Overcoming BRAF and CDK4/6 inhibitor resistance by inhibiting MAP3K3-dependent protection against YAP lysosomal degradation

Transcriptional programs governed by YAP play key roles in conferring resistance to various molecular-targeted anticancer agents. Strategies aimed at inhibiting YAP activity have garnered substantial interest as a means to overcome drug resistance. However, despite extensive research into the canonical Hippo-YAP pathway, few clinical agents are currently available to counteract YAP-associated drug resistance. Here, we present a novel mechanism of YAP stability regulation by MAP3K3 that is independent of Hippo kinases. Furthermore, we identified MAP3K3 as a target for overcoming anticancer drug resistance. Depletion of MAP3K3 led to a substantial reduction in the YAP protein level in melanoma and breast cancer cells. Mass spectrometry analysis revealed that MAP3K3 phosphorylates YAP at serine 405. This MAP3K3-mediated phosphorylation event hindered the binding of the E3 ubiquitin ligase FBXW7 to YAP, thereby preventing its p62-mediated lysosomal degradation. Robust YAP activation was observed in CDK4/6 inhibitor-resistant luminal breast cancer cells. Knockdown or pharmacological inhibition of MAP3K3 effectively suppressed YAP activity and restored CDK4/6 inhibitor sensitivity. Similarly, elevated MAP3K3 expression supported the prosurvival activity of YAP in BRAF inhibitor-resistant melanoma cells. Inhibition of MAP3K3 decreased YAP-dependent cell proliferation and successfully restored BRAF inhibitor sensitivity. In conclusion, our study reveals a previously unrecognized mechanism for the regulation of YAP stability, suggesting MAP3K3 inhibition as a promising strategy for overcoming resistance to CDK4/6 and BRAF inhibitors in cancer treatment.

Comparison of posterior capsule rupture rates during phacoemulsification using 3D heads-up visualization system and traditional microscopes

PURPOSE

To compare the posterior capsule rupture (PCR) rates of cataract surgery using a traditional ophthalmic surgical microscope (OSM) and a 3D heads-up visualization system (HUVS).

SETTING

Single tertiary referral center.

DESIGN

Retrospective study.

METHODS

This study included 10 101 eyes that underwent phacoemulsification cataract surgery. Surgeries were performed using either 3D HUVS (1964 eyes, performed by 2 surgeons, HUVS group) or traditional OSM (8137 eyes, performed by 6 surgeons, OSM group) from February 2018 to June 2022. Data were collected based on the diagnosis-related group system, and the rate of PCR requiring vitrectomy and the surgical time were evaluated.

RESULTS

The PCR rates were not significantly different between the OSM (n = 63; 0.7%) and HUVS (n = 19; 0.9%, P = .392) groups. The mean surgical time was significantly longer in the HUVS group (14.7 ± 10.6 minutes) than in the OSM group (12.9 ± 9.9 minutes, P < .001). In the 3D HUVS group, there were no PCR cases among the initial 100 patients. In both groups, no significant difference was observed in the PCR rates over time. Although the difference was not statistically significant, the PCR rate decreased over time in the HUVS group.

CONCLUSIONS

The results indicate that 3D HUVS-based cataract surgery performed by experienced cataract surgeons had a PCR rate similar to that of traditional OSM-based surgery during the 4-year study period. Although the surgical time was slightly longer with 3D HUVS, cataract surgery using 3D HUVS can be performed safely by experienced surgeons.

Training intensity of robot-assisted gait training in children with cerebral palsy

AIM

We compared three different intensities of robot-assisted gait training (RAGT) for achieving favourable outcomes in children with cerebral palsy (CP).

METHOD

This study was conducted using a randomized controlled, single-blind design. Thirty children (19 males and 11 females; mean age 6 years 1 month, SD 2 years) with CP classified in Gross Motor Function Classification System levels II and III were assigned to three different RAGT intensity groups: high-intensity (fastest walking speed and lowest body weight support [BWS]), low-intensity (slowest speed and highest BWS), and comfortable intensity (intermediate speed and intermediate BWS). The RAGT intervention was performed three times a week for 6 weeks. Outcome measures included the 88-item Gross Motor Function Measure, stability index, spatiotemporal parameters of gait analysis, paediatric functional independence measure, and the Canadian Occupational Performance Measure.

RESULTS

The 88-item Gross Motor Function Measure was significantly improved after training in the high-intensity (D Δ8.3 ± 15.6; E Δ3.8 ± 4.1) and comfortable intensity (D Δ2.9 ± 3.1; E Δ1.2 ± 2.0) groups, whereas gait speed was improved in the comfortable intensity group, without statistically significant group differences. Only the low-intensity group showed improvement on the stability index (Δ -0.6 ± 0.9, p = 0.05). Everyday functional performance significantly improved in all three groups, with the comfortable intensity group showing the greatest improvement.

INTERPRETATION

Different training intensities produced improvement in different areas; individualized RAGT intensity adjustment is therefore needed based on the rehabilitation goal.

A simplified cranial cavity model to understand the relationship between intracranial pressure and dural sinus pressure

Although accurate intracranial pressure (ICP) monitoring is essential for the diagnosis and treatment of severe brain diseases, current methods are performed invasively. Therefore, a safe and less invasive ICP measurement is required. The purpose of our study was to develop a simplified cranial cavity model for a better understanding of the relationship between the ICP and the pressure measurement within the dural venous sinus (DVS) to support the validity of using sinus pressure as the surrogate of the ICP. The in-house cranial cavity model had three components: the brain part, the DVS part, and the subarachnoid space (SAS) part. Pressure in other parts was measured when the pressure in the SAS part and, separately, brain part was increased from 0 (baseline) to 50 mmHg at intervals of 10 mmHg. When the pressure in the SAS part was increased from 10 to 50 mmHg at 10 mmHg interval, pressures of both the brain and DVS parts increased without significant difference (all P > 0.05). However, pressures in both the SAS and DVS parts differed while the pressure in the brain part was increased. The pressures in both parts showed about 70% of the increase in the brain part. Nevertheless, the pressures in the SAS and DVS parts were not significantly different (P > 0.05). A simplified in-house cranial cavity model was developed consisting of three compartments to represent the actual intracranial spaces. The pressure measurement within the DVS was feasible to use as a surrogate for the ICP measurement.

A nationwide real-world study for evaluation of effectiveness and safety of T-DM1 in patients with HER2-positive metastatic breast cancer in Korea (KCSG BR19-15)

Purpose

This study aimed to investigate clinical practices and factors related to the outcomes of T-DM1 use in patients with HER2-positive metastatic breast cancer (mBC).

Methods

We included patients with HER2-positive mBC who received T-DM1 as a palliative therapy between August 2017 and December 2018. The safety and outcomes of T-DM1, including overall response rate (ORR), progression-free survival (PFS), and overall survival (OS), were evaluated. A Cox proportional hazards model was used to estimate the hazard ratio and 95% confidence interval (CI) for mortality or progression to HER2-positive mBC.

Results

In total, 824 patients were enrolled during the study period. The mean age of patients was 58 years, and 516 (62.6%) patients relapsed after curative treatment. Excluding a history of endocrine therapy, 341 (41.4%) patients previously received none or first-line chemotherapy, 179 (21.7%) received second-line therapy, and 303 (36.9%) received third-or later-line chemotherapy before T-DM1 therapy. During a median follow-up of 16.8 months, the ORR was 35%, the median PFS was 6.6 months, and the median OS was not reached. The clinical factors associated with the hazard of progression were age (<65 years), poor performance status (⩾2), advanced line of palliative chemotherapy (⩾2), prior pertuzumab use, and treatment duration of palliative trastuzumab (<10 months). Common grade 3-4 adverse events were thrombocytopenia (n = 107, 13.2%), neutropenia (n = 23, 2.8%), anemia (n = 21, 2.6%), and elevated liver enzyme (n = 20, 2.5%). Hypokalemia (⩽3.0 mmol/L) and any-grade bleeding events occurred in 25 (3.1%) and 94 (22.6%) patients, respectively.

Conclusion

This is the first nationwide real-world study of T-DM1 use in patients with HER2-positive mBC in Korea. The effectiveness and toxicity profiles of T-DM1 in real-world practice were comparable to those in randomized trials. Moreover, patient factors and previous anti-HER2 therapy could predict the outcomes of T-DM1 therapy.

Automatic Quantitative Assessment for Diagnostic and Therapeutic Response in Rodent Myocardial Infarct Model

The purpose of this study was to investigate the most appropriate methodological approach for the automatic measurement of rodent myocardial infarct polar map using histogram-based thresholding and unsupervised deep learning (DL)-based segmentation. A rat myocardial infarction model was induced by ligation of the left coronary artery. Positron emission tomography (PET) was performed 60 min after the administration of 18F-fluoro-deoxy-glucose (18F-FDG), and PET was performed after injecting 64Cu-pyruvaldehyde-bis(N4-methylthiosemicarbazone). Single photon emission computed tomography was performed 60 min after injection of 99mTc-hexakis-2-methoxyisobutylisonitrile and 201Tl. Delayed contrast-enhanced magnetic resonance imaging was performed after injecting Gd-DTPA-BMA. Three types of thresholding methods (naive thresholding, Otsu's algorithm, and multi-Gaussian mixture model (MGMM)) were used. DL segmentation methods were based on a convolution neural network and trained with constraints on feature similarity and spatial continuity of the response map extracted from images by the network. The relative infarct sizes measured by histology and estimated R2 for 18F-FDG were 0.8477, 0.7084, 0.8353, and 0.9024 for naïve thresholding, Otsu's algorithm, MGMM, and DL segmentation, respectively. DL-based method improved the accuracy of MI size assessment.

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.

Clinical activity of nivolumab in combination with eribulin in HER2-negative metastatic breast cancer: A phase IB/II study (KCSG BR18-16)

AIM

We evaluated the efficacy and safety of nivolumab and eribulin combination therapy for metastatic breast cancer (BC) in Asian populations.

METHODS

In this parallel phase II study, adult patients with histologically confirmed recurrent/metastatic hormone receptor-positive/HER2-negative (HR+HER2-) or triple-negative BC (TNBC) were prospectively enroled from 10 academic hospitals in Korea (ClinicalTrials.gov Identifier: NCT04061863). They received nivolumab (360 mg) on day 1 plus eribulin (1.4 mg/m2) on days 1 and 8 every 3 weeks until disease progression or intolerable toxicity. The primary endpoint was the investigator-assessed 6-month progression-free survival (PFS) rate in each subtype. Secondary endpoints included investigator-assessed objective response rate (ORR) as per Response Evaluation Criteria in Advanced Solid Tumors version 1.1, disease control rate, overall survival, and treatment toxicity. The association between PD-L1 expression and efficacy was investigated.

RESULTS

Forty-five patients with HR+HER2- BC and 45 with TNBC were enroled. Their median age was 51 (range, 31-71) years, and 74 (82.2%) received one or two prior treatments before enrolment. Six-month PFS was 47.2% and 25.1% in the HR+HER2- and TNBC cohorts, respectively. Median PFS was 5.6 (95% confidence interval [CI]: 5.3-7.4) and 3.0 (95% CI: 2.1-5.2) months in the HR+HER2- and TNBC groups, respectively. ORRs were 53.3% (complete response [CR]: 0, partial response [PR]: 24) and 28.9% (CR: 1, PR: 12). Patients with PD-L1+ tumours (PD-L1 expression ≥1%) and PD-L1- tumours (ORR 50% versus 53.8% in HR+HER2-, 30.8% versus 29.0% in TNBC) had similar ORRs. Neutropenia was the most common grade 3/4 adverse event; the most common immune-related adverse events (AEs) were grades 1/2 hypothyroidism and pruritus. Five patients discontinued therapy because of immune-related AEs.

CONCLUSION

Nivolumab plus eribulin showed promising efficacy and tolerable safety in previously treated HER2- metastatic BC.

TRIAL REGISTRATION

NCT04061863.

Pembrolizumab Plus Chemotherapy Followed by Pembrolizumab in Patients With Early Triple-Negative Breast Cancer: A Secondary Analysis of a Randomized Clinical Trial

Importance

In the phase 3 KEYNOTE-522 study, addition of pembrolizumab to neoadjuvant chemotherapy followed by adjuvant pembrolizumab significantly increased pathologic complete response (pCR) and event-free survival (EFS) vs neoadjuvant chemotherapy in patients with early triple-negative breast cancer.

Objective

To evaluate efficacy and safety outcomes for patients enrolled in East/Southeast Asia (Asia) in KEYNOTE-522.

Design, Setting, and Participants

KEYNOTE-522, a multicenter, double-blind, randomized clinical trial, enrolled 1174 patients between March 7, 2017, and September 13, 2018. For interim EFS and overall survival (OS) analyses (data cutoff, March 23, 2021), median follow-up was 39.8 months (range, 30.4-46.9 months) for pembrolizumab plus chemotherapy and 40.8 months (range, 30.1-46.9 months) for placebo plus chemotherapy. Data cutoff for pCR analysis was September 24, 2018. This secondary analysis included adults enrolled in Asia with newly diagnosed, previously untreated, nonmetastatic triple-negative breast cancer (tumor stage T1c and nodal stage N1-2 or tumor stage T2-4 and nodal stage N0-2) and Eastern Cooperative Oncology Group performance status of 0 to 1, regardless of programmed cell death ligand 1 (PD-L1) status.

Intervention

Patients were randomized 2:1 to 4 cycles of pembrolizumab (200 mg every 3 weeks) or placebo plus carboplatin and paclitaxel and another 4 cycles of pembrolizumab or placebo plus doxorubicin or epirubicin and cyclophosphamide before surgery. After definitive surgery, patients received pembrolizumab or placebo every 3 weeks for 9 cycles or until recurrence or unacceptable toxic effects.

