Olaparib plus Durvalumab, with or without Bevacizumab, as Treatment in PARP Inhibitor-Naïve Platinum-Sensitive Relapsed Ovarian Cancer: A Phase II Multi-Cohort Study

PURPOSE

Early results from the phase II MEDIOLA study (NCT02734004) in germline BRCA1- and/or BRCA2-mutated (gBRCAm) platinum-sensitive relapsed ovarian cancer (PSROC) showed promising efficacy and safety with olaparib plus durvalumab. We report efficacy and safety of olaparib plus durvalumab in an expansion cohort of women with gBRCAm PSROC (gBRCAm expansion doublet cohort) and two cohorts with non-gBRCAm PSROC, one of which also received bevacizumab (non-gBRCAm doublet and triplet cohorts).

PATIENTS AND METHODS

In this open-label, multicenter study, PARP inhibitor-naïve patients received olaparib plus durvalumab treatment until disease progression; the non-gBRCAm triplet cohort also received bevacizumab. Primary endpoints were objective response rate (ORR; gBRCAm expansion doublet cohort), disease control rate (DCR) at 24 weeks (non-gBRCAm cohorts), and safety (all cohorts).

RESULTS

The full analysis and safety analysis sets comprised 51, 32, and 31 patients in the gBRCAm expansion doublet, non-gBRCAm doublet, and non-gBRCAm triplet cohorts, respectively. ORR was 92.2% [95% confidence interval (CI), 81.1-97.8] in the gBRCAm expansion doublet cohort (primary endpoint); DCR at 24 weeks was 28.1% (90% CI, 15.5-43.9) in the non-gBRCAm doublet cohort (primary endpoint) and 74.2% (90% CI, 58.2-86.5) in the non-gBRCAm triplet cohort (primary endpoint). Grade ≥ 3 adverse events were reported in 47.1%, 65.6%, and 61.3% of patients in the gBRCAm expansion doublet, non-gBRCAm doublet, and non-gBRCAm triplet cohorts, respectively, most commonly anemia.

CONCLUSIONS

Olaparib plus durvalumab continued to show notable clinical activity in women with gBRCAm PSROC. Olaparib plus durvalumab with bevacizumab demonstrated encouraging clinical activity in women with non-gBRCAm PSROC. No new safety signals were identified.

The Role of 68 Ga-FAPI PET/CT in Breast Cancer Response Assessment and Follow-Up

PURPOSE

68 Ga-fibroblast activation protein inhibitor (FAPI), a new PET/CT radiotracer targeting cancer-associated fibroblasts in tumor microenvironment, can detect many types of cancer. We aimed to assess whether it can also be used for response assessment and follow-up.

METHODS

We followed up patients with FAPI-avid invasive lobular breast cancer (ILC) before and after treatment changes and correlated qualitative maximal intensity projection images and quantitative tumor volume with CT results and blood tumor biomarkers.

RESULTS

Six consenting ILC breast cancer patients (53 ± 8 years old) underwent a total of 24 scans (baseline for each patient and 2-4 follow-up scans). We found a strong correlation between 68 Ga-FAPI tumor volume and blood biomarkers ( r = 0.7, P < 0.01), but weak correlation between CT and 68 Ga-FAPI maximal intensity projection-based qualitative response assessment.

CONCLUSIONS

We found a strong correlation between ILC progression and regression (as assessed by blood biomarkers) and 68 Ga-FAPI tumor volume. 68 Ga-FAPI PET/CT could possibly be used for disease response assessment and follow-up.

Clinical outcomes in estrogen receptor-positive early-stage breast cancer patients with Recurrence Score 26-30: observational real-world cohort study

Data on adjuvant chemotherapy (CT) benefit in ER + HER2‒ early-stage breast cancer (EBC) patients with Recurrence Score (RS) 26-30 are limited. This real-world study evaluated the relationships between the RS, adjuvant treatments, and outcomes in 534 RS 26-30 patients tested through Clalit Health Services (N0: n = 394, 49% CT-treated; N1mi/N1: n = 140, 62% CT-treated). The CT-treated and untreated groups were imbalanced (more high-risk clinicopathologic characteristics in CT-treated patients). With median follow-up of 8 years, Kaplan-Meier estimates for overall survival (OS), distant recurrence-free survival (DRFS), and BC-specific mortality (BCSM) were not significantly different between CT-treated and untreated N0 patients. Seven-year rates (95% CI) in CT-treated vs untreated: OS, 97.9% (94.4-99.2%) vs 97.9% (94.6-99.2%); DRFS, 91.5% (86.6-94.7%) vs 91.2% (86.0-94.6%); BCSM, 0.5% (0.1-3.7%) vs 1.6% (0.5-4.7%). For N1mi/N1 patients, OS/DRFS did not differ significantly between treatment groups; whereas BCSM did (1.3% [0.2-8.6%] vs 6.2% [2.0-17.7%] for CT-treated and untreated patients, respectively, p = 0.024).

