An additional cohort of 30 patients with tumors expressing low levels of PD1, where PD1/PD-L1 antibodies in monotherapy are standard treatment, will also be included (cohort 2). Primary end point is overall response rate in cohort 1. Trial registration number: NCT04802876 (ClinicalTrials.gov).

Abstract P1-07-02: Primary results of ONAWA (SOLTI-1802) trial: A window of opportunity trial of onapristone in postmenopausal women with progesterone receptor-positive/HER2-negative early breast cancer (EBC)

Background PgR expression is a biomarker of ER functionality, cellular progression to malignancy, and response to endocrine therapy (ET) in HR+ BC. Onapristone (ONA), a type 1 antiprogestin, was shown to have a single agent anti-tumor activity in patients with metastatic breast cancer (Robertson et al., 1999; Jonat et al., 2002). However, this once daily immediate-release formulation was associated with liver function test abnormalities in one-third of patients. A new, extended-release formulation (ONA XR) was developed and was evaluated in a BID schedule that reduced peak serum concentrations while sustaining the minimum plasma concentrations previously associated with the higher dose. Safety results of two phase I-II studies confirmed this hypothesis (Cottu et al., 2018; Jayaram et al., 2017; Lewis et al, 2020). Considering BC heterogeneity and that PgR analysis by standard immunohistochemistry (IHC) does not perfectly correlate with PgR target gene expression, the identification of biomarkers allowing the selection of patients with PgR-driven tumors that may benefit from antiprogestins treatment is currently an unmet need. Patients and Methods ONAWA (NCT04142892) is an open-label, single-arm, multicenter window of opportunity clinical trial of ONA XR (50 mg BID for 21 days) for postmenopausal women with EBC amenable to receive a short course of ET before surgery. Ten patients with ER+/PgR+/HER2- and Ki-67 ≥ 15% BC were enrolled. The primary objective is to evaluate the biological activity of ONA by the rate of Complete Cell Cycle Arrest (CCCR) determined by Ki-67 (≤2.7%). Secondary endpoints include safety and correlating biological activity with IHC of tumor expression (ER, PgR, Ser294-PgR, CD24, CD44, ALDH1, Ki-67), estradiol, and progesterone blood levels, and gene expression profile (NanoString nCounter® Breast 360TM panel). Relative Ki-67 suppression was defined as (1 - Ln(Ki-67 Baseline)/Ln(Ki-67 surgery)) Results Assessment of the treatment effects was possible for the 10 patients who successfully completed the protocol and the 10 paired samples (100%) were analyzed. Main patient characteristics were mean age 68 (range 53-81 years), mean tumor size 20.2 mm (range 15-26 mm), stage I (40%) and grade 2 (100%). No patients achieved a CCCR. Tumor Ki-67 expression decreased in six patients was stable in one patient and increased three patients. The mean percentage suppression of Ki-67 was 19.58%. Overall, no statistically significant change was observed in Ki-67 between paired samples (p=0.234). Baseline IHC PgR (%) expression correlated with Ki-67 decrease (r = -0.635). Mean percentage suppression of Ki-67 for tumors with IHC PgR expression ≥90% (N=4) and &lt;90% (N=6) was -25.23.0% and +2.54%, respectively. Six (60%) patients reported AEs at any grade. Most common grade 1 or 2 AEs were post-procedural pain, dry mouth and GGT increased. Grade 3 reversible GGT and AST increase occurred in 1 patient. Conclusion: ONA XR significantly increases suppression of tumor cell proliferation in PgR-high primary breast cancer. The safety profile was consistent with that previously reported. Additional correlative analysis including gene expression will be presented. Acknowledgments: Funding and drug provided by Context Therapeutics Inc., USA.

Citation Format: Meritxell Bellet, Serafin Morales, Ariadna Gasol, Kepa Amillano, Nuria Chic, Xavier González-Farré, Patricia Villagrasa, Laia Paré, Claudette Falato, Paolo Nuciforo, Débora Martínez, Juan M Ferrero-Cafiero, Tomás Pascual, Aleix Prat, Carol Lange, Cristina Saura. Primary results of ONAWA (SOLTI-1802) trial: A window of opportunity trial of onapristone in postmenopausal women with progesterone receptor-positive/HER2-negative early breast cancer (EBC) [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-07-02.

Abstract OT2-11-07: Solti-1905. Elacestrant in preoperative setting, a window of opportunity study (ELIPSE trial)

