D-Y Oh

Phase II study and biomarker analysis of cetuximab combined with modified FOLFOX6 in advanced gastric cancer.

This prospective study was conducted with the Korean Cancer Study Group to evaluate the efficacy and safety of cetuximab combined with modified FOLFOX6 (mFOLFOX6) as first-line treatment in recurrent or metastatic gastric cancer and to identify potential predictive biomarkers. Patients received cetuximab 400 mg m−2 at week 1 and 250 mg m−2 weekly thereafter until disease progression. Oxaliplatin (100 mg m−2) and leucovorin (100 mg m−2) were administered as a 2-h infusion followed by a 46-h continuous infusion of 5-fluorouracil (2400 mg m−2) every 2 weeks for a maximum of 12 cycles. Biomarkers potentially associated with efficacy were analysed. Among 38 evaluable patients, confirmed response rate (RR) was 50.0% (95% CI 34.1–65.9). Median time-to-progression (TTP) was 5.5 months (95% CI 4.5–6.5) and overall survival (OS) 9.9 months. Eleven patients having tumour EGFR expression by immunohistochemistry with low serum EGF and TGF-α levels showed a 100% RR compared to 37.0% in the remaining 27 patients (P<0.001). Moreover, ligand level increased when disease progressed in seven out of eight patients with EGFR expression and low baseline ligand level. No patient exhibited EGFR amplification or K-ras mutations. Gastric cancer patients with EGFR expression and low ligand levels had better outcomes with cetuximab/mFOLFOX6 treatment.

High tumour islet macrophage infiltration correlates with improved patient survival but not with EGFR mutations, gene copy number or protein expression in resected non-small cell lung cancer.

The purpose of this study was to investigate the prognostic value of tumour-associated macrophages with a focus on micro-anatomical localisation and determine whether molecular changes of the epidermal growth factor receptor (EGFR) are related to macrophage infiltration in resected non-small cell lung cancer (NSCLC). One hundred and forty-four patients were included in this study. Immunohistochemistry was used to identify CD68+ macrophages in the tumour islet and surrounding stroma. Epidermal growth factor receptor mutations were studied by direct sequencing. The EGFR gene copy number and protein expression were analysed by fluorescence in situ hybridisation and immunohistochemistry. Patients with a high tumour islet macrophage density survived longer than did the patient with a low tumour islet macrophage density (5-year overall survival rate was 63.9 vs 38.9%, P=0.0002). A multivariate Cox proportional hazard analysis revealed that the tumour islet macrophage count was an independent prognostic factor for survival (hazard ratio 0.471, 95% confidence interval 0.300–0.740). However, EGFR mutations, gene copy number, and protein expression were not related to the macrophage infiltration. In conclusion, tumour islet macrophage infiltration was identified as a strong favourable independent prognostic marker for survival but not correlated with the molecular changes of the EGFR in patients with resected NSCLC.

Age and HER2 expression status affect MRI accuracy in predicting residual tumor extent after neo-adjuvant systemic treatment

BACKGROUND Although recent studies suggest high accuracy of breast magnetic resonance imaging (MRI) in predicting residual tumor extent after neo-adjuvant systemic treatment (NST), its use is still controversial. In this study, we aimed to identify predictive factors of MRI accuracy after NST to determine a subgroup of patients in whom the use of MRI provides best additional benefit. MATERIALS AND METHODS Clinicopathologic and molecular profiles of breast cancer patients were investigated and their relationships with MRI accuracy were analyzed. RESULTS From January 2006 to February 2008, 195 patients received NST and preoperative MRI. In overall, MRI predicted residual tumor extent with higher accuracy than ultrasonography. Triple-negative (TN) tumors showed highest correlation between MRI-measured and pathologic tumor size (r = 0.781) when compared with other subtypes. Multivariate analysis showed age and HER2 expression status as independent factors predicting MRI accuracy. When patients were classified based on their age and HER2 status, relatively older patients (>45) with HER2-negative tumors showed highest MRI accuracy. This finding was further validated using an independent cohort of 63 consecutive patients. CONCLUSION Age and HER2 status independently affected MRI accuracy after NST. This observation may guide more tailored approach in using MRI in breast cancer patients undergoing NST.