Main Outcomes and Measures

The main outcome was pCR (no evidence of primary tumor after neoadjuvant therapy or carcinoma in situ after neoadjuvant therapy and no regional lymph node involvement after neoadjuvant therapy) at the time of definitive surgery and EFS.

Results

A total of 216 of 1174 randomized patients (all female; median [range] age, 46.0 [24.0-71.0] years) were from Korea, Japan, Taiwan, and Singapore (136 in the pembrolizumab plus chemotherapy group and 80 in the placebo plus chemotherapy group). Of these patients, 104 (76.5%) in the pembrolizumab plus chemotherapy group and 60 (75.0%) in the placebo plus chemotherapy group had a tumor PD-L1 combined positive score of 1 or greater. Pathologic complete response was 58.7% (95% CI, 46.7%-69.9%) with pembrolizumab plus chemotherapy and 40.0% (95% CI, 26.4%-54.8%) with placebo plus chemotherapy; benefit was observed regardless of PD-L1 status. Thirteen patients (9.6%) in the pembrolizumab plus chemotherapy group and 20 patients (25.0%) in the placebo plus chemotherapy group had EFS events (hazard ratio, 0.35; 95% CI, 0.17-0.71). The 36-month EFS rate was 91.2% (95% CI, 85.0%-94.9%) with pembrolizumab plus chemotherapy and 77.2% (95% CI, 66.3%-85.0%) with placebo plus chemotherapy. Grade 3 to 4 treatment-related adverse events occurred in 109 patients (80.1%) receiving pembrolizumab plus chemotherapy and 64 patients (81.0%) receiving placebo plus chemotherapy.

Conclusions and Relevance

In this subgroup analysis of patients enrolled in Asia in KEYNOTE-522, neoadjuvant pembrolizumab plus chemotherapy followed by adjuvant pembrolizumab led to clinically meaningful improvements in pCR and EFS vs neoadjuvant chemotherapy alone. These findings support the use of neoadjuvant pembrolizumab plus chemotherapy followed by adjuvant pembrolizumab as a standard-of-care therapy for patients in Asian countries with early triple-negative breast cancer.

Trial Registration

ClinicalTrials.gov Identifier: NCT03036488.

Cerebral Infarction and Recovery in a 12-Year-Old Child With Intracranial Fibromuscular Dysplasia

Fibromuscular dysplasia (FMD) is a congenital vascular anomaly resulting in arterial stenosis and weakening of typically medium-sized arteries. It is a noninflammatory, nonatherosclerotic arterial disease that affects most commonly the renal and internal carotid arteries, but intracranial FMD in the pediatric population is very rare. We report a young age-onset ischemic stroke patient with FMD affecting the middle cerebral artery (MCA). A 14-year-old boy was admitted with left-side weakness during physical education at school. The brain magnetic resonance (MR) imaging revealed an acute ischemic stroke in the right basal ganglia and internal capsule, while the MR angiogram showed segmental intraluminal stenosis in the left proximal MCA. The transfemoral angiography revealed the pathognomonic sign of a "string of beads" at the proximal MCA area. The clinical course was stable, and the boy gradually recovered from the motor weakness of his arm and leg. FMD should be considered as a potential cause of pediatric stroke.

Efficacy of Limited Dose Modifications for Palbociclib-Related Grade 3 Neutropenia in Hormone Receptor-Positive Metastatic Breast Cancer

PURPOSE

Frequent neutropenia hinders uninterrupted palbociclib treatment in patients with hormone receptor (HR)-positive breast cancer. We compared the efficacy outcomes in multicenter cohorts of patients with metastatic breast cancer (mBC) receiving palbociclib following conventional dose modification or limited modified schemes for afebrile grade 3 neutropenia.

MATERIALS AND METHODS

Patients with HR-positive, human epidermal growth factor receptor 2-negative mBC (n=434) receiving palbociclib with letrozole as first-line therapy were analyzed and classified based on neutropenia grade and afebrile grade 3 neutropenia management as follows: group 1 (maintained palbociclib dose, limited scheme), group 2 (dose delay or reduction, conventional scheme), group 3 (no afebrile grade 3 neutropenia event), and group 4 (grade 4 neutropenia event). The primary and secondary endpoints were progression-free survival (PFS) between groups 1 and 2 and PFS, overall survival, and safety profiles among all groups.

RESULTS

During follow-up (median 23.7 months), group 1 (2-year PFS, 67.9%) showed significantly longer PFS than did group 2 (2-year PFS, 55.3%; p=0.036), maintained across all subgroups, and upon adjustment of the factors. Febrile neutropenia occurred in one and two patients of group 1 and group 2, respectively, without mortality.

CONCLUSION

Limited dose modification for palbociclib-related grade 3 neutropenia may lead to longer PFS, without increasing toxicity, than the conventional dose scheme.

Copy number aberrations in circulating tumor DNA enables prognosis prediction and molecular characterization of breast cancer

BACKGROUND

Low-pass whole-genome sequencing (LP-WGS)-based circulating tumor DNA (ctDNA) analysis is a versatile tool for somatic copy number aberration (CNA) detection, and this study aims to explore its clinical implication in breast cancer.

METHODS

We analyzed LP-WGS ctDNA data from 207 metastatic breast cancer (MBC) patients to explore prognostic value of ctDNA CNA burden and validated it in 465 stage II-III triple-negative breast cancer (TNBC) patients who received neoadjuvant chemotherapy in phase III PEARLY trial (NCT02441933). The clinical implication of locus level LP-WGS ctDNA profiling was further evaluated.

RESULTS

We found that a high baseline ctDNA CNA burden predicts poor overall survival and progression-free survival of MBC patients. The post hoc analysis of the PEARLY trial showed that a high baseline ctDNA CNA burden predicted poor disease-free survival independent from pathologic complete response (pCR), validating its robust prognostic significance. The 24-month disease-free survival rate was 96.9% and 55.9% in [pCR(+) and low I-score] and [non-pCR and high I-score] patients, respectively. The locus-level ctDNA CNA profile classified MBC patients into 5 molecular clusters and revealed targetable oncogenic CNAs. LP-WGS ctDNA and in vitro analysis identified the BCL6 amplification as a resistance factor for CDK4/6 inhibitors. We estimated ctDNA-based homologous recombination deficiency status of patients by shallowHRD algorithm, which was highest in the TNBC and correlated with platinum-based chemotherapy response.

CONCLUSIONS

These results demonstrate LP-WGS ctDNA CNA analysis as an essential tool for prognosis prediction and molecular profiling. Particularly, ctDNA CNA burden can serve as a useful determinant for escalating or de-escalating (neo)adjuvant strategy in TNBC patients.

Comparison of the Effects of DOTA and NOTA Chelators on 64Cu-Cudotadipep and 64Cu-Cunotadipep for Prostate Cancer

BACKGROUND

This study compared the effects of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) and 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA) as 64Cu-chelating agents in newly developed prostate-specific membrane antigen (PSMA) target compounds, 64Cu-cudotadipep and 64Cu-cunotadipep, on pharmacokinetics.

METHODS

The in vitro stability of the chelators was evaluated using human and mouse serum. In vitro PSMA-binding affinity and cell uptake were compared using human 22Rv1 cells. To evaluate specific PSMA-expressing tumor-targeting efficiency, micro-positron emission tomography (mcroPET)/computed tomography (CT) and biodistribution analysis were performed using PSMA+ PC3-PIP and PSMA- PC3-flu tumor xenografts.

RESULTS

The serum stability of DOTA- or NOTA-conjugated 64Cu-cudotadipep and 64Cu-cunotadipep was >97%. The Ki value of the NOTA derivative, cunotadipep, in the in vitro affinity binding analysis was higher (2.17 ± 0.25 nM) than that of the DOTA derivative, cudotadipep (6.75 ± 0.42 nM). The cunotadipep exhibited a higher cellular uptake (6.02 ± 0.05%/1 × 106 cells) compared with the cudotadipep (2.93 ± 0.06%/1 × 106 cells). In the biodistribution analysis and microPET/CT imaging, the 64Cu-labeled NOTA derivative, 64Cu-cunotadipep, demonstrated a greater tumor uptake and lower liver uptake than the DOTA derivative.

CONCLUSIONS

This study indicates that the PSMA-targeted 64Cu-cunotadipep can be applied in clinical practice owing to its high diagnostic power for prostate cancer.

Genomic analysis of plasma circulating tumor DNA in patients with heavily pretreated HER2 + metastatic breast cancer

We explored accumulated genomic alterations in patients with heavily treated HER2 + metastatic breast cancer enrolled in the KCSG BR18-14/KM10B trial. Targeted sequencing was performed with circulating tumor DNAs (ctDNAs) collected before the treatment of 92 patients. ctDNAs collected at the time of disease progression from seven patients who had a durable response for > 12 months were also analyzed. Sixty-five genes were identified as pathogenic alterations in 99 samples. The most frequently altered genes were TP53 (n = 48), PIKCA (n = 21) and ERBB3 (n = 19). TP53 and PIK3CA mutations were significantly related with shorter progression free survival (PFS), and patients with a higher ctDNA fraction showed a worse PFS. The frequency of homologous recombination deficiency (HRD)-related gene mutations was higher than that in matched tumor tissues, and these mutations tended to be associated with shorter PFS. New pathogenic variants were found at the end of treatment in all seven patients, including BRCA2, VHL, RAD50, RB1, BRIP1, ATM, FANCA, and PIK3CA mutations. In conclusion, TP53 and PIK3CA mutations, as well as a higher ctDNA fraction, were associated with worse PFS with trastuzumab and cytotoxic chemotherapy. The enrichment of HRD-related gene mutations and newly detected variants in ctDNA may be related to resistance to treatment.

Development of a scintillator-based optical soft x-ray (OSXR) diagnostic system for KSTAR tokamak

We have developed a new scintillator-based optical soft x-ray (OSXR) diagnostic system for KSTAR. By utilizing fiber optic faceplates, mm-size lens arrays, and fiber bundles, we have successfully constructed a novel optical system for scintillator-based soft x-ray detection to overcome the limited vacuum-port conditions in KSTAR. P47 (Y2SiO5), which has a fast rise (∼7 ns) and decay (∼100 ns) time sufficient for detecting plasma instabilities observed in the kHz-MHz spectral range, was selected as the scintillator material for the KSTAR OSXR system. Scintillation toward each detection channel is collected by the lens arrays coupled to optical fiber cores, which are connected to the photodetector system. Initial results obtained during the 2022 KSTAR experimental campaign support the validity of the OSXR data through the consistency of OSXR measurement results with other diagnostics. We also observe that the OSXR system can capture magnetohydrodynamic activities, such as sawtooth oscillations, and provide valuable information for disruption mitigation studies using shattered pellet injection.

Integrative modeling of tumor genomes and epigenomes for enhanced cancer diagnosis by cell-free DNA

Multi-cancer early detection remains a key challenge in cell-free DNA (cfDNA)-based liquid biopsy. Here, we perform cfDNA whole-genome sequencing to generate two test datasets covering 2125 patient samples of 9 cancer types and 1241 normal control samples, and also a reference dataset for background variant filtering based on 20,529 low-depth healthy samples. An external cfDNA dataset consisting of 208 cancer and 214 normal control samples is used for additional evaluation. Accuracy for cancer detection and tissue-of-origin localization is achieved using our algorithm, which incorporates cancer type-specific profiles of mutation distribution and chromatin organization in tumor tissues as model references. Our integrative model detects early-stage cancers, including those of pancreatic origin, with high sensitivity that is comparable to that of late-stage detection. Model interpretation reveals the contribution of cancer type-specific genomic and epigenomic features. Our methodologies may lay the groundwork for accurate cfDNA-based cancer diagnosis, especially at early stages.

Evaluation of PSMA target diagnostic PET tracers for therapeutic monitoring of [177Lu]ludotadipep of prostate cancer: Screening of PSMA target efficiency and biodistribution using [18F]DCFPyL and [68Ga]PSMA-11

We have compared the similarity of the in vivo distribution of the prostate-specific membrane antigen (PSMA)-targeted positron emission tomography (PET) imaging agents [¹⁸F]DCFPyL, [⁶⁸Ga]galdotadipep, and [⁶⁸Ga]PSMA-11. This study is designed for a further selection of a PSMA-targeted PET imaging agent for the therapeutic evaluation of [¹⁷⁷Lu]ludotadipep, our previously developed prostate-specific membrane antigen (PSMA)-targeted prostate cancer therapeutic radiopharmaceutical. In vitro cell uptake was performed to evaluate the affinity to PSMA using PSMA + PC3-PIP, and PSMA- PC3-flu was used for the study. MicroPET/CT 60 min dynamic imaging and biodistribution were performed at 1, 2, and 4 h after injection. Autoradiography and immunohistochemistry were performed to evaluate the PSMA + tumor target efficiency. In the microPET/CT image, [⁶⁸Ga]PSMA-11 showed the highest uptake in the kidney among all three compounds. [¹⁸F]DCFPyL and [⁶⁸Ga]PSMA-11 showed similar patterns of in vivo biodistribution and high tumor targeting efficiency, similar to those of[⁶⁸Ga]galdotadipep. All three agents showed high uptake in tumor tissue on autoradiography, and PSMA expression was confirmed by immunohistochemistry. Thus, [¹⁸F]DCFPyL or [⁶⁸Ga]PSMA-11 can be used as a PET imaging agent to monitor [¹⁷⁷Lu]ludotadipep therapy in prostate cancer patients.