Background.Patients with hormone receptor-positive/HER2-negative (HR+/HER2-) breast cancer (BC) are mainly treated with therapies that target estrogen receptor (ER) signaling to impair tumor cell proliferation. Several drugs targeting the ER pathway are currently used in the clinical practice including aromatase inhibitors (AI) that limit the production of estradiol, selective ER modulators (SERMs) that compete with estradiol for binding ER, and selective ER degraders (SERDs) that induce ER degradation. Despite the availability of these drugs, finding new ET remains a clinical unmet need since some patients do not initially respond to these treatments or become resistant to available endocrine agents. Elacestrant is an orally bioavailable drug that acts as SERD in breast tissue promoting degradation of ER and inhibiting breast cancer cell proliferation. Several clinical studies have confirmed the tolerable safety profile of elacestrant in BC (Bardia A et al. ASCO, 2021) and a phase III trial investigating elacestrant versus standard ET in metastatic BC patients is ongoing for patients treated with at least 1 prior ET and a CDK4/6 inhibitor for advanced BC (EMERALD; NCT03778931). In this study, we aim to investigate the biological effect of elacestrant on cell proliferation in patients with ER+/HER2- resectable BC. Study design. ELIPSE is prospective, multicenter, single-arm, window-of-opportunity study designed to evaluate the biological effect of elacestrant in treatment naïve patients with ER+/HER2- resectable BC. The study population consists of postmenopausal women with clinically negative axillary lymph node (cN0) and whose primary tumors are≥ 1.5 cm by ultrasound with Ki67 ≥10% locally assessed. Patients will receive 400 mg of elacestrant in monotherapy orally, once a day, continuously. After 4 weeks of treatment, surgery will be performed in accordance with local practice. Two biopsies of the same lesion will be obtained as mandatory: a baseline sample and a surgical sample (tumor core-biopsy is permitted if surgery is not performed after 4 weeks of treatment). Plasma samples for biomarkers will be collected at baseline, surgery and end of study visit. The primary objective is to evaluate the Complete Cell Cycle Arrest rate (defined as Ki67 ≤ 2.7%) by central assessment after 4 weeks of elacestrant therapy. Secondary endpoints include:. 1) safety,. 2) correlation of biological activity determined by changes in: Ki67 as a continuous variable, intrinsic PAM50 subtypes, proliferative signatures, tumor cellularity and tumor-infiltrating lymphocytes (CelTIL, Nuciforo P et al., Ann Oncol, 2018) in tumor samples taken before and at the end of treatment, and. 3) analysis of ctDNA dynamics after treatment. As of July 2021, 7 patients have been enrolled in 4 sites in Spain. NCT04797728. Acknowledgement. This study is financially supported by Radius Pharmaceuticals, Inc.

Citation Format: María Vidal, Montserrat Muñoz, Mireia Margeli, Xavier González, Kepa Amillano, Rodrigo Sánchez-Bayona, Fernando Salvador, Tomás Pascual, Aleix Prat, Meritxell Bellet. Solti-1905. Elacestrant in preoperative setting, a window of opportunity study (ELIPSE trial) [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr OT2-11-07.

Adjuvant Palbociclib for Early Breast Cancer: The PALLAS Trial Results (ABCSG-42/AFT-05/BIG-14-03)

PURPOSE

Palbociclib is a cyclin-dependent kinase 4 and 6 inhibitor approved for advanced breast cancer. In the adjuvant setting, the potential value of adding palbociclib to endocrine therapy for hormone receptor-positive breast cancer has not been confirmed.

PATIENTS AND METHODS

In the prospective, randomized, phase III PALLAS trial, patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative early breast cancer were randomly assigned to receive 2 years of palbociclib (125 mg orally once daily, days 1-21 of a 28-day cycle) with adjuvant endocrine therapy or adjuvant endocrine therapy alone (for at least 5 years). The primary end point of the study was invasive disease-free survival (iDFS); secondary end points were invasive breast cancer-free survival, distant recurrence-free survival, locoregional cancer-free survival, and overall survival.

RESULTS

Among 5,796 patients enrolled at 406 centers in 21 countries worldwide over 3 years, 5,761 were included in the intention-to-treat population. At the final protocol-defined analysis, at a median follow-up of 31 months, iDFS events occurred in 253 of 2,884 (8.8%) patients who received palbociclib plus endocrine therapy and in 263 of 2,877 (9.1%) patients who received endocrine therapy alone, with similar results between the two treatment groups (iDFS at 4 years: 84.2% v 84.5%; hazard ratio, 0.96; CI, 0.81 to 1.14; P = .65). No significant differences were observed for secondary time-to-event end points, and subgroup analyses did not show any differences by subgroup. There were no new safety signals for palbociclib in this trial.

CONCLUSION

At this final analysis of the PALLAS trial, the addition of adjuvant palbociclib to standard endocrine therapy did not improve outcomes over endocrine therapy alone in patients with early hormone receptor-positive breast cancer.

Fulvestrant-Palbociclib vs Letrozole-Palbociclib as Initial Therapy for Endocrine-Sensitive, Hormone Receptor-Positive, ERBB2-Negative Advanced Breast Cancer: A Randomized Clinical Trial

Importance

The cyclin-dependent kinase 4 and 6 inhibitor palbociclib in combination with letrozole has become a standard first-line treatment for patients with endocrine-sensitive, hormone receptor-positive, ERBB2-negative advanced breast cancer. Meanwhile, the antiestrogen fulvestrant was shown to be superior to anastrozole in the absence of cyclin-dependent kinase 4 and 6 inhibition for this patient population.

Objective

To assess whether fulvestrant is superior to letrozole when combined with palbociclib in the first-line scenario.