Immune modulation of pathologic complete response after neoadjuvant HER2-directed therapies in the NeoSphere trial

BACKGROUND To investigate in the NeoSphere trial the contribution of the immune system to pathologic complete response in the breast (pCRB) after neoadjuvant docetaxel with trastuzumab (TH), pertuzumab (TP), or both (THP), or monoclonal antibodies alone (HP). PATIENTS AND METHODS Immune gene mRNA expression (n = 350, 83.8%), lymphocyte infiltration (TIL, n = 243, 58.3%), and PDL1 by immunohistochemistry (n = 305, 73.1%) were correlated with pCRB. We studied five selected genes (IFNG, PD1, PDL1, PDL2, CTLA4) and six immune metagenes corresponding to plasma cells (IGG), T cells (CD8A), antigen-presenting cells (MHC2), and to MHC1 genes (MHC1), STAT1 co-expressed genes (STAT1), and interferon-inducible genes (IF-I). Gene expression data from the NOAH trial were used for validation. RESULTS TIL as continuous variable and PDL1 protein expression were not significantly associated with pCRB. Expression of immune genes/metagenes had different association with pCRB after THP than after other therapies. With THP, higher expression of PD1 and STAT1, or any among PDL1, CTLA4, MHC1, and IF-I were linked with lower pCRB. In the combined TH/TP/HP treatment group, in multivariate analysis, higher expression of PD1, MHC2, and STAT1 were linked with pCRB, and higher PDL1, MHC1, or IF-I to lower pCRB. In the NOAH, a similar association of higher STAT1 with higher pCRB, and higher MHC1 and IF-I with lower pCRB was found for trastuzumab/chemotherapy but not for chemotherapy treatment only. CONCLUSIONS The immune system modulates response to therapies containing trastuzumab and pertuzumab. Greatest benefit from THP is observed for low expression of some immune markers (i.e. MHC1, CTLA4). The involvement of PDL1 in resistance supports testing combinations of HER2-directed antibodies and immune-checkpoint inhibitors.

Prognostic implication of mucinous histology in colorectal cancer patients treated with adjuvant FOLFOX chemotherapy

Background:There have been controversies in prognostic impact of mucinous histology on colorectal cancer, and its implication in patients treated with adjuvant 5-fluorouracil, leucovorin, and oxaliplatin (FOLFOX) is unclear.Methods:Stage II and III colorectal cancer patients who underwent curative resection followed by adjuvant FOLFOX were included. Patients were grouped according to the mucinous content: >50%, mucinous adenocarcinoma (MAC); <50%, adenocarcinoma with intermediated mucinous component (AIM); and without any mucinous component, non-MAC (NMA). Clinicopathological features and disease-free survival (DFS) were compared.Results:Among a total of 521 patients, 27 patients (5.2%) had MAC, 41 patients (7.9%) had AIM, and 453 patients (86.9%) had NMA. Mucinous adenocarcinoma and AIM had higher frequency of proximal location and microsatellite instability, but lower frequency of angiolymphatic invasion. Disease-free survival was significantly worse in the MAC compared with NMA (3-year DFS 57% and 86%, respectively; P<0.001) and AIM (3-year DFS 87%, P=0.01 vs MAC). Multivariate analysis revealed MAC as an independent negative prognostic factor of DFS (adjusted hazard ratio 7.96, 95% confidence interval 3.76–16.8).Conclusion:Adenocarcinoma with intermediated mucinous component and MAC have distinct clinicopathological features compared with NMA. Mucinous adenocarcinoma has an adverse prognostic impact on stage II or III colorectal cancer treated with adjuvant FOLFOX.

