Entrectinib Induces Apoptosis and Inhibits the Epithelial-Mesenchymal Transition in Gastric Cancer with NTRK Overexpression

Tropomyosin receptor kinase (TRK) and receptor tyrosine kinase (RTK class VII) expression are important in many human diseases, especially cancers, including colorectal, lung, and gastric cancer. Using RNA sequencing analysis, we evaluated the mRNA expression and mutation profiles of gastric cancer patients with neurotropic tropomyosin receptor kinase (NTRK) 1-3 overexpression (defined as a ≥2.0-fold change). Furthermore, we screened eight TRK inhibitors in NCI-N87, SNU16, MKN28, MKN7, and AGS cells. Among these inhibitors, entrectinib showed the highest inhibitory activity; therefore, this drug was selected for analysis of its therapeutic mechanisms in gastric cancer. Entrectinib treatment induced apoptosis in NTRK1-3-expressing and VEGFR2-expressing NCI-N87 and AGS cells, but it had no effect on NTRK1-3-, VEGFR2-, TGFBR1-, and CD274-expressing MKN7 cells. SNU16 and MKN28 cells with low NTRK1-3 expression were not affected by entrectinib. Therefore, a mechanistic study was conducted in NCI-N87 (high expression of NTRK1-3 but mutation of NTRK3), AGS (high expression of NTRK1-3) and MKN28 (low expression of NTRK1-3) gastric cancer cell lines. Entrectinib treatment significantly reduced expression levels of phosphorylated NFκB, AKT, ERK, and β-catenin in NCI-N87 and AGS cells, whereas it upregulated the expression levels of ECAD in NCI-N87 cells. Together, these results suggest that entrectinib has anti-cancer activity not only in GC cells overexpressing pan NTRK but also in VEGFR2 GC cells via the inhibition of the pan NTRK and VEGFR signaling pathways.

Clinical insights into hematologic malignancies and comparative analysis of molecular signatures of acute myeloid leukemia in different ethnicities using an artificial intelligence offering

Next generation sequencing generates copious amounts of genomics data, causing manual interpretation to be laborious and non-scalable while remaining subjective (even for highly trained specialists). We evaluated the performance of the artificial intelligence-based offering Watson for Genomics (WfG), a variant interpretation platform, in hematologic malignancies for the first time.Next generation sequencing was performed for patients treated for various hematological malignancies at Hallym University Sacred Heart Hospital, South Korea, between December 2017 and August 2020 using a 54-gene panel. Both WfG and expert manual curation were used to evaluate the performance of WfG. Acute myeloid leukemia (AML) molecular profiles were compared between Koreans and other ethnic groups using a publicly available dataset.Seventy-seven patients were analyzed (AML: 45, myeloproliferative neoplasms: 12, multiple myeloma: 7, myelodysplastic syndromes: 6, and others: 7). The concordance between the manual and WfG interpretations of 35 variants in 11 random patients was 94%. Among all patients, WfG identified 39 (51%) with at least 1 clinically actionable therapeutic alteration (i.e., a variant targeted by a United States Food and Drug Administration [US FDA]-approved drug, off-label drug, or clinical trial). Moreover, 46% of these patients (18/39) had genes that were targeted by a US FDA-approved therapy. WfG identified diagnostic or prognostic insights in 65% of the patients with no targetable alterations. In those with AML, FLT3-internal tandem duplications or tyrosine kinase domain mutations were less frequent among Koreans than among Caucasians (6.7% vs 30.2%, P < .001) or Hispanics (6.7% vs 28.3%, P = .005), suggesting ethnic differences.Variant interpretation using WfG correlated well with manually curated expert opinions. WfG provided therapeutic insights (including variant-specific drugs and clinical trials that cannot easily be provided by expert manual curation), as well as diagnostic and/or prognostic information.

Recommendations for the Use of Next-Generation Sequencing and the Molecular Tumor Board for Patients with Advanced Cancer: A Report from KSMO and KCSG Precision Medicine Networking Group

Next-generation sequencing (NGS) is becoming essential in the fields of precision oncology. With implementation of NGS in daily clinic, the needs for continued education, facilitated interpretation of NGS results and optimal treatment delivery based on NGS results have been addressed. Molecular tumor board (MTB) is multidisciplinary approach to keep pace with the growing knowledge of complex molecular alterations in patients with advanced solid cancer. Although guidelines for NGS use and MTB have been developed in western countries, there is limitation for reflection of Korea’s public health environment and daily clinical practice. These recommendations provide a critical guidance from NGS panel testing to final treatment decision based on MTB discussion.

409 Trial in progress: a phase 2 study to assess the safety, efficacy of FLX475 combined with pembrolizumab in patients with advanced or metastatic gastric cancer

Background

Regulatory T-cells (Treg) are essential in maintaining self tolerance, but they can also suppress anti-tumor immunity in the tumor microenvironment (TME). Treg are recruited into tumors by C-C motif chemokine ligand 17 (CCL17), and 22 (CCL22), which are produced by tumor cells and other cells in the TME. These chemokines serve as a ”homing signal” to Treg by binding to their cognate receptor, C-C chemokine receptor type 4 (CCR4), the predominant chemokine receptor on human Treg.1 2 3 FLX475, is an orally available and selective small-molecule antagonist of CCR4. In preclinical studies it has demonstrated potent inhibition of CCL17- and CCL22-induced CCR4-mediated chemotaxis, an increase in the intratumoral Teff/Treg ratio, and anti-tumor efficacy as a single agent and in combination with checkpoint inhibitors. In a first-in-human healthy volunteer study, the orally-available CCR4 antagonist was well tolerated, with solid safety profile. A receptor occupancy (RO) pharmacodynamic (PD) assay using peripheral blood Treg demonstrated the ability to safely achieve exposure levels predicted to maximally inhibit Treg recruitment into tumors.4 The proposed mechanism of action, pharmacokinetics (PK), PD, and safety profile of FLX475 have enabled the optimized design of an ongoing Phase 2 study to assess the safety, efficacy of FLX475 in combination with pembrolizumab in patients with advanced or metastatic gastric cancer.