The Role of 68 Ga-FAPI PET/CT in Detection of Metastatic Lobular Breast Cancer

PURPOSE

Invasive lobular breast cancer (ILC) may be hard to detect using conventional imaging modalities and usually shows less avidity to 18 F-FDG PET/CT. 68 Ga-fibroblast activation protein inhibitor (FAPI) PET/CT has shown promising results in detecting non- 18 F-FDG-avid cancers. We aimed to assess the feasibility of detecting metastatic disease in patients with non- 18 F-FDG-avid ILC.

METHODS

This prospective study included patients with metastatic ILC, infiltrative to soft tissues, which was not 18 F-FDG avid. The patients underwent 68 Ga-FAPI PET/CT for evaluation, which was correlated with the fully diagnostic CT performed at the same time.

RESULTS

Seven women (aged 57 ± 10 years) were included. Among the 30 organs and structures found to be involved by tumor, the number of findings observed by FAPI PET/CT was significantly higher than that observed by CT alone ( P = 0.022), especially in infiltrative soft tissue and serosal locations.

CONCLUSIONS

This small pilot trial suggests a role for 68 Ga-FAPI PET/CT in ILC, which needs to be confirmed by subsequent trials.

Abstract P5-05-04: Estrogen receptor 1 (ESR1) mutations in circulating tumor DNA (ctDNA) from patients with ER+/HER2- metastatic breast cancer (mBC) treated with lasofoxifene or fulvestrant in the ELAINE 1 study

Introduction: Acquired ESR1 mutations (mutESR1) after long-term endocrine therapy drive treatment resistance, metastasis, and poor prognosis for patients (pts) with ER+/HER2- metastatic breast cancer (mBC). Lasofoxifene (LAS), a selective estrogen receptor modulator, alone or with a CDK4/6 inhibitor (CDK4/6i) reduced tumor growth better than fulvestrant (Fulv) in mutESR1 BC xenograft models. ELAINE 1 is a randomized trial of LAS vs Fulv in pts with mutESR1 and prior progression on aromatase inhibitor and CDK4/6i. Preliminary results (ESMO 2022) showed that LAS prolonged median progression-free survival (mPFS) compared with Fulv with a favorable safety profile. Here, we report changes in ESR1 ctDNA mutant allele frequency (MAF) from baseline to 8 wks and their associations with clinical benefit (CB) and mPFS.

Methods: ELAINE 1 pts were randomized to oral LAS 5 mg daily or IM Fulv 500 mg on days 1, 15, and 29, then every 4 wks, until disease progression or severe toxicity. ctDNA mutESR1 mutations (baseline and 8 wks) were assessed using the Sysmex Inostics OncoBeam or SafeSeq assays—which detect mutESR1 at low allele fractions. MAF changes from baseline to wk 8 were characterized as decreased (decrease in ESR1 MAF or fully cleared), increased (increase in MAF), or equivocal (polyclonal patients [&gt;1 mutESR1] with some increasing and decreasing MAF trends); correlations with PFS and CB were explored. Efficacy measures included objective response rate (ORR), PFS, and CB at 24 wks (CB defined as response or stable disease ≥24 wks).

Results: 103 pts received LAS (n=52) or Fulv (n=51). Most common baseline ESR1 variants detected were D538G (56%), Y537S (39%), Y537N (29%), E380Q (22%); 56 (54%) pts were polyclonal. Of the 61 pts with evaluable baseline and wk 8 ctDNA, LAS decreased mutESR1 MAF in 29/35 pts (83% [11 complete clearance]) while Fulv decreased mutESR1 MAF in 16/26 pts (61.5% [6 complete clearance]) (Table).

mPFS with LAS was 8 and 4 mos for pts with decreased/cleared MAF and increased MAF, respectively, and with Fulv was 4.5 and 2.8 mos, respectively (Table). LAS decreased the common mutESR1 variants more frequently than Fulv (median relative change -87.1% vs -14.7%). In pts with decreased MAF, CB was observed in 16/29 LAS pts (55%) and 4/16 Fulv pts (25%). The predictiveness of ESR1 MAF clearance for CB was also explored. Of 11 pts with ESR1 MAF clearance taking LAS, 10 achieved CB, yielding a positive predictive value (PPV) of 90.9%. In contrast, 2/6 pts with ESR1 MAF clearance taking Fulv had CB for a PPV of 33.3%. Sensitivity for predicting CB based on direction of ESR1 MAF change was 94% with LAS and 80% with Fulv. In pts with Y537S MAF (n=33), LAS decreased Y537S in 13/15 (87%), with a median relative MAF decrease of 89%. In marked contrast, Fulv increased Y537S MAF in 11/18 pts (61%), corresponding to an MAF relative increase of 82%. LAS and Fulv resulted in complete clearance of Y537S MAF in 33% and 6% of pts, respectively.