Abstract 178: Establishment of patient-derived organoid of breast cancer

A patient-derived organoid (PDO) is an in vitro three-dimensional model which shows similar features in phenotypic and genetic aspects with primary tissue from patients. PDOs are useful for preclinical studies including drug sensitivity tests of tumors from individual patients as well as development of novel targeted agents. Collectively, PDOs are recently introduced as an emerging platform for personalized medicine. We obtained a total of 100 surgical specimens from 100 patients with breast cancer at the Yonsei Cancer Center, Severance Hospital, Seoul, Korea. One of the tissue specimens was acquired from a breast cancer patient-derived xenograft model. We dissociated the tissues and isolated breast cancer primary tumor cells from the samples, and then the cells were cultured in basement membrane-like matrix in 3D manner with growth medium with supplements. We defined successful establishment of PDOs as continuous growth after 3 passaging. Among all 100 cases, 32 cases failed to culture or passage, however, 41 cases were successfully cultured over 3 passages. In addition, the remaining 27 cases are still in progress of establishment. Success rate of PDO was 68% (68/100). Subtypes of primary tumors of the PDO were 33.8% (23/68) of luminal A, 26.5% (18/68) of luminal B, 26.5% (18/68) of triple-negative, 5.9% (4/68) of triple-positive and 7.4% (5/68) of HER2-enriched. Success rates of each subtype were 69.7% (23/33) of luminal A, 72.0% (18/25) of luminal B, 66.7% (18/27) of triple-negative, 66.7% (4/6) of triple-positive and 55.6% (5/9) of HER2-enriched. Pathologic evaluation using immunohistochemistry revealed that PDOs showed similar morphologic and immunohistochemical features with primary tumors. The selective sensitivity of PARP inhibitor, olaparib, was confirmed in PDOs harboring mutant BRCA1/2 compared with BRCA1/2 wild-type PDOs. Overall, PDOs can be used as a real-time platform for drug sensitivity and screening analyses, and a robust tool for preclinical studies in breast cancer.

Citation Format: Won-Ji Ryu, Shinyoung Park, Jeong Dong Lee, Yumi Hwang, Seongyeon Jo, Kweon Tae Yong, Ja Seung Koo, Min Hwan Kim, Joo Hyuk Sohn, Hyung Seok Park. Establishment of patient-derived organoid of breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 178.

Abstract P5-14-04: Genomic characterization of hormone receptor-positive advanced breast cancer with high tumor mutational burden: fresh-frozen tissue genomic analysis from MUTATION-1 study (KCSG BR17-04)

Background The hormone receptor (HR)-positive metastatic breast cancer (MBC) patients show a diverse range of tumor mutational burden (TMB), but its biological and clinical implication has been largely unrevealed. Here we report genomic landscape of 117 HR+ MBC patients who were included in the pre-screening tissue genomic analysis of MUTATION-1 study (SABCS 2021; Abs P1-19-03) according to TMB of tumors. Patients and method The MUTATION-1 study (NCT03608865) enrolled HR-positive MBC patients who received prior ≥ 1 line of systemic therapy, and performed prescreening with whole exome sequencing (WES) and RNA-seq of fresh-frozen tissue of metastatic or recurred tumors. Patients who met upper 30% of TMB were eligible for treatment phase and received durvalumab plus tremelimumab. This study analyzed 117 prescreening tissues of MUTATION-1 study patients for mutation and transcriptomic landscape analysis. (WES, n=117; RNA-seq, n=107) Results The 117 patients showed diverse TMB (range 0~21.7 mut/Mb, median 2.0 mut/Mb) and genomic alterations. The most frequently mutated gene included PIK3CA (29.1%), TP53 (27.4%), ESR1 (23.9%), GATA3 (19.7%), and MAP3K1 (12.0%). There was no association between patient survival and TMB. We estimated single base substitution (SBS) mutational signature of patients with SigMA algorithm. The patients were classified according to their dominant mutational signatures: APOBEC (25.6%), HRD (41.0%), clockwise (28.2%), SBS8, and SBS17. The APOBEC patients showed higher TMB (median 3.47 mut/Mb) and higher mutation prevalence in PIK3CA (63.3% vs. 29.1%), ARID1A (16.7% vs. 6.0%), and NF1 (16.7% vs. 6.8%) compared with other patients. The high TMB positively correlated with time from MBC diagnosis to biopsy. Tumors with TMB ≥ 5 mut/Mb were exclusively found in patients diagnosed as MBC ≥ 36 months before the timing of biopsy. In the matched RNA-seq analysis, TMB was higher in luminal B and HER2-enriched intrinsic subtype patients than basal or luminal A subtype. The high TMB (≥ 3.16 mut/Mb, cutoff used for treatment phase patient selection) patients showed upregulation of G2/M checkpoint, MYC, E2F1, and MTORC1 signature compared to low TMB patients. In the tumor microenvironment analysis by CIBESORT, PIK3CA mutant patients showed lower score of cytotoxic T cell than others. Conclusions The high TMB in HR+ breast cancer was associated with longer time duration from MBC diagnosis to biopsy, high APOBEC signature, and cell cycle/MYC signature gene upregulation. Further therapeutic targeting of high TMB patients is warranted based on their genomic and immunologic characteristics.

Citation Format: Min Hwan Kim, Yohan Yang, Eunyoung Kim, Yong Wha Moon, Gun Min Kim, Seul-Gi Kim, Yee Soo Chae, Jieun Lee, Jae Ho Jeong, Kyung-Hun Lee, Han Jo Kim, Joo Young Jung, Su-Jin Koh, Kyoung Eun Lee, Hee-Jun Kim, Kyong Hwa Park, Seungtaek Lim, Yeon Hee Park, Sangwoo Kim, Joo Hyuk Sohn. Genomic characterization of hormone receptor-positive advanced breast cancer with high tumor mutational burden: fresh-frozen tissue genomic analysis from MUTATION-1 study (KCSG BR17-04) [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 P5-14-04.

A multi-institutional, single-arm, phase II trial of neoadjuvant modified-FOLFIRINOX for resectable pancreatic ductal adenocarcinoma

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Background: Various peri-operative treatments have been tested to increase the survival of localized PDAC. Even with superior survival among various disease extent of PDAC, resectable PDAC still shows poor outcomes with surgery followed by adjuvant chemotherapy. We report the result of a multi-institutional phase II trial of modified-FOLFIRINOX as neoadjuvant treatment for resectable PDAC. Methods: Treatment naïve pts with histologically confirmed resectable PDAC were enrolled. Resectability was confirmed by both CT and MRI according to NCCN resectability criteria (no arterial tumor contact to celiac axis, SMA or CHA; no tumor contact with SMV or PV or ≤180° contact without vein contour irregularity) in multidisciplinary team meeting. Patients received oxaliplatin 85mg/m2 D1 + leucovorin 400mg/m2 D1 + irinotecan 150mg/m2 D1 + 5-FU 2,000mg/m2 46h continuous infusion, every other week for 6 cycles (12 weeks). Response assessments were performed every 6 weeks using the RECIST criteria version 1.1. Baseline MRI, PET-CT scan, and pre-surgery MRI after 6 cycles were mandatory. The primary endpoint was R0 resection rate. Secondary endpoints included survivals, ORR, safety, resection rate, and correlative biomarker exploration. (NCT05066802). Results: Total of 27 pts were enrolled between May 2020 and Feb 2022. Among total 27 pts, 24 pts underwent curative aim surgery after neoadjuvant treatment (resection rate 88.9%), and 23 pts showed R0 resection (23/27=85.2%), meeting the primary endpoint. Among 27 pts, 19 pts (70.4%) completed the neoadjuvant treatment per protocol. The reasons for neoadjuvant treatment discontinuation included progression of the disease (n=3, 11.1%) and pts withdrawal (n=5, 18.5%). Among 19 patients who underwent surgery per protocol, only one patient was R1 resected (R0 resection rate=94.7%). As of Sep 1, 2022 (median follow-up duration = 15.2 months) 6 pts recurred after surgery (6/19=31.6%). Median recur-free survival was 18.7 months (95%CI 13.6-NR) and median OS was not reached (95%CI 17.6-NR) for the per protocol treated pts. Treatment-related AE (≥G3) occurred in 10 pts (37.0%) including 7 (25.9%) with neutropenia G3-4. Conclusions: Three months of neoadjuvant mFOLFIRINOX was feasible and tolerable for resectable PDAC. Larger randomized trial is needed to validate the impact of neoadjuvant chemotherapy for resectable pancreatic cancer and to find subgroup of pts who would get benefit most from the neoadjuvant treatment. Post hoc genomic analyses with paired pre-neoadjuvant treatment and surgical tissues are ongoing. Clinical trial information: NCT05066802 .

Trastuzumab plus FOLFOX for HER2-positive biliary tract cancer refractory to gemcitabine and cisplatin: a multi-institutional phase 2 trial of the Korean Cancer Study Group (KCSG-HB19-14)

BACKGROUND

HER2 overexpression or amplification, which is present in 15% of all cases of biliary tract cancer, has been identified as a druggable molecular target by genomic profiling. In the phase 3 ABC-06 trial, the folinic acid, fluorouracil, and oxaliplatin (FOLFOX) regimen showed a survival benefit compared with active symptom control as second-line therapy for biliary tract cancer. We aimed to evaluate the clinical activity of FOLFOX plus anti-HER2 antibody trastuzumab as a second-line or third-line treatment for HER2-positive biliary tract cancer.

METHODS

This study was an investigator-initiated, open-label, non-randomised, single-arm, multi institutional, phase 2 trial in participants aged 19 years or older with HER2-positive (defined as immunohistochemistry 3+ or immunohistochemistry 2+ and in-situ hybridisation positive or ERBB2 gene copy number ≥6·0 by next-generation sequencing) biliary tract cancer (intrahepatic cholangiocarcinoma, extrahepatic cholangiocarcinoma, and gallbladder cancer) who progressed on chemotherapy containing gemcitabine and cisplatin (with one or two previous chemotherapy lines permitted). In cycle one, patients received intravenous trastuzumab-pkrb at 6 mg/kg on day 1, and FOLFOX (consisting of intravenous oxaliplatin [85 mg/m²], intravenous leucovorin [200 mg/m²], and fluorouracil [400 mg/m² bolus] all on day 1, and fluorouracil [2400 mg/m² infusion] on days 1-2. In cycle two onwards, participants were administered intravenous trastuzumab-pkrb at 4 mg/kg and FOLFOX, every 2 weeks, until unacceptable toxic effects or disease progression. The primary endpoint of the study was objective response rate based on RECIST version 1.1, assessed in the participants who completed at least one study cycle. The response rate threshold for a positive objective response rate was 25%. This trial is registered with ClinicalTrials.gov (NCT04722133) and is ongoing.

FINDINGS

34 participants were enrolled between June 26, 2020, and Sept 1, 2021. At the time of data cutoff on May 1, 2022, median follow-up was 13·0 months (IQR 11·0-16·9), with three participants remaining on treatment. Ten patients had a partial response and 17 had stable disease; the overall response rate was 29·4% (95% CI 16·7-46·3) and the disease control rate was 79·4% (95% CI 62·9-89·9). Median progression-free survival was 5·1 months (95% CI 3·6-6·7); median overall survival was 10·7 (95%CI 7·9-not reached). The most common treatment-related grade 3 or 4 adverse events were neutropenia (ten [29%] participants with grade 3 and nine [26%] with grade 4), grade 3 anaemia (five [15%] participants), and grade 3 peripheral sensory neuropathy (four [12%] participants). There were no treatment-related cardiac toxic effects or deaths. The overall health assessment (EuroQoL-VAS) score did not change significantly throughout the treatment. Sensory and motor neuropathy symptoms as assessed by the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Chemotherapy-Induced Peripheral Neuropathy twenty-item scale questionnaire did not change significantly over time.

INTERPRETATION

For HER2-positive biliary tract cancer, second-line or third-line trastuzumab biosimilar plus FOLFOX exhibited promising activity with acceptable toxicity, warranting further investigation.

FUNDING

Boryung Pharmaceutical, Celltrion, National Research Foundation of Korea, National R&D Program for Cancer Control through the National Cancer Center, Yonsei University College of Medicine.

On-treatment derived neutrophil-to-lymphocyte ratio and survival with palbociclib and endocrine treatment: analysis of a multicenter retrospective cohort and the PALOMA-2/3 study with immune correlates

BACKGROUND

Cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors have been established as a standard treatment for hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer (ABC); however, predictive biomarkers with translational relevance have not yet been elucidated.

METHODS

Data from postmenopausal women who received the CDK4/6 inhibitor palbociclib and letrozole for HR-positive, HER2-negative ABC from tertiary referral centers were analyzed (N = 221; exploratory cohort). Pre- and on-treatment neutrophil-to-lymphocyte ratio (NLR) and derived NLR (dNLR; neutrophil/[leukocyte-neutrophil]) were correlated with survival outcomes. Data from the PALOMA-2 (NCT01740427) and PALOMA-3 studies (NCT01942135) involving patients treated with endocrine treatment with or without palbociclib were also analyzed (validation cohort). Prospectively enrolled patients (N = 20) were subjected to immunophenotyping with circulating immune cells to explore the biological implications of immune cell dynamics.