Methods

This clinical trial is a Phase 2, open-label study to assess the safety and efficacy of FLX475 in combination with pembrolizumab in patients with advanced or metastatic gastric cancer (NCT04768686). Approximately 90 subjects may be enrolled across 2 cohorts to examine the safety and efficacy when administered 100mg PO QD of FLX475 with 200mg IV Q3W of pembrolizumab. In cohort 1, checkpoint inhibitor naïve Epstein-Barr Virus (EBV)-negative gastric cancer subjects who have progressed on at least 2 prior systemic treatments for advanced or metastatic gastric cancer will be enrolled, and in cohort 2, checkpoint inhibitor naïve EBV-positive gastric cancer subjects who had at least 1 prior systemic treatment for advanced or metastatic gastric cancer will be enrolled. Both EBV negative and positive gastric cancer are predicted to express high levels of CCR4 ligands and enriched in Treg (i.e. ‘charged tumor’). The study is planned initially as a 2-stage design for each cohort, and an interim analysis reviewing efficacy and safety results as well as available PK and PD data for both cohorts will be performed prior to stage 2.

Acknowledgements

Thanks to the patients, and to their families and caregivers for allowing us to be part of the journey.RAPT Therapeutics, Inc., South San Francisco, CA, USA is providing FLX475 for the study.Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA is providing pembrolizumab for the study.

Trial Registration

NCT04768686

References

Talay O, et al. Potent and selective C-C chemokine receptor (CCR4) antagonists potentiate anti-tumor immune responses by inhibiting regulatory T cells (Treg). J Immunother Cancer 2017;5(Suppl 2):P467 (SITC 2017).

Curiel, Tyler J, et al. Specific recruitment of regulatory T cells in ovarian carcinoma fosters immune privilege and predicts reduced survival. Nature medicine 10.9 (2004):942–949.

Nakayama et al. Selective induction of Th2-attracting chemokines CCL17 and CCL22 in human B cells by latent membrane protein 1 of Epstein-Barr virus. J Virol 2004 February; 78(4):1665–74.

van Marle S, et al. Pharmacokinetics, pharmacodynamics, and safety of FLX475, an orally-available, potent, and selective small-molecule antagonist of CCR4, in healthy volunteers. J Immunother Cancer 2018;6(Suppl 1):P484 (SITC 2018).

TRK inhibitors block NFKB and induce NRF2 in TRK fusion-positive colon cancer

Tropomyosin receptor kinase (TRK) fusion is one of the oncogenic driver causes of colon cancer, and tropomyosin 3-neurotrophic receptor tyrosine kinase 1 (TPM3-NTRK1) fusion has been detected in the KM12SM cell line. In the present study, we investigated anticancer mechanisms in the KM12SM cell line using three different form of dovitinib (dovitinib (free base), dovitinib lactate (mono acid), and dovitinib dilactic acid (diacid)) and four TRK inhibitors (LOXO-101, entrectinib, regorafenib, and crizotinib). Exposure of TRK inhibitors at concentrations of 10 nM resulted in the apoptosis of KM12SM cells, whereas regorafenib had no effect. Treatment with all inhibitors except regorafenib also significantly increased the expression levels of the genes nuclear factor-erythroid 2-related factor 2 (NRF2) and glutamyl cysteine ligase catalytic subunit (GCLC) in KM12SM. These drugs significantly reduced expression of the phosphorylated proteins NFκB and COX-2 in the KM12SM cell line, and significantly attenuated KM12SM cell migration, according to a Transwell migration assay. Together, these results suggest that TRK inhibitors block products of carcinogenesis by negatively regulating the NFκB signaling pathway and positively regulating the antioxidant NRF2 signaling pathway.

A Bayesian network meta-analysis on systemic therapy for previously treated gastric cancer

We conducted a systemic literature review of randomized controlled trials (RCTs) to identify phase III RCTs on salvage treatment of advanced gastric cancer (AGC) and performed a Bayesian network meta-analysis with random-effects model. The overall survival (OS) was the primary outcome of interest. A total of 20 randomized phase III trials were selected. For the second-line treatment, olaparib plus paclitaxel had the highest surface under the cumulative ranking curve value (90.5%), followed by paclitaxel plus ramucirumab (88.4%) and pembrolizumab (86.5%), indicating that these treatments could be the most effective regimens in terms of OS. Nivolumab, chemotherapy, and apatinib showed significant OS benefit compared with best supportive care for the third-line treatment. In conclusion, pembrolizumab may be the most preferable regimen as a second-line treatment for patients with PD-L1-expressing AGC, while paclitaxel-based combinations are recommended for PD-L1-negative AGC. Nivolumab might be the most preferable third-line treatment.

Ramucirumab plus paclitaxel as second-line treatment in patients with advanced gastric or gastroesophageal junction adenocarcinoma: a nationwide real-world outcomes in Korea study (KCSG-ST19-16)

Background:

Ramucirumab as monotherapy or in combination with paclitaxel is a second-line treatment option recommended for patients with locally advanced unresectable or metastatic gastric or gastroesophageal junction (GEJ) adenocarcinoma. However, real-world data from large study cohorts focused on ramucirumab plus paclitaxel in gastric cancer are limited.

Methods:

The study population comprised all patients with gastric or GEJ cancer who received ramucirumab plus paclitaxel in South Korea between 1 May 2018 and 31 December 2018. We included patients with advanced gastric or GEJ adenocarcinoma and disease progression after first-line platinum and fluoropyrimidine-containing combination chemotherapy.

