The Impact of Pembrolizumab as a Salvage Therapy Based on HER2 Expression in Advanced Gastric Cancer.

Immune checkpoint inhibitors (ICIs) are used as salvage treatments for advanced gastric cancer (AGC) regardless of HER2 status. This study assessed the efficacy of ICIs based on HER2 expression in AGC patients who received pembrolizumab as salvage monotherapy at Samsung Medical Center from November 2017 to March 2023. HER2 status was determined via immunohistochemistry, and tumor response and survival outcomes were compared accordingly. Among the 113 patients analyzed, with a median age of 61 years and 64.6% being male, 12 patients (10.6%) were HER2-positive, and 101 patients (89.4%) were HER2-negative. Of 92 evaluable patients, none had a complete response. However, 50% of HER2-positive patients had a partial response, compared to 4.9% of HER2-negative patients (p < 0.001). The disease control rate was 70% in HER2-positive and 37.8% in HER2-negative patients (p = 0.086). Median progression-free survival was 5.53 months for HER2-positive patients versus 1.81 months for HER2-negative patients (p = 0.037). Pembrolizumab as a salvage chemotherapy for the treatment of AGC demonstrated superior effectiveness in HER2-positive patients compared with HER2-negative patients.

Prevalence of KRAS amplification in patients with metastatic cancer: Real-world next-generation sequencing analysis.

BACKGROUND: The Kirsten rat sarcoma virus (KRAS) is a prominent proto-oncogene. Several treatments for KRAS mutations have been developed. However, KRAS amplification, a KRAS alteration, is poorly understood, and there is currently no appropriate treatment other than conventional chemotherapy. This study aimed to elucidate the role of KRAS amplification in different types of cancers. METHODS: From October 2019 to June 2023, we performed next-generation sequencing using Trusight Oncology 500 on 3895 patients with 37 different cancer types at the Samsung Medical Center. We analyzed the distribution of KRAS amplification according to cancer type and its correlation with tumor mutation burden (TMB). Concomitant KRAS mutations were also identified. RESULTS: Of the total 3895 patients, 99 (2.5 %) had KRAS amplification. The highest frequency of KRAS amplification was detected in 2 % (27/1350) of patients with colorectal cancer, followed by 3.48 % (32/920) of patients with gastric cancer and 3.88 % (9/232) patients with of pancreatic cancer. MSI-High was not detected in patients with KRAS amplification. There was no correlation between KRAS copy number variation and TMB status. Among patients with KRAS amplification, 27.3 % (27/99) had a concomitant KRAS mutation. More than 50 % of patients had G12D or G12V mutations. In gastric cancer, patients with both KRAS amplification and mutation were extremely rare at 3.1 % (1/32); however, in colorectal cancer, more than half of the patients had KRAS amplification and mutation (51.9 %, 14/27). KRAS amplification and mutations are associated with mutations in tumor suppressor genes TP53, BRCA2, ARID1B, and PTCH1. CONCLUSIONS: Of the 3895 patients with metastatic solid tumors, 99 (2.5 %) had KRAS amplification, and next-generation sequencing analysis provided a deeper understanding of KRAS amplification.

Efficacy of chemotherapy containing bevacizumab in patients with metastatic colorectal cancer according to programmed cell death ligand 1.

BACKGROUND: Bevacizumab, an anti-vascular endothelial growth factor (VEGF) monoclonal antibody, inhibits angiogenesis and reduces tumor growth. Serum VEGF-C, lactate dehydrogenase, and inflammatory markers have been reported as predictive markers related to bevacizumab treatment. Programmed cell death ligand 1 (PD-L1) could act upon VEGF receptor 2 to induce cancer cell angiogenesis and metastasis. AIM: To investigate the efficacy of bevacizumab-containing chemotherapy in patients with metastatic colorectal cancer (CRC) according to the expression of PD-L1. METHODS: This analysis included CRC patients who received bevacizumab plus FOLFOX or FOLFIRI as first-line therapy between June 24, 2014 and February 28, 2022, at Samsung Medical Center (Seoul, South Korea). Analysis of patient data included evaluation of PD-L1 expression by the combined positive score (CPS). We analyzed the efficacy of bevacizumab according to PD-L1 expression status in patients with CRC. RESULTS: A total of 124 patients was included in this analysis. Almost all patients were treated with bevacizumab plus FOLFIRI or FOLFOX as the first-line chemotherapy. While 77% of patients received FOLFOX, 23% received FOLFIRI as backbone first-line chemotherapy. The numbers of patients with a PD-L1 CPS of 1 or more, 5 or more, or 10 or more were 105 (85%), 64 (52%), and 32 (26%), respectively. The results showed no significant difference in progression-free survival (PFS) and overall survival (OS) with bevacizumab treatment between patients with PD-L1 CPS less than 1 and those with PD-L1 CPS of 1 or more (PD-L1 < 1% vs PD-L1 ≥ 1%; PFS: P = 0.93, OS: P = 0.33), between patients with PD-L1 CPS less than 5 and of 5 or more (PD-L1 < 5% vs PD-L1 ≥ 5%; PFS: P = 0.409, OS: P = 0.746), and between patients with PD-L1 CPS less than 10 and of 10 or more (PD-L1 < 10% vs PD-L1 ≥ 10%; PFS: P = 0.529, OS: P = 0.568). CONCLUSION: Chemotherapy containing bevacizumab can be considered as first-line therapy in metastatic CRC irrespective of PD-L1 expression.