Design, Setting, and Participants

In this international, randomized, open-label, phase 2 clinical study conducted from July 30, 2015, to January 8, 2018, patients with hormone receptor-positive, ERBB2-negative advanced breast cancer with no prior therapy in the metastatic setting and endocrine-sensitive criteria were recruited from 47 centers in 7 countries. Data were analyzed from February 11 to May 15, 2020.

Interventions

Patients were randomly assigned (1:1 ratio) to receive palbociclib with either fulvestrant or letrozole. Stratification factors were type of disease presentation (de novo vs recurrent) and the presence of visceral involvement (yes vs no).

Main Outcomes and Measures

The primary end point was investigator-assessed progression-free survival determined by Response Evaluation Criteria in Solid Tumors, version 1.1.

Results

A total of 486 women (median age, 63 years [range, 25-90 years]; 3 Asian women [0.6%]; 4 Black women [0.8%]; 461 White women [94.9%]; 18 women of unknown race [3.7%]) were randomized (243 to fulvestrant-palbociclib and 243 to letrozole-palbociclib). Median investigator-assessed progression-free survival was 27.9 months (95% CI, 24.2-33.1 months) in the fulvestrant-palbociclib group vs 32.8 months (95% CI, 25.8-35.9 months) in the letrozole-palbociclib group (hazard ratio, 1.13; 95% CI, 0.89-1.45; P = .32). This result was consistent across the stratification factors. No significant differences were observed in objective response rate (46.5% vs 50.2%) and 3-year overall survival rate (79.4% vs 77.1%) for fulvestrant-palbociclib and letrozole-palbociclib, respectively. Grade 3-4 adverse events were comparable among treatment groups, and no new safety signals were identified. No treatment-related deaths were reported.

Conclusions and Relevance

Although fulvestrant-palbociclib demonstrated significant antitumor activity, this randomized clinical trial failed to identify an improvement in progression-free survival with this regimen over letrozole-palbociclib in patients with endocrine-sensitive, hormone receptor-positive, ERBB2-negative advanced breast cancer.

Trial Registration

ClinicalTrials.gov Identifier: NCT02491983.

Abstract PS10-17: Palbociclib (P) in combination with fulvestrant (F) or letrozole (L) in endocrine-sensitive patients (pts) with hormone receptor (HR)[+]/HER2[-] metastatic breast cancer (MBC): detailed safety analysis from a multicenter, randomized, open-label, phase II trial (PARSIFAL)

Background: P led to a meaningful improvement in clinical outcomes when used in combination with endocrine therapy for first- or later-line regimen in HR[+]/HER2[-] MBC. Grade 3-4 neutropenia was the most common adverse event (AE) in the P-containing regimens. Although venous thromboembolic events (VTE) have been rarely reported in registrational trials, a systematic review and meta-analysis of randomized controlled trials demonstrated a higher rate of these AEs. Moreover, rare but severe cases of interstitial lung disease (ILD)/pneumonitis have been observed during post-approval use of P. Here, we present a comprehensive toxicity profile of pts included in the PARSIFAL study, with particular emphasis given to AEs of special interest of the overall safety population. Methods: A total of 486 pts with HR[+]/HER2[-] MBC with no prior therapy in the advanced setting and endocrine sensitive criteria (relapse &gt;12 months [mo] after the end of adjuvant endocrine therapy or diagnosed with de novo metastatic disease) were randomly assigned 1:1 to receive P (oral 125 mg/day [d]; 3 weeks on/1 week off) plus either F (intramuscular injection 500 mg/d; d 0, 14, 28, and then every 28 ds) or L (oral 2.5 mg/d). Pts were stratified by visceral involvement and type of disease presentation (de novo/recurrent). Safety assessments included blood analysis and collection of vital signs at screening, d1 of each cycle, and end of treatment/withdrawal. Severity was graded as per the NCI Common Terminology Criteria for Adverse Events v.4.03. Results: The incidence rate of any grade, grade 3-4, and serious AEs was 99.6%, 80.9%, and 29.9%, respectively, in the FP arm, and 99.2%, 78.5%, and 21.1% in the LP arm. Discontinuations due to AEs were 5.4% in the FP arm and 2.1% in the LP arm. Neutropenia, leukopenia, anemia, asthenia, arthralgia, fatigue, and diarrhea were the most frequent AEs in both arms. Febrile neutropenia was reported in 1.2% (3 pts) and 0.4% (1 patient) in the FP and LP arms, respectively. The rate of VTE of any grade was 5.8% (14 pts) in the FP arm and 4.5% (11 pts) in the LP arm (p = 0.531). Among 18 pts who had grade ≥ 3 pulmonary embolism (PE), the incidence reported in the FP and LP arms was 5% (12 pts) vs 2.5% (6 pts), respectively, and many of them (n=16, 88.9%) were unrelated PE. Asymptomatic grade 3 PE was reported in 10 pts of the entire study population on every 3-mo CT scan. Further, in 5 pts PE was detected in the context of progressive disease. Median time from the first dose of study drugs to occurrence of PE was 4.1 mo (range 1.4-32.0 mo) in the FP arm and 7 mo (range 1.8-19.3 mo) in the LP arm. Analysis of baseline characteristics in the whole population revealed that older pts had a significantly increased risk for developing PE (69.5 years [range 47-84 years]; p &lt; 0.01). ECOG performance status, menopausal status, metastatic disease, visceral involvement, number of disease sites, and prior therapies including antithrombotic agents did not significantly increase the risk for developing PE. Grade 3 ILD/pneumonitis was rarely observed in the FP and LP arms (0.8% vs 1.2%, respectively) with no grade 4 AE. Conclusions: First-line treatment with FP and LP for HR[+]/HER2[-] MBC in the PARSIFAL study confirmed the favorable safety profile, with neutropenia representing the most common AE. Although rare, ILD/pneumonitis can be a side effect of P-based regimens. VTE and PE incidence rates were low and consistent with age-specific analyses from PALOMA trials and breast cancer population. Early detection of these AEs may assist in optimizing their management.