Results:

In total, 1063 patients were included in the present study. The objective response rate and disease control rate were 15.1% and 57.7%, respectively. The median progression-free survival was 4.03 months (95% confidence interval, 3.80–4.27) and the median overall survival was 10.03 months (95% confidence interval, 9.33–10.73). Grade 3 or higher treatment-related adverse events with incidence of ⩾5% were neutropenia (35.1%) and anemia (10.5%). Based on multivariable analysis, overall survival was negatively associated with Eastern Cooperative Oncology Group performance status ⩾2, weight loss ⩾10% in the previous 3 months, GEJ of primary tumor, poor or unknown histologic grade, number of metastatic sites ⩾3, presence of peritoneal metastasis, no prior gastrectomy, and time to second-line since first-line treatment <6 months.

Conclusion:

Our large-scale, nationwide, real-world data analysis of an unselected real-world population adds evidence for the efficacy and safety of second-line ramucirumab plus paclitaxel in patients with locally advanced unresectable or metastatic gastric or GEJ adenocarcinoma.

Modified FOLFIRINOX versus S-1 as second-line chemotherapy in gemcitabine-failed metastatic pancreatic cancer patients: A randomised controlled trial (MPACA-3)

BACKGROUND

The efficacy of modified FOLFIRINOX (mFOLFIRINOX) as a second-line chemotherapy treatment for metastatic pancreatic adenocarcinoma (mPAC), remains unclear. This multi-center randomised phase III trial aimed to elucidate the efficacy of mFOLFIRINOX as a second-line chemotherapy treatment for mPAC patients with good performance status.

PATIENTS AND METHODS

Eighty mPAC patients (age, 19-75 years) refractory to first-line gemcitabine-based chemotherapy were randomly selected to receive mFOLFIRINOX or S-1. mFOLFIRINOX comprised oxaliplatin (65 mg/m²), irinotecan (135 mg/m²), and leucovorin (400 mg/m²) on day 1 and continuous 5-FU infusion (1000 mg/m²) over 24 h on days 1-2 every 2 weeks. S-1 comprised body surface area-dependent oral S-1, divided into two doses per day on days 1-28 every 6 weeks.

RESULTS

Overall survival was the primary endpoint. The objective response and disease control rates were higher in the mFOLFIRINOX than in the S-1 group (15% versus 2%; p = .04 and 67% versus 37%; p = .007). The median progression-free survival rates were 5.2 and 2.2 months in the mFOLFIRINOX and S-1 groups, respectively (adjusted hazard ratio [HR]: .4; 95% confidence interval [CI]: .2-.6; p < .001). The median overall survival rates were 9.2 and 4.9 months in the mFOLFIRINOX and S-1 groups, respectively (adjusted HR: .4; 95% CI: .2-.7; p = .002). Grade 3-4 adverse events occurred in 56% and 17% of the patients in the mFOLFIRINOX and S-1 groups, respectively (p < .001).

CONCLUSION

Administration of mFOLFIRINOX as a second-line chemotherapy treatment for mPAC patients refractory to gemcitabine-based chemotherapy resulted in increased survival rates than S-1 treatment alone.

Treatment and Outcomes of Metastatic Pancreatic Cancer in Elderly Patients

BACKGROUND AND AIMS

Although pancreatic cancers are common in older age-groups, the prognosis remains poor due to limited studies on treatment approaches and outcomes in a given population. We aimed to examine treatment patterns and their outcomes in older patients with metastatic pancreatic cancer in a real-world context.

MATERIALS AND METHODS

We conducted a retrospective study including 167 patients with metastatic pancreatic cancer (aged ≥70 years and male/female: 78/89) between January 2010 and July 2015. Patients' retrieved data from medical records were analyzed according to treatment types, followed by a review of clinicopathologic variables and treatment outcomes.

RESULTS

Of the 167 eligible patients for the study, only 21.6% (n = 36) received palliative chemotherapy. The median age of the chemotherapy group was 74.0 years and 78.6 years for the supportive care group. The median survival of the chemotherapy group was 9.2 months (range: 1.0-24.9 months), compared with that of the supportive care group, which was 2.3 months (range: 0.1-31.8 months). Among the patients in the chemotherapy group, 50% (n = 18) received gemcitabine-based double therapy, and 30% patients (n = 9) received second-line chemotherapy.

CONCLUSIONS

Our results showed that older patients with metastatic pancreatic cancer were less likely to receive chemotherapy. However, the survival benefit from chemotherapy was comparable to that of younger patients' counterpart. Thus, further study involving identification of older patients who would benefit from cytotoxic chemotherapy is needed.

PRODIGY: A Phase III Study of Neoadjuvant Docetaxel, Oxaliplatin, and S-1 Plus Surgery and Adjuvant S-1 Versus Surgery and Adjuvant S-1 for Resectable Advanced Gastric Cancer

Adjuvant chemotherapy after D2 gastrectomy is standard for resectable locally advanced gastric cancer (LAGC) in Asia. Based on positive findings for perioperative chemotherapy in European phase III studies, the phase III PRODIGY study (ClinicalTrials.gov identifier: NCT01515748) investigated whether neoadjuvant docetaxel, oxaliplatin, and S-1 (DOS) followed by surgery and adjuvant S-1 could improve outcomes versus standard treatment in Korean patients with resectable LAGC.

RNF43 and PWWP2B inhibit cancer cell proliferation and are predictive or prognostic biomarker for FDA-approved drugs in patients with advanced gastric cancer

Background: Abnormal regulation of genes has been closely related to gastric cancer. The characterization of gastric cancer has necessitated the development of new therapeutics as well as the identification of prognostic markers to predict the response to novel drugs. In our study, we used RNA sequencing analyses to show that on gastric cancer tissues to identification of gastric cancer prognostic markers. We specifically chose to study RNF43 because it inhibits gastric cancer-related Wnt/β-catenin signaling by interacting with Wnt receptors. PWWP2B was chosen because it is a gene which is downregulated in gastric cancer.