RESULTS

In the exploratory cohort, palbociclib administration significantly reduced leukocyte, neutrophil, and lymphocyte counts on day 1 of cycle 2. Although the baseline dNLR was not significantly associated with progression-free survival (PFS), higher on-treatment dNLRs were associated with worse PFS (hazard ratio = 3.337, P < 0.001). In the PALOMA-2 validation cohort, higher on-treatment dNLRs were associated with inferior PFS in patients treated with palbociclib and letrozole (hazard ratio = 1.498, P = 0.009), and reduction in the dNLR after treatment was predictive of a survival benefit (hazard ratio = 1.555, P = 0.026). On-treatment dNLRs were also predictive of PFS following palbociclib and fulvestrant treatment in the PALOMA-3 validation cohort. Using flow cytometry analysis, we found that the CDK4/6 inhibitor prevented T cell exhaustion and diminished myeloid-derived suppressor cell frequency.

CONCLUSIONS

On-treatment dNLR significantly predicted PFS in patients with HR-positive, HER2-negative ABC receiving palbociclib and endocrine treatment. Additionally, we observed putative systemic immune responses elicited by palbociclib, suggesting immunologic changes upon CDK4/6 inhibitor treatment.

Relation of Flatfoot Severity with Flexibility and Isometric Strength of the Foot and Trunk Extensors in Children

BACKGROUND

Flatfoot is a deformity in which the foot is flattened due to a decrease in or loss of the medial longitudinal arch.

STATEMENT OF THE PROBLEM

Few studies have investigated the relationship between the severity of flat feet, trunk strength, and joint flexibility.

PURPOSE

The aim of this study is to investigate the relationship between the severity of flatfoot and joint flexibility and foot and trunk strength in children with flexible flatfoot.

METHODS

This study included 16 children (boys, 12; girls, 4; age, 4~8 years) with flexible flatfeet. We examined the resting calcaneal stance position angle (RCSPA) and foot posture index (FPI) scores for clinical severity and radiographic parameters, such as calcaneal pitch angle, talometatarsal angle (TMA), and talocalcaneal angle (TCA). Muscle thicknesses of the tibialis posterior (TP), peroneus longus (PL), and L1 multifidus were measured by sonography. Isometric contraction of ankle inversion, eversion in a seating position, and lumbar extension at a prone position were induced using a handheld dynamometer to measure the maximum muscle strength for each muscle. Beighton's scoring system was used to assess joint flexibility by evaluating the hyperextension of the joint for each category when performing stretching motion. Spearman's rank correlation coefficient for nonparametric data was used.

RESULTS

The FPI showed a moderately negative correlation with the muscle thickness of TP (r = -0.558, p = 0.009) and L1 multifidus (r = -0.527, p = 0.012), and the strength of the ankle inverter (r = -0.580 p = 0.005) and lumbar extensor (r = -0.436 p = 0.043). RCSPA showed a moderately positive correlation with TCA (r = 0.510, p = 0.006). Beighton's score showed no significant correlation with all parameters.

CONCLUSION

In children with flatfoot, FPI reflected the clinical severity; thus, the more severe the symptoms, the weaker the ankle inverter and lumbar extensor.

Dilute lattice doping of 64Cu into 2D-nanoplates: its impact on radio-labeling efficiency and stability for target selective PET imaging

A quintinite nanoplate (⁶⁴Cu-QT-NP) isomorphically substituted with ⁶⁴Cu, as the positron emission tomography (PET) imaging material, was prepared via two-step processes. A ⁶⁴Cu labeling efficiency of 99% was realized, for the first time, by immobilizing the ⁶⁴Cu radioisotope directly in the octahedral site of the 2-dimensional (2D) quintinite lattice. Furthermore, the ⁶⁴Cu labeling stability of ⁶⁴Cu-QT-NPs was also achieved to be more than ∼99% in various solutions such as saline, phosphate-buffered saline (PBS), and other biological media (mouse and human serums). In an in vivo xenograft mouse model, the passive targeting behavior of ⁶⁴Cu-QT-NPs into tumor tissue based on the enhanced permeability and retention (EPR) effect was also demonstrated by parenteral administration, and successfully visualized using a PET scanner. For enhancing the tumor tissue selectivity, bovine serum albumin (BSA) was coated on ⁶⁴Cu-QT-NPs to form ⁶⁴Cu-QT-NPs/BSA, resulting in better colloidal stability and longer blood circulation time, which was eventually evidenced by the 2-fold higher tumor uptake rate when intravenousely injected in an animal model. It is, therefore, concluded that the present ⁶⁴Cu-QT-NPs/BSA with tumor tissue selectivity could be an advanced nano-device for radio-imaging and diagnosis as well.

Effect of early hysterectomy on a risk of incident cardiovascular disease in women: a nationwide population-based cohort study

Aim

Women who inevitably underwent surgical hysterectomy before natural menopause may have an earlier increase in hematocrit and storage iron than women who continue menstruation, thereby increasing the risk of cardiovascular disease (CVD) early. We aimed to evaluate the association of women with hysterectomy vs. without hysterectomy before their 50s with the risk of incident CVD.

Methods

This was a retrospective-cohort study, 135,575 women aged 40 to 50 years in 2011–2014 were extracted from the Korean Health Insurance Review and Assessment Service data and after propensity score matching, 55,539 pairs were included in hysterectomy and non-hysterectomy group respectively. The primary endpoint was major adverse cardiac and cerebrovascular events (MACCE), a composite of cardiovascular death, myocardial infarction (MI), stroke, and coronary artery revascularization.

Results

After adjustment for confounding factors, hysterectomy group had an increased risk of MACCE compared with non-hysterectomy group (hazard ratio [HR], 1.25; 95% confidence interval [CI], 1.09–1.44). Regarding individual outcomes, cardiovascular death, MI, and coronary revascularization were comparable between the groups, whereas, the risk of stroke was significantly higher in hysterectomy group than non-hysterectomy group (HR, 1.31; 95% CI, 1.12–1.53). Even after excluding women who underwent oophorectomy, hysterectomy group had a higher risk of MACCE than non-hysterectomy group (HR, 1.24; 95% CI 1.06–1.44).

Conclusions

Early surgical menopause due to hysterectomy, not hormonal menopause, was associated with an increased risk for a composite of CVD, especially stroke. This suggest that the role of “uterus” as well as sex hormones may be important for the sharp increase in the risk of CVD in women after menopause.

Funding Acknowledgement

Type of funding sources: None.

Blunted atrial reverse remodeling a year after catheter ablation for atrial fibrillation and their long-term rhythm outcome

Background

Although active rhythm control by atrial fibrillation (AF) catheter ablation (AFCA) reduces left atrial (LA) dimension, blunted atrial reverse remodeling can be observed in patients with significant atrial myopathy. We explored the characteristics and long-term outcomes of AF patients who showed blunted atrial reverse remodeling despite no AF recurrence within a year after AFCA.

Methods

Among a total of 2,756 patients with AFCA, we included 1,685 patients (74.8% male, 60.2±10.1 years old, 54.5% paroxysmal AF) who underwent both baseline and 1-year follow-up echocardiogram, baseline LA&gt;40mm, and did not recur within a year. We divided them into tertile groups (T1–T3) based on one-year percent change of LA dimension after propensity matching for age, sex, AF type, and baseline LA dimension. We also investigated the patients' genetic characteristics with blunted LA reverse remodeling (T1) using a genome-wide association study (GWAS).

Results

Patients with blunted LA reverse remodeling (T1, n=424) were independently associated with body mass index (OR 1.082 [1.010–1.160], p=0.025), LA peak pressure (OR 1.010 [1.002–1.019], p=0.019), LA wall thickness (OR 0.448 [0.252–0.789], p=0.006), LA voltage (OR 0.651 [0.463–0.907], p=0.012), and pericardial fat volume (OR 1.004 [1.001–1.008], p=0.014). Throughout 65.9±37.4 months of follow-up, the incidence of AF recurrence a year after the procedure was significantly higher in the T1 group than in T2 or T3 groups (Log-rank p&lt;0.001). Among 894 patients with GWAS, ATXN1, XPO7, KRR1_PHLDA1, ZFHX3, and their polygenic risk score were associated with blunted LA reverse remodeling.

Conclusions

Patients with blunted LA reverse remodeling after AFCA were independently associated with low LA voltage, thin wall thickness, high LA pressure, and fat volume, and have a genetic background. Long-term clinical recurrence a year after AFCA was higher in this patient group with suspicious atrial myopathy.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Ministry of Health and WelfareNational Research Foundation of Korea

Phase II study to investigate the efficacy of trastuzumab biosimilar (Herzuma®) plus treatment of physician's choice (TPC) in patients with heavily pretreated HER-2+ metastatic breast cancer (KCSG BR 18–14/KM10B)

We investigated the efficacy and safety of a trastuzumab biosimilar, Herzuma®, in combination with treatment of physician's choice (TPC) in patients with HER2+ metastatic breast cancer (MBC) who had failed at least two HER2 directed chemotherapies.

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Treatment of HER2-positive breast cancer is rapidly evolving with the development of new agents. However, treatment options are still limited after progression with proven anti-HER2 therapies.

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The combination of chemotherapy with a trastuzumab biosimilar, Herzuma®, was effective and safe in patients with heavily pre-treated HER2+ MBC.

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Duration of response to previous anti-HER2 therapy, PIK3CA and ERBB2 mutations were associated with clinical efficacies of trastuzumab biosimilar plus chemotherapy.

Response Rate and Safety of a Neoadjuvant Pertuzumab, Atezolizumab, Docetaxel, and Trastuzumab Regimen for Patients With ERBB2-Positive Stage II/III Breast Cancer: The Neo-PATH Phase 2 Nonrandomized Clinical Trial

Importance

Addition of immune checkpoint inhibitors to anti-ERBB2 treatment has shown synergistic efficacy in preclinical studies and is thus worth investigating as a neoadjuvant treatment to maximize efficacy and to minimize toxic effects.

Objective

To determine if neoadjuvant atezolizumab, docetaxel, trastuzumab, and pertuzumab therapy for ERBB2-positive early breast cancer warrants continuation to the next phase.

Design, Setting, and Participants

This nonrandomized, open label, multicenter, phase 2 trial was conducted by the Korean Cancer Study Group and enrolled patients across 6 institutions in Korea from May 2019 to May 2020. Eligible patients were diagnosed with ERBB2-positive breast cancer (primary tumor size >2 cm or pathologically confirmed lymph node-positive cancer, without distant metastases) with a clinical stage of II or III.

Interventions

Patients received 6 cycles of neoadjuvant pertuzumab (840 mg at first cycle, 420 mg during subsequent cycles), atezolizumab (1200 mg), docetaxel (75 mg/m2), and trastuzumab (600 mg via subcutaneous injection) every 3 weeks, followed by surgery. Patients with pathologic complete response (pCR) received 12 cycles of adjuvant atezolizumab, trastuzumab, and pertuzumab every 3 weeks after surgery. Patients without pCR were treated with 14 cycles of atezolizumab, 1200 mg, plus trastuzumab emtansine, 3.6 mg/kg, every 3 weeks.

Main Outcomes and Measures

The primary end point was pCR rate, which was defined as the absence of invasive cancer cells in the primary tumor and regional lymph nodes (ypT0/isN0). Secondary end points included clinical objective response rate, 3-year event-free survival rate according to pCR achievement, disease-free survival, overall survival, toxic effects, and quality-of-life outcomes.

Results

A total of 67 women (median [range] age, 52 [33-74] years) were enrolled. Hormone receptor expression was positive in 32 (48%) patients. Curative surgery was performed in 65 patients because 2 patients showed disease progression during neoadjuvant treatment and their tumors became unresectable. The overall pCR rate was 61% (41 of 67 patients). The pCR rate was higher in hormone receptor-negative disease vs hormone receptor-positive disease (27 of 35 [77%] patients vs 14 of 32 [44%] patients) and in programmed cell death 1-positive expression vs programmed cell death 1-negative expression (13 of 13 [100%] patients vs 28 of 53 [53%] patients). Grade 3 and 4 neutropenia and febrile neutropenia occurred in 8 (12%) patients and 5 (8%) patients, respectively. Grade 3 and 4 immune-related adverse events occurred in only 4 patients (grade 3 skin rash, encephalitis, hepatitis, and fever). No treatment-related death occurred during the neoadjuvant phase.

Conclusions and Relevance

In this nonrandomized clinical trial, treatment with the neoadjuvant atezolizumab, docetaxel, trastuzumab, and pertuzumab regimen in patients with stage II or III ERBB2-positive breast cancer appears to have had an acceptable pCR rate and modest toxic effects. Further investigation of this immunotherapy combination in ERBB2-positive early breast cancer is warranted.

Trial Registration

ClinicalTrials.gov Identifier: NCT03881878.

Anaemia and pathologic complete response rate according to carboplatin dose in HER2+ breast cancer treated with neoadjuvant TCHP

Grade 3/4 anaemia, which is mainly induced by carboplatin, frequently occurs in patients treated with neoadjuvant docetaxel/carboplatin/trastuzumab/pertuzumab (TCHP). However, dose reduction of carboplatin may raise concerns about the oncological outcome. This study investigated the pathologic complete response (pCR) rate, occurrence of grade 3/4 anaemia, and transfusion rate according to carboplatin dose in patients treated with neoadjuvant TCHP. We retrospectively analysed 294 patients treated with neoadjuvant TCHP between April 2015 and December 2020. Case matching was performed using propensity score matching. Among patients treated with neoadjuvant TCHP, carboplatin area under the plasma concentration-time curve 6 (AUC6) was used in 234 patients (79.6%) and upfront carboplatin AUC5 was used in 60 patients (20.4%). No significant difference in pCR rate was found between the two groups (AUC6: 70.9%, AUC5: 80.0%). In both oestrogen receptor-positive (ER+) and ER- patients, no significant differences were observed between the AUC6 and AUC5 groups (ER+: 54.3% vs. 50.0%, ER-: 81.7% vs. 86.0%). The case-matched cohort showed consistent findings. The AUC5 group had lower frequencies of grade 3/4 anaemia (18.3% vs. 34.2%) and transfusion events (10.0% vs. 21.8%) than the AUC6 group. Compared with AUC5, carboplatin at AUC6 would associate with a 2.7-fold increased risk of grade 3 or 4 chemotherapy-induced anaemia. Carboplatin AUC5 has comparable cytotoxic effects to carboplatin AUC6 in patients with HER2+ breast cancer treated with six cycles of neoadjuvant TCHP, with fewer complications associated with clinically meaningful anaemia. AUC5 may be the optimal carboplatin dose to reduce TCHP-induced anaemia in patients with HER2+ breast cancer treated with TCHP.