Conclusion: Our data demonstrate that LAS more effectively decreased or cleared mutESR1 than Fulv. Further, mutESR1 clearance was associated with prolonged PFS and more CB in LAS but not Fulv pts, suggesting that LAS results in robust mutESR1 target engagement. Taken together, our data suggest mutESR1 as a potential liquid biomarker for predicting response to LAS in mutESR1, endocrine-resistant mBC pts.

Table. Change from baseline to week 8 in ESR1 MAF and clinical benefit at 24 weeks. CI, confidence interval; MAF, mutant allele fraction; ND, none detected; PFS, progression-free survival.

Citation Format: Matthew P. Goetz, Einav Gal-Yam, Daniel Stover, Sarah L. Sammons, Stephanie L. Graff, Grace Wang, Massimo Cristofanilli, Gary Riordan, Hillary S. Sloane, Dominic Carroll, Paul V. Plourde, David J Portman. Estrogen receptor 1 (ESR1) mutations in circulating tumor DNA (ctDNA) from patients with ER+/HER2- metastatic breast cancer (mBC) treated with lasofoxifene or fulvestrant in the ELAINE 1 study [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 P5-05-04.

Health-related quality of life with palbociclib plus endocrine therapy versus capecitabine in postmenopausal patients with hormone receptor-positive metastatic breast cancer: Patient-reported outcomes in the PEARL study

BACKGROUND

The PEARL study showed that palbociclib plus endocrine therapy (palbociclib/ET) was not superior to capecitabine in improving progression-free survival in postmenopausal patients with metastatic breast cancer resistant to aromatase inhibitors, but was better tolerated. This analysis compared patient-reported outcomes.

PATIENTS AND METHODS

The PEARL quality of life (QoL) population comprised 537 patients, 268 randomised to palbociclib/ET (exemestane or fulvestrant) and 269 to capecitabine. Patients completed the European Organisation for Research and Treatment of Cancer QLQ-C30 and QLQ-BR23 and EQ-5D-3L questionnaires. Changes from the baseline and time to deterioration (TTD) were analysed using linear mixed-effect and stratified Cox regression models, respectively.

RESULTS

Questionnaire completion rate was high and similar between treatment arms. Significant differences were observed in the mean change in global health status (GHS)/QoL scores from the baseline to cycle 3 (2.9 for palbociclib/ET vs. -2.1 for capecitabine (95% confidence interval [CI], 1.4-8.6; P = 0.007). The median TTD in GHS/QoL was 8.3 months for palbociclib/ET versus 5.3 months for capecitabine (adjusted hazard ratio, 0.70; 95% CI, 0.55-0.89; P = 0.003). Similar improvements for palbociclib/ET were also seen for other scales as physical, role, cognitive, social functioning, fatigue, nausea/vomiting and appetite loss. No differences were observed between the treatment arms in change from the baseline in any item of the EQ-5D-L3 questionnaire as per the overall index score and visual analogue scale.

CONCLUSION

Patients receiving palbociclib/ET experienced a significant delay in deterioration of GHS/QoL and several functional and symptom scales compared with capecitabine, providing additional evidence that palbociclib/ET is better tolerated.

TRIAL REGISTRATION NUMBER

NCT02028507 (ClinTrials.gov).

EUDRACT STUDY NUMBER

2013-003170-27.

Palbociclib in combination with endocrine therapy versus capecitabine in hormonal receptor-positive, human epidermal growth factor 2-negative, aromatase inhibitor-resistant metastatic breast cancer: a phase III randomised controlled trial-PEARL

BACKGROUND

Palbociclib plus endocrine therapy (ET) is the standard treatment of hormone receptor-positive and human epidermal growth factor receptor 2-negative, metastatic breast cancer (MBC). However, its efficacy has not been compared with that of chemotherapy in a phase III trial.