The beneficial effect of palliative resection in metastatic colorectal cancer

Background:We aimed to determine the role of palliative resection in metastatic colorectal cancer (mCRC) and ascertain which patient populations would benefit most from this treatment.Methods:A total of 1015 patients diagnosed with mCRC at Seoul National University Hospital between 2000 and 2009 were retrospectively studied.Results:Of the 1015 patients, 168 patients with only liver and/or lung metastasis received curative resection. The remaining 847 patients were treated with palliative chemotherapy and/or palliative resection combined with best supportive care. Palliative resection was performed in 527 (62.2%) cases (complete resection with negative margin (R0) in 93, R1/2 in 434). Resected patients had a more prolonged median overall survival (OS) than unresected patients (21.3 vs 14.1 months; P<0.001). In multivariate analysis, R0 resection was found to be associated with a superior OS compared with R1/2 resection (51.3 vs 19.1 months; P<0.001) and no resection (51.3 vs 14.1 months; P<0.001). When we performed propensity score matching, palliative resection was found to be related to prolonged OS (hazard ratio=0.72, 95% confidence interval=0.59–0.89; P=0.003).Conclusion:Palliative resection without residual disease and chemotherapy confers a longer-term survival outcome than palliative chemotherapy alone in mCRC patient subset.

Lapatinib can restore capecitabine sensitivity in HER2-positive breast cancer.

Abstract #3157 Background: Lapatinib in combination with capecitabine is an effective treatment option in HER2-positive metastatic breast cancer (MBC) that has progressed after trastuzumab-based therapy. However, the efficacy of lapaptinib plus capecitabine in capacitabine resistant MBC patients and mechanism of sensitivity in these patients is unclear.
 Methods: In the preclinical part of the study, the effect of lapatinib on 5-FU sensitivity was investigated in a HER2 amplified breast cancer cell line (SKBr3). In the clinical part, MBC patients who progressed after treatments with trastuzumab, anthracycline, and taxane were enrolled in an open-label expanded-access study of lapatinib plus capecitabine (GlaxoSmithKline, USA) at Seoul National University Hospital from Mar 2007 to Apr 2008. Patients received lapatinib (1,250mg/day, 1-21) and capecitabine (2,000mg/m 2 , D1-14) combination treatment every 3weeks. The clinical data were prospectively collected.
 Results: In SKBr3 cell line, genes related to 5-FU sensitivity [TS, thymidine kinase 1(TK1), dihydrofolate reductase (DHFR), and ribonucleotide reductase M2 (RRM2)] were downregulated after lapatinib treatment. These genes were more significantly reduced after lapatinib-treatment compared with gefitinib or trastuzumab. In addition, TS reporter gene expression was enhanced by EGFR/HER2. Nuclear translocation of EGFR/HER2 induced by EGF and its association with TS promoter was effectively abolished by lapatinib. In the clinical study, a total of 37 female patients with HER2-positive MBC were analyzed. Sixteen (43%) patients had previously been treated with capecitabine. Overall response rate (RR) was 27.0% (95% CI 12.7-41.3), and disease control rate (DCR) was 83.8% (95% CI 71.9-95.7). During the median follow-up duration of 9.1 months, median progression-free survival (PFS) was 5.6 months (95% CI 4.0-7.2), and median overall survival has not been reached yet. There was no significant difference in RR/DCR and PFS according to prior capecitabine use. Prior capecitabine treatment had been discontinued due to disease progression during treatment in 13 patients. Among these patients with resistance to capecitabine, lapatinib and capecitabine resulted in DCR/PFS comparable to that of patients without exposure to capecitabine. Biomarker analysis of tissue specimen is currently underway and will be presented at the meeting.
 Conclusion: Lapatinib plus capecitabine demonstrated clinical activity in capecitabine pretreated MBC. Our data suggests that lapatinib may resensitize capecitabine resistant tumors to capecitabine by downregulation of nuclear EGFR/HER2 and TS. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3157.