Abstract 6371: Deep learning algorithm for multi-cancer detection and classification using cf-WGS

Purpose: Several cell-free DNA (cf-DNA) features, such as genome-wide coverage, fragment size, and fragment end motif frequency, have shown their potentials for cancer detection. In this study, we developed two independent models, GC (gross chromatin), and FEMS (fragment end motif frequency and size). Each model uses images generated from genome-wide normalized sequencing coverage and cf-DNA fragment end motif frequencies according to the different cf-DNA size profiles. Then we integrated them into a single ensemble model to improve cancer detection and multi-cancer type classification accuracy.

Methods: Low depth cf-WGS data was generated from 1,396 patients (stage I: 14.9%, stage II: 35.6%, stage III: 24.9%, stage IV: 24.2%, unknown: 0.4%) with breast (n=702), liver (n=213), esophageal (n=155), ovarian (n=151), pancreatic (n=85), lung (n=53), head and neck (n=16), biliary tract (n=15), and colon cancer (n=6) and 417 healthy individuals. Samples were randomly split into training, validation, and test set stratifying cancer type and stages. Cancer types with a small number of samples (&lt;20) were excluded for multi-cancer type classification. Each model was trained using a convolutional neural network, then integrated into a single ensemble model by averaging the predicted probabilities calculated from each model.

Results: For cancer detection, the ensemble model achieved sensitivities of 85.2% [95% confidence interval (CI): 71.8% to 94.5%], 74.9% (CI: 68.0% to 88.0%), 73.2% (CI: 66.7% to 85.9%) at a specificity of 95%, 98% and 99% and the AUC value of 0.97(CI: 0.95-0.99) in the test dataset. By the cancer stages, sensitivity was 62.8% (CI: 48.8% to 83.7%) in stage I, 66.3% (CI: 57.7% to 82.7%) in stage II, 85.9% (CI: 77.5% to 94.4%) in stage III, and 76.1% (CI: 63.4% to 87.3%) in stage IV at 99% specificity. For multi-cancer classification, the overall accuracy of 85.1% (CI: 80.4% to 89.3%) was achieved including 6 cancer types.

Conclusions: Highly sensitive and accurate deep learning model for cancer detection and multi-cancer classification was generated by combining different types of cf-DNA features. This result provides the opportunity for general population multi-cancer screening using various cf-DNA features.

Citation Format: Tae-Rim Lee, Jin Mo Ahn, Joo Hyuk Sohn, Sook Ryun Park, Min Hwan Kim, Gun Min Kim, Ki-Byung Song, Eunsung Jun, Dongryul Oh, Jeong-Won Lee, Joseph J Noh, Young Sik Park, Sun-Young Kong, Sang Myung Woo, Bo Hyun Kim, Eui Kyu Chie, Hyun-Cheol Kang, Youn Jin Choi, Ki-Won Song, Jeong-Sik Byeon, Junnam Lee, Dasom Kim, Chang-Seok Ki, Eunhae Cho. Deep learning algorithm for multi-cancer detection and classification using cf-WGS [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6371.

Abstract 6082: TP53-GATA3 mutation status predisposes luminal-to-basal subtype conversion in advanced breast cancer patients

Background The molecular selective pressure on anti-tumor therapy drives lineage plasticity in several cancer types to develop drug resistance. The subtype conversion from luminal to triple-negative breast cancer (TNBC) subtype fuels endocrine resistance and disease aggressiveness. In this study, we analyzed mechanisms of luminal to basal subtype conversion by clinical sample sequencing and molecular study.

Method We performed whole-exome sequencing (WES) of primary and metastatic tumor tissues from breast cancer patients with luminal to basal [from HR(+)/HER2(-) to TNBC] subtype conversion (experimental, n=14) and patients with subtype maintenance (luminal to luminal subtype, control, n= 36) after adjuvant endocrine therapy. For RNA-sequencing, the subset of patients (experimental, n=14; control n=7) was further analyzed. The differences in genetic alterations and gene expression were compared between two patient groups to identify genetic predictors of subtype conversion. We also manipulated genetic factors related to subtype conversion in MCF7 cells to identify molecular signaling to drive lineage change.

Results In WES analysis, TP53 mutation was more frequently observed in luminal breast cancer patients with subtype conversion to TNBC [60% (12 out of 20 tissues in experimental group) versus 20% (8/40 tissues in control group)]. Whereas, GATA3 mutations were only observed in patients of subtype maintenance (0% versus 20%), and the mRNA level of GATA3 was downregulated after luminal-to-basal conversion. The TP53 and GATA3 mutations were both observed in the matched primary and metastatic tissues, suggesting that these mutations predisposed subtype conversion but were not acquired during the adjuvant endocrine therapy. In expression signature analysis, the patients with subtype conversion showed the upregulation of KRAS signaling and the suppression of GATA3 signature in metastatic TNBC tumors compared to primary luminal tumors. In primary tumors, RELA and MYC signatures were only upregulated in tumors that underwent subtype conversion later. We found ESR1 expression was decreased by knockdown of TP53 and GATA3 in MCF7 cells. The knockdown of TP53 and GATA3 also induced basal marker expressions, cytokeratin 5 and 14, in MCF7 cells. ESR1 expression and luminal markers were also decreased by GATA3 suppression in T47D harboring TP53 mutation.

Conclusion In luminal-type breast cancer, the subtype conversion is the one of the major obstacles for their treatment and preventing recurrence. We found the genetic alterations of TP53 mutation was the key predisposing factor of luminal to basal subtype conversion, whereas GATA3 mutation is a protecting factor for subtype conversion in luminal breast cancers. Thus, targeting TP53-GATA3 axis would be a potential therapeutic strategy to overcome endocrine resistance and block the subtype conversion in luminal type breast cancer.

Citation Format: Won-Ji Ryu, Hyun-Yi Kim, Tae Yeong Kim, Yeona Choi, Hyun Ju Hahn, Seul-Gi Kim, Gun Min Kim, Ja Seung Koo, Seung Il Kim, Joohyuk Sohn, Min Hwan Kim. TP53-GATA3 mutation status predisposes luminal-to-basal subtype conversion in advanced breast cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6082.

Data collection framework for electronic medical record-based real-world data to evaluate the effectiveness and safety of cancer drugs: a nationwide real-world study of the Korean Cancer Study Group (KCSG)

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Background: Electronic medical record (EMRs) have the highest reliability among real-world data (RWD), but controlling for biases that may affect study outcomes remains challenging. This study aimed to establish a data collection framework of EMR-based RWD to evaluate the effectiveness and safety of cancer drug by conducting a nationwide real-world study based on Korean Cancer Study Group. Methods: We selected ramucirumab plus paclitaxel (RAM/PTX) and trastuzumab-emtansine (T-DM1), which are currently used to treat advanced gastric cancer and breast cancer, respectively, under the national health insurance, and systematically collected EMR-based RWD at relevant institutions in South Korea. Investigator reliability was evaluated using the concordance rate between the recommended input value for representative fictional cases and the input value of each investigator. Reliability of collected data was evaluated twice during study period at three institutions randomly selected by statisticians using the concordance rate between the previously collected data and data collected by the independent investigator. Two statisticians independently analyzed the same data and compared their results to evaluate the data analysis reproducibility. Results: Between the starting date of medical insurance coverage and December 2018, a total of 1,063 patients at 56 institutions in the RAM/PTX cohort and 824 patients at 60 institutions in the T-DM1 cohort were included. Mean investigator reliability for major case report form (CRF) variables in the RAM/PTX and T-DM1 cohorts was 73.5% and 71.9%, respectively. The most common CRF variable with a concordance rate < 70% between the recommended input value and the input value of each investigator was related to adverse events in both cohorts. Mean reliability of collected data for major CRF variables in the RAM/PTX and T-DM1 cohort was 90.0% for both cohorts in the first analysis, and 88.0% and 89.0% in the second analysis, respectively. The input data discrepancies between previously collected data and data collected by independent investigators were due to the input for variables that were not categorized and were in textual form in the EMRs (performance status, reason for discontinuation, adverse events, best response or disease progression, and survival data). Conclusions: This real-world study provides a framework that ensures relevance and reliability of EMR-based RWD for evaluating the effectiveness and safety of cancer drugs. There is a need for a digital healthcare system in which EMR-based RWD can be structured, defined, formatted, and exchanged with an integrated computer system and converted into scientific data. Clinical trial information: NCT04192734 and NCT04202328.

A phase IB/II study of nivolumab in combination with eribulin in HER2-negative metastatic breast cancer (KCSG BR18-16)

1098

Background: Combining immune checkpoint inhibitors with chemotherapy has become a promising therapeutic strategy in metastatic breast cancer. Eribulin is a potent microtubule inhibitor and modulates the immune microenvironment of tumor cells. Therefore, combining eribulin to nivolumab may synergize antitumor efficacy in metastatic breast cancer. Methods: Adult patients with histologically confirmed recurrent/metastatic HER2- breast cancer were enrolled prospectively from 10 academic hospitals in Korea (ClinicalTrials.gov Identifier: NCT04061863). Key eligibility criteria included prior treatment with taxanes and/or anthracyclines, ≥1 measurable disease, and ≤2 prior cytotoxic chemotherapies in the metastatic setting. Patients received nivolumab 200 mg intravenously (IV) on day 1 plus eribulin 1.4 mg/m2 IV on day 1 and 8 of every 3 weeks until disease progression or intolerable toxicity. The dose level was determined from safety profile of three patients in run-in phase. The primary endpoint was investigator-assessed progression-free survival (PFS) rate at 6 months. Secondary endpoints included investigator-assessed objective response rate (ORR) per RECIST v1.1, disease control rate (DCR), overall survival (OS), and toxicity profile of the combination treatment. The association between PD-L1 expression by SP142 Ab and efficacy was analyzed. Results: From August 2019 to June 2021, 90 patients (HR+HER2- 45 pts/TNBC 45 pts), with a median age of 51 (range 31–71), were enrolled in the study. With a median study follow-up time of 16.3 months, 68 (75.6%) patients experienced progressive disease. PFS rate at 6-months was 49.6% and 24.1% in patients with HR+HER2- and TNBC group, respectively. Median PFS was 5.6 months (95% CI: 4.3-6.8) and 3.0 months (95% CI: 1.3-4.7) for HR+HER2- and TNBC group, respectively. ORRs were 53.3% (CR:0, PR: 24) for HR+HER2- and 21.8% (CR1, PR: 12) for TNBC. Patients with PD-L1+ tumors (PD-L1 expression ≥ 1% on TC or IC) had similar ORR compared to PD-L1- tumors (ORR 50% vs. 53.8% in HR+HER2-, 30.8% vs. 29.0% in TNBC). The most common grade 3/4 adverse event was neutropenia (15/90, 16.7%), and the most common immune-related adverse events were grade 1/2 hypothyroidism (19/90, 21.1%) and grade 1/2 pruritus (16/90, 17.8%). Five patients had discontinued study treatment due to immune-related adverse events (3 pneumonitis, 1 hepatitis, 1 skin rash). Conclusions: In this parallel phase II clinical trial, the addition of nivolumab to eribulin showed promising efficacy and tolerable safety profile in previously treated HER2- MBC. Further survival and exploratory analyses to find predictive markers will be followed. Clinical trial information: NCT04061863. [Table: see text]

Safety and efficacy of YBL-006, an anti-PD-1 monoclonal antibody in advanced solid tumors: A phase I study

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Background: YBL-006 is a fully human anti-programmed death-1 (PD-1) antibody under evaluating its safety and efficacy in phase I clinical trial. We have reported interim analysis of dose escalation cohort which showed a tolerable safety profile. Here, we present the updated clinical activity of YBL-006 in dose escalation and expansion cohorts. Methods: Dose escalation (0.5, 2, 5, 10 mg/kg) and dose expansion (flat doses of 200 mg every 2 weeks [Q2W] and 300 mg every 3 weeks [Q3W]) cohorts explored the safety, pharmacokinetics (PK) and objective response rate (ORR) in the patients with advanced solid tumors who failed or were ineligible to the standard of care. Adverse events (AEs) were graded using the CTCAE v5. ORR was assessed using the RECIST (v1.1). Lunit SCOPE IO, an H&E analysis tool, was applied as an exploratory biomarker, and samples with “Immune inflamed phenotype” were defined as those with high intratumoral TIL density in ≥ 20% of the tumor microenvironment. The cut-off date for analysis was Jan 4th, 2022. Results: A total of 67 patients (safety set) with advanced solid tumors were enrolled in the study. Median follow-up duration of the safety set was 1.6 months (range 0.2-16.8). There was no dose-limiting toxicity during dose escalation phase. Most frequent AEs were grade 1 or 2; fatigue (19.4%), pruritus (10.4%), and fever (7.5%), and two hypothyroidism (3.0%), one pneumonitis (1.5%), and one cytokine-releasing syndrome (1.5%) were observed. One subject experienced grade 3 diarrhea in the safety set. PK study showed that half-life was 8.0 days, and mean Cmax and AUC0-inf were 4.15 x 104 ng/ml and 1.12 x 107 ng/ml*h for 200 mg dose, and 6.26 x 104 ng/ml and 1.53 x 107 ng/ml*h for 300 mg dose, respectively. A total of 52 patients were evaluable for efficacy. ORR was 15.4%, including 1 complete response (penile squamous cell carcinoma [SqCC]), and 7 partial responses (two gastric adenocarcinomas, anal SqCC, paranasal sinus SqCC, nasopharyngeal carcinoma, neuroendocrine carcinoma, and thyroid Hurthle cell carcinoma). Durable responses were seen in 2 patients for over 12 months. Median duration of response was 4.9 weeks (range 1-65). Among efficacy set, 32 samples were available for Lunit SCOPE IO. ORR was significantly higher in inflamed immune phenotype compared to non-inflamed samples (62.5% vs 8.3% p = 0.005). Conclusions: Interim analysis of phase I trial of YBL-006 shows a tolerable safety profile and clinical activity. Notable anti-tumor efficacy was observed in inflamed immune phenotype. Clinical trial information: NCT04450901.