Citation Format: José Manuel Pérez-García, Antonio Llombart-Cussac, Meritxell Bellet, Florence Dalenc, Miguel J. Gil Gil, Manuel Ruiz Borrego, Joaquín Gavilá, Miguel Sampayo-Cordero, Elena Aguirre, Peter Schmid, Frederik Marmé, Serena Di Cosimo, Joseph Gligorov, Andreas Schneeweiss, Joan Albanell, Pilar Zamora, Duncan Wheatley, Eduardo Martínez-De Dueñas, Vicente Carañana, Kepa Amillano, Andrea Malfettone, Javier Cortés. Palbociclib (P) in combination with fulvestrant (F) or letrozole (L) in endocrine-sensitive patients (pts) with hormone receptor (HR)[+]/HER2[-] metastatic breast cancer (MBC): detailed safety analysis from a multicenter, randomized, open-label, phase II trial (PARSIFAL) [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS10-17.

Metformin induces a fasting- and antifolate-mimicking modification of systemic host metabolism in breast cancer patients

Certain dietary interventions might improve the therapeutic index of cancer treatments. An alternative to the “drug plus diet” approach is the pharmacological reproduction of the metabolic traits of such diets. Here we explored the impact of adding metformin to an established therapeutic regimen on the systemic host metabolism of cancer patients. A panel of 11 serum metabolites including markers of mitochondrial function and intermediates/products of folate-dependent one-carbon metabolism were measured in paired baseline and post-treatment sera obtained from HER2-positive breast cancer patients randomized to receive either metformin combined with neoadjuvant chemotherapy and trastuzumab or an equivalent regimen without metformin. Metabolite profiles revealed a significant increase of the ketone body β-hydroxybutyrate and of the TCA intermediate α-ketoglutarate in the metformin-containing arm. A significant relationship was found between the follow-up levels of homocysteine and the ability of treatment arms to achieve a pathological complete response (pCR). In the metformin-containing arm, patients with significant elevations of homocysteine tended to have a higher probability of pCR. The addition of metformin to an established anti-cancer therapeutic regimen causes a fasting-mimicking modification of systemic host metabolism. Circulating homocysteine could be explored as a clinical pharmacodynamic biomarker linking the antifolate-like activity of metformin and biological tumor response.

PARSIFAL: A randomized, multicenter, open-label, phase II trial to evaluate palbociclib in combination with fulvestrant or letrozole in endocrine-sensitive patients with estrogen receptor (ER)[+]/HER2[-] metastatic breast cancer

1007

Background: The CDK4/6 inhibitor palbociclib (P) in combination with letrozole (L) has become a standard first-line treatment for patients (pts) with luminal metastatic breast cancer (MBC) (PALOMA-1 & 2 trials). Meanwhile, the anti-estrogen fulvestrant (F) showed to be superior to anastrozole in the same population (FALCON trial). We aimed to identify the best endocrine agent to combine with P in this first-line scenario. Methods: A total of 486 pts with ER[+]/HER2[-] MBC with no prior therapy in the advanced setting and endocrine sensitive criteria (relapse > 12 months [mo] after the end of adjuvant endocrine therapy or diagnosed with “de novo” metastatic disease) were randomly assigned (1:1 ratio) to receive P (oral 125 mg/day [d]; 3 wks on/1 wk off) plus F 500 mg/d (I.M Days 0, 14, 28, and then every 28 d) or PL (oral 2.5 mg/d). Pts were stratified by visceral involvement and type of disease presentation (“de novo”/recurrent). Primary endpoint was investigator-assessed progression-free survival (PFS). Secondary endpoints included overall survival (OS), overall response rate (ORR), clinical benefit rate (CBR), and safety. 254 events were needed with 80% power to detect a hazard ratio (HR) ≤0.7 in favor of PF (2-sided α = 0.05). Results: By March 9th, 2020, 256 PFS events occurred. Pts characteristics were well balanced. Median age was 62 years (range: 25–90), 56.6% were ECOG 0, 40.7% had “de novo” metastatic disease, 48% had visceral disease, and 43.6% with ≥3 organ sites involved. At median follow-up of 32 mo, median PFS was 27.9 mo (95% confidence interval [CI], 24.2-33.1) with PF and 32.8 mo (95% CI, 25.8-35.9) with PL (HR: 1.1; 95% CI, 0.9-1.5; P = 0.321). No differences were observed for pts with or without visceral involvement (HR: 1.3 and HR: 0.97 respectively, interaction P = 0.275), and for “de novo” or recurrent metastatic disease (HR: 1.1 and HR: 1.1 respectively, P = 0.979). The 4-year OS rate was 67.6% in PF and 67.5% in PL arm (HR: 1; 95% CI, 0.7-1.5; P = 0.986). No differences were observed in ORR or CBR between arms. Grade ≥3 adverse events were similar in both arms, being neutropenia and leukopenia the most frequent. No treatment-related deaths were reported. Conclusion: This study was not able to identify an improvement in PFS for PF over PL in patients with endocrine-sensitive ER[+]/HER2[-] MBC. As both arms demonstrated comparable 4 years-OS, PF is a reasonable alternative to PL in this setting. Clinical trial information: NCT02491983 .