CDK4/6 inhibition to resensitize BRAF/EGFR inhibitor in patient-derived BRAF/PTEN-mutant colon cancer cells.

Background: In v-raf murine sarcoma viral oncogene homolog B1 (BRAF)-mutant colorectal cancer (CRC), encorafenib-cetuximab has been established as standard second-line therapy, but not all patients respond and the duration of response is relatively short. Overcoming intrinsic or acquired resistance to BRAF/EGFR inhibitors is crucial for enhancing treatment outcomes in metastatic BRAF-mutated CRC. The aim of the study is to investigate the resistance mechanisms in BRAF-mutant CRC patient refractory to BRAF/EGFR targeted therapy. Methods: We established patient-derived cells (PDCs) from a patient with BRAF/PTEN-mutant metastatic colon cancer who progressed rapidly on encorafenib plus cetuximab. To explore potential treatment options for inherent resistance caused by simultaneous PTEN mutation in BRAF-mutated CRC, we conducted cell viability assays using PDCs treated with encorafenib-cetuximab in combination with a cyclin-dependent kinase-4 and 6 (CDK4/6) inhibitor. Results: The patient's tumor had concurrent PTEN loss-of-function alteration at diagnosis and PDCs were generated from ascites after resistance to the BRAF/EGFR inhibitor. The PDCs were resistant to the encorafenib-cetuximab combination even at a high concentration of cetuximab (up to 500 µg/mL). Adding the CDK4/6 inhibitor, ribociclib, to encorafenib-cetuximab showed a synergistic effect in a proliferation assay. Ribociclib plus encorafenib-cetuximab represented a significantly lower expression of Ki-67 compared to the dual combination alone. An MTS assay showed that triplet therapy with ribociclib, encorafenib, and cetuximab suppressed cell viability more efficiently than the two-drug combinations. Investigating the combined effect of triplet therapy using the calculated combination index (CI) showed that ribociclib had a synergistic effect with encorafenib-cetuximab when applied to PDCs with a concurrent BRAF/PTEN mutation. Conclusions: Our results suggest that combining the CDK4/6 inhibitor with the BRAF/EGFR inhibitor might be a novel treatment strategy for concomitant BRAF and PTEN-mutant CRC.

The safety and efficacy outcomes of Minnelide given alone or in combination with paclitaxel in advanced gastric cancer: A phase I trial.

Minnelide is a water-soluble disodium salt variant of triptolide, an HSP70 inhibitor that can prevent tumor progression and induce apoptosis. Maximum tolerated dose (MTD), safety, and antitumor activity of Minnelide alone and its combination with paclitaxel were evaluated in this open-label, single-center, dose-escalation phase I study (NCT05566834) in patients who were previously treated for advanced gastric cancer (AGC). Minnelide was administered orally using a 3 + 3 dose-escalation design as monotherapy (Regimen A), and in combination with paclitaxel (Regimen B & C). Our results show that no patients experienced dose limiting toxicity (DLT) in the combination group (Regimen B& C) while 2 patients experienced DLT from the Regimen A group (n = 11) (Minnelide 1.5 mg). The MTD was Minnelide 1.25 mg once daily for 21days Q4 weeks as monotherapy. The most common Grade ≥3 AEs were neutropenia (19.4 %) and abdominal pain (11.1 %). In Regimen C, 71.5 % achieved either a partial response or a stable disease with the median PFS of 4.5 months, and the median OS of 10.7 months. The combination of Minnelide plus paclitaxel as salvage treatment in AGC patients showed meaningful clinical activity with a manageable safety profile. Based on these encouraging results, a phase II study is being initiated to test the effectiveness of the combination regimen in patients with advanced gastric cancer.