Trastuzumab plus FOLFOX for gemcitabine/cisplatin refractory HER2-positive biliary tract cancer: A multi-institutional phase II trial of the Korean Cancer Study Group (KCSG-HB19-14)

4096

Background: HER2 over-expression/amplification, which accounts for roughly 15% of total biliary tract cancer (BTC) patients, has been identified as a druggable molecular target by recent genomic profilings, Trastuzumab is a humanized monoclonal antibody against HER2 that has been shown to be effective in patients with HER2-positive breast and gastric cancer, but it has not been studied prospectively in HER2-positive BTC. In the phase III ABC-06 trial, the FOLFOX regimen showed survival benefit as a second-line therapy of BTC. We report the result of a multi-institutional phase II trial of Trastuzumab plus modified-FOLFOX as a second- or third-line treatment for HER2-positive BTC (KCSG-HB19-14; NCT04722133). Methods: HER2-positive (defined as IHC3+ or IHC2+/ISH+ or ERBB2 gene copy number ≥6.0 by NGS) BTC (intrahepatic cholangiocarcinoma, extrahepatic cholangiocarcinoma, gallbladder cancer and ampulla of vater cancer) patients who progressed on gemcitabine/cisplatin containing chemotherapy (1 or 2 previous chemotherapy lines permitted) were enrolled. Pts received trastuzumab 4mg/kg (after 6mg/kg load) D1, oxaliplatin 85mg/m2 D1, Leucovorin 200mg/m2 D1, 5-FU 400mg/m2 bolus D1, and 5-FU 2400mg/m2 infusion D1-2 every 2 weeks until unacceptable toxicities or disease progression. The primary endpoint was ORR per RECIST v1.1. Secondary endpoints included PFS, DCR, OS, safety, QOL and correlative biomarker exploration. Results: Total of 34 pts were treated with median follow up of 9.9 months, and 6 pts remained on treatment (treatment duration range: 1.0 to 14.7 months). The primary endpoint was met, with 29.4% (95%CI 15.1-47.5) ORR (PR n = 10), and 79.4% DCR. Median PFS was 5.1 months (95%CI 3.6-6.7) and median OS was not reached (95%CI 7.1-NR; 12-months OS rate 50.6%, 95%CI 29.3-63.6). Pts with HER2 IHC3+ (n = 23, 67.6%) showed tendency for better PFS compared to pts with HER2 IHC 2+/ISH+ (median 5.5 vs 4.9 months, HR 0.52, 95%CI 0.23-1.16). Pts with HER2 3+ tumor cell proportion ≥30% (n = 10) by an artificial intelligence-powered automated HER2 IHC analyzer (Lunit SCOPE HER2) showed significantly better PFS compared to pts without (median 6.67 vs 4.87 months, HR 0.33 95%CI 0.13-0.88). Targeted-panel sequencings were done with tumor tissues from 32 pts and tissue HER2-amplification by NGS did not confer better survival. Treatment-related AE (≥G3) occurred in 29 pts (85.3%) including 19 pts (55.9%) with neutropenia G3-4 and 4 pts (11.8%) with peripheral neuropathy G3-4. No pt showed cardiac AE nor treatment-related study discontinuation. Conclusions: For HER2-positive BTC, 2nd- or 3rd-line trastuzumab plus FOLFOX exhibited a promising efficacy with acceptable toxicity, warranting further investigations. Targeted NGS analyses with ctDNAs from pre-treatment and post-progression liquid biopsies are ongoing. Clinical trial information: NCT04722133.

Copy number aberration burden on circulating tumor DNA predicts recurrence risk after neoadjuvant chemotherapy in patients with triple-negative breast cancer: Post-hoc analysis of phase III PEARLY trial

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Background: Our previous study reported prognostic significance of copy number aberration (CNA) burden on low-pass whole genome sequencing (LP-WGS) based circulating tumor DNA (ctDNA) analysis in metastatic breast cancer patients. Here, we report the prognostic value of ctDNA CNA burden measured before neoadjuvant chemotherapy in stage II-III triple-negative breast cancer (TNBC) patients enrolled in phase III PEARLY trial (NCT02441933, BIG Supporter Study BIG 19-01, KCSG BR15-01). Methods: The PEARLY trial was performed as a randomized, open-label, multicenter, phase III study to test the efficacy and safety of adding carboplatin to (neo)adjuvant chemotherapy in patients with stage II-III TNBC. Patients were randomized in a 1:1 ratio to receive 4 cycles of AC followed by the taxane or taxane plus carboplatin (AUC 5, tri-weekly 4 cycles) as neoadjuvant or adjuvant therapy. This post-hoc baseline ctDNA analysis (before neoadjuvant chemotherapy) included only the neoadjuvant patient cohort with available baseline ctDNA results (n = 465, median follow-up 16.8 months), while it was blinded for randomization information (carboplatin or not). We used "I-score" method to estimate CNA burden of ctDNA by LP-WGS to be matched with disease-free survival (DFS) after primary surgery. Results: The baseline ctDNA I-score level was positively associated with clinical T and N stage, while baseline I-score was not different between patients with pathologic complete response (pCR) and non-pCR. We listed 465 patients in the order in which they underwent primary surgery, and then alternated patients to be assigned to exploratory cohort (n =232) and validation cohort (n = 233). The DFS was significantly shorter in high I-score (I-score ≥ 7.81) patients compared with low I-score (I-score < 7.81) patients in exploratory cohort. The high I-score independently predicted poor DFS adjusted for clinical T stage, clinical N stage, and pCR status (hazard ratio [HR] 3.88, p = 0.003). In the validation cohort, high I-score was validated to be associated poorer DFS, and multivariate Cox analysis validated the independent prognostic impact of I-score on DFS (HR 2.04 , p = 0.050). The high baseline I-score patients showed shorter DFS both in pCR-positive and pCR-negative patients. The 12-month DFS rate for pCR (+)/Low I-score patients was 98%, whereas that of pCR(-)/High I-score patients was 61.3 % in the validation cohort. Conclusions: The baseline ctDNA CNA burden on LP-WGS before neoadjuvant chemotherapy robustly predicts recurrence risk in stage II-III TNBC patients. The ctDNA I-score showed prognostic value independently from pCR status, suggesting ctDNA I-score can serve as a useful clinical determinant for escalating or de-escalating (neo)adjuvant strategy in TNBC patients. Clinical trial information: NCT02441933.

Molecular Characterization of BRCA1 c.5339T>C Missense Mutation in DNA Damage Response of Triple-Negative Breast Cancer

BRCA1 L1780P BRCT domain mutation has been recognized as a pathogenic mutation in patients with breast cancer. However, the molecular significance of this mutation has not yet been studied in triple-negative breast cancer (TNBC) cells in vitro. We established MDA-MB 231, HCC1937, and HCC1395 TNBC cell lines expressing BRCA1 L1780P mutant. BRCA1 L1780P mutant TNBC cells showed increased migration and invasion capacity, as well as increased sensitivity to olaparib and carboplatin compared to BRCA1 wild-type cells. BRCA1 L1780P mutant TNBC cells showed decreased RAD51 expression and reduced nuclear RAD51 foci formation following carboplatin and olaparib treatment. The molecular interaction between p-ATM and BRCA1 was abrogated following introduction of BRCA1 L1780P mutant plasmid in TNBC cells, suggesting that the BRCA1 L1780P mutation disrupts the p-ATM-BRCA1 protein-protein interaction. We established an olaparib-resistant BRCA1 L1780P mutant TNBC cell line by chronic drug treatment. Olaparib-resistant cell lines showed upregulation of RAD51 expression upon olaparib treatment, and reduction in RAD51 expression in olaparib-resistant cells restored olaparib sensitivity. Collectively, these results suggest that the BRCA1 L1780P mutation impairs RAD51 recruitment by disrupting p-ATM-BRCA1 interaction, which is a crucial molecular factor in homologous recombination and olaparib sensitivity. Further therapeutic targeting of RAD51 in BRCA1 L1780P mutant breast cancer is warranted.

Trastuzumab Deruxtecan versus Trastuzumab Emtansine for Breast Cancer

BACKGROUND

Trastuzumab emtansine is the current standard treatment for patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer whose disease progresses after treatment with a combination of anti-HER2 antibodies and a taxane.

METHODS

We conducted a phase 3, multicenter, open-label, randomized trial to compare the efficacy and safety of trastuzumab deruxtecan (a HER2 antibody-drug conjugate) with those of trastuzumab emtansine in patients with HER2-positive metastatic breast cancer previously treated with trastuzumab and a taxane. The primary end point was progression-free survival (as determined by blinded independent central review); secondary end points included overall survival, objective response, and safety.

RESULTS

Among 524 randomly assigned patients, the percentage of those who were alive without disease progression at 12 months was 75.8% (95% confidence interval [CI], 69.8 to 80.7) with trastuzumab deruxtecan and 34.1% (95% CI, 27.7 to 40.5) with trastuzumab emtansine (hazard ratio for progression or death from any cause, 0.28; 95% CI, 0.22 to 0.37; P<0.001). The percentage of patients who were alive at 12 months was 94.1% (95% CI, 90.3 to 96.4) with trastuzumab deruxtecan and 85.9% (95% CI, 80.9 to 89.7) with trastuzumab emtansine (hazard ratio for death, 0.55; 95% CI, 0.36 to 0.86; prespecified significance boundary not reached). An overall response (a complete or partial response) occurred in 79.7% (95% CI, 74.3 to 84.4) of the patients who received trastuzumab deruxtecan and in 34.2% (95% CI, 28.5 to 40.3) of those who received trastuzumab emtansine. The incidence of drug-related adverse events of any grade was 98.1% with trastuzumab deruxtecan and 86.6% with trastuzumab emtansine, and the incidence of drug-related adverse events of grade 3 or 4 was 45.1% and 39.8%, respectively. Adjudicated drug-related interstitial lung disease or pneumonitis occurred in 10.5% of the patients in the trastuzumab deruxtecan group and in 1.9% of those in the trastuzumab emtansine group; none of these events were of grade 4 or 5.

CONCLUSIONS

Among patients with HER2-positive metastatic breast cancer previously treated with trastuzumab and a taxane, the risk of disease progression or death was lower among those who received trastuzumab deruxtecan than among those who received trastuzumab emtansine. Treatment with trastuzumab deruxtecan was associated with interstitial lung disease and pneumonitis. (Funded by Daiichi Sankyo and AstraZeneca; DESTINY-Breast03 ClinicalTrials.gov number, NCT03529110.).

Abstract P2-12-13: Pathologic complete response rate according to the carboplatin dose in patients with non-metastatic HER2+ breast cancer treated with neoadjuvant docetaxel/carboplatin/trastuzumab/pertuzumab (TCHP)

Purpose In the patients treated with neoadjuvant docetaxel/carboplatin/trastuzumab/pertuzumab (TCHP) regimen, grade 3-4 anemia occurs frequently during the treatment course. Anemia develops mainly by cytotoxic drug including carboplatin. By contrast, dose reduction of carboplatin could raise concerns about the oncologic outcome. We compared the pathologic complete response (pCR) rate and grade 3-4 anemia/transfusion rate according to the dose of carboplatin among the patients undergoing neoadjuvant TCHP. Method We retrospectively analyzed 294 patients who treated with neoadjuvant TCHP between Apr 1, 2015 and Dec 31, 2020. Clinicopathological features were collected by electronic medical record review. Hemoglobin levels were measured at baseline, before each cycle of chemotherapy, and after the chemotherapy completion. Multivariable binary logistic regression analysis was performed to identify predictive factors for grade 3-4 anemia and transfusion event. Result In a total of 294 patients, neoadjuvant TCHP with carboplatin AUC6 were initiated in 234 (79.6%, 234 of 294), whereas upfront carboplatin AUC5 were concurrently administered in 60 (20.4%, 60 of 294). There was no statistical difference in the pCR rate between the two groups (70.9% in the AUC6, 80.0% in the AUC5; p=0.159). In the both ER+ and ER-, there were no significant differences between the AUC6 and AUC5 (54.3% and 50.0% in the ER+; 81.7% and 86.0% in the ER-). Tumor and nodal stage were not different between the two groups. The AUC5 group had less grade 3-4 anemia (18.3%, 11 of 60 vs 34.2%, 80 of 234) and transfusion event (10.0%, 6 of 60 vs 21.8%, 51 of 234) compared with the AUC6 group. Multivariable analysis demonstrated that baseline hemoglobin level under 12g/dL and ≥2g/dL hemoglobin down after first chemotherapy are independent risk factors for grade3-4 anemia or blood transfusion before surgery. Conclusion The pCR rate was not different according to the initial carboplatin dose in the HER2+ breast cancer treated with neoadjuvant TCHP. We suggest that the dose of carboplatin could be optimized as AUC5 to reduce TCHP-induced anemia and transfusion rate among Asian HER2-positive breast cancer patients treated with TCHP. Baseline low hemoglobin level under 12 g/dL or rapid hemoglobin down after first cycle are risk factors for TCHP-induced anemia.