Effects of radiotherapy on plasma energy metabolites in patients with breast cancer who received neoadjuvant chemotherapy

PURPOSE

Neoadjuvant chemotherapy (NACT) is employed in patients with breast cancer (BC) with the aim of reducing tumor burden and improving surgical outcomes. We evaluated the levels of energy metabolites pre- and post-radiotherapy (RT) in breast cancer (BC) patients who previously received NACT and investigated the alterations of these metabolites in relation to the patient achieving a pathologic complete response to NACT.

MATERIALS AND METHODS

We included 37 BC patients who were treated with NACT following surgery and analyzed the concentrations of energy balance-related metabolites using targeted metabolomics before and one month after the end of RT. The control group was composed of 44 healthy women.

RESULTS

Pre-radiotherapy, patients had significant decreases in the plasma levels of 12 metabolites. RT corrected these alterations and the improvement was superior in patients with a pathologic complete response.

CONCLUSION

Our results highlight the importance of metabolism in the outcomes of patients with BC.

Oral metronomic vinorelbine combined with endocrine therapy in hormone receptor-positive HER2-negative breast cancer: SOLTI-1501 VENTANA window of opportunity trial

Background

The biological effect of oral metronomic vinorelbine (mVNB) alone or in combination with endocrine therapy in patients with hormone receptor-positive (HR+)/HER2-negative breast cancer has been scarcely addressed.

Methods

Postmenopausal women with untreated stage I–III HR+/HER2-negative breast cancer were randomized (1:1:1) to receive 3 weeks of letrozole (LTZ) 2.5 mg/day, oral mVNB 50 mg 3 days/week, or the combination. The primary objective was to evaluate, within PAM50 Luminal A/B disease, if the anti-proliferative effect of LTZ+mVNB was superior to monotherapy. An anti-proliferative effect was defined as the mean relative decrease of the PAM50 11-gene proliferation score in combination arm vs. both monotherapy arms. Secondary objectives included the evaluation of a comprehensive panel of breast cancer-related genes and safety. An unplanned analysis of stromal tumor-infiltrating lymphocytes (sTILs) was also performed. PAM50 analyses were performed using the nCounter®-based Breast Cancer 360™ gene panel, which includes 752 genes and 32 signatures.

Results

Sixty-one patients were randomized, and 54 paired samples (89%) were analyzed. The main patient characteristics were mean age of 67, mean tumor size of 1.7 cm, mean Ki67 of 14.3%, stage I (55.7%), and grades 1–2 (90%). Most baseline samples were PAM50 Luminal A (74.1%) or B (22.2%). The anti-proliferative effect of 3 weeks of LTZ+mVNB (− 73.2%) was superior to both monotherapy arms combined (− 49.9%; p = 0.001) and mVNB (− 19.1%; p < 0.001). The anti-proliferative effect of LTZ+mVNB (− 73.2%) was numerically higher compared to LTZ (− 65.7%) but did not reach statistical significance (p = 0.328). LTZ+mVNB induced high expression of immune-related genes and gene signatures, including CD8 T cell signature and PDL1 gene and low expression of ER-regulated genes (e.g., progesterone receptor) and cell cycle-related and DNA repair genes. In tumors with ≤ 10% sTILs at baseline, a statistically significant increase in sTILs was observed following LTZ (paired analysis p = 0.049) and LTZ+mVNB (p = 0.012). Grade 3 adverse events occurred in 3.4% of the cases.

Conclusions

Short-term mVNB is well-tolerated and presents anti-proliferative activity alone and in combination with LTZ. The high expression of immune-related biological processes and sTILs observed with the combination opens the possibility of studying this combination with immunotherapy. Further investigation comparing these biological results with other metronomic schedules or drug combinations is warranted.

Trial registration

NCT02802748, registered 16 June 2016.

Supplementary information

Supplementary information accompanies this paper at 10.1186/s13058-019-1195-z.