Patient-derived tumor spheroid-induced angiogenesis preclinical platform for exploring therapeutic vulnerabilities in cancer.

This study addresses the demand for research models that can support patient-treatment decisions and clarify the complexities of a tumor microenvironment by developing an advanced non-animal preclinical cancer model. Based on patient-derived tumor spheroids (PDTS), the proposed model reconstructs the tumor microenvironment with emphasis on tumor spheroid-driven angiogenesis. The resulting microfluidic chip system mirrors angiogenic responses elicited by PDTS, recapitulating patient-specific tumor conditions and providing robust, easily quantifiable outcomes. Vascularized PDTS exhibited marked angiogenesis and tumor proliferation on the microfluidic chip. Furthermore, a drug that targets the vascular endothelial growth factor receptor 2 (VEGFR2, ramucirumab) was deployed, which effectively inhibited angiogenesis and impeded tumor invasion. This innovative preclinical model was used for investigating distinct responses for various drug combinations, encompassing HER2 inhibitors and angiogenesis inhibitors, within the context of PDTS. This integrated platform could potentially advance precision medicine by harmonizing diverse data points within the tumor microenvironment with a focus on the interplay between cancer and the vascular system.

Neoadjuvant Cisplatin-Based Chemotherapy Followed by Selective Bladder Preservation Chemoradiotherapy in Muscle-Invasive Urothelial Carcinoma of the Bladder: Post Hoc Analysis of Two Prospective Studies.

PURPOSE: Bladder preservation chemoradiotherapy (CRT) in patients with a clinical complete response (cCR) following cisplatin-based neoadjuvant chemotherapy (NAC) is a promising treatment strategy for muscle-invasive bladder urothelial carcinoma (MIBC). A combined analysis of raw data from two prospective phase II studies was performed to better evaluate the feasibility of selective bladder preservation CRT. MATERIALS AND METHODS: The analysis was based on primary efficacy data from two independent studies, including 76 MIBC patients receiving NAC followed by bladder preservation CRT. The efficacy data included metastasis-free survival (MFS) and disease-free survival (DFS). For the present analysis, starting point of survival was defined as the date of commencing CRT. RESULTS: Among 76 patients, 66 had a cCR following NAC. Sixty-four patients received gemcitabine and cisplatin (GC) combination chemotherapy in neoadjuvant setting, and 12 received nivolumab plus GC. Bladder preservation CRT following NAC was generally well-tolerated, with low urinary tract symptoms being the most common late complication. With a median follow-up of 64 months, recurrence was recorded in 43 patients (57%): intravesical only (n=20), metastatic only (n=16), and both (n=7). In 27 patients with intravesical recurrence, transurethral resection, and Bacillus Calmette-Guerin treatment was given to 17 patients. Salvage cystectomy was performed in 10 patients. Median DFS was 46.3 (95% confidence interval [CI], 25.1 to 67.5) months, and the median MFS was not reached. Neither DFS nor MFS appeared to be affected by any of the baseline characteristics. However, DFS was significantly longer in patients with a cCR than in those without (hazard ratio, 0.465; 95% CI, 0.222 to 0.976). CONCLUSION: The strategy of NAC followed by selective bladder preservation CRT based on the cCR is feasible in the treatment of MIBC. A standardized definition of cCR is needed to better assess disease status post-NAC.

Real-world outcomes of third-line immune checkpoint inhibitors versus irinotecan-based chemotherapy in patients with advanced gastric cancer: a Korean, multicenter study (KCSG ST22-06).

BACKGROUND: Immune checkpoint inhibitor (ICI) or irinotecan-based chemotherapy is frequently used after failure of second-line paclitaxel plus ramucirumab treatment for patients with locally advanced unresectable or metastatic advanced gastric cancer (AGC). This study aimed to compare the efficacy between ICI and irinotecan-based chemotherapy as third-line treatment in patients with AGC. METHODS: We retrospectively reviewed patients with AGC, whose third-line treatment started between July 2019 and June 2021 at 17 institutions in Korea. The ICI group included patients who received nivolumab or pembrolizumab, and the irinotecan-based chemotherapy group included patients who received irinotecan or FOLFIRI (5-fluorouracil, leucovorin and irinotecan). RESULTS: A total of 363 patients [n = 129 (ICI) and n = 234 (irinotecan-based chemotherapy)] were analyzed. The median progression-free survival was 2.3 and 2.9 months in ICI and irinotecan-based chemotherapy groups, respectively (p = 0.802). The median overall survival (OS) was 5.5 and 6.0 months in ICI and irinotecan-based chemotherapy groups, respectively (p = 0.786). For all patients included in this study, multivariable analysis showed that weight loss, peritoneal metastasis, low serum sodium or albumin, and short duration of second-line treatment were associated with inferior OS (p < 0.05). ICI showed significantly longer OS than irinotecan-based chemotherapy in patients without peritoneal metastasis. Whereas ICI showed significantly shorter OS in patients without PD-L1 expression than irinotecan-based chemotherapy. CONCLUSIONS: No significant difference in survival outcome was observed between ICI and irinotecan-based chemotherapy as third-line treatment for AGC patients. ICI might be preferred for patients without peritoneal metastasis and irinotecan-based chemotherapy for patients with tumors without PD-L1 expression. TRIAL REGISTRATION: This study was registered in the Clinical Trial Registry of Korea ( https://cris.nih.go.kr : KCT 0007732).

