Jinhyun Cho

Acquired C797S Mutation upon Treatment with a T790M-Specific Third-Generation EGFR Inhibitor (HM61713) in Non–Small Cell Lung Cancer

T790M mutation is most common resistant mechanism to epidermal growth factor receptor gene (EGFR) tyrosin kinasexa0inhibitor (TKI). Several third-generation EGFR-mutant selective TKI, such as AZD9291 (AstraZeneca), Rociletinib (Clovis), or HM61713 (Hanmi) have been developed. Acquired resistant C797S mutation was known to be one of the resistance mechanisms of AZD9291, which has not been reported for HM61713 yet. This is the first case report of C797S mutation as resistance mechanism of HM61713.

Clinicopathologic Features and Long-Term Outcomes of Elderly Breast Cancer Patients: Experiences at a Single Institution in Korea

Purpose The purpose of this study was to assess the tumor characteristics and long-term clinical outcomes of adjuvant treatments after surgery with a curative aim for patients with breast cancer who are 65 years and older. Materials and Methods Patients with breast cancer who underwent curative surgery from 2000 to 2009 were analyzed (n=4,388). Tumor characteristics and survival outcome were compared by dividing the patients into two age groups (< 65 and ≥ 65 years old). The Kaplan-Meier method was used for comparison of survival rates by log-rank test, and a Cox regression model was used to examine the effect of variables. Results Among 4,388 patients with invasive breast cancer, 317 patients (7.2%) were 65 years or older and the median age of all patients was 47 years (range, 18 to 91 years). Tumor characteristics were similar between the two age groups, but the older patients were treated less often with adjuvant treatments. During a median follow-up period of 122 months, recurrence-free survival (RFS) was equivalent for patients 65 years and older compared to younger patients, but significantly worse in overall survival (OS) and breast cancer–specific survival (BCSS) (5-year OS, 94.3% vs. 90.5%; p < 0.001 and 5-year BCSS, 94.7% vs. 91.8%; p=0.031). In the multivariate model, age ≥ 65 years old was identified as an independent risk factor for OS and RFS. Conclusion Elderly breast cancer appeared to have worse outcomes with very low prevalence in Korea, despite similar tumor characteristics. More active adjuvant therapies would have a role for aggressive subtypes for fit, elderly patients.

Efficacy of BRAF Inhibitors in Asian Metastatic Melanoma Patients: Potential Implications of Genomic Sequencing in BRAF-Mutated Melanoma

BACKGROUND: The BRAF inhibitors vemurafenib and dabrafenib are currently the standard treatment for metastatic melanoma with BRAF V600 mutations. However, given the rarity of noncutaneous melanoma, including acral and mucosal subtypes, the efficacy of BRAF inhibitors for this subset of patients has not been extensively investigated. Acquired resistance generally appears 6 to 8 months after treatment with a BRAF inhibitor, and the mechanism of resistance is not well established. METHODS: We examined treatment outcomes for patients diagnosed with metastatic melanoma and treated with BRAF inhibitors at Samsung Medical Center between April 2013 and December 2015. We analyzed genomic alterations in selected patients using targeted sequencing. RESULTS: Twenty-seven patients with a median age of 49 years (range 23-82 years) with metastatic melanoma and treated with a BRAF inhibitor were identified. Of these patients, 19 (70.3%) had noncutaneous melanoma, including acral and mucosal melanoma. All patients had BRAFV600E mutations. The median progression-free survival of all patients was 9.2 months (95% confidence interval, 1.6-16.7), and the objective response rate was 78.9% in the mucosal/acral melanoma group and 75.0% in the cutaneous melanoma group. Three (11.1%) patients achieved complete response, and 19 (70.4%) showed a partial response. Targeted sequencing in five patients demonstrated NF1 mutations in three patients who did not respond to BRAF inhibitors. CONCLUSION: BRAF inhibitors were an effective therapeutic option for Korean patients with metastatic melanoma harboring a BRAF V600 mutation regardless of melanoma subtype (acral/mucosa versus cutaneous).

Loss of Tuberous Sclerosis Complex 2 (TSC2) as a Predictive Biomarker of Response to mTOR Inhibitor Treatment in Patients with Hepatocellular Carcinoma

BACKGROUND: Hepatocellular carcinoma (HCC) is a leading cause of cancer-related death globally. Mechanistic target of rapamycin (mTOR) is frequently up-regulated in HCC and plays an important role in HCC tumorigenesis. Tumors with loss of tuberous sclerosis complex 2 (TSC2), a negative regulator of mTOR signaling, tend to respond well to mTOR inhibitors. We analyzed TSC2 expression status in Korean patients with HCC and evaluated the correlation between TSC2 loss and response to the mTOR inhibitor, everolimus. METHODS: We retrospectively assessed 36 patients with advanced HCC who had received sorafenib at a single center in Korea between 2008 and 2014, and for whom tumor specimens were available for TSC2 immunohistochemical analysis (IHC). Three patient-derived tumor cell lines (PDCs) were analyzed by western blotting to determine TSC2 expression and drug sensitivity to mTOR. RESULTS: Twelve of 36 patients (33.3%) showed low to undetectable levels of TSC2 expression. No significant differences were observed in progression-free survival (PFS) or overall survival with sorafenib treatment based on TSC2 expression status. Two patients were treated with everolimus after sorafenib failure; one patient, with moderate TSC2 expression, experienced stable disease with a PFS of 5.8 months; the other, with high TSC2 expression, experienced rapid progression. PDC models demonstrated that the TSC2-low HCC PDC line was significantly more sensitive to everolimus than the TSC2-high HCC PDC lines. CONCLUSION: Loss of TSC2 may predict improved response to everolimus in HCC patients, but further studies are needed to confirm the predictive role of TSC2 expression for everolimus treatment.