The C Allele of ATM rs11212617 Associates With Higher Pathological Complete Remission Rate in Breast Cancer Patients Treated With Neoadjuvant Metformin

Background: The minor allele (C) of the single-nucleotide polymorphism (SNP) rs11212617, located near the ataxia telangiectasia mutated (ATM) gene, has been associated with an increased likelihood of treatment success with metformin in type 2 diabetes. We herein investigated whether the same SNP would predict clinical response to neoadjuvant metformin in women with early breast cancer (BC). Methods: DNA was collected from 79 patients included in the intention-to-treat population of the METTEN study, a phase 2 clinical trial of HER2-positive BC patients randomized to receive either metformin combined with anthracycline/taxane-based chemotherapy and trastuzumab or equivalent regimen without metformin, before surgery. SNP rs11212617 genotyping was assessed using allelic discrimination by quantitative polymerase chain reaction. Results: Logistic regression analyses revealed a significant relationship between the rs11212617 genotype and the ability of treatment arms to achieve a pathological complete response (pCR) in patients (odds ratio [OR]_{genotype×arm} = 10.33, 95% confidence interval [CI]: 1.29-82.89, p = 0.028). In the metformin-containing arm, patients bearing the rs11212617 C allele had a significantly higher probability of pCR (OR _A/C,C/C = 7.94, 95%CI: 1.60-39.42, p = 0.011). Conversely, no association was found between rs11212617 and clinical response in the reference arm (OR _A/C,C/C = 0.77, 95%CI: 0.20-2.92, p = 0.700). After controlling for tumor size and hormone receptor status, the rs11212617 C allele remained a significant predictor of pCR solely in the metformin-containing arm. Conclusions: If reproducible, the rs11212617 C allele might warrant consideration as a predictive clinical biomarker to inform the personalized use of metformin in BC patients. Trial Registration: EU Clinical Trials Register, EudraCT number 2011-000490-30. Registered 28 February 2011, https://www.clinicaltrialsregister.eu/ctr-search/trial/2011-000490-30/ES.

Abstract P5-11-04: Anti-proliferative effect of oral metronomic vinorelbine (mVNB) in PAM50 Luminal/HER2-negative early breast cancer (SOLTI-1501 VENTANA): A randomized, three-arm, window-of-opportunity study

BACKGROUND: The anti-proliferative effect of mVNB alone or in combination with endocrine therapy in patients with hormone receptor-positive/HER2- breast cancer (BC) has been scarcely addressed.

METHODS: Postmenopausal women with untreated stage I-III BC were randomized (1:1:1) to receive 3 weeks of letrozole (LTZ) 2.5mg/day, oral mVNB 50mg 3 days/week or the combination. The 1ary objective was to evaluate, within PAM50 Luminal A/B disease, if the anti-proliferative effect of mVNB+LTZ was superior to monotherapy. An anti-proliferative effect was defined as the mean relative decrease of the PAM50 11-gene Proliferation Score in each arm. 2ary objectives included safety and the comparison of the anti-proliferative effect between arms. An unplanned analysis of stromal tumor infiltrating lymphocytes (sTILs) was performed. PAM50 analyses were performed using the nCounter®-based Breast Cancer 360TM panel. Changes in the expression of 790 genes/signatures tracking multiple biological processes from tumor cells and the microenvironment were evaluated within each arm using paired (surgery vs. baseline) univariate analyses. P-values were corrected for multiple comparisons using false discovery rate (FDR).

RESULTS: A total of 61 patients were randomized and 54 paired samples (89%) were analyzed. Main patient characteristics were mean age 67, mean tumor size 1.7 cm, stage I (55.7%) and grade 1-2 (90%). Grade 3 toxicities occurred in 3.3% of cases. Baseline samples were Luminal A (72.3%) or B (27.7%). The anti-proliferative effect of mVNB+LTZ (-73.2%) was superior to both monotherapy arms combined (-49.9%; p=0.001) and mVNB (-19.1%; p&lt;0.001). The anti-proliferative effect of mVNB+LTZ (-73.2%) was higher compared to LTZ (-65.7%) but did not reach statistical significance (p=0.328). Across the mVNB+LTZ, LTZ and VNB arms, 413 (52.3%), 403 (51.0%) and 21 (2.6%) genes/signatures were found differentially expressed (FDR&lt;5%) between baseline and surgery samples. Compared to mVNB+LTZ baseline samples, surgical samples showed higher expression of AP-1 transcription factor subunits FOS and JUN, inflammatory chemokines (e.g. CCL4 and IL6), stromal-related genes (e.g. CAV1 and stroma signature) and immune infiltration (e.g. CD8 T-cell signature) and lower expression of proliferation-related genes (e.g. MKI67 and UBE2C), estrogen receptor-signaling and Risk of Recurrence. Of the 413 genes found differentially expressed in surgical samples compared to baseline samples in the mVNB+LTZ arm, 108 (26.2%) were not found in the LTZ arm. Among them, high expression of LAG3, CD24, CD84 and CCR5. Under the microscope, sTILs (≥10% at week 3) were observed in 6.6% (mVNB), 15% (LTZ) and 26% (mVNB+LTZ) of the cases. In tumors with ≤10% TILs at baseline, an increase in TILs was observed following LTZ (p=0.049) and mVNB+LTZ (p=0.012).

