Pragmatic nationwide master observational trial based on genomic alterations in advanced solid tumors: KOrean Precision Medicine Networking Group Study of MOlecular profiling guided therapy based on genomic alterations in advanced Solid tumors (KOSMOS)-II study protocol KCSG AL-22-09

BACKGROUND

Next-generation sequencing (NGS) has been introduced to many Korean institutions to support molecular diagnostics in cancer since 2017, when it became eligible for reimbursement by the National Health Insurance Service. However, the uptake of molecularly guided treatment (MGT) based on NGS results has been limited because of stringent regulations regarding prescriptions outside of approved indications, a lack of clinical trial opportunities, and limited access to molecular tumor boards (MTB) at most institutions. The KOSMOS-II study was designed to demonstrate the feasibility and effectiveness of MGT, informed by MTBs, using a nationwide precision medicine platform.

METHODS

The KOSMOS-II trial is a large-scale nationwide master observational study. It involves a framework for screening patients with metastatic solid tumors for actionable genetic alterations based on local NGS testing. It recommends MGT through a remote and centralized MTB meeting held biweekly. MGT can include one of the following options: Tier 1, the therapeutic use of investigational drugs targeting genetic alterations such as ALK, EGFR, ERBB2, BRAF, FH, ROS1, and RET, or those with high tumor mutational burden; Tier 2, comprising drugs with approved indications or those permitted for treatment outside of the indications approved by the Health Insurance Review and Assessment Service of Korea; Tier 3, involving clinical trials matching the genetic alterations recommended by the MTB. Given the anticipated proportion of patients receiving MGT in the range of 50% ± 3.25%, this study aims to enroll 1,000 patients. Patients must have progressed to one or more lines of therapy and undergone NGS before enrollment.

DISCUSSION

This pragmatic master protocol provides a mass-screening platform for rare genetic alterations and high-quality real-world data. Collateral clinical trials, translational studies, and clinico-genomic databases will contribute to generating evidence for drug repositioning and the development of new biomarkers.

TRIAL REGISTRATION

NCT05525858.

Varlitinib and Paclitaxel for EGFR/HER2 Co-Expressing Advanced Gastric Cancer: a Multicenter Phase Ib/II Study (K-MASTER-13)

Purpose

Varlitinib is a pan-human epidermal growth (HER) inhibitor targeting epidermal growth factor receptor (EGFR), HER2, and HER4. We present a phase Ib/II study of a combination of varlitinib and weekly paclitaxel as a second-line treatment for patients with EGFR/HER2 co-expressing advanced gastric cancer (AGC).

Materials and Methods

Patients whose tumors with EGFR and HER2 overexpression by immunohistochemistry (IHC) (≥1+) were enrolled. Varlitinib and paclitaxel were investigated every 4 weeks. After determining the recommended phase II dose (RP2D) in phase Ib, a phase II study was conducted to evaluate the antitumor activity.

Results

RP2D was treated with a combination of varlitinib (300 mg twice daily) and paclitaxel. Among 27 patients treated with RP2D, the median PFS and overall survival (OS) were 3.3 months and 7.9 months, respectively, with a median follow-up of 15.7 months. Among 16 patients with measurable disease, the objective response rate (ORR) and disease control rate were 31% and 88%, respectively. Patients with strong HER2 expression (n=8) had a higher ORR and longer OS, whereas those with strong EGFR expression (n=3) had poorer outcomes. The most common adverse events (AEs) of any grade were neutropenia (52%), diarrhea (27%), AST/ALT elevation (22%), and nausea (19%). No treatment-related deaths or unexpected AEs resulting from treatment cessation were observed in patients with RP2D.

Conclusion

A combination of varlitinib and paclitaxel displayed manageable toxicity and modest antitumor activity in patients with EGFR/HER2 co-expressing AGC who progressed after first-line chemotherapy.

Comparison of Tepotinib, Paclitaxel, or Ramucirumab Efficacy According to the Copy Number or Phosphorylation Status of the MET Gene: Doublet Treatment versus Single Agent Treatment

Although conventional combination chemotherapies for advanced gastric cancer (GC) increase survival, such therapies are associated with major adverse effects; more effective and less toxic treatments are required. Combinations of different anti-cancer drugs, for example, paclitaxel plus ramucirumab, have recently been used as second-line treatments for advanced GC. This study evaluated how copy number variations of the MET gene, MET mutations, and MET gene and protein expression levels in human GC cells modulate the susceptibility of such cells to single-agent (tepotinib, ramucirumab, or paclitaxel) and doublet (tepotinib-plus-paclitaxel or ramucirumab-plus-paclitaxel treatment regimens. Compared with ramucirumab-plus-paclitaxel, tepotinib-plus-paclitaxel better inhibited the growth of GC cells with MET exon 14 skipping mutations and those lacking MET amplification but containing phosphorylated MET; such inhibition was dose-dependent and associated with cell death. Tepotinib-plus-paclitaxel and ramucirumab-plus-paclitaxel similarly inhibited the growth of GC cells lacking MET amplification or MET phosphorylation, again in a dose-dependent manner, but without induction of cell death. However, tepotinib alone or tepotinib-plus-ramucirumab was more effective against c-MET-positive GC cells (>30 copy number variations) than was ramucirumab or paclitaxel alone or ramucirumab-plus-paclitaxel. These in vitro findings suggest that compared with ramucirumab-plus-paclitaxel, tepotinib-plus-paclitaxel better inhibits the growth of c-MET-positive GC cells, cells lacking MET amplification but containing phosphorylated MET, and cells containing MET mutations. Clinical studies are required to confirm the therapeutic effects of these regimens.