Table 1.The pathologic complete response (pCR) rate, distribution of anemia grade and transfusion rate according to AUCVariablesAUC6AUC5TotalP-valueOverall (N=294)0.159pCR166 (70.9%)48 (80.0%)214 (72.8%)Non-pCR68 (29.1%)12 (20.0%)80 (27.2%)Total234 (100.0%)60 (100.0%)294 (100.0%)ER-positive (N=102)0.793pCR50 (54.3%)5 (50.0%)55 (53.9%)Non-pCR42 (45.7%)5 (50.0%)47 (16.1%)Total92 (100.0%)10 (100.0%)102 (100.0%)ER-negative (N=192)0.487pCR116 (81.7%)43 (86.0%)159 (82.8%)Non-pCR26 (18.3%)7 (14.0%)33 (17.2%)Total142 (100.0%)50 (100.0%)192 (100.0%)Anemia grade (N=294)0.0181 or 2154 (65.8%)49 (81.7%)203 (69.0%)3 or 480 (34.2%)11 (18.3%)91 (31.0%)Transfusion (N=294)0.039No183 (78.2%)54 (90.0%)237 (80.6%)Yes51 (21.8%)6 (10.0%)57 (19.4%)

Citation Format: Jung Hwan Ji, Soong June Bae, Seul-Gi Kim, Min Hwan Kim, Gun-Min Kim, Joohyuk Sohn, Jee Hung Kim, Sung Gwe Ahn, Joon Jeong. Pathologic complete response rate according to the carboplatin dose in patients with non-metastatic HER2+ breast cancer treated with neoadjuvant docetaxel/carboplatin/trastuzumab/pertuzumab (TCHP) [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 P2-12-13.

Abstract P1-19-03: Phase II trial of durvalumab and tremelimumab in the hormone receptor-positive metastatic breast cancer with high tumor mutational burden selected by whole exome sequencing: Korean cancer study group trial (KCSG BR17-04)

Background: Hormone-receptor (HR) positive breast cancer is the main subtype of breast cancer. Although overall survival of HR-positive metastatic breast cancer (MBC) patients has improved by various therapies including endocrine therapies, CDK4/6 inhibitors, and cytotoxic chemotherapy, it is still considered incurable. Immune checkpoint inhibitors have rarely been clinically tested in HR-positive breast cancer, despite proving anti-cancer activity in early and metastatic triple-negative breast cancer in various trials. We evaluated efficacy and safety of combined durvalumab and tremelimumab in the HR-positive MBC, which was enriched with high tumor mutational burden (TMB). Methods: HR-positive MBC patients who received prior 1 or more lines of therapy in metastatic setting were prescreened with whole exome sequencing (WES) using metastatic or recurred tumor biopsies. Criterion of high TMB was defined as upper 30%. In the beginning, the criterion of high TMB was 2.1 mutations per Mb, based on the retrospective WES database in Yonsei Cancer Center and this criterion was recalculated every 30 cases. Patients who met upper 30% of TMB were treated with combined durvalumab (1500mg every 4 weeks upto 13 doses) and tremelimumab (75mg every 4 weeks upto 4 doses). Response was evaluated every 2 cycles using RECIST 1.1 and toxicity was evaluated using NCI-CTCAE 4.03. Tumor-infiltrating lymphocyte (TIL) and PD-L1 expression were also analyzed to investigate a correlation with TMB. Results: Biopsies of recurrent or metastatic tumors were taken from a total of 119 patients for WES assay. A median turn-around-time of TMB data was 30.0 days (range, 16~67). Of these 119 patients, a median number of nonsynonymous mutations was 2.0 per Mb (range, 0~21.7) with upper 30% criterion of 3.1. High TMB showed a trend toward old age (P=0.074) and single positivity of estrogen receptor (ER) or progesterone receptor (PR) compared to positivity of both ER and PR (P=0.055). TMB was positively correlated with TILs (r=0.289, P=0.005). Thirty patients with high TMB received study treatment with a median 2 cycles (range, 1~13). A median prior lines of therapies in metastatic setting was 4 (range, 1~9). The objective response and clinical benefit rates were 6.3% (2 PRs of 30) and 20% (2 PRs plus 4 SDs of 30). There was one treatment-related mortality due to pneumonitis. Immune-related adverse events included endocrinopathy (n=3; hypothyroidism in 2, hyperthyroidism in 1), enteritis (n=2), skin rash (n=2), pneumonitis (n=1), and so on. Biomarker analyses are underway. Conclusions: WES-based TMB using metastatic tumor biopsy was a feasible platform to prescreen HR-positive MBC patients. Combined durvalumab and tremelimumab showed a modest activity and good tolerability in heavily treated, HR-positive MBC with high TMB.

Citation Format: Yong Wha Moon, Eunyoung Kim, Min Hwan Kim, Gun Min Kim, Seul-Gi Kim, YeeSoo Chae, Jieun Lee, Jae Ho Jeong, Kyung-Hun Lee, Han Jo Kim, Joo Young Jung, Su-Jin Koh, Kyoung Eun Lee, Hee-Jun Kim, Kyong Hwa Park, Seungtaek Lim, Yeon Hee Park, Tae Hoen Kim, Sewha Kim, Yohan Yang, Sangwoo Kim, Joohyuk Sohn. Phase II trial of durvalumab and tremelimumab in the hormone receptor-positive metastatic breast cancer with high tumor mutational burden selected by whole exome sequencing: Korean cancer study group trial (KCSG BR17-04) [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 P1-19-03.

Abstract PD6-07: Whole genome sequencing-based circulating tumor DNA profiling of metastatic breast cancer patients for molecular characterization and therapy response prediction

Background Previous studies proposed low-pass whole genome sequencing (LP-WGS)-based circulating tumor DNA (ctDNA) analysis as a versatile tool for genomic profiling and therapeutic monitoring of cancer patients. Here we demonstrate LP-WGS ctDNA genomic profiles and its clinical significance in metastatic breast cancer patients. Patients and methods This prospective exploratory study enrolled 207 treatment-naïve metastatic breast cancer patients from Feb 2017 to September 2020 in Yonsei Cancer Center. The median follow-up duration of patients was 35 months. The baseline (n=207) and post-progression (n=48) plasma samples were prospectively collected on first-line systemic therapy, and LP-WGS was employed for ctDNA somatic copy number alteration (CNA) analysis. The CNA burden of ctDNA was scored by “I-score” method, which was developed to measure genome-wide chromosomal instabilities, to be matched with therapy response. The unsupervised molecular clustering and homologous recombination deficiency (HRD) estimation by shallowHRD algorithm were performed using locus-level CNA profiles with 1 mega base pair resolution. Results The baseline I-score ctDNA CNA burden was highest in triple-negative breast cancer (TNBC) patients among subtypes, and the patients were dichotomized by median I-score level 5.54 (range 2.55 to 12.98). The high baseline ctDNA I-score was independently associated with poor overall survival (hazard ratio [HR] = 3.98, p &lt; 0.001) with adjustment of tumor subtype, visceral metastasis, and disease status (de novo stage IV versus recurrent). The progression-free survival (PFS) on endocrine plus CDK4/6 inhibitors (HR = 2.75, p = 0.005), anti-HER2 therapy (HR = 2.52, p = 0.032), and cytotoxic chemotherapy (HR = 2.33, p = 0.012) was also shorter in high baseline I-score patients than in low I-score patients. The locus-level CNA profile was analyzed in high I-score patients (n=103), and the patients were classified into five molecular clusters with distinct overall survival by unsupervised k-means clustering of CNA profile: basal-like, EGFR-high basal-like, CCND1-high, luminal, and HER2-enriched clusters. Patients with BCL6 (p = 0.009) and PIK3CA amplification (p &lt; 0.001) on baseline ctDNA showed significantly shorter PFS on CDK4/6 inhibitor treatment. The matched baseline and post-progression ctDNA analysis found emergence of FGFR1 amplification and MYC amplification after CDK4/6 inhibitor treatment (n=1, each). The ctDNA shallowHRD score was highest in TNBC patients among subtypes, and TNBC patients with high shallowHRD score (≥10) showed high response rate on (58.3% versus 28.6%) on platinum-based chemotherapy. Conclusion LP WGS-based ctDNA analysis provides a robust tool for non-invasive genomic clustering, therapy response prediction, and HRD estimation in metastatic breast cancer patients.

All patients (n=207)Low I-score (n=104)High I-score (n=103)N (%)N (%)N (%)Age, Median (Interquartile range)54 (46-62)53 (47-60)54(44-62)GenderFemale205 (99)102 (98.1)103Male2 (1)2 (1.9)0SubtypeHR+ HER2-106 (51.2)61 (58.7)45 (43.7)HR- HER2+33 (15.9)14 (13.5)19 (18.4)HR+ HER2+22 (10.6)11 (10.6)11 (10.7)HR- HER2- (TNBC)46 (22.2)18 (17.3)28 (27.2)Disease statusDe novo stage IV74 (35.7)31 (29.8)43 (41.7)Recurrent133 (64.3)73 (70.2)60 (58.3)Primary therapyEndocrine + CDK 4/6 inhibitor97 (46.9)55 (52.9)42 (40.8)Anti-HER2 based therapy54 (26.1)24 (23.1)30 (29.1)Chemotherapy45 (21.7)16 (15.4)29 (28.2)Others11 (5.3)9 (8.7)2 (1.9)Visceral metastasisYes142 (68.6)60 (57.7)82 (79.6)No65 (31.4)44 (42.3)21 (20.4)Metastasis SitesLung89 (43)43 (41.3)46 (44.7)Brain19 (9.2)4 (3.8)15 (14.6)Liver59 (28.5)13 (12.5)46 (44.7)Bone120 (58)47 (45.2)73 (70.9)Lymph node90 (43.7)32 (30.8)58 (56.9)Pleura33 (15.9)17 (16.3)16 (15.5)

Citation Format: Joohyuk Sohn, Min Hwan Kim, Jin Mo Ahn, Won-Ji Ryu, Seul-Gi Kim, Jee Hung Kim, Tae Yeong Kim, Hyun Ju Han, Jee Ye Kim, Hyung Seok Park, Seho Park, Byeong Woo Park, Seung Il Kim, Eun Hae Cho, Gun Min Kim. Whole genome sequencing-based circulating tumor DNA profiling of metastatic breast cancer patients for molecular characterization and therapy response prediction [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 PD6-07.

Abstract P5-16-03: Phase II study of trastuzumab biosimilar (Herzuma®) plus gedatolisib in patients with HER-2 positive metastatic breast cancer who progressed after 2 or more HER-2 directed chemotherapy (BR 18-13, KM-10A): Interim analysis

Background: Prognosis of patients with HER-2 positive metastatic breast cancer (MBC) has been revolutionized with the development of monoclonal antibodies targeting HER-2 and antibody-drug conjugate, but resistance to anti-HER-2 therapy is inevitable ultimately. PI3K-AKT-mTOR pathway aberration is known to be one of the key resistance mechanisms. BR18-13(KM-10A) study is a phase 2 clinical trial evaluating efficacy and safety of Herzuma® (trastuzumab biosimilar) plus Gedatolisib (dual PI3K/mTORC inhibitor) in patients with HER-2 positive MBC who progressed after multiple lines of therapy. Methods: Patients with HER-2 positive MBC with known PIK3CA pathologic mutation or amplification whose disease progressed after more than 2 HER-2 directed therapy were enrolled in the study. They received Herzuma® (8mg/kg IV for 1st cycle loading dose, and then 6mg/kg IV every 3 weeks) plus Gedatolisib (180mg on D1, 8, 15 of every 21 days). We evaluated efficacy of the combination treatment as interim analysis. The data cutoff of this interim analysis was June 8, 2021. Results: 17 patients were enrolled and followed for a median of 6.2 months. At data cutoff, 17 patients were eligible for response assessment. All patients were confirmed to have pathologic PIK3CA aberrations: 9 kinase mutations (H1047X), 5 helical mutations (E545X), 2 other point mutations, and 1 amplification. Overall, response rate was 64.7% and disease control rate was 82.4%. Eleven patients reached partial response (PR) as their best response, three were stable disease (SD), and three had progressive disease (PD). Two patients who have reached PR remain on investigational treatment until the data cutoff point, and the longest one is on treatment for 12.0 months. The median progression-free survival assessed in data cutoff time was 5.9 months. One patient ended treatment due to CNS disease progression, but her visceral metastatic lesions were decreased with experimental treatment. No fatal adverse events related to trial medication were reported. Conclusion: In this phase 2 study, Trastuzumab biosimilar plus Gedatolisib presented 64.7% of response rate with manageable toxicity in patients with HER-2 positive MBC with PIK3CA mutation. Clinical trial information: NCT03698383 Acknowledgement: this research was supported by a grant of the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health &Welfare, Republic of Korea (Grant number: HI17C2206).