Methods: Utilizing RNA sequencing analysis, we evaluated the mRNA expression profile in gastric cancer patients. Also, we used HAP1 cells which is a human near-haploid cell line derived from the male chronic myelogenous leukemia cell line KBM-7. These cell line has one copy of each gene, ensuring the edited allele will not be masked by additional alleles. We investigated the screening of 1,449 FDA-approved drugs in HAP1, HAP1 RNF43 KO and HAP1 PWWP2B KO cells. RNA sequencing data reveals that RNF43 and PWWP2B expression were down-regulated in recurrence gastric cancer patients. Next, we investigated the anti-cancer effects of selected drugs in RNF43 and PWWP2B down-regulated MKN45 gastric cancer cells and xenograft model.

Results: Among these FDA-approved drugs, three drugs (docetaxel trihydrate, pelitinib and uprosertib) showed strong inhibitory effects in RNF43 KO cells and PWWP2B KO cells. In MKN45 xenograft model, tumor volumes were significantly reduced in the docetaxel trihydrate, uprosertib or pelitinib-treated group. Our data demonstrated that RNF43 and PWWP2B are a biomarker that predict recurrence of gastric cancer.

Conclusions: Our findings suggest that docetaxel trihydrate, uprosertib and pelitinib could be used as novel therapeutic agents for the prevention and treatment of gastric cancer with a decrease in RNF43 and PWWP2B expression.

Multicenter phase Ib/II study of second-line trastuzumab, ramucirumab, and paclitaxel in patients with HER2-positive advanced gastric or gastroesophageal junction cancer (HER-RAM study)

4063

Background: We evaluated the safety and efficacy of adding trastuzumab to ramucirumab and paclitaxel (TRP) as a second line treatment in human epidermal growth factor receptor 2 (HER-2)-positive advanced gastric or gastroesophageal junction (G/GEJ) cancer progressed from trastuzumab containing chemotherapy. Methods: Patients with HER-2-positive advanced G/GEJ cancer who progressed after first-line chemotherapy with trastuzumab in combination with fluoropyrimidine and platinum were eligible. Trastuzumab (Herzuma[CT-P6], Celltrion Inc.) 4mg/kg on day 1 followed by 2mg/kg on days 8, 15, and 22, ramucirumab 8mg/kg on days 1 and 15, and paclitaxel (dose level 1: 80mg/m2, dose level -1: 70 mg/m2) on days 1, 8, and 15 of a 28-day cycle was tested. After safety analysis of lead-in safety cohort (phase 1b), phase 2 part was conducted to evaluate the primary endpoint of progression-free survival (PFS). Secondary endpoints included objective response rate (ORR), disease control rate (DCR), overall survival (OS), and safety. Results: At the phase 1b part, as there was no dose limiting toxicity in 3 patients at the dose level 1, dose level 1 with full dose combination was determined as recommended phase 2 dose. At the time of data lock on Jan. 31, 2021, 45 patients among enrolled 50 patients were evaluable for response and safety including 3 patients from phase 1b part. Median age was 59 years old (range 30-82) and most patients were male (37/45). At baseline, 33 patients had tumors with HER-2 3+ by immunohistochemistry (IHC) and 12 had those with HER-2 2+ by IHC with ERBB2 amplification by in situ hybridization. With median follow-up duration of 11.6 months, median PFS and OS were 7.2 months (95% confidence interval [CI]: 6.0-8.5 months) and 13.6 months (95% CI: 10.3-16.9 months), respectively. ORR was 55.6% (25/45, complete response = 1, partial response = 24) and DCR was 95.6% (43/45), respectively. Most common hematologic adverse event (AE) was neutropenia (all grade: 64.4%, grade 3/4: 51.1%) with 1 case of febrile neutropenia (2.2%). Most common non-hematologic AE was peripheral sensory neuropathy (all grade: 33.3%, grade 3: 2.2%). Gastrointestinal (GI) bleeding occurred in 4 patients (grade 3 upper GI bleeding: 6.7%, grade 1 lower GI bleeding: 2.2%), whereas GI perforation was not observed. Hypertension occurred in 3 patients (all grade: 6.7%, grade 3: 4.4%). No new or unexpected AEs resulting in treatment cessation were observed with this combination regimen. Conclusions: The continuous use of trastuzumab beyond progression in combination with ramucirumab and paclitaxel showed promising activity and manageable safety profile in HER2 positive G/GEJ cancer patients who progressed after trastuzumab containing chemotherapy. Updated outcomes for ongoing patients will be presented.

Real-world outcomes of second-line ramucirumab plus paclitaxel in patients with advanced gastric or gastroesophageal junction adenocarcinoma: A nationwide retrospective study in Korea (KCSG-ST19-16)