Abstract P1-02-05: Prognostic role of PIK3CA mutational status in circulating tumor DNA (ctDNA) from HER2-positive metastatic breast cancer patients

Phosphatidylinositol-4, 5-biphosphate 3-kinase, catalytic subunit alpha (PIK3CA) is one of the most commonly mutated genes in breast cancer. But the prognostic and predictive role of PIK3CA mutations remains a matter of debate. It has been suggested that PIK3CA mutations are related to resistance to trastuzumab-based therapies, but they were also related to relatively indolent disease with better progression-free survival. Recently, circulating tumor DNA has been proposed to be a sensitive biomarker for detecting the presence of specific genetic aberrations in various cancer types, providing prognostic and predictive information. In this study, we evaluated prognostic and predictive role of PIK3CA mutations in patients with HER2-positive metastatic breast cancer treated with 1 st line trastuzumab and taxane combination chemotherapy. Thirty-four patients with blood samples obtained before 1 st line trastuzumab and taxane combination chemotherapy were included in the study. We analyzed two PIK3CA hotspot mutations (E545K, H1047R) in ctDNA by digital droplet PCR (Raindrop TM ). The samples were collected from April 2005 to December 2011, centrifuged and stored as plasma, and were analyzed in 2015, after 4-10 years of storage period. Median age was 47 years (range: 31 to 75 years), and histologic type of cancer was ductal carcinoma in all cases. PIK3CA mutations were detected in 21 (61.8%) of 34 patients. Patients with mutated PIK3CA in ctDNA had longer progression-free survival (PIK3CA wild type vs mutant, 11.0 months vs 22.0 months; P = 0.013). In hormone receptor positive group, patients with mutated PIK3CA had longer progression-free survival (PIK3CA wild type vs mutant, 12 months vs 18 months, P=0.17). Patients with PIK3CA mutations had a lower objective response rate than patients with wild-type, but there was no statistical significance (CR+PR; PIK3CA wild type vs mutant, 84.6% vs 66.7%, P=0.43). There was no significant difference in response rate (P = 0.48) or PIK3CA mutational status (P = 0.44) according to hormonal receptor status (estrogen receptor and/or progesterone receptor). In conclusion, PIK3CA mutations were frequently detected by digital PCR from ctDNA of patients with HER2-positive breast cancer and they were related to significantly better PFS. We plan to analyze the PIK3CA mutation status in matched tumor tissue. Citation Format: Lim J, Lee K-H, Min A, Kim S-G, Kim J-E, Kim T-Y, Han S-W, Oh D-Y, Kim T-Y, Lim S-A. Prognostic role of PIK3CA mutational status in circulating tumor DNA (ctDNA) from HER2-positive metastatic breast cancer patients [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-02-05.

Abstract P4-07-08: The prognostic significance of ataxia-telangiectasia-mutated (ATM) and p53 expression in breast cancer

The purpose of this study was to investigate the correlation of ataxia-telangiectasia-mutated (ATM) protein and p53 expression with clinicopathological features and prognosis in patients with sporadic breast cancers. The expression of ATM and p53 was determined by immunohistochemistry in 420 surgically resected breast cancers. Loss of ATM was observed in 126 out of 407 evaluable cases (31.0%), and was significantly associated with aggressive features with large tumor size, lymph node metastasis, higher tumor grade, and negativity of ER and/or PR. ATM loss was associated with a significantly shorter disease-free survival (DFS) (p = 0.019). Abnormal p53 expression was found in 39.3% of tumors (157 out of 400), conferring a worse DFS as well (p = 0.002). When investigated together, combined ATM and p53 expression status were associated with a worse DFS (p = 0.002). On multivariate analysis, ATM loss and abnormal p53 expression status was an independent predictor of poorer DFS (intact ATM and normal p53 vs. ATM loss and abnormal p53, HR 3.350; 95% CI 1.496 - 7.502; p = 0.003). Furthermore, in patients treated with adjuvant anthracyclines, either p53 alone or p53 combined with ATM significantly influenced DFS (p = 0.004, p = 0.015, respectively). The present study demonstrates that expression of ATM and p53 is an independent prognostic marker in breast cancers, and might be a practical tool for predicting benefits from anthracycline-based adjuvant therapy. Citation Format: Suh KJ, Ryu HS, Lee K-H, Im S-A, Kim T-Y, Kim H, Yang Y, Moon H-G, Han S-W, Oh D-Y, Han W, Kim T-Y, Park IA, Noh D-Y, Bang Y-J. The prognostic significance of ataxia-telangiectasia-mutated (ATM) and p53 expression in breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-07-08.