PATIENTS AND METHODS

PEARL is a multicentre, phase III randomised study in which patients with aromatase inhibitor (AI)-resistant MBC were included in two consecutive cohorts. In cohort 1, patients were randomised 1 : 1 to palbociclib plus exemestane or capecitabine. On discovering new evidence about estrogen receptor-1 (ESR1) mutations inducing resistance to AIs, the trial was amended to include cohort 2, in which patients were randomised 1 : 1 between palbociclib plus fulvestrant and capecitabine. The stratification criteria were disease site, prior sensitivity to ET, prior chemotherapy for MBC, and country of origin. Co-primary endpoints were progression-free survival (PFS) in cohort 2 and in wild-type ESR1 patients (cohort 1 + cohort 2). ESR1 hotspot mutations were analysed in baseline circulating tumour DNA.

RESULTS

From March 2014 to July 2018, 296 and 305 patients were included in cohort 1 and cohort 2, respectively. Palbociclib plus ET was not superior to capecitabine in both cohort 2 [median PFS: 7.5 versus 10.0 months; adjusted hazard ratio (aHR): 1.13; 95% confidence interval (CI): 0.85-1.50] and wild-type ESR1 patients (median PFS: 8.0 versus 10.6 months; aHR: 1.11; 95% CI: 0.87-1.41). The most frequent grade 3-4 toxicities with palbociclib plus exemestane, palbociclib plus fulvestrant and capecitabine, respectively, were neutropenia (57.4%, 55.7% and 5.5%), hand/foot syndrome (0%, 0% and 23.5%), and diarrhoea (1.3%, 1.3% and 7.6%). Palbociclib plus ET offered better quality of life (aHR for time to deterioration of global health status: 0.67; 95% CI: 0.53-0.85).

CONCLUSIONS

There was no statistical superiority of palbociclib plus ET over capecitabine with respect to PFS in MBC patients resistant to AIs. Palbociclib plus ET showed a better safety profile and improved quality of life.

Abstract 4011: Tumor evolution inferred by patterns of miRNA expression through the course of disease, therapy and recurrence in breast cancer

Tumor heterogeneity frequently develops through the course of disease, therapy and metastasis. This molecular evolution is a major challenge in the clinical setting and is the main reason for resistance to therapy. Although metastatic disease is the cause of death in breast cancer, most studies involve primary tumors compared to normal breast. An alternative approach of serial assessments can add an informative value and highlight important molecular players that may be otherwise underestimated.

We sought to explore alterations through the course of disease by profiling serial samples from individual breast cancer cases followed from diagnosis to recurrence. We have assembled a unique cohort of patients having matched samples from pre-treatment, post-treatment and recurrent events. We collected paraffin-embedded samples and profiled miRNA expression across all samples for each patient using NanoString analysis.

We hypothesized that expression modulations in individual patients through their course of disease can target miRNAs sets that differentially function at the various stages of the disease. We therefore used an innovative approach for analysis, identifying modulation patterns as opposed to differential absolute expression. We defined all the 8 possible patterns of expression modulations in 3 time points across the course of disease. For each pattern, we identified a set of miRNAs that are shared between patients by limiting the search algorithm to find modulations of at least 1.5 fold in at least 3 patients. Each miRNA set was examined for enrichments in known miRNAs datasets (METABRIC), for target predictions and for literature evidences.

We found an agreement between the predicted pattern of each assigned miRNAs and the observed trend. For example, miRNAs assigned to a pattern of an increased expression post-treatment and a decrease at recurrence were found to be down-regulated in breast cancer and negatively correlated with the cell cycle pathway. Interestingly, we found that this miRNAs set can differentiate between individual patients, based on their response to therapy. All patients sharing the same pattern for its assigned set of miRNAs had a partial response to therapy. In contrast, patients that showed the opposite pattern demonstrated a minimal response to therapy. Finally, although this miRNA set were identified by the pattern dynamics, we found a significant difference in its average absolute expression level between patients having recurrence and patients that are recurrence free, suggesting that the identified miRNA set may have a prognostic value.

In summary, examining serial assessments enabled us to identify significant molecular signatures characterizing breast cancer progression based on expression patterns through the course of disease. This longitudinal approach of profiling individual patients may have important consequences for personalized medicine.

Citation Format: Maya Dadiani, Noa Bossel, Shani Paluch-Shimon, Gili Peri, Anya Pavlovski, Smadar Kahana-Edwin, Nora Balint, Adi Yosepovich, Adi Zundelevich, Einav Gal-Yam, Raanan Berger, Iris Barshack, Eytan Domany, Bella Kaufman. Tumor evolution inferred by patterns of miRNA expression through the course of disease, therapy and recurrence in breast cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4011. doi:10.1158/1538-7445.AM2015-4011