4056

Background: Ramucirumab as monotherapy or in combination with paclitaxel is a second-line treatment option recommended for patients with locally advanced unresectable or metastatic gastroesophageal junction (GEJ) or gastric adenocarcinoma. However, real-world data of large samples focused on ramucirumab plus paclitaxel in gastric cancer are limited. We conducted a nationwide retrospective study to evaluate the efficacy, safety, and factors potentially associated with survival in patients with gastric or GEJ adenocarcinoma who received second-line ramucirumab plus paclitaxel in a real-world setting. Methods: The study population comprised all patients with gastric or GEJ cancer who received ramucirumab plus paclitaxel in South Korea between May 1, 2018, and December 31, 2018. We included patients with advanced gastric or GEJ adenocarcinoma and disease progression after first-line platinum and fluoropyrimidine-containing combination chemotherapy. Results: A total of 1,063 patients with advanced gastric or GEJ adenocarcinoma who received ramucirumab plus paclitaxel were included. The objective response rate and disease control rate were 15.1% and 57.7%, respectively; the median progression-free survival was 4.03 months (95% CI, 3.80–4.27), and the median overall survival was 10.3 months (95% CI, 9.33–10.73). The common treatment-related adverse events (TRAEs) at any grade were neutropenia (44.7%), anemia (41.8%), neuropathy (29.1%), fatigue (25.9%), and anorexia (25.0%). Grade 3 or higher TRAEs with incidences of ≥5% were neutropenia (35.1%) and anemia (10.5%). Adverse events of special interest were infrequent, including hypertension (2.1%) and proteinuria (3.0%). Based on multivariate analysis, overall survival was negatively associated with Eastern Cooperative Oncology Group performance status ≥2, weight loss in the previous 3 months ≥10%, GEJ of primary tumor, poor or unknown histology grade, number of metastatic sites ≥3, presence of peritoneal metastasis, no prior gastrectomy, and time to second-line since first-line treatment < 6 months. Conclusions: Our large-scale, nationwide, real-world data analysis of an unselected real-world population added evidence for the efficacy and safety of second-line ramucirumab plus paclitaxel in patients with locally advanced unresectable or metastatic gastric or GEJ adenocarcinoma. Clinical trial information: NCT04192734.

Modified FOLFIRINOX versus S-1 as second-line chemotherapy in patients with gemcitabine-failed metastatic pancreatic cancer: A randomized phase III trial (MPACA-3)

4119

Background: Modified FOLFIRINOX (mFOLFIRINOX) consisting of 5-fluorouracil/leucovorin, irinotecan, and oxaliplatin has been assessed as second-line treatment of patients with advanced pancreatic cancer in retrospective and phase II studies. However, the result was not confirmed by randomized controlled trial. Methods: A randomized, open-label, phase III trial was conducted at 9 institutions in Korea. Patients with metastatic pancreatic adenocarcinoma (mPAC) and Eastern Cooperative Oncology Group performance status of 0-1 who failed to first-line gemcitabine-based chemotherapy were randomly assigned to receive mFOLFIRINOX or S-1. The primary endpoint was overall survival. Results: A total of 80 patients were enrolled from March 2017 to December 2019. The accrual of patients was early terminated due to clear difference of efficacy in the interim analysis and expectation of poor recruitment due to conflicting adjuvant regimens. Objective response and disease control rates were 15.4% vs. 2.4% ( p= 0.041) and 66.7% vs. 36.6% ( p= 0.007) in the mFOLFIRINOX and S-1 arms, respectively. The median progression-free survival was 5.2 and 2.2 months in the mFOLFIRINOX and S-1 arms, respectively ( p= 0.002). The median overall survival was 9.2 and 4.9 months in the mFOLFIRINOX and S-1 arms, respectively ( p= 0.048). The adjusted hazard ratio of the mFOLFIRINOX arm to the S-1 arm for overall survival was 0.402 (95% confidence interval 0.223-0.725, p= 0.002). All grade 3-4 adverse events occurred in 56.5% and 17.1% in the mFOLFIRINOX and S-1 arms, respectively ( p< 0.001). However, only one patient in each arm prematurely discontinued treatment due to toxicity and there was no treatment-related mortality in both arms. Minimally important differences in the health-related quality of life were not observed in both arms. Conclusions: mFOLFIRINOX as second-line treatment in mPAC patients failed to gemcitabine-based chemotherapy demonstrated a survival benefit versus S-1 alone with acceptable toxicities. Clinical trial information: KCT0003534.

Efficacy and safety of bosutinib versus imatinib for newly diagnosed chronic myeloid leukemia in the Asian subpopulation of the phase 3 BFORE trial

Bosutinib is approved in the United States, Europe, Japan, and other countries for treatment of newly diagnosed chronic phase (CP) chronic myeloid leukemia (CML), and CML resistant/intolerant to prior therapy. In the phase 3 BFORE trial (Clinicaltrials.gov, NCT02130557), patients were randomized 1:1 to first-line bosutinib or imatinib 400 mg once daily. We examined efficacy, safety, and patient-reported outcomes of bosutinib vs imatinib and pharmacokinetics of bosutinib in the Asian (n = 33 vs 34) and non-Asian (n = 235 vs 234) subpopulations of BFORE followed for at least 24 months. At the data cutoff date, 72.7 vs 66.7% of Asian and 70.6 vs 66.4% of non-Asian patients remained on treatment. The major molecular response rate at 24 months favored bosutinib vs imatinib among Asian (63.6 vs 38.2%) and non-Asian (60.9 vs 52.6%) patients, as did the complete cytogenetic response rate by 24 months (86.7 vs 76.7%, 81.5 vs 76.3%). Treatment-emergent adverse events in both subpopulations were consistent with the primary BFORE results. Trough bosutinib concentration levels tended to be higher in Asian patients. Health-related quality of life was maintained after 12 months of bosutinib in both subpopulations. These results support bosutinib as a first-line treatment option in Asian patients with CP CML.

Appropriate Starting Dose of Dasatinib Based on Analyses of Dose-Limiting Toxicities and Molecular Responses in Asian Patients With Chronic Myeloid Leukemia

BACKGROUND

Dasatinib is administered at a fixed starting dosage of 100 mg once daily regardless of patient-specific factors. However, such fixed dosing may not be optimal for the treatment of Asian patients with chronic myeloid leukemia in chronic phase (CP-CML).

PATIENTS AND METHODS

The dose-limiting toxicities (DLTs) and molecular responses (MRs) of dasatinib therapy were evaluated using clinical data obtained from 102 patients newly diagnosed with CP-CML at 17 hospitals in South Korea.