CONCLUSIONS: mVNB is well-tolerated and presents antiproliferative activity alone and in combination with LTZ. The increase of activated CD8 T-cells or TILs observed with LTZ+mVNB opens the possibility of studying combinations with immunotherapy. Further investigation comparing these biological results with other metronomic schedules or combinations is warranted.

Citation Format: Prat A, Adamo B, Pascual T, Perez Fidalgo JA, Blanch S, Martínez N, Gomez Pardo P, Lopez Gonzalez A, Murillo Jaso L, Amillano K, Vidal M, Paré L, Canes J, Galvan P, Gonzalez Farre B, Ortega Cebrián V, Gonzalez X, Bellet Ezquerra M, Villagrasa P, Ciruelos E. Anti-proliferative effect of oral metronomic vinorelbine (mVNB) in PAM50 Luminal/HER2-negative early breast cancer (SOLTI-1501 VENTANA): A randomized, three-arm, window-of-opportunity study [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 P5-11-04.

A phase 2 trial of neoadjuvant metformin in combination with trastuzumab and chemotherapy in women with early HER2-positive breast cancer: the METTEN study

The METTEN study assessed the efficacy, tolerability, and safety of adding metformin to neoadjuvant chemotherapy plus trastuzumab in early HER2-positive breast cancer (BC). Women with primary, non-metastatic HER2-positive BC were randomized (1:1) to receive metformin (850 mg twice-daily) for 24 weeks concurrently with 12 cycles of weekly paclitaxel plus trastuzumab, followed by four cycles of 3-weekly FE75C plus trastuzumab (arm A), or equivalent regimen without metformin (arm B), followed by surgery. Primary endpoint was the rate of pathological complete response (pCR) in the per-protocol efficacy population. pCR rate was numerically higher in the metformin-containing arm A (19 of 29 patients [65.5%, 95% CI: 47.3-80.1]) than in arm B (17 of 29 patients [58.6%, 95% CI: 40.7-74.5]; OR 1.34 [95% CI: 0.46-3.89], P = 0.589). The rate of breast-conserving surgery was 79.3% and 58.6% in arm A and B (P = 0.089), respectively. Blood metformin concentrations (6.2 μmol/L, 95% CI: 3.6-8.8) were within the therapeutic range. Seventy-six percent of patients completed the metformin-containing regimen; 13% of patients in arm A dropped out because of metformin-related gastrointestinal symptoms. The most common adverse events (AEs) of grade ≥3 were neutropenia in both arms and diarrhea in arm A. None of the serious AEs was deemed to be metformin-related. Addition of anti-diabetic doses of metformin to a complex neoadjuvant regimen was well tolerated and safe. Because the study was underpowered relative to its primary endpoint, the efficacy data should be interpreted with caution.

Abstract CT165: A two-stage Simon Design phase II study for NOn-BRCA metastatic BReast cancer (MBC)patients with homologous recombination deficiency treated with OLAparib single agent.(NOBROLA study)

BACKGROUND: Olaparib is a well-tolerated oral PARP inhibitor. Olaparib has shown promising monotherapy activity in patients with germline mutations in BRCA genes and cancers that exhibited a failure in DNA repair mechanism. The aim of this trial is to evaluate the efficacy of olaparib as single agent in non-BRCA MBC patients whose tumors exhibit an homologous recombination deficiency (HRD) signature.

TRIAL DESIGN: This is an open label, non-randomized, multicenter two-stage phase IIA clinical trial. Patients will receive oral olaparib 300 mg twice a day during 28 days cycles until progression or unacceptable toxicity. HRD signature will be evaluated with one tumor tissue-based test: FMI Lynparza HRR. The stage I principal selection criteria are: (1) Confirmed non-BRCA triple negative locally advance (LA) or MBC; (2) HRD signature; (3) one to three previous lines for the MBC and prior taxanes exposure; (4) RECIST v1.1 evaluable disease. In stage II the study will be extended to patients with luminal subtype and confirmed non-BRCA LA or MBC with HRD signature. The primary goal is to evaluate the efficacy of olaparib monotherapy. Primary endpoint are the clinical benefit rate (CBR), defined as the percentage of patients who experienced overall response (as best response) or stable disease ≥24 weeks in accordance with RECISTv1.1. The trial uses a Simon's minimax two-stage design. We hypothesized that excluding a CBR ≤5% while targeting an improvement of the CBR to ≥20% would be an optimal approach to evaluation of the study strategy. At first stage, ≥1 patient with clinical benefit among 17 patients will be necessary to continue. At the study end, ≥5 subjects with clinical benefit out of 35 evaluable subjects are required to justify this strategy in further clinical trials. Considering a drop-out rate of 10%, a sample size of 39 patients will be needed to attain 80% power at nominal level of one-sided alpha of 0.05. We anticipate a 40% of screened TNBC and 25% of luminal (RH-positive HER2-negative) non-BRCA patients will exhibit HRD signature. Therefore, we expect to screen 48 patients in the 1st stage and 80 patients in the 2nd stages to accomplish with the accrual goal (a total of 128 patients screened). Secondary objectives include (1) efficacy measures: objective response rate (ORR), progression-free survival (PFS) and overall survival; (2) the assessment of HRD signatures agreement and validity to predict clinical benefit and overall response; and (3) safety-related outcomes.