Pembrolizumab for Patients With Refractory or Relapsed Thymic Epithelial Tumor: An Open-Label Phase II Trial

Purpose Limited treatment options exist for patients with thymic epithelial tumor (TET) whose disease progresses after platinum-based chemotherapy. We conducted a phase II study of pembrolizumab in patients with TET to evaluate its efficacy and safety. Methods Patients with histologically confirmed TET whose disease progressed after at least one line of platinum-based chemotherapy were eligible for the study. Patients were excluded if they had an active autoimmune disease requiring systemic treatment within the past year or documented history of clinically severe autoimmune disease. Patients received 200 mg of pembrolizumab intravenously every 3 weeks until tumor progression or unacceptable toxicity. The primary objective of response rate was assessed every 9 weeks by investigators. Results Of 33 patients enrolled, 26 had thymic carcinoma and seven had thymoma. Of seven thymoma, two (28.6%; 95% CI, 8.2% to 64.1%) had partial response, and five (71.6%) had stable disease. Of 26 thymic carcinoma, five (19.2%; 95% CI, 8.5% to 37.9%) had partial response and 14 (53.8%) had stable disease. The median progression-free survival was 6.1 months for both groups. The most common adverse events of any grade included dyspnea (11; 33.3%), chest wall pain (10; 30.3%), anorexia (seven; 21.2%), and fatigue (seven; 21.2%). Five (71.4%) of seven patients with thymoma and four (15.4%) of 26 patients with thymic carcinoma reported grade ≥ 3 immune-related adverse events, including hepatitis (four; 12.1%), myocarditis (three; 9.1%), myasthenia gravis (two; 6.1%), thyroiditis (one; 3.0%), antineutrophil cytoplasmic antibody-associated rapidly progressive glomerulonephritis (one; 3.0%), colitis (one; 3.0%), and subacute myoclonus (one; 3.0%). Conclusions Pembrolizumab showed encouraging antitumor activity in patients with advanced TET. Given the high incidence of autoimmunity, additional studies are needed to identify those who can benefit from pembrolizumab without immune-related adverse events.

Early Decline in Left Ventricular Ejection Fraction Can Predict Trastuzumab-Related Cardiotoxicity in Patients with Breast Cancer: A Study Using 13 Years of Registry Data

Purpose While concerns regarding trastuzumab-related cardiac dysfunction (TRCD) in patients with breast cancer are increasing, there is a lack of evidence supporting the current recommendations for TRCD monitoring. We aimed to investigate the clinical predictors of TRCD in the adjuvant setting of human epidermal growth factor receptor 2–positive breast cancer patients. Materials and Methods From August 2003 to April 2016, consecutive 998 patients who were treated with adjuvant trastuzumab for breast cancer were retrospectively evaluated. TRCD was defined as a decrease ≥10% in left ventricular ejection fraction (LVEF), with a decline below the normal limit or symptomatic heart failure. Results Among 787 eligible patients who had complete data sets consisting of both baseline and follow-up assessment of left ventricular systolic function by echocardiography (mean age, 49.9±9.5 years), 58 (7.4%) developed TRCD. TRCD patients had lower baseline LVEF (63% [59–66] vs. 65% [61–68], p=0.016) and more frequently administered Adriamycin (98% vs. 89%, p=0.022) than those without TRCD. On follow-up echocardiography, a drop in LVEF ≥5% within the first 3 months was more frequent in TRCD patients (78.3% vs. 38.4%, p<0.001). Regardless of baseline LVEF and Adriamycin treatment, a drop in LVEF ≥5% within the first 3 months of trastuzumab administration was strongly associated with the development of TRCD (adjusted hazard ratio, 45.1[17.0–127.6], p<0.001). Conclusion The overall incidence of TRCD was 7.4% in Asian breast cancer patients treated with adjuvant trastuzumab. A decline in LVEF ≥5% within the first 3 months of trastuzumab initiation was strongly associated with TRCD development in patients with breast cancer.

A Randomized, Open-Label, Phase II Study Comparing Pemetrexed Plus Cisplatin Followed by Maintenance Pemetrexed versus Pemetrexed Alone in Patients with Epidermal Growth Factor Receptor (EGFR)-Mutant Non-small Cell Lung Cancer after Failure of First-Line EGFR Tyrosine Kinase Inhibitor: KCSG-LU12-13

Purpose The optimal cytotoxic regimens have not been established for patients with non-small cell lung cancer (NSCLC) who develop disease progression on first-line epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI). Materials and Methods We conducted a multi-center randomized phase II trial to compare the clinical outcomes between pemetrexed plus cisplatin combination therapy followed by maintenance pemetrexed (PC) and pemetrexed monotherapy (P) after failure of first-line EGFR-TKI. The primary objective was progression-free survival (PFS), and secondary objectives included overall response rate (ORR), overall survival (OS), health-related quality of life (HRQOL), and safety and toxicity profiles. Results A total of 96 patientswere randomized, and 91 patientswere treated at 14 centers in Korea. The ORR was 34.8% (16/46) for the PC arm and 17.8% (8/45) for the P arm (p=0.066). With 23.4 months of follow-up, the median PFS was 5.4 months in the PC arm and 6.4 months in the P arm (p=0.114). The median OS was 17.9 months and 15.7 months in PC and P arms, respectively (p=0.787). Adverse events ≥ grade 3 were reported in 12 patients (26.1%) in the PC arm and nine patients (20.0%) in the P arm (p=0.491). The overall time trends of HRQOL were not significantly different between the two arms. Conclusion The outcomes of pemetrexed therapy in NSCLC patients with disease progression after firstline EGFR-TKI might not be improved by adding cisplatin.