RESULTS

By 36 months after the initiation of a fixed dose regimen of dasatinib 100 mg once daily as the first-line therapy, 55.9% of patients experienced at least one type of DLT. The 3 most frequent DLTs were thrombocytopenia (45.5%), pericardial or pleural effusion (30.9%), and anemia (7.3%). Patients with higher dasatinib dose adjusted for body weight (Dose/BW) had a greater rate of DLT occurrence (logit [P] = 1.58 × [Dose/BW] - 2.27, P = .03). As median Dose/BW increased from 1.23 to 2.00 mg/kg, the rate of DLT occurrence increased from 43.5% to 66.7% (P = .03). However, Dose/BW did not affect the achievement rate of major MR (60.9% to 69.6%, P = .92).

CONCLUSION

The starting dosage of dasatinib may need to be reduced (eg, 80 mg once daily or lower) for Asian patients with CP-CML, especially with lighter BW, to alleviate the risk of DLT occurrence without compromising the achievement of MR.

A multi-institutional phase Ib/II trial of first-line triplet regimen (Pembrolizumab, Trastuzumab, Chemotherapy) for HER2-positive advanced gastric and gastroesophageal junction cancer (PANTHERA Trial): Molecular profiling and clinical update

218

Background: We report the updated clinical data and molecular profiling results of a multi-institutional phase Ib/II trial of triple combination (pembrolizumab, trastuzumab, and chempotherapy) as first line therapy for HER2 positive advanced gastric and gastroesophageal junction (AGC/GEJ) cancer. (PANTHERA trial; NCT02901301). Methods: Pembrolizumab 200mg IV D1, Trastuzumab 6mg/kg (after 8mg/kg load) D1, Capecitabine 1000mg/m2 bid D1-14, and Cisplatin 80mg/m2 D1 every 3 weeks was selected as recommended phase II dose. The primary endpoint for phase II was ORR per RECIST v1.1. Secondary endpoints included PFS, OS, DOR, safety, and predictive biomarker analysis by targeted NGS. Results: At the time of data lock on Aug 31, 2020, total of 43 patients were treated with median follow up of 18.2 months, and 3 patients remained on the treatment, and 6 patients finished 2-year treatment without progression. ORR was 76.7% (CR 16.3%, PR 60.5%, conversion surgery 4.6%) with 26 pts (56.6%) showing more than 50% of tumor burden reduction. Median PFS was 8.6 months (95% CI 7.2-16.5) and median OS was 19.3 months (95% CI 16.5-NR). There were no MSI-H/dMMR or EBV-positive pts. No patient discontinued pembrolizumab because of immune-related adverse events. Clinical features including PD-L1 status (55.3% of pts ≥ CPS 1 and 13.2% of pts ≥ CPS 10 among available 38 pts), metastatic organ or baseline tumor burden was not related to the survival. Ninety-eight tumor tissues from 39 pts (paired tumor tissues from 22 pts) were analyzed with targeted NGS. Although every pts were HER2 IHC-positive, baseline HER2 amplification by NGS was related to the survival ( HER2 amp (n=8) vs HER2 non-amp (n=23); mPFS, not reached vs 7.7 months, P=0.0178; mOS, not reached vs 17.9 months, P=0.044) but no other signaling pathways predicted pts’ survival. HER2 mutations including L869R or D769H were related to the acquired resistance. High TMB showed a tendency toward better survival (mPFS; High (n=7) vs Low (n=24) TMB, 22.0 vs 8.2, P=0.2835) due to small number of patients. Updated immune markers and serial NGS analyses will be presented. Conclusions: First-line triplet regimen (Pembrolizumab, Trastuzumab, and Chemotherapy) showed promising efficacy based on HER2 amplification by NGS regardless of PD-L1 status in AGC/GEJ cancer. Correlative biomarkers found from NGS study need to be validated through on-going phase III Keynote-811 study. Clinical trial information: NCT02901301. [Table: see text]

A phase II study of gemcitabine, erlotinib and S-1 in patients with advanced pancreatic cancer

Background: We evaluated the efficacy and safety of gemcitabine in combination with erlotinib and S-1 for the treatment of advanced pancreatic cancer.

Methods: Chemotherapy-naïve patients with pathologically-proven locally advanced, recurrent, or metastatic pancreatic adenocarcinoma were assessed for eligibility. Gemcitabine was administered at 1,000 mg/m² intravenously on days 1 and 8, erlotinib was administered at 100 mg/day on days 1-21, and S-1 was administered at 60 mg/m² on days 1-14 every 21 days and continued to a maximum of 8 cycles of treatment. Dose escalation of S-1 to 80 mg/m² was permitted from the second cycle for pre-defined tolerable patients.

Results: Thirty-seven patients (median age 61.5 years) were enrolled. A total of 140 cycles of chemotherapy were administered (median of 3.8; range 1-8 cycles). Toxicities were evaluated in 36 patients, and the responses were evaluated in 32 patients. Major grade 3/4 toxicities included neutropenia (25%), febrile neutropenia (2.8%), fatigue (22.2%), infection (8.3%), vomiting (5.6%), and mucositis (5.6%). The confirmed overall response rate was 12.5% [95% confidence interval (CI), 5.1-28.9%] and the disease control rate was 71.9% (95% CI, 56.8-86.3%). The median progression-free survival and overall survival were 3.7 months (95% CI, 2.8-4.6 months) and 6.7 months (95% CI, 3.4-9.9 months), respectively.

Conclusion: The combination of gemcitabine, erlotinib, and S-1 provided an acceptable toxicity profile and modest clinical benefits in patients with advanced pancreatic cancer.

A randomized phase III trial comparing adjuvant single-agent S1, S-1 with oxaliplatin, and postoperative chemoradiation with S-1 and oxaliplatin in patients with node-positive gastric cancer after D2 resection: the ARTIST 2 trial☆

BACKGROUND

Adjuvant chemotherapy and chemoradiotherapy are some of the standards of care for gastric cancer (GC). The Adjuvant chemoRadioTherapy In Stomach Tumors (ARTIST) 2 trial compares two adjuvant chemotherapy regimens and chemoradiotherapy in patients with D2-resected, stage II or III, node-positive GC.