Open-Label, Multicenter, Randomized, Biomarker-Integrated Umbrella Trial for Second-Line Treatment of Advanced Gastric Cancer: K-Umbrella Gastric Cancer Study

PURPOSE

This study aimed to screen targeted agents as second-line treatment with a standard-of-care (SOC) controlled umbrella trial design in advanced gastric cancer (AGC).

PATIENTS AND METHODS

Patients with HER2-negative AGC from eight Korean cancer centers were screened for druggable targets using immunohistochemistry (IHC) and in situ hybridization, and randomly assigned to the biomarker versus control group at a 4:1 ratio. In the biomarker group, patients were treated with specific targeted agent plus paclitaxel: pan-ERBB inhibitor for epidermal growth factor receptor (EGFR) 2+/3+ patients (afatinib; EGFR cohort), PIK3Cβ inhibitor for phosphatase and tensin homolog (PTEN) loss/null patients (GSK2636771; PTEN cohort), and anti-PD-1 inhibitor for PD-L1+, deficient mismatch repair/microsatellite instability-high, or Epstein-Barr virus-related cases (nivolumab; NIVO cohort). NONE cohort in the biomarker group without predefined biomarkers and control group received SOC (paclitaxel with or without ramucirumab). The primary end point was progression-free survival (PFS), and the secondary end points were efficacy and safety.

RESULTS

A total of 318 patients were randomly assigned into the control (n = 64) and biomarker (n = 254; EGFR, n = 67; PTEN, n = 37; NIVO, n = 48; NONE, n = 102) groups. Median follow-up was 35 months. Median PFS and overall survival (OS) were 3.7 (95% CI, 3.1 to 4.1) and 8.6 (95% CI, 7.6 to 9.8) months in the biomarker group and 4.0 (95% CI, 3.0 to 4.6) and 8.7 (95% CI, 7.1 to 9.9) months in the control group. Afatinib addition led to marginal survival benefits to patients with EGFR 3+ compared with SOC (PFS, 4.0 v 2.2 months; P = .09), but GSK2636771 did not prolong the survival of patients with PTEN loss. Addition of nivolumab showed a durable survival benefit (median OS, 12.0 v 7.6 months; P = .08).

CONCLUSION

Although biomarker group did not show better survival than the control group, IHC-based screening and allocation of patients with AGC to the second-line treatment in an umbrella design were feasible for effective early screening of novel agents.

A Phase 3 Randomized Clinical Trial to Compare Efficacy and Safety between Combination Therapy and Monotherapy in Elderly Patients with Advanced Gastric Cancer (KCSG ST13-10)

PURPOSE

This study evaluated whether combination therapy is more effective than monotherapy in elderly patients with metastatic or recurrent gastric cancer (MRGC) as first-line chemotherapy.

MATERIALS AND METHODS

Elderly (≥ 70 years) chemo-naïve patients with MRGC were allocated to receive either combination therapy (group A: 5-fluorouracil [5-FU]/oxaliplatin, capecitabine/oxaliplatin, capecitabine/cisplatin, or S-1/cisplatin) or monotherapy (group B: 5-FU, capecitabine, or S-1). In group A, starting doses were 80% of standard doses, and they could be escalated to 100% at the discretion of the investigator. Primary endpoint was to confirm superior overall survival (OS) of combination therapy vs. monotherapy.

RESULTS

After 111 of the planned 238 patients were randomized, enrollment was terminated due to poor accrual. In the full-analysis population (group A [n=53] and group B [n=51]), median OS of combination therapy vs. monotherapy was 11.5 vs. 7.5 months (hazard ratio [HR], 0.86; 95% confidence interval [CI], 0.56 to 1.30; p=0.231). Median progression-free survival (PFS) was 5.6 vs. 3.7 months (HR, 0.53; 95% CI, 0.34 to 0.83; p=0.005). In subgroup analyses, patients aged 70-74 years tended to have superior OS with combination therapy (15.9 vs. 7.2 months, p=0.056). Treatment-related adverse events (TRAEs) occurred more frequently in group A vs. group B. However, among severe TRAEs (≥ grade 3), there were no TRAEs with a frequency difference of > 5%.

CONCLUSION

Combination therapy was associated with numerically improved OS, although statistically insignificant, and a significant PFS benefit compared with monotherapy. Although combination therapy showed more frequent TRAEs, there was no difference in the frequency of severe TRAEs.