Abstract P4-13-19: Poziotinib, an oral, irreversible pan-HER inhibitor, demonstrates promising clinical activity in metastatic HER2 positive breast cancer patients

Background: Poziotinib is a novel, oral, irreversible pan-HER inhibitor that has been studied in two completed Phase 1 clinical trials in patients with advanced solid tumors (HM-PHI-101; HM-PHI-102) and is currently being studied in several Phase 2 clinical trials. Preclinical studies have shown poziotinib to be more potent in vitro than other EGFR- and HER2-directed tyrosine kinase inhibitors. This study collates the clinical experience of poziotinib in patients with advanced HER2 positive breast cancer from the two completed Phase 1 trials. Results: The maximum tolerated dose (MTD) and safety of poziotinib were evaluated in HM-PHI-101 (once daily, Day 1-14 q3 weeks) and in HM-PHI-102 (continuous dosing). The Dose Limiting Toxicity (DLT) was diarrhea in both studies. Anti-diarrheal medicine was allowed, but prophylactic anti-diarrheal therapy was not used. The most frequently reported Grade 3 AE was diarrhea (40%). The MTD for intermittent dosing of poziotinib was 24 mg and the MTD for continuous dosing was 16 mg. The Dose Limiting Toxicity (DLT) was diarrhea in both studies. Anti-diarrheal medicine was allowed, but prophylactic anti-diarrheal therapy was not used. In total, 10 patients with HER2 positive metastatic breast cancer were treated in the two trials (median age 56.5, range 30-69). These patients were heavily pretreated (median number of previous treatment regimens 5, range 3-9), and all patients had failed treatment with both trastuzumab and lapatinib. The Overall Response Rate (ORR) in these breast cancer patients was 60% and Clinical Benefit Rate (CBR) was 80%. The median duration of response was 32.5 weeks (range 18 - 56 weeks). Two patients in the early dose cohorts of 1 or 2mg had progressive disease. The median progression free survival (PFS) was 28 weeks (6, 6, 12, 17, 25, 31, 37, 49, 57, and 98 weeks). Conclusions: Poziotinib showed very promising clinical activity in Phase 1 patients with metastatic HER2 positive breast cancer, who had been heavily pretreated and failed two prior HER2-directed therapies. The ORR in this patient population was 60% and the CBR was 80% in these two early dose finding studies. The AEs observed in these studies was consistent with other pan-HER and EGFR inhibitors. While the majority of DLT cases involves diarrhea, toxicity of other adverse events was relatively tolerable. An intermittent dosing schedule seemed appropriate for poziotinib. Multiple Phase 2 studies with poziotinib are ongoing in patients with breast cancer and other solid tumors. Citation Format: Im S-A, Kim J-H, Lee K-H, Kim SH, Oh D-Y, Kim Y-J, Han S-W, Kim T-Y, Kim T-Y, Jung J, Bang Y-J. Poziotinib, an oral, irreversible pan-HER inhibitor, demonstrates promising clinical activity in metastatic HER2 positive breast cancer patients. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-13-19.