PATIENTS AND METHODS

The ARTIST 2 compared, in a 1:1:1 ratio, three adjuvant regimens: oral S-1 (40-60 mg twice daily 4 weeks on/2 weeks off) for 1 year, S-1 (2 weeks on/1 week off) plus oxaliplatin 130 mg/m² every 3 weeks (SOX) for 6 months, and SOX plus chemoradiotherapy 45 Gy (SOXRT). Randomization was stratified according to surgery type (total or subtotal gastrectomy), pathologic stage (II or III), and Lauren histologic classification (diffuse or intestinal/mixed). The primary endpoint was disease-free survival (DFS) at 3 years; a reduction of 33% in the hazard ratio (HR) for DFS with SOX or SOXRT, when compared with S-1, was considered clinically meaningful. The trial is registered at clinicaltrials.gov (NCT0176146).

RESULTS

A total of 546 patients were recruited between February 2013 and January 2018 with 182, 181, and 183 patients in the S-1, SOX, and SOXRT arms, respectively. Median follow-up period was 47 months, with 178 DFS events observed. Estimated 3-year DFS rates were 64.8%, 74.3%, and 72.8% in the S-1, SOX, and SOXRT arms, respectively. HR for DFS in the control arm (S-1) was shorter than that in the SOX and SOXRT arms: S-1 versus SOX, 0.692 (P = 0.042) and S-1 versus SOXRT, 0.724 (P = 0.074). No difference in DFS was found between SOX and SOXRT (HR 0.971; P = 0.879). Adverse events were as anticipated in each arm, and were generally well-tolerated and manageable.

CONCLUSIONS

In patients with curatively D2-resected, stage II/III, node-positive GC, adjuvant SOX or SOXRT was effective in prolonging DFS, when compared with S-1 monotherapy. The addition of radiotherapy to SOX did not significantly reduce the rate of recurrence after D2 gastrectomy.

Impact of Sampling Period on Population Pharmacokinetic Analysis of Antibiotics: Why do You Take Blood Samples Following the Fourth Dose?

To date, many population pharmacokinetic models of antibiotics have been developed using blood sampling data after the fourth or fifth dose, which represents steady-state levels. However, if a model developed using blood sampled after the first dose is equivalent to that using blood sampled after the fourth dose, it would be advantageous to utilize the former. The aim of this study was to investigate the effect of blood sampling after the first and/or fourth drug administration on the accuracy and precision of parameter estimates. A previously reported robust, two-compartment model of vancomycin was used for simulation to evaluate the performances of the parameter estimates. The parameter estimation performances were assessed using relative bias and relative root mean square error. Performance was investigated in 72 scenarios consisting of a combination of two blood sampling periods (the first and fourth dose), two total clearances, three infusion times, and four sample sizes. The population pharmacokinetic models from data collected at the first dose and those collected at the fourth dose produced parameter estimates that were similar in accuracy and precision. This study will contribute to increasing the efficiency and simplicity of antibiotic pharmacokinetic studies.

Tepotinib Inhibits the Epithelial-Mesenchymal Transition and Tumor Growth of Gastric Cancers by Increasing GSK3β, E-Cadherin, and Mucin 5AC and 6 Levels

Aberrant expression of mucins (MUCs) can promote the epithelial–mesenchymal transition (EMT), which leads to enhanced tumorigenesis. Carcinogenesis-related pathways involving c-MET and β-catenin are associated with MUCs. In this study, we characterized the expression of EMT-relevant proteins including MET, β-catenin, and E-cadherin in human gastric cancer (GC) cell lines, and further characterized the differential susceptibility of these cell lines compared with the c-MET inhibitor tepotinib. We assessed the antitumor activity of tepotinib in GC cell lines. The effects of tepotinib on cell viability, apoptotic cell death, EMT, and c-MET and β-catenin signaling were evaluated by 3-(4,5 dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl-2-(4-sulfophenyl)-2H-tetrazolium (MTS), flow cytometry, Western blotting, and qRT-PCR. The antitumor efficacy was assessed in MKN45 xenograft mice. Tepotinib treatment induced apoptosis in c-MET-amplified SNU620, MKN45, and KATO III cells, but had no effect on c-MET-reduced MKN28 or AGS cells. Tepotinib treatment also significantly reduced the protein levels of phosphorylated and total c-MET, phosphorylated and total ERK, β-catenin, and c-MYC in SNU620 and MKN45 cells. In contrast, this drug was only slightly active against KATO III cells. Notably, tepotinib significantly reduced the expression of EMT-promoting genes such as MMP7, COX-2, WNT1, MUC5B, and c-MYC in c-MET-amplified GC cells and increased the expression of EMT-suppressing genes such as MUC5AC, MUC6, GSK3β, and E-cadherin. In a mouse model, tepotinib exhibited good antitumor growth activity along with increased E-cadherin and decreased phosphorylated c-MET (phospho-c-MET) protein levels. Collectively, these results suggest that tepotinib suppresses tumor growth and migration by negatively regulating c-MET-induced EMT. These findings provide new insights into the mechanism by which MUC5AC and MUC6 contribute to GC progression.