Adjuvant Chemotherapy for Upper Tract Urothelial Carcinoma: A Real-World, Retrospective Study.

PURPOSE: The aim of this retrospective study was to evaluate the efficacy of adjuvant cisplatin-based chemotherapy in patients with locally advanced upper tract urothelial carcinoma (UTUC), administered following radical nephroureterectomy. MATERIALS AND METHODS: Patients with UTUC, arising from renal pelvis or ureter, staged pT3/T4 or N+ were treated with adjuvant chemotherapy following surgery. The chemotherapy consisted of gemcitabine 1,000 mg/m2 on days 1 and 8, cisplatin 70 mg/m2 on day 1. Treatment was repeated every 3 weeks for up to 4 cycles. Endpoints included disease-free survival (DFS), metastasis-free survival (MFS), and safety. RESULTS: Among 89 eligible patients, 85 (95.5%) completed at least 3 cycles of adjuvant chemotherapy. Chemotherapy was well tolerated, the main toxicities being mild-to-moderate gastrointestinal toxic effects and pruritus. With a median follow-up of 37 months, median DFS was 30 months (95% confidence interval, 22 to 39), and the median MFS was not reached. The 3-year DFS and MFS were 44% and 56%, respectively. Multivariate analyses revealed that the main factor associated with DFS and MFS was the lymph node involvement, whereas age, T category, grade, or the primary site of UTUC were not significantly associated with DFS or MFS. CONCLUSION: Adjuvant cisplatin-based chemotherapy after radical surgery of pT3/T4 or N+ UTUC was feasible and may demonstrate benefits in DFS and MFS. Whether novel agents added to the chemotherapy regimen, as a concurrent combination or maintenance, impacts on survival or reduces the development of metastases remains to be studied.

Treatment Patterns and Prognosis of Palliative Chemotherapy Combined With Targeting Agents in Patients With Unresectable Metastatic Colorectal Cancer: CHOICE, A Multicenter Longitudinal Observational Study.

BACKGROUND/AIM: This study investigated the treatment patterns and prognosis of patients with metastatic or unresectable colorectal cancer (mCRC) treated with chemotherapy with targeting agents. PATIENTS AND METHODS: This longitudinal multicenter study included 963 patients with mCRC who were treated in Korea between 2016 and 2020. Treatment patterns and efficacy were compared according to the mutation status and clinical factors. RESULTS: As first-line therapy, most of the patients (83.5%) received FOLFOX plus bevacizumab (35.4%), followed by FOLFIRI plus bevacizumab (18.8%), FOLFIRI plus cetuximab (17.0%), and FOLFOX plus cetuximab (12.3%). Bevacizumab was the most frequent agent (78.8%) combined with chemotherapy in RAS-mutated CRC, while cetuximab (57.2%) in RAS wild-type CRC. Cetuximab was frequently combined with a doublet regimen in patients with left-sided CRC than in those with right-sided CRC (34.4% vs. 16%). As second-line therapy, most patients (63.4%) also received doublet regimens with bevacizumab, and FOLFIRI plus aflibercept was administered in 15.1%. The objective response rate with FOLFIRI plus cetuximab was significantly higher in patients with left-sided CRC than in those with right-sided CRC (59.2% vs. 30.8%, p=0.008) and marginally higher in patients with RAS wild-type CRC than in those with RAS-mutated CRC (55.6% vs. 0.0%, p=0.092). Progression-free survival (PFS) with FOLFOX plus bevacizumab was significantly shorter than that with FOLFIRI plus bevacizumab (p=0.030) in RAS-mutated CRC, whereas there were no significant differences between regimens in RAS wild-type CRC. CONCLUSION: In patients with unresectable metastatic colorectal cancer, doublet chemotherapy with targeting agents is the most common therapy and efficacy depends on the mutation status as well as clinical factors.