Citation Format: Ju Won Kim, Hee Kyung Ahn, Jong Gwon Choi, Yee Soo Chae, Gyeong-Won Lee, Keon Uk Park, Eunmi Lee, Sung Hoon Sim, Jee Hyun Kim, Yeon Hee Park, Miso Kim, Jin Hyun Park, Jeong Eun Kim, Han Jo Kim, Mi Sun Ahn, So Yeon Oh, Min Hwan Kim, Su-Jin Koh, Kyoung Eun Lee, Myoung Joo Kang, Jae Ho Byun, Joo Young Ha, Jung Hye Kwon, Joo Young Jung, Su Ee Lee, Inhae Park, Kyong Hwa Park. Phase II study of trastuzumab biosimilar (Herzuma®) plus gedatolisib in patients with HER-2 positive metastatic breast cancer who progressed after 2 or more HER-2 directed chemotherapy (BR 18-13, KM-10A): Interim analysis [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 P5-16-03.

Abstract P1-17-09: Efficacy of limited dose modifications for palbociclib-related grade 3 neutropenia in hormone receptor positive metastatic breast cancer

Background. Endocrine therapy plus CDK 4/6 inhibitors is the foremost treatment for hormone receptor (HR) positive metastatic breast cancers (mBC). Previously, we reported safety profiles of palbociclib use with grade 3 neutropenia in HR-positive mBC. Here, we investigated two cohorts’ patients who had received palbociclib with or without dose interruptions and/or reductions on afebrile grade 3 neutropenia in terms of efficacy outcomes. Patients and methods. The combined cohort of consecutive mBC patients who received palbociclib with letrozole in 1st line setting (in four major cancer centers in Republic of Korea) was reviewed. We classified patients into 4 groups: Group 1 (patients who maintained palbociclib dose on afebrile grade 3 neutropenia, representing limited dose modification scheme), Group 2 (patients who experienced any dose modification on afebrile grade 3 neutropenia, representing conventional dose modification scheme), Group 3 (patients without the event of afebrile grade 3 neutropenia), and Group 4 (patients who experienced only grade 4 neutropenia) within the first 5 cycles. The primary endpoint was PFS difference between Group 1 and Group 2, and secondary endpoints included PFS and overall survival difference in all groups, and safety profiles of each group. Results. A total of 434 eligible patients recruited from Jan 2017 to Sep 2020 were allocated into 4 groups; Group 1 (n=172, 40.1%), Group 2 (n=128, 29.5%), Group 3 (n=102, 23.5%), and Group 4 (n=30, 6.9%). The overall incidence of palbociclib dose reductions was 272 (62.7%) and dosing delay was 181 (42.2%) in all groups. The median time to first dose reduction for all eligible patients was 3 months (2-5 months) and the median time to second dose reduction was 9 months (2-30 months). At the 12th cycle of treatment, 70.5% (105/at-risk patients of 149) of Group 1 patients still remained on 125mg of palbociclib, whereas no patient was on 125mg dose level but 66.3% patients (65/at-risk patients of 98) were on 100mg in Group 2. At the median follow-up of 23.7 months (95% CI: 21.6-25.8), Group 1 patients showed significantly longer PFS than Group 2 patients (P-value = 0.036, 2-year PFS rate: 67.9% in Group 1 and 55.3% in Group 2). The OS between Group 1 and 2 was not significantly different. The favorable PFS trend of Group 1 over Group 2 was observed across all subgroups. The overall toxicity profiles were not significantly different between Group 1 and Group 2. Conclusion. Our study demonstrates that the clinical practice of limited dose modifications for palbociclib-related grade 3 neutropenia might have more therapeutic benefits than the conventional dose scheme without increasing toxicities. Permissive approach to afebrile grade 3 neutropenia and prospective clinical trials for this new dose scheme are warranted. Funding: This study was supported by a grant from Pfizer.

Citation Format: Seul-Gi Kim, Min Hwan Kim, Sejung Park, Gun Min Kim, Jee Hung Kim, Jee Ye Kim, Hyung Seok Park, Seho Park, Byeong Woo Park, Seung Il Kim, Jung Hwan Ji, Joon Jeong, Kabsoo Shin, Jieun Lee, Hyung-Don Kim, Kyung Hae Jung, Joohyuk Sohn. Efficacy of limited dose modifications for palbociclib-related grade 3 neutropenia in hormone receptor positive metastatic breast cancer [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 P1-17-09.

Abstract P2-13-14: Pattern of recurrence after pathologic complete response after neoadjuvant chemotherapy in patients with early HER2-positive breast cancer: Real-world evidence

Background The real-world risk of disease recurrence in patients with HER2-positive early breast cancer who achieved pathologic complete response (pCR) after neoadjuvant chemotherapy (NAC) and/or HER2-targeted therapy is unclear. This study aims to identify the patterns and risk factors of disease recurrence after NAC in patients with HER2-positive early breast cancer who achieved a pCR or not. Methods 930 HER2 positive early breast cancer patients who received NAC were identified in the Severance Breast Cancer Registry at the Yonsei Cancer Center and Gangnam Severance Hospital in Seoul, Republic of Korea, between 2006 and 2020. NAC included 3 regimens: only chemotherapy. (CTx), chemotherapy plus trastuzumab (CTx+H), and chemotherapy plus dual anti-HER2 therapy (TCHP). The pCR was defined as the absence of residual invasive cancer in the resected breast specimen and the axillary lymph nodes (ypT0/TisN0) after neoadjuvant systemic therapy. Recurrence of disease was defined as recurrence of ipsilateral locoregional invasive breast cancer, distant disease recurrence, or death. Results The median follow-up duration was 42.0 months (range 4-171), and median age was 51 years old (range 22-80). The rate of pCR was 52.2% (485/930). Depending on the achieved a pCR, the loco-regional recurrence rate was 4.0% (18/445) vs 1.0% (5/485), and the distant recurrence rate was 11.0% (49/445) vs 3.9% (19/445). Of the 79 patients who relapsed, 30.4% (n=24) had achieved a pCR and 69.6% (n=55) had residual disease. The 4-year recurrence risk was 6.9% for patients who achieved pCR versus 12.8% for those who did not (p&lt;0.001). Of the 24 patients who achieved pCR who relapse, 22 (91.7%) occurred within 4 years of diagnosis. Of the 55 patients who did not achieve a pCR who relapse, 48 (87.3%) occurred within 4 years of diagnosis. Among the 19 patients who developed distant recurrence who attained a PCR, the most common first recurrent sites were lung (42.1%), brain (36.8%), and distant lymph nodes (36.1%). Lung and brain metastases occurred in 87.5% and 85.7% within 3years of diagnosis. If pCR was reached, the NAC regimen or HR status did not affect the recurrence-free survival. However, clinical stages II and III at diagnosis (HR (hazard ratio) =35.3 and HR=114.5, p=0.037) were independent predictor of inferior recurrence-free survival in the pCR group. Conclusion Overall, patients who attained a pCR have a better outcome compared to those with residual disease, regardless of hormone status or type of NAC regimen. However, despite achieving pCR after NAC, patients with HER2-positive, clinical stage II/III remain at risk for disease recurrence within 4 years of diagnosis.

Citation Format: Jee Hung Kim, Jii Bum Lee, Soong Joon Bae, Sung Gwe Ahn, Joon Jeong, Min Hwan Kim, Seul-Gi Kim, Gun Min Kim, Jee Ye Kim, Hyung Seok Park, Seho Park, Byeong Woo Park, Seung Il Kim, Joohyuk Sohn. Pattern of recurrence after pathologic complete response after neoadjuvant chemotherapy in patients with early HER2-positive breast cancer: Real-world evidence [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 P2-13-14.

A multi-institutional, single-arm, phase II trial of neoadjuvant modified-FOLFIRINOX for resectable pancreatic ductal adenocarcinoma

TPS624

Background: Within the next decade, pancreatic ductal adenocarcinoma (PDAC) is expected to rise to the second leading cause of cancer-related mortality. To increase the survival, various peri-operative treatments have been tested, and adjuvant FOLFIRINOX or gemcitabine plus capecitabine is now standard of care after surgical resection for localized PDAC. Even with superior survival among various disease extent of PDAC, resectable PDAC still shows poor outcomes with surgery followed by adjuvant chemotherapy. This phase II study is investigating the role of modified-FOLFIRINOX as neoadjuvant treatment for resectable PDAC. Methods: This study is a phase II, multi-institutional, single-arm trial to evaluate the efficacy and safety of modified-FOLFIRINOX in resectable PDAC. The main inclusion criteria are histologically confirmed PDAC; resectable PDAC confirmed by both computed tomography (CT) and magnetic resonance imaging (MRI) according to NCCN guideline resectability criteria (no arterial tumor contact to celiac axis, SMA or CHA; no tumor contact with SMV or PV or ≤180° contact without vein contour irregularity); no previous treatment (surgery or chemotherapy); ECOG 0 or 1; and adequate organ function. Patients receive oxaliplatin 85 mg/m2 D1 + leucovorin 400mg/m2 D1 + irinotecan 150 mg/m2 D1 + 5-FU 2,000 mg/m2 46h continuous infusion, every other week for 6 cycles (12 weeks). Response assessments are performed every 6 weeks using the RECIST criteria version 1.1. Baseline MRI, PET-CT scan before treatment, and pre-surgery MRI after 6 cycles are mandatory. The primary endpoint was R0 resection rate. Secondary endpoints included progression-free survival, overall survival, disease-free survival, objective response rate, safety, resection rate, and correlative biomarker exploration. The study will enroll up to 27 patients and is currently recruiting at four sites in South Korea. As of September 2021, 20 patients have been enrolled. Clinical trial information: KCT0004421 (Registration ongoing for clinicaltrials.gov).

Protective effect of bisphosphonate on the cortical bone at key locations of the femur in aromatase inhibitor-associated bone loss: A three-dimensional cortical bone mapping study

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Aromatase inhibitor use was associated with cortical bone loss in the hip.

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Bisphosphonate protected hip cortical bone against aromatase inhibitor use.

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The effect was prominent at the superior femoral neck and greater trochanter.

Aromatase inhibitor treatment in breast cancer is associated with accelerated bone loss and an increased risk of fracture. Bisphosphonates (BPs) are the mainstay treatment of aromatase inhibitor-associated bone loss (AIBL), which might improve femoral bone at key locations prone to fracture. To test this hypothesis, we performed three-dimensional cortical bone mapping based on quantitative computed tomography (QCT) scans in postmenopausal women with early breast cancer who were receiving aromatase inhibitors. Data of subjects who had both baseline and at least one follow-up QCT at Severance Hospital (South Korea) between 2005 and 2015 were analyzed (BP users, n = 93; BP non-users, n = 203). After exclusion of BP users with low medication persistence (proportion of days covered: <50%), BP users and non-users were 1:1 matched (n = 54 for each group) in terms of age, lumbar spine volumetric bone mineral density (LSvBMD), femoral neck areal BMD (FNaBMD), and total hip areal BMD (THaBMD). During a median follow-up of 2.1 years, BP use attenuated bone loss in LSvBMD (+7.2% vs. −3.8%, p < 0.001), FNaBMD (+1.3% vs. −2.7%, p < 0.001), and THaBMD (-0.3% vs. −2.5%, p = 0.024). BP had a protective effect on cortical parameters of femoral bone: estimated cortical thickness (CTh) (+3.3% vs. + 0.1%, p = 0.007) and cortical mass surface density (CMSD, cortical mass per unit surface area was calculated by multiplying cortical BMD with CTh) (+3.4% vs. −0.3%, p < 0.001). CMSD increased by up to 15% at key locations such as the superior part of the femoral neck and greater trochanter. BP prevented the thinning of average CTh of the femoral neck (-1.4% vs. −6.1%, p < 0.001), particularly at the superior anterior quadrant of femoral neck (absolute difference: +12.8% point vs. non-users). Compared to BP non-users, BP users had improved cross-sectional moment of inertia (+4.4% vs. −0.7%, p = 0.001) and less increase in buckling ratio (+1.3% vs. + 7.5%, p < 0.001). In summary, BP use prevented cortical bone deficits observed in AIBL at key locations of the proximal femur.

Data collection framework for electronic medical record-based real-world data to evaluate the effectiveness and safety of cancer drugs: a nationwide real-world study of the Korean Cancer Study Group

Background:

Electronic medical records (EMRs) have the highest value among real-world data (RWD). The aim of the present study was to propose a data collection framework of EMR-based RWD to evaluate the effectiveness and safety of cancer drugs by conducting a nationwide real-world study based on the Korean Cancer Study Group.

Methods:

We considered all patients who received ramucirumab plus paclitaxel (RAM/PTX) for gastric cancer and trastuzumab emtansine (T-DM1) for breast cancer at relevant institutions in South Korea. Standard operating procedures for systematic data collection were prospectively developed. Investigator reliability was evaluated using the concordance rate between the recommended input value for representative fictional cases and the input value of each investigator. Reliability of collected data was evaluated twice during the study period at three institutions randomly selected using the concordance rate between the previously collected data and data collected by an independent investigator. The reliability results of the investigators and collected data were used for revision of the electronic data capture system and site training.

Results:

Between the starting date of medical insurance coverage and December 2018, a total of 1063 patients at 56 institutions in the RAM/PTX cohort and 824 patients at 60 institutions in the T-DM1 cohort were included. Mean investigator reliability in the RAM/PTX and T-DM1 cohorts was 73.5% and 71.9%, respectively. Mean reliability of collected data in the RAM/PTX and T-DM1 cohort was 90.0% for both cohorts in the first analysis and 89.0% and 84.0% in the second analysis, respectively. Mean missing values of the RAM/PTX and T-DM1 cohorts at the time of simulation of fictional cases and final data analysis decreased from 20.7% to 0.46% and from 18.5% to 0.76%, respectively.

Conclusion:

This real-world study provides a framework that ensures relevance and reliability of EMR-based RWD for evaluating the effectiveness and safety of cancer drugs.