Genomic analysis of myeloproliferative neoplasm (MPN) patients from a single institution in South Korea to reveal novel pathogenic mutations and perturbed pathways

e19533

Background: Therapeutic, prognostic, and diagnostic insights gained from next generation sequencing (NGS) are a key premise of genomics-informed cancer care in hematological diseases. Particularly in BCR-ABL negative myeloproliferative neoplasms (MPN), insights gained from NGS is integral for risk stratification and prognostication. In this study, MPN patients of South Korean descent were sequenced, interpreted, and compared with a published validation cohort to identify variations in mutational profiles specific to demographics. Methods: 31 South Korean MPN patients including 12 essential thrombocythemia, 6 polycythemia vera, 6 primary myelofibrosis, and 7 chronic myelogenous leukemia were sequenced in 2018 and 2019 using the 54 gene Illumina TruSight Myeloid Panel at Hallym University College of Medicine. Orthogonal testing for CALR mutations was done by Sanger sequencing. Watson for Genomics (WfG), an artificial intelligence offering was used for variant interpretation and annotation. A cohort of 151 MPN patients previously published in the New England Journal of Medicine (NEJM) was used for comparison (PMID:24325359). Results: The table shows identified actionable mutations. Conclusions: Two novel pathogenic mutations in CALR (c.1162delG and c.1100_1145del)) were identified in Korean MPN patients. NOTCH1 pathogenic mutations were exclusive while TP53 mutations were significantly enriched in the Korean cohort suggesting that these pathways may play a role in MPN. TP53 mutations in MPN are clinically significant as they have been associated with increased risk for leukemic transformation. Of note, MPL mutations were not detected in the Korean cohort. In conclusion, race and ethnicity may contribute to some mutational signatures in cancer. [Table: see text]

Tepotinib inhibits the epithelial-mesenchymal transition and tumor growth of gastric cancers via increasing GSK3β, ECAD, MUC5AC, and MUC6

e16562

Background: Aberrant expression of mucins can promote the epithelial-mesenchymal transition (EMT), which leads to enhanced tumorigenesis. Carcinogenesis-related pathways involving c-MET and beta-catenin involve mucins. This study characterized expressions of MET, MUC5AC, MUC5B, and MUC6 EMT signaling in human gastric cancer (GC) cell lines, and further characterized the differential susceptibility of these cell lines to tepotinib. Methods: We assessed the antitumor activity of tepotinib in GC cell lines. The effect of tepotinib on cell viability (IC50), apoptotic cell death, the EMT, and c-MET and beta-catenin signaling were evaluated by MTS assay, flow cytometry, western blotting, and qRT-PCR. Antitumor efficacy was assessed in MKN45 xenograft mice. Results: Tepotinib treatment showed dose-dependent growth inhibition of c-MET-amplified SNU620, MKN45, and KATO III cells with concomitant induction of apoptosis, but tepotinib treatment did not have an effect on c-MET-reduced MKN28 and AGS cells. Tepotinib treatment also significantly reduced expressions of phospho-c-MET, total c-MET, phospho-ERK, total ERK, beta-catenin, and c-Myc protein in SNU620 and MKN45 cells. In contrast, this drug was only slightly active against KATO III cells. Notably, tepotinib significantly reduced the expressions of EMT promotion genes such as MMP7, COX-2, WNT1, MUC5B, and c-Myc in c-MET-expressed GC cells, and increased expressions of EMT suppression genes such as MUC5AC, MUC6, GSK3beta, and ECAD. In a murine xenograft model, tumor volumes were significantly reduced in the tepotinib-treated group, when administered by daily oral gavage at a dose of 10mg/kg/day. Histologically, tepotinib induced more necrosis than in the control group. Conclusions: These data show the possibility that tepotinib may have therapeutic effects in c-MET-amplified GC, suggesting that clinical studies need to confirm the therapeutic effect.

Targeting HER2 in combination with anti-PD-1 and chemotherapy confers a significant tumor shrinkage of gastric cancer: A multi-institutional phase Ib/II trial of first-line triplet regimen (pembrolizumab, trastuzumab, chemotherapy) for HER2-positive advanced gastric cancer (AGC)

3081

Background: Combining anti-PD-1 agent and trastuzumab has shown synergy in HER2 positive preclinical cancer models. We first report the result of a multi-institutional phase Ib/II trial of triple combination (pembrolizumab, trastuzumab, and chempotherapy) as first line therapy for HER2 positive AGC. (PANTHERA trial; NCT02901301). Methods: Pembrolizumab 200mg IV D1, Trastuzumab 6mg/kg (after 8mg/kg load) D1, Capecitabine 1000mg/m2 bid D1-14, and Cisplatin 80mg/m2 D1 every 3 weeks was selected as recommended phase II dose. The primary endpoint for phase II was ORR per RECIST v1.1. Secondary endpoints included PFS, OS, DoR, safety, and molecular analysis by targeted NGS. Results: Total of 43 patients were treated with median follow up of 16.1 months, and 11 pts remained on the treatment (treatment duration range: 1.4 to 24 months). There was significant tumor shrinkage of 95.3% with 54.6% median depth of response, with 76.7% ORR (CR 16.3%, PR 60.5%, conversion surgery 4.6%), and 97.7% DCR. Median PFS was 8.6 months (95% CI 7.2-22.0) and median OS was 18.4 months (95% CI 17.9-NA). Subsequent chemotherapy was given to 83.3% of 30 progressed pts. There were no MSI-H/dMMR or EBV-positive pts. PD-L1 status (57.1% of pts ≥ CPS 1 and 14.3% of pts ≥ CPS 10 among 35 pts), metastatic organ or baseline tumor burden was not related to the survival. Treatment-related AE (≥G3) occurred in 32 pts (74.4%) including 17 pts (39.5%) with neutropenia G3-4. Immune-related AEs (≥G3) occurred in 4 pts (10%). Ninety-six tumor tissues from 32 pts (paired tumor tissues from 25 pts) were analyzed with targeted NGS. TMB (median 12.7 mut/MB with range of 9.45-16.71) was not related to the PD-L1 expression or survival. Conclusions: First-line triplet regimen (Pembrolizumab, Trastuzumab, and Chemotherapy) confers a significant tumor shrinkage for HER2 positive AGC, regardless of PD-L1 status. Phase III Keynote-811 study (NCT03615326) is ongoing based on the protocol of this study. Clinical trial information: NCT02901301 . [Table: see text]