Phase I trial of the MET inhibitor tepotinib in Japanese patients with solid tumors

OBJECTIVES

Tepotinib (MSC2156119J) is an oral, potent and highly selective small molecule mesenchymal-epithelial transition factor (MET) inhibitor for which the recommended Phase II dose of 500 mg once daily has been defined, based on the first-in-man trial conducted in the USA and Europe. We carried out a multicenter Phase I trial with a classic `3 + 3' design to determine the recommended Phase II dose in Japanese patients with solid tumors (NCT01832506).

METHODS

Patients aged ≥20 years with advanced solid tumors (refractory to standard therapy or for whom no effective standard therapy was available) received tepotinib at 215, 300 or 500 mg once daily in a 21-day cycle. Occurrence of dose-limiting toxicities during cycle 1 was used to determine the maximum tolerated dose. Efficacy, safety and pharmacokinetics were also evaluated to support the dose assessment.

RESULTS

Twelve patients were treated. Tepotinib was generally well tolerated with no observed dose-limiting toxicities; treatment-related adverse events were mainly grades 1-2. The tolerability profile of tepotinib was similar to that observed in non-Japanese populations. Pharmacokinetics in Japanese and Western patients was comparable. One patient with gastric cancer and one patient with urachal cancer had stable disease of ≥12 weeks in duration. The observed safety profile and pharmacokinetics are comparable with those in patients from the USA and Europe, and the recommended Phase II dose of tepotinib in Japanese patients was confirmed as 500 mg once daily.

CONCLUSIONS

These results, including initial signals of antitumor activity, support further development of tepotinib in Japanese patients with cancer.

A phase 1 study of crenigacestat (LY3039478), the Notch inhibitor, in Japanese patients with advanced solid tumors

Background This phase 1, single-center, nonrandomized, single-arm, open-label, dose-escalation study, evaluated the tolerability of crenigacestat, a γ-secretase inhibitor as an oral Notch inhibitor in Japanese patients with advanced solid tumors. Methods The study consisted of 2 dose levels of crenigacestat (25 mg and 50 mg), administered orally 3 times per week (TIW) over a 28-day cycle until disease progression, development of unacceptable toxicity, or any other discontinuation criteria were met. The primary objective was to evaluate the tolerability and determine the recommended dose of crenigacestat for Japanese patients. Secondary objectives were to characterize the safety and toxicity, the pharmacokinetic parameters, and to document any antitumor activity of crenigacestat. Results Eleven Japanese patients with advanced solid tumors were enrolled; 4 patients (median age of 64 years) received 25 mg of crenigacestat, and 7 patients (median age of 72 years) received 50 mg of crenigacestat. Median treatment duration was 8 weeks in the 25-mg treatment arm and 4 weeks in the 50-mg treatment arm. There were no dose-limiting toxicities or dose-limiting equivalent toxicities observed. None of the patients had a complete or partial response to the treatment. One patient (14.3%) with a desmoid tumor in the 50-mg treatment arm showed tumor size shrinkage of 22.4% and had stable disease for 22.5 months. Frequent (>14%) treatment-related-adverse events in both treatment arms included diarrhea, malaise, and vomiting. Conclusions Crenigacestat was tolerated in Japanese patients but with limited clinical activity. The recommended crenigacestat dose in Japanese patients is 50 mg TIW.

Trial registration: NCT02836600 (ClinicalTrials.gov) registered on July 19, 2016.

The PD-1 expression balance between effector and regulatory T cells predicts the clinical efficacy of PD-1 blockade therapies

Immune checkpoint blockade has provided a paradigm shift in cancer therapy, but the success of this approach is very variable; therefore, biomarkers predictive of clinical efficacy are urgently required. Here, we show that the frequency of PD-1⁺CD8⁺ T cells relative to that of PD-1⁺ regulatory T (T_reg) cells in the tumor microenvironment can predict the clinical efficacy of programmed cell death protein 1 (PD-1) blockade therapies and is superior to other predictors, including PD ligand 1 (PD-L1) expression or tumor mutational burden. PD-1 expression by CD8⁺ T cells and T_reg cells negatively impacts effector and immunosuppressive functions, respectively. PD-1 blockade induces both recovery of dysfunctional PD-1⁺CD8⁺ T cells and enhanced PD-1⁺ T_reg cell-mediated immunosuppression. A profound reactivation of effector PD-1⁺CD8⁺ T cells rather than PD-1⁺ T_reg cells by PD-1 blockade is necessary for tumor regression. These findings provide a promising predictive biomarker for PD-1 blockade therapies.