Citation Format: Elena Aguirre, Kepa Amillano, Alfonso Cortés, María José Juan, Antonia Márquez, Manuel Ruiz, Sonia Servitja, Ander Urrutikoetxea, Antonio Llombart, José Perez, Javier Cortes. A two-stage Simon Design phase II study for NOn-BRCA metastatic BReast cancer (MBC)patients with homologous recombination deficiency treated with OLAparib single agent.(NOBROLA study) [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 CT165.

Exogenous FABP4 increases breast cancer cell proliferation and activates the expression of fatty acid transport proteins

Adipose tissue plays an important role in tumor progression, because it provides nutrients and adipokines to proliferating cells. Fatty acid binding protein 4 (FABP4) is a key adipokine for fatty acid transport. In metabolic pathologies, plasma levels of FABP4 are increased. However, the role of this circulating protein is unknown. Recent studies have demonstrated that FABP4 might have a role in tumor progression, but the molecular mechanisms involved are still unclear. In this study, we analysed the role of eFABP4 (exogenous FABP4) in breast cancer progression. MCF-7 and MDA-MB-231 breast cancer cells did not express substantial levels of FABP4 protein, but intracellular FABP4 levels increased after eFABP4 incubation. Moreover, eFABP4 enhanced the proliferation of these breast cancer cells but did not have any effect on MCF-7 and MDA-MB-231 cell migration. Additionally, eFABP4 induced the AKT and MAPK signaling cascades in breast cancer cells, and the inhibition of these pathways reduced the eFBAP4-mediated cell proliferation. Interestingly, eFABP4 treatment in MCF-7 cells increased levels of the transcription factor FoxM1 and the fatty acid transport proteins CD36 and FABP5. In summary, we showed that eFABP4 plays a key role in tumor proliferation and activates the expression of fatty acid transport proteins in MCF-7 breast cancer cells. © 2016 Wiley Periodicals, Inc.

SOLTI NeoPARP: A phase II, randomized study of two schedules of iniparib plus paclitaxel and paclitaxel alone as neoadjuvant therapy in patients with triple-negative breast cancer (TNBC)

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Background: Iniparib is an anticancer agent with a mechanism of action still under investigation. A phase 2 randomized neoadjuvant study in patients (pts) with TNBC was designed to explore the activity and tolerability of two schedules of iniparib with weekly paclitaxel (PTX). Here we report the efficacy and safety results from a planned interim analysis (IA). Methods: The trial accrued a total of 141 pts in October 2011, of whom, 74 are included in this IA. All were chemo-naive, histologicallyconfirmed Stage II-IIIA TNBC (IIA 47%; IIB 35%; IIIA 16%) with a median age of 50 yr. Triple negative status was centrally confirmed [ER/PR <10%, HER2 IHC (0+, 1+) or FISH negative]. Pts were randomized (1:1:1) to receive weekly PTX (80 mg/m2, IV, d 1; N=25) alone or in combination with iniparib, either on a once weekly (QW) (11.2 mg/kg, IV, d 1; N=25) or twice weekly (BIW) (5.6 mg/kg, IV, d 1, 4; N=24) schedule. The total planned treatment duration was 12 wks. The IA endpoint is pathological complete response in the breast (pCR) as assessed by independent pathologists. Results: Two/2/3 pts in the PTX/QW/BIW arms, respectively, discontinued due to progressive disease per RECIST. Another 3/2/2 pts, respectively, discontinued due to investigator decision or an adverse event (AE). Thirteen pts presented with Grade 3/4 Treatment Emergent AE: 3 pts in PTX arm (1 neutropenia, 1 presyncope, 1 ALT elevation), 3 in QW arm (1 lymphopenia, 1 hyperkalemia, 1 pulmonary embolism), and 8 in the BIW arm (1 febrile neutropenia, 3 neutropenia, 1 aphonia, 1 syncope, 1 radius fracture and 1 vertigo). Laboratory Grade 3/4 neutropenia occurred in 4% of pts in PTX, 0% in QW and 21% of BIW arms, with 1/2/3 pts, respectively, requiring G-CSF usage. There were 4/7/6 pts in the PTX/QW/BIW arms with PTX dose modifications. Four pts (16%) in PTX arm, 4 pts (16%) in the QW arm and 6 pts (25%) in the BIW arm had confirmed pCR in the breast. Conclusions: In this IA population, the addition of iniparib regardless of the schedule to weekly PTX did not seem to add clinically significant toxicity. pCR rate in the breast is similar across treatment arms at this IA. NCT01204125.