Trastuzumab Combined With Ramucirumab and Paclitaxel in Patients With Previously Treated Human Epidermal Growth Factor Receptor 2-Positive Advanced Gastric or Gastroesophageal Junction Cancer

PURPOSE

Trastuzumab-containing chemotherapy is the recommended first-line regimen for human epidermal growth factor receptor 2 (HER2)-positive advanced gastric or gastroesophageal junction (G/GEJ) cancer. We evaluated the safety and efficacy of trastuzumab combined with ramucirumab and paclitaxel as second-line treatment for HER2-positive G/GEJ cancer.

PATIENTS AND METHODS

Patients with HER2-positive advanced G/GEJ cancer who progressed after first-line treatment with trastuzumab-containing chemotherapy were enrolled from five centers in the Republic of Korea. Patients were administered a 28-day cycle of trastuzumab (once on days 1, 8, 15, and 22: 2 mg/kg followed by 4 mg/kg loading dose), ramucirumab (once on days 1 and 15: 8 mg/kg), and paclitaxel (once on days 1, 8, and 15: dose level 1, 80 mg/m2; or dose level -1, 70 mg/m2). Phase II was conducted with the recommended phase II dose (RP2D). Primary end points were determination of RP2D during phase Ib and investigator-assessed progression-free survival (PFS) in patients treated with RP2D.

RESULTS

Dose-limiting toxicity at dose level 1 was not documented during phase Ib, and a full dose combination was selected as the RP2D. Among 50 patients with a median follow-up duration of 27.5 months (95% CI, 17.4 to 37.6), median PFS and overall survival were 7.1 months (95% CI, 4.8 to 9.4) and 13.6 months (95% CI, 9.4 to 17.7), respectively. Objective response rate was 54% (27 of 50, including one complete response), and disease control rate was 96% (48 of 50). Loss of HER2 expression was observed in 34.8% (8 of 23) patients after first-line treatment, and no definite association between HER2 expression and the outcome was revealed. Safety profiles were consistent with previous reports.

CONCLUSION

Trastuzumab combined with ramucirumab and paclitaxel showed appreciable efficacy with manageable safety profiles in patients with previously treated HER2-positive G/GEJ cancer.

AZD8186 in Combination With Paclitaxel in Patients With Advanced Gastric Cancer: Results From a Phase Ib/II Study (KCSG ST18-20)

BACKGROUND

Loss of PTEN function leads to increased PI3Kβ signaling. AZD8186, a selective PI3Kβ/δ inhibitor, has shown anti-tumor activity in PTEN-deficient preclinical models. Although the combination of AZD8186 and paclitaxel was well tolerated, limited clinical efficacy was observed in advanced gastric cancer with PTEN loss.

METHODS

In the phase Ib dose-escalation, subjects with advanced solid tumors received oral AZD8186 (60 mg or 120 mg; twice daily (BID); 5 days on/2 days off) plus intravenous paclitaxel (70 mg/m2 or 80 mg/m2; days 1, 8, and 15) every 4 weeks. In the phase II part, MRGC patients with PTEN loss or PTEN/PIK3CB gene abnormality were enrolled and received recommended phase II dose (RP2D) of AZD8186 plus paclitaxel. Primary endpoints were to determine maximum tolerated dose (MTD) and RP2D in phase Ib and 4-month progression-free survival (PFS) rate in phase II.

RESULTS

In phase Ib, both MTD and RP2D were determined at paclitaxel 80 mg/m2 and AZD8186 120 mg BID. In phase II, 18 patients were enrolled [PTEN loss (n = 18) and PIK3CB mutation (n = 1)]. The 4-month PFS rate was 18.8% (3 of 16 evaluable patients) and further enrollment stopped due to futility.

CONCLUSION

Although the combination of AZD8186 and paclitaxel was well tolerated, limited clinical efficacy was observed.ClinicalTrials.gov Identifier: NCT04001569.

Phase II study of the combination of durvalumab, tremelimumab, and paclitaxel as second-line chemotherapy in biomarker-selected patients with metastatic gastric cancer

401

Background: Currently, ramucirumab plus paclitaxel is the standard second-line chemotherapy in metastatic gastric cancer (mGC), however, its efficacy is very limited. MSI, PD-L1 (CD274), and EBV have been suggested as predictive biomarkers for immune checkpoint inhibitors in mGC. This study was conducted to evaluate efficacy and safety of the combination of durvalumab, tremelimumab, and paclitaxel as a second-line chemotherapy in mGC with potential biomarkers for immune checkpoint inhibitors. Methods: The combination of durvalumab, tremelimumab, and paclitaxel consisted of 1500 mg of i.v. durvalumab on day 1, every 4 weeks for 13 cycles, 75 mg of i.v. tremelimumab on day 1 every 4 weeks for 4 cycles, and 60 mg/m2 of i.v. paclitaxel on days 1, 8, and 15, every 4 weeks until disease progression or unacceptable toxicities. Patients (pts) with MSI-high mGC, EBV-positive mGC, or mGC with CD274 amplification, mutations of mismatch repair or POL gene, or tumor mutation burden (TMB) >5/Mb were included in second-line setting. Results: Forty-eight pts were enrolled. Overall response rate (ORR) was 52.1% with complete response in 4 (8.3%) pts, partial response in 21 (43.8%), stable disease in 14 (29.2%), and progressive disease in 8 (16.7%), and with response not evaluable in 1 (2.0%). With a median follow-up of 18.0 months (range, 7.1-39.4), the median progression-free survival (PFS) and overall survival (OS) were 5.3 months (95% CI, 3.7-6.9) and 13.1 months (95% CI, 5.2-21.0 ), respectively. Compared to mGC with other genetic alterations (n=25), mGC with TMB >20/Mb or MSI-high mGC (n=23) tended to have a higher ORR (56.5% vs 48%), and a prolonged PFS (median 7.2 vs 4.5 months; 44.0 vs 20.8% at 1 year). The combination chemotherapy was generally well tolerable; treatment-related grade 3 or 4 adverse events with frequency >5% included only neutropenia (10.4%) and anemia (8.3%), and there was no treatment-related death. Conclusions: The combination chemotherapy of durvalumab, tremelimumab, and paclitaxel showed encouraging efficacy, especially in mGC with TMB >20/Mb or MSI-high mGC, as a second-line chemotherapy with manageable toxicities in biomarker-selected mGC. Clinical trial information: NCT03751761 .

Randomized phase II study of capecitabine plus cisplatin with or without sorafenib in patients with metastatic gastric cancer (STARGATE)

BACKGROUND

In this randomized phase II study, we evaluated the efficacy and safety of sorafenib in combination with capecitabine and cisplatin (XP) as first-line chemotherapy in advanced gastric cancer.

PATIENTS AND METHODS

Patients with metastatic gastric or gastroesophageal junction adenocarcinoma were randomized (1:1) to receive either sorafenib plus XP (S + XP) or XP alone. In cases of disease progression in the XP arm, crossover to sorafenib alone was allowed. The primary endpoint was progression-free survival (PFS). The secondary endpoints included overall survival (OS), response rates, safety profiles, and biomarkers, and the response rates and PFS with secondline sorafenib alone after progression in the XP arm.

RESULTS

Between Jan 2011 and Feb 2013, a total of 195 patients were accrued (97 in the S + XP arm and 98 in the XP alone arm). The overall response rate was 54% with S + XP, and 52% with XP alone (p = 0.83). With a median follow-up of 12.6 months (range, 0.1-29.2), the median PFS assessed by independent review was 5.6 months in the S + XP arm and 5.3 months in the XP arm (hazard ratio [HR] 0.92, 95% confidence interval [CI] 0.67-1.27, p = 0.61). Overall survival was not different between the two arms (median 11.7 vs. 10.8 months; HR 0.93, 95% CI 0.65-1.31, p = 0.66). Frequencies of grade 3/4 toxicities were similar between the S + XP and XP alone arms, except for neutropenia (21% vs. 37%), anorexia (0% vs. 5%), and hand-foot skin reaction (7% vs. 1%). Among 51 patients who crossed over to sorafenib alone after disease progression in the XP arm, there was no objective response and their median PFS was 1.3 months (95% CI, 1.2-1.7).

CONCLUSION

The addition of sorafenib to XP chemotherapy was safe but not more effective than XP alone for first-line treatment of metastatic gastric cancer.

Oxaliplatin (3 months v 6 months) With 6 Months of Fluoropyrimidine as Adjuvant Therapy in Patients With Stage II/III Colon Cancer: KCSG CO09-07

PURPOSE

The combination of oxaliplatin and fluoropyrimidine for 6 months is one of the standard options for adjuvant therapy for high-risk stage II and III colorectal cancers (CRCs). The optimal duration of oxaliplatin to diminish neurotoxicity without compromising efficacy needs to be clarified.

PATIENTS AND METHODS

This open-label, randomized, phase III, noninferiority trial randomly assigned patients with high-risk stage II and III CRC to 3 and 6 months of oxaliplatin with 6 months of fluoropyrimidine groups (3- and 6-month arms, respectively). The primary end point was disease-free survival (DFS), and the noninferiority margin was a hazard ratio (HR) of 1.25.

RESULTS

In total, 1,788 patients were randomly assigned to the 6-month (n = 895) and 3-month (n = 893) arms, and 83.6% in the 6-month arm and 85.7% in the 3-month arm completed the treatment. The neuropathy rates with any grade were higher in the 6-month arm than in the 3-month arm (69.5% v 58.3%; P < .0001). The 3-year DFS rates were 83.7% and 84.7% in the 6-month and 3-month arms, respectively, with an HR of 0.953 (95% CI, 0.769 to 1.180; test for noninferiority, P = .0065) within the noninferiority margin. Among patients with stage III CRC treated by capecitabine plus oxaliplatin, the 3-year DFS of the 3-month arm was noninferior as compared with that of the 6-month arm with an HR of 0.713 (95% CI, 0.530 to 0.959; P = .0009). However, among patients with high-risk stage II and stage III CRC treated by infusional fluorouracil, leucovorin, and oxaliplatin, the noninferiority of the 3-month arm compared with the 6-month arm was not proven.

CONCLUSION

This study suggests that adding 3 months of oxaliplatin to 6 months of capecitabine could be considered an alternative adjuvant treatment for stage III CRC (ClinicalTrials.gov identifier: NCT01092481).

A single arm phase Ib/II trial of first-line pembrolizumab, trastuzumab and chemotherapy for advanced HER2-positive gastric cancer

In this multi-center phase II trial, we evaluated the efficacy and safety of a quadruplet regimen (pembrolizumab, trastuzumab, and doublet chemotherapy) as first-line therapy for unresectable or metastatic human epidermal growth factor receptor 2 (HER2)-positive advanced gastric cancer (AGC) (NCT02901301). The primary endpoints were recommended phase 2 dose (RP2D) for phase Ib and objective response rate (ORR) for phase II. The secondary endpoints included progression-free survival (PFS), overall survival (OS), duration of response, time to response and safety. Without dose-limiting or unexpected toxicities, the starting dose in the phase Ib trial was selected as RP2D. In 43 patients, the primary endpoint was achieved: the objective response rate was 76.7% (95% confidence interval [CI]: 61.4-88.2), with complete and partial responses in 14% and 62.8% of patients, respectively. The median progression-free survival, overall survival, and duration of response were 8.6 months, 19.3 months, and 10.8 months, respectively. No patients discontinued pembrolizumab because of immune-related adverse events. Programmed death ligand-1 status was not related to survival. Post hoc analyses of pretreatment tumor specimens via targeted sequencing indicated that ERBB2 amplification, RTK/RAS pathway alterations, and high neoantigen load corrected by HLA-B were positively related to survival. The current quadruplet regimen shows durable efficacy and safety for patients with HER2-positive AGC.

PWWP2B promotes DNA end resection and homologous recombination

Genome instability is one of the leading causes of gastric cancers. However, the mutational landscape of driver genes in gastric cancer is poorly understood. Here, we investigate somatic mutations in 25 Korean gastric adenocarcinoma patients using whole-exome sequencing and show that PWWP2B is one of the most frequently mutated genes. PWWP2B mutation correlates with lower cancer patient survival. We find that PWWP2B has a role in DNA double-strand break repair. As a nuclear protein, PWWP2B moves to sites of DNA damage through its interaction with UHRF1. Depletion of PWWP2B enhances cellular sensitivity to ionizing radiation (IR) and impairs IR-induced foci formation of RAD51. PWWP2B interacts with MRE11 and participates in homologous recombination via promoting DNA end-resection. Taken together, our data show that PWWP2B facilitates the recruitment of DNA repair machinery to sites of DNA damage and promotes HR-mediated DNA double-strand break repair. Impaired PWWP2B function might thus cause genome instability and promote gastric cancer development.

Long-term follow-up results of cytarabine-containing chemotherapy for acute promyelocytic leukemia

BACKGROUND/AIMS

We evaluated the feasibility and long-term efficacy of the combination of cytarabine, idarubicin, and all-trans retinoic acid (ATRA) for treating patients with newly diagnosed acute promyelocytic leukemia (APL).

METHODS

We included 87 patients with newly diagnosed acute myeloid leukemia and a t(15;17) or promyelocytic leukemia/retinoic acid receptor alpha (PML-RARα) mutation. Patients received 12 mg/m2/day idarubicin intravenously for 3 days and 100 mg/m2/day cytarabine for 7 days, plus 45 mg/m2/day ATRA. Clinical outcomes included complete remission (CR), relapse-free survival (RFS), overall survival (OS), and the secondary malignancy incidence during a 20-year follow-up.

RESULTS

The CR, 10-year RFS, and 10-year OS rates were 89.7%, 94.1%, and 73.8%, respectively, for all patients. The 10-year OS rate was 100% for patients that achieved CR. Subjects were classified according to the white blood cell (WBC) count in peripheral blood at diagnosis (low-risk, WBC < 10,000/mm3; high-risk, WBC ≥ 10,000/mm3). The low-risk group had significantly higher RFS and OS rates than the high-risk group, but the outcomes were not superior to the current standard treatment (arsenic trioxide plus ATRA). Toxicities were similar to those observed with anthracycline plus ATRA, and higher than those observed with arsenic trioxide plus ATRA. The secondary malignancy incidence after APL treatment was 2.7%, among the 75 patients that achieved CR, and 5.0% among the 40 patients that survived more than 5 years after the APL diagnosis.

CONCLUSION

Adding cytarabine to anthracycline plus ATRA was not inferior to anthracycline plus ATRA alone, but it was not comparable to arsenic trioxide plus ATRA. The probability of secondary malignancy was low.

Safety and efficacy of nilotinib in adult patients with chronic myeloid leukemia: a post-marketing surveillance study in Korea

Background

Nilotinib is a tyrosine kinase inhibitor approved by the Ministry of Food and Drug Safety for frontline and 2nd line treatment of Philadelphia chromosome-positive chronic myeloid leukemia (Ph⁺ CML). This study aimed to confirm the safety and efficacy of nilotinib in routine clinical practice within South Korea.

Methods

An open-label, multicenter, single-arm, 12-week observational post-marketing surveillance (PMS) study was conducted on 669 Korean adult patients with Ph⁺ CML from December 24, 2010, to December 23, 2016. The patients received nilotinib treatment in routine clinical practice settings. Safety was evaluated by all types of adverse events (AEs) during the study period, and efficacy was evaluated by the complete hematological response (CHR) and cytogenetic response.

Results

During the study period, AEs occurred in 61.3% (410 patients, 973 events), adverse drug reactions (ADRs) in 40.5% (271/669 patients, 559 events), serious AEs in 4.5% (30 patients, 37 events), and serious ADRs in 0.7% (5 patients, 8 events). Furthermore, unexpected AEs occurred at a rate of 6.9% (46 patients, 55 events) and unexpected ADRs at 1.2% (8 patients, 8 events). As for the efficacy results, CHR was achieved in 89.5% (442/494 patients), and minor cytogenetic response or major cytogenetic response was achieved in 85.8% (139/162 patients).

Conclusion

This PMS study shows consistent results in terms of safety and efficacy compared with previous studies. Nilotinib was well tolerated and efficacious in adult Korean patients with Ph⁺ CML in routine clinical practice settings.

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

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

The first report of K-Umbrella Gastric Cancer Study: An open label, multi-center, randomized, biomarker-integrated trial for second-line treatment of advanced gastric cancer (AGC)

4001

Background: To explore proper agents for AGC patients as 2nd-line treatment based on optimal biomarker, we conducted K-Umbrella GC study with standard of care (SOC) controlled umbrella trial design. Methods: HER2-negative AGC patients from 6 Korean cancer centers were centrally screened for druggable targets by IHC and in situ hybridization. Patients were randomized to the biomarker vs. control group with SOC as 4:1 ratio. In the biomarker group, patients were treated with specific targeted agents in combination with weekly paclitaxel; 1) EGFR 2+/3+ patients for pan-ERBB inhibitor (afatinib; EGFR cohort), 2) PTEN loss/null (H-score <100) patients for PIK3Cβ inhibitor (GSK2636771; PTEN cohort), and 3) PD-L1+, dMMR/MSI-high, or EBV-related cases for anti-PD-1 inhibitor (nivolumab; NIVO cohort). Control group and NONE cohort in biomarker group without predefined biomarkers were treated with SOC (weekly Paclitaxel±Ramucirumab). Primary endpoint was PFS between control and biomarker groups. Secondary endpoints included efficacy and safety of each cohort. Results: Between Feb 2016 and Feb 2021, total 722 patients were centrally screened. 329 patients were enrolled and randomized to control group (n=63) or biomarker group (n=266; EGFR cohort n=67; PTEN cohort n=42; NIVO cohort n=54; NONE cohort n=103). With a median follow-up of 35 months (95%CI 26.1-55.3), median PFS and OS were 3.8 (95%CI 3.2-4.3) and 8.9 (95%CI 7.8-10.1) months for biomarker group and 4.1 (95%CI 3.0-4.8) and 8.7 months (95%CI 7.2-10.2) for control group. In control group, PTEN loss/null was poor prognostic marker; patients with PTEN loss/null (n=12) showed worse survival compared to PTEN intact patients (n=51) (mPFS, 2.8 vs 4.3 months, P=0.03; mOS, 8.7 vs 9.1 months), where other biomarkers showed similar prognosis. Afatinib for EGFR cohort or GSK2636771 for PTEN cohort did not show significant survival benefit compared to control group (Table). Among patients with immune-related biomarkers, addition of nivolumab showed durable survival benefit (mOS 12.0 vs 7.6 months, P=0.08) compared to SOC. Conclusions: Considering the characteristics of umbrella design with multiple biomarkers having different biological roles, biomarker group did not show the improved survival over control arm with these 3 drugs. For optimal biomarker-driven targeted agent applications, NGS-based biomarker driven K-Umbrella GC-2 study is ongoing. Clinical trial information: NCT02951091. [Table: see text]

Responses to the MET inhibitor tepotinib in gastric cancers with MET amplification or both high PD-L1 expression and an MET exon 14 skipping mutation

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Background: Aberrant expression of MET involving MET exon 14 (METex14) alteration and high CNV, which leads to enhanced tumorigenesis. In addition, the PD-L1 (CD274) is often upregulated in cancers. This study characterized expressions of MET (including METex14 skipping mutation), PD-L1 and CD44 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. CNV analysis using targeted next-generation sequencing (NGS) techniques. The effect of tepotinib on cell viability (IC50), apoptotic cell death, migration, the PD-L1, CD44 and c-MET signaling were evaluated by MTS assay, flow cytometry, wound-healing assay, western blotting, and qRT-PCR. Results: Tepotinib treatment showed dose-dependent growth inhibition of c-MET-amplified SNU620, MKN45, Hs746T, SNU638 and KATO III cells with concomitant induction of apoptosis. Tepotinib treatment also significantly reduced expressions of phospho-c-MET, total c-MET, VEGFR2, Snail and c-Myc protein in SNU620, MKN45 and Hs746T cells. Especially, tepotinib significantly reduced the expressions of CD44 and PD-L1 in METex14 skipping mutated Hs746T cells. In contrast, this drug was only slightly active against KATO III and SNU638 cells. Migrations were more reduced in the tepotinib-treated group than in the control group. Conclusions: These data show the possibility that tepotinib may have therapeutic effects in c-MET-amplified GC and both high PD-L1 expression and an MET exon 14 skipping mutation, suggesting that clinical studies need to confirm the therapeutic effect.

Ramucirumab plus paclitaxel as a second-line treatment in HER2-positive gastric cancer: subgroup analysis of a nationwide, real-world study in Korea (KCSG-ST19-16)

BACKGROUND

A subgroup analysis of data from a nationwide study (KCSG-ST19-16) was performed to evaluate the efficacy and safety of second-line ramucirumab plus paclitaxel treatment in patients with human epidermal growth factor receptor 2 (HER2)-positive advanced gastric or gastro-esophageal junction (GEJ) adenocarcinoma.

METHODS

The KCSG-ST19-16 study enrolled a total of 1063 patients from 56 hospitals in South Korea with advanced gastric or GEJ adenocarcinoma, who had received second-line treatment with ramucirumab plus paclitaxel. HER2 status was known for 994 (93.5%) of these patients, who were thus included in the subgroup analysis.

RESULTS

In total, 163 of 994 patients (16.4%), had HER2-positive gastric or GEJ adenocarcinoma. The objective response rate to ramucirumab plus paclitaxel treatment was significantly higher in patients with HER2-positive disease compared to those with HER2-negative disease (23.0% [95% confidence interval (CI), 15.9-30.1] vs. 15.1% [95% CI, 12.3-17.9], p = 0.025). The median progression-free survival was longer in patients with HER2-positive versus HER2-negative disease, but the difference was not statistically significant (4.3 months [95% CI, 3.7-5.3] vs 3.7 months [95% CI, 3.4-4.0], p = 0.054). There was no statistically significant difference in median overall survival (OS) between the groups (9.8 months [95% CI, 8.9-12.3] vs 10.1 months [95% CI, 9.2-10.9], p = 0.564).

CONCLUSIONS

In patients with HER2-positive gastric or GEJ adenocarcinoma, the objective response rate to second-line treatment with ramucirumab plus paclitaxel was significantly higher compared to patients with HER2-negative disease. However, an increased response to treatment was not associated with an improvement in OS.

RNF43 R117fs mutant positively regulates Wnt/β-catenin signaling by failing to internalize FZD expressed on the cell surface

RING finger protein 43 (RNF43) encodes the transmembrane E3 ubiquitin ligase, which targets the Wnt receptor Frizzled (FZD). RNF43 mutations have been discovered in various human cancers including colon, pancreatic, stomach, ovarian, and liver cancers. Functional studies on RNF43 missense mutations have shown that they negatively regulate Wnt signaling; however, there are few functional studies on RNF43 frameshift mutations. In this study, we showed that R117fs and P441fs mutants enhanced Wnt/β-catenin signaling, whereas Q409fs and G659fs mutants retained the ability to suppress Wnt/β-catenin signaling. Specifically, R117fs was unable to ubiquitinate FZD5 due to lack of the RING domain, although it was able to interact with FZD5. Immunofluorescence showed that R117fs failed to internalize FZD5 expressed on the cell surface. We also showed that LGK974, a potent Wnt inhibitor, decreased the Wnt/β-catenin activity by R117fs and P441fs mutations. Together, these results demonstrate that RNF43 frameshift mutations retain normal functionality; thus, targeted anti-cancer therapy can be developed according to the mutation type of RNF43.

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

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Background: HER-RAM study is the phase Ib/II multicenter study to evaluate the safety and efficacy of adding trastuzumab to ramucirumab and paclitaxel as a second-line treatment in HER2-positive advanced gastric or gastroesophageal junction (G/GEJ) cancer progressed from trastuzumab containing chemotherapy. We report survival follow up and exploratory biomarker results. Methods: Patients with HER2-positive advanced G/GEJ cancer who progressed after first-line trastuzumab containing chemotherapy were enrolled. Trastuzumab 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: No dose limiting toxicity at the dose level 1 was observed at the phase Ib part, the dose level 1 with full dose combination was determined as recommended phase 2 dose. At the time of data lock on September 7th, 2021, 50 patients including 3 patients from the phase 1b part were evaluable for response and safety. Median age was 60 years old (range 29-82) and most patients were male (40/50). At baseline, 39 patients had tumors with HER-2 3+ by immunohistochemistry (IHC) and 11 had those with HER-2 2+ by IHC with ERBB2 amplification by in situ hybridization. With median follow-up duration of 18.8 months, median PFS and OS were 7.0 months (95% confidence interval [CI]: 4.9-9.2 months) and 13.6 months (95% CI: 9.5-17.6 months), respectively. ORR was 54% (27/50, complete response = 1, partial response = 26) and DCR was 96% (48/50), respectively. On the exploratory analysis, HER-2 positivity of tumor tissue was lost after fist-line chemotherapy in 8 of 23 patients (34.7%) without any definite association between loss of HER-2 and outcomes. Most common hematologic adverse event (AE) was neutropenia (all grade: 64%, grade 3/4: 52%) with 1 case of febrile neutropenia (2%). Most common non-hematologic AE was peripheral sensory neuropathy and anorexia (all grade: 32%, grade 3: 2%, respectively). Gastrointestinal (GI) bleeding occurred in 6 cases (grade 3 upper GI bleeding: 3 patients, grade 1/2 lower GI bleeding: 3 patients), whereas GI perforation was not observed. Hypertension occurred in 3 patients (grade 1/2: 1 patient, grade 3: 2 patients). No new or unexpected AEs were observed. Conclusions: The continuous use of trastuzumab 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. Clinical trial information: NCT04888663.

A phase II study of chemotherapy in combination with telomerase peptide vaccine (GV1001) as second-line treatment in patients with metastatic colorectal cancer

Background: GV1001 is a human telomerase peptide vaccine that induces a CD4/CD8 T-cell response against cancer cells, thereby affording an immunological anti-tumor effect. Here, we evaluated the efficacy and safety of GV1001 in combination with chemotherapy in patients with metastatic colorectal cancer who had failed first-line chemotherapy.

Methods: This multicenter, non-randomized, single-arm phase II study recruited recurrent or metastatic colorectal cancer patients with measurable disease who had failed first-line chemotherapy. Patients received GV1001 and chemotherapy concomitantly based on a pre-established schedule. Cytotoxic chemotherapy and targeted agents (bevacizumab, cetuximab, or aflibercept) were allowed to be used at the discretion of the investigator. The primary endpoint was the disease control rate; secondary endpoints were the objective response rate, progression-free survival, overall survival, and safety outcomes. The baseline serum eotaxin level (a potential predictive biomarker of GV1001) was analyzed. To determine whether an adequate immune response had been induced, a delayed-type hypersensitivity test and a T-cell proliferation test were performed.

Results: From May 13, 2015 to October 13, 2020, 56 patients with recurrent or metastatic colorectal cancer treated in seven hospitals of South Korea were enrolled. The median patient age was 64 years (range, 29-82 years); 67.9% were men. Of all patients, 66.1% had left-side colorectal cancer and the RAS mutation was present in 25%. The disease control rate and the objective response rates were 90.9% (95% confidence interval [CI]: 82.4-99.4%) and 34.1% (95% CI, 20.1-48.1%), respectively. The median progression-free survival was 7.1 months (95% CI, 5.2-9.1 months) and the median overall survival was 12.8 months (95% CI, 9.9-15.8 months). The most common all-grade adverse events were neutropenia (48.2%), nausea (26.8%), neuropathy (25.0%), stomatitis (21.4%), and diarrhea (21.4%). Immune response analysis showed that no patient had positive delayed-type hypersensitivity test results; antigen-specific T-cell proliferation was observed in only 28% of patients. The baseline eotaxin level was not associated with any efficacy outcome.

Conclusion: Although no clear GV1001-specific immune response was observed, the addition of GV1001 vaccination to chemotherapy was tolerable and associated with modest efficacy outcomes.

Real-world experience of safety and effectiveness of regorafenib for treatment of metastatic colorectal cancer, advanced gastrointestinal stromal tumors, and hepatocellular carcinoma: a post-marketing surveillance study in Korea

Purpose: This regulatory post-marketing surveillance (PMS) study was performed to evaluate the safety and effectiveness of regorafenib on Korean patients with colorectal cancer (CRC), gastrointestinal stromal tumors (GIST), and hepatocellular carcinoma (HCC) in a real-world clinical setting.

Methods: This PMS was conducted as a multi-center, prospective, observational study at 34 centers in Korea from August 2013 to August 2019. The primary objective was to evaluate the safety of regorafenib in real-world practice, with the secondary objective to investigate its effectiveness, including its overall response rate (ORR), progression-free survival (PFS), and overall survival (OS).

Results: In total, 301 patients were included in the analysis (254 patients with CRC, 14 patients with GIST, and 33 patients with HCC). The incidence rates of adverse events (AEs) were 85.0%, 78.6%, and 81.8% in patients with CRC, GIST, and HCC, respectively. The most frequent AE related to regorafenib in the three cancer types was palmar-plantar erythrodysesthesia syndrome (PPES). The ORRs of patients with CRC, GIST, and HCC were 4.7%, 0%, and 41.4%, respectively. The median PFS and OS were 2.1 and 6.1 months for CRC, respectively; 9.2 and 16.4 months for GIST, respectively; and 5.5 months and not estimated (NE) for HCC, respectively. Patients who experienced a dose modification or discontinuation of regorafenib showed significantly shorter median PFS and OS (2.2 vs. 2.6 months, respectively, P = 0.0335 for PFS; 5.3 vs. 8.5 months, respectively, P = 0.0010 for OS).

Conclusion: This PMS study, which is the largest surveillance study of CRC in Korea, found no newly identified safety concerns for patients who received regorafenib in the real-world setting. Additionally, the results of this study were consisted with those previously reported in phase III trials.

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

Background:

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

Methods:

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

Results:

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

Conclusion:

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