Enhanced tumor response to radiotherapy after PD-1 blockade in metastatic gastric cancer

BACKGROUND

Immune checkpoint inhibitors may enhance the efficacy of radiotherapy (RT) in cancer treatment but the effect remains unknown in metastatic gastric cancer (mGC). This study aimed to compare the tumor shrinkage by palliative RT for mGC patients with or without previous exposure to anti-PD-1 therapy.

METHODS

Data of 36 mGC patients who had received palliative RT from April 2013 to May 2019 were analyzed. Primary tumor responses were evaluated through a volumetric measurement-based method using computed tomography (CT) and endoscopic responses were evaluated in patients who underwent endoscopy before and after RT. Tumor microenvironment (TME) immune status was investigated by analyzing tumor-infiltrating lymphocytes by flow cytometry.

RESULTS

Among 36 patients, 18 had previous exposure to anti-PD-1 before RT showing no significant differences in baseline characteristics with the other 18 patients without exposure to anti-PD-1 treatment. Tumor responses were observed in 28% (5/18) and none (0/18) in the anti-PD-1-exposed vs. naïve group, respectively (P = 0.045). Five out of eight patients in the anti-PD-1-exposed group, who underwent endoscopy after RT showed partial response, but none in the anti-PD-1-naïve patients showed response (P = 0.026). Increase in the CD8⁺ T cell/effector regulatory T cell ratio in TILs after anti-PD-1 therapy was noted in three responders to RT, but not in the other three non-responders.

CONCLUSIONS

Prior exposure to anti-PD-1 therapy increases tumor response to RT. Immune profiling suggests that anti-PD-1 therapy may enhance the efficacy of RT by immunoactivation in the TME.

Abstract CT282: KEYNOTE-975: A randomized, double-blind, placebo-controlled phase 3 trial of pembrolizumab vs placebo in participants with esophageal carcinoma receiving concurrent definitive chemoradiotherapy

Background: For patients with unresectable esophageal cancer (EC), definitive chemoradiotherapy (dCRT) is a standard treatment option. Platinum plus fluoropyrimidine-based regimens are comparable in dCRT and are considered standard options; however, overall survival (OS) is still poor, indicating a need for more effective therapies. The programmed cell death 1 inhibitor pembrolizumab showed promising response as third- and second-line monotherapy in patients with advanced, unresectable EC in the KEYNOTE-180 and KEYNOTE-181 studies, respectively. In the phase 3 KEYNOTE-181 trial, pembrolizumab extended OS vs chemotherapy in patients with a PD-L1 combined positive score (CPS) ≥10. KEYNOTE-975 is a randomized, multicenter, double-blind, phase 3 study investigating pembrolizumab in combination with dCRT. Methods: Key patient eligibility criteria are age ≥18 years; presence of cTX N+M0 or cT2-T4a NXM0, locally advanced esophageal squamous cell carcinoma (SCC) or adenocarcinoma or Siewert type 1 adenocarcinoma of the esophagogastric junction; ineligible for curative surgery; no previous chemotherapy or radiation for EC; and suitable for dCRT. Patients will be randomly assigned 1:1 to pembrolizumab or placebo added to dCRT, administered as pembrolizumab 200 mg or placebo Q3W for 8 cycles followed by pembrolizumab 400 mg or placebo Q6W for 5 cycles (13 cycles total). The dCRT regimen will be the site's choice of continuous infusion 5-FU + cisplatin (FP) with radiotherapy (RT) 50 Gy, FP with RT 60 Gy, or FOLFOX with RT 50 Gy. Randomization will be stratified by PD-L1 positivity (CPS ≥10 vs CPS <10), RT dose (50 Gy vs 60 Gy), and region/histology (SCC East Asia vs SCC rest of world and adenocarcinoma regardless of region). The primary objectives of KEYNOTE-975 are to compare pembrolizumab and placebo added to dCRT in OS and event-free survival within the prespecified analysis cohorts: patients with CPS ≥10, patients with SCC, and all patients (intention-to-treat population). The secondary objective is to assess the safety and tolerability profile of pembrolizumab vs placebo added to dCRT (adverse events, overall and leading to study drug discontinuation). Exploratory objectives include comparing time to deterioration and change from baseline in quality of life measures, characterizing health utility scores, and identifying molecular biomarkers that may be determinants of response.

Citation Format: Manish A. Shah, Jaafar Bennouna, Toshihiko Doi, Lin Shen, Ken Kato, Antoine Adenis, Harvey Mamon, Markus Moehler, Xiaolong Fu, Byoung Chul Cho, Pooja Bhagia, Chie-Schin Shih, Anjali Desai, Peter Enzinger. KEYNOTE-975: A randomized, double-blind, placebo-controlled phase 3 trial of pembrolizumab vs placebo in participants with esophageal carcinoma receiving concurrent definitive chemoradiotherapy [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT282.

Abstract 5181: Therapeutic targeting of GPR20, selectively expressed in gastrointestinal stromal tumor (GIST), with DS-6157a, an antibody-drug conjugate (ADC)

More than 85% of GISTs are driven by activating mutations in KIT proto-oncogene receptor tyrosine kinase (KIT) or platelet-derived growth factor receptor alpha (PDGFRA). Currently, the only approved treatments for GIST are KIT directed tyrosine kinase inhibitors (TKIs). However, treatment with approved TKIs eventually results in disease progression most often due to the development of secondary resistance mutations in KIT. In addition, these agents have limited activity in PDGFRA mutant GIST and KIT/PDGFRA wild type (WT) GIST as primary therapy. Therefore, it is essential to develop novel therapeutic strategies with different modes of action in advanced GIST. G protein-coupled receptor 20 (GPR20) is an orphan GPCR selectively and abundantly expressed in GIST. GPR20 expression is regulated by FOXF1 and ETV1, transcription factors that play critical roles in KIT-driven GIST initiation, proliferation, and survival. We hypothesize that GPR20 is a potential therapeutic target for ADC development for the treatment of GIST. In this study, 1) GPR20 and KIT protein expression was assessed by IHC staining on GIST samples from DFCI (n=144) and NCCHE (n=100) as well as on normal and malignant tissue microarrays obtained commercially, and 2) an anti-GPR20 ADC (DS-6157a) was generated to evaluate antitumor activity in GIST models and to assess safety. GPR20 was expressed in more than 88% of the GIST samples analyzed, with higher expression levels in samples that: (I) received multiple treatment lines compared to naïve/early treated samples, (II) expressed higher KIT levels, (III) were small intestinal GIST, and/or (IV) had no KIT mutation, including succinate dehydrogenase (SDH) deficient GIST and neurofibromatosis type 1 (NF1)-associated GIST. The interstitial cells of Cajal were the only normal cells positive for GPR20. Normal mast cells expressed KIT but not GPR20. DS-6157a is an ADC composed of a humanized anti-GPR20 antibody, a Gly-Gly-Phe-Gly tetra-peptide-based linker, and a DNA topoisomerase I (TOP1) inhibitor Dxd. DS-6157a exhibited GPR20 expression-dependent cell growth-inhibitory activity and induced tumor regression with dosing at 3 to 10 mg/kg in multiple GIST xenograft models. In addition, DS-6157a showed antitumor activity in a GIST patient-derived xenograft model that was resistant to imatinib, sunitinib, and regorafenib. In vitro, DS-6157a induced TOP1 inhibitor-associated markers of DNA damage (phosphorylation of Chk1) and apoptosis (cleaved PARP) in GPR20 expressing cells. In preclinical toxicology studies using rats and cynomolgus monkeys, the pharmacokinetics and safety profile of DS-6157a were favorable at up to 200 mg/kg and 30 mg/kg, respectively. These data support the clinical development of DS-6157a as a potential novel GIST therapy with activity in patients that are resistant, refractory, or intolerant to approved TKIs.

Citation Format: Kenji Iida, Amr H. Abdelhamid, Akiko Kawano Nagatsuma, Tomoko Shibutani, Satoru Yasuda, Michiko Kitamura, Chiharu Hattori, Manabu Abe, Jun Hasegawa, Takuma Iguchi, Tsuyoshi Karibe, Takashi Nakada, Koichiro Inaki, Reiko Kamei, Yuki Abe, Jessica L. Andersen, Sandro Santagata, Matthew L. Hemming, Suzanne George, Toshihiko Doi, Atsushi Ochiai, George D. Demetri, Toshinori Agatsuma. Therapeutic targeting of GPR20, selectively expressed in gastrointestinal stromal tumor (GIST), with DS-6157a, an antibody-drug conjugate (ADC) [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5181.

Report of the use of patient-derived xenograft models in the development of anticancer drugs in Japan

Cell line‐derived xenograft (CDX) models created by implanting cancer cell lines into immunodeficient mice have contributed largely to the development of cancer drug therapies. However, cell lines often lose their original biological characteristics through many passages and cancer tissues in CDX models have many cancer cells and few cancer stromal cells, therefore CDX models are currently considered not suitable for predicting the results of clinical studies. Conversely, patient‐derived xenograft (PDX) models are gaining importance, as human cancer biological characteristics and microenvironments are recreated by implanting tumor tissue into immunodeficient mice. These highly expected, evidently beneficial PDX models have been used in some basic research and are becoming more generalized. However, quality control and quality assurance criteria have not been established for them, and challenges and problems in the utilization of valuable PDX models in drug development have yet to be clarified. In this report, we conducted a questionnaire survey among researchers in Japanese academic institutions and pharmaceutical companies to understand the current status of PDX models in Japan. Based on the questionnaire results, we summarized the situations surrounding respondent's utilization and quality control in the development of anticancer drugs and proposed several measures to facilitate the utilization of PDX models in the development of anticancer drugs.

Clinical and molecular factors for selection of nivolumab or irinotecan as third-line treatment for advanced gastric cancer

BACKGROUND

The use of nivolumab or irinotecan as the third-line treatment for patients with advanced gastric cancer (AGC) remains controversial.

METHODS

This study analyzed patients with AGC treated with nivolumab or irinotecan (nivolumab group or irinotecan group, respectively) from May 2016 to April 2019 following two or more previous lines of chemotherapy. Univariate survival analysis was conducted to identify the clinical and molecular factors associated with progression-free survival (PFS).

RESULTS

A total of 156 patients (74 treated with nivolumab and 82 treated with irinotecan) were analyzed. The median PFS was 1.9 months in both treatment groups. The median overall survival (OS) was 7.2 and 6.2 months in the nivolumab and irinotecan groups, respectively. Eastern Cooperative Oncology Group performance status of 1 or more, liver metastasis, a large tumor size at baseline, and HER2-positive status were associated with a worse PFS in the nivolumab group compared with the irinotecan group. The nivolumab group showed a significantly longer PFS (median 3.1 versus 2.0 months) and OS (median 12.9 versus 7.8 months) than the irinotecan group in patients with 0 or 1 of these factors, whereas the irinotecan group showed a significantly longer PFS (median 1.0 versus 1.8 months) and a trend of longer OS (median 3.9 versus 6.1 months) in patients with ⩾2 of these factors.

CONCLUSIONS

Some clinical and molecular factors were associated with outcomes following nivolumab or irinotecan as the third- or later-line treatment in patients with AGC. These factors must be considered while selecting an optimal treatment option.

Improved efficacy of taxanes and ramucirumab combination chemotherapy after exposure to anti-PD-1 therapy in advanced gastric cancer

BACKGROUND

The efficacy and safety of chemotherapy (CTx) after anti-PD-1 therapy in patients with advanced gastric cancer (AGC) remains unclear.

METHODS

Medical records of consecutive patients with AGC treated with both CTx (taxanes plus ramucirumab, taxanes monotherapy or irinotecan) and anti-PD-1 therapy from June 2015 to April 2019 were retrospectively analysed. Patients were divided into two groups based on prior exposure to anti-PD-1 therapy: anti-PD-1-exposed and anti-PD-1-naïve groups. CTx-related outcomes were compared between two groups in the overall population and each CTx population.

RESULTS

In total, 233 patients (67 anti-PD-1-exposed, 166 anti-PD-1-naïve) were included. In the overall population, the objective response rate (ORR) to CTX was 44.6% in the anti-PD-1-exposed group and 19.6% in the anti-PD-1-naïve group (p=0.001); the median progression-free survivals (PFS) were 3.7 months and 3.3 months (HR=0.82, p=0.20), respectively. Among patients receiving taxanes plus ramucirumab (n=149), ORR (60.6% vs 20.0%, p<0.001) and median PFS (4.8 vs 3.4 months, p=0.004, HR=0.56) were significantly better in the anti-PD-1-exposed group (n=39) compared with the anti-PD-1-naïve group (n=110). These differences were not observed in patients receiving taxane monotherapy (n=34) or irinotecan (n=50). CTx after anti-PD-1 therapy showed no severe or unexpected adverse events.

CONCLUSIONS

Prior anti-PD-1 therapy might increase tumour response to taxanes plus ramucirumab without unexpected adverse events, which warrants further investigations in a large cohort.

Phase 1 dose-escalation study of a novel oral PI3K/mTOR dual inhibitor, LY3023414, in patients with cancer

LY3023414 is an oral, selective adenosine triphosphate-competitive inhibitor of class I phosphatidylinositol 3-kinase isoforms, mammalian target of rapamycin, and DNA-protein kinase in clinical development. We report results of a 3 + 3 dose-escalation Phase 1 study for twice-daily (BID) dosing of LY3023414 monotherapy in Japanese patients with advanced malignancies. The primary objective was to evaluate tolerability and safety of LY3023414. Secondary objectives were to evaluate pharmacokinetics and to explore antitumor activity. A total of 12 patients were enrolled and received 150 mg (n = 3) or 200 mg (n = 9) LY3023414 BID. Dose-limiting toxicities were only reported at 200 mg LY3023414 for 2 patients with Grade 3 stomatitis. Common treatment-related adverse events (AEs) across both the dose levels included stomatitis (75.0%), nausea (66.7%), decreased appetite (58.3%), diarrhea, and decreased platelet count (41.7%), and they were mostly mild or moderate in severity. Related AEs Grade ≥ 3 reported for ≥1 patient included anemia, stomatitis, hypophosphatemia, and hyperglycemia (n = 2, 16.7%). Two patients discontinued due to AEs (interstitial lung disease and stomatitis). No fatal events were reported. The pharmacokinetic profile of LY3023414 was characterized by rapid absorption and elimination. Five patients had a best overall response of stable disease (150 mg, n = 3; 200 mg, n = 2) for a 55.6% disease control rate. LY3023414 up to 200 mg BID is tolerable and safe in Japanese patients with advanced malignancies.

The safety and tolerability of epacadostat alone and in combination with pembrolizumab in patients with advanced solid tumors: results from a first-in-Japanese phase I study (KEYNOTE-434)

PURPOSE

Part A of the open-label, phase I KEYNOTE-434 study evaluated the safety and tolerability of epacadostat, an indoleamine 2,3-dioxygenase-1 inhibitor, alone and in combination with pembrolizumab in Japanese patients with advanced solid tumors.

METHODS

Japanese patients with refractory/recurrent metastatic or locally advanced tumors were enrolled. Cohort 1 received oral epacadostat 25 mg or 100 mg twice daily (BID) and subsequently received epacadostat in combination with intravenous pembrolizumab 200 mg every 3 weeks. Cohort 2 received epacadostat 25 mg or 100 mg BID with pembrolizumab 200 mg every 3 weeks. The primary objective was evaluation of safety and tolerability using a modified toxicity probability interval method. Secondary objectives were pharmacokinetic (PK) and pharmacodynamic profiles of epacadostat alone and in combination with pembrolizumab.

RESULTS

Six patients were enrolled in cohort 1 (epacadostat 25 mg, n = 3; epacadostat 100 mg, n = 3); none experienced dose-limiting toxicities (DLTs). Nine patients were enrolled in cohort 2 (epacadostat 25 mg and pembrolizumab, n = 3; epacadostat 100 mg and pembrolizumab, n = 6); one patient receiving epacadostat 100 mg and pembrolizumab experienced grade 4 rhabdomyolysis-a DLT. Grade 3 or 4 treatment-related adverse events occurred in two patients (13.3%). There were no treatment-related deaths. Pembrolizumab had no impact on epacadostat PK and vice versa. The PK profile of pembrolizumab in the current study was comparable with historical pembrolizumab PK data.

CONCLUSION

Epacadostat in combination with pembrolizumab was generally safe and well tolerated among Japanese patients with advanced solid tumors. Clinical trial registration NCT02862457.

A phase I/II, two-part, multicenter, first-in-human study of DS-7300a in patients with advanced solid malignant tumors

TPS3646

Background: B7 homologue 3 (B7-H3) is a protein that is overexpressed in various cancer types, including lung, head and neck squamous cell carcinoma, prostate, esophageal, and breast. B7-H3 overexpression is associated with poor prognosis because it promotes increased invasive and metastatic potential of cancer cells (Dong P, et al. Front Oncol. 2018;8:264). Currently, no B7-H3–targeted cancer therapies are approved. DS-7300a is an antibody-drug conjugate composed of a humanized anti–B7-H3 IgG1 monoclonal antibody (MABX-9001a) conjugated to a drug linker that releases its payload upon internalization by cancer cells. The payload, DXd, is an exatecan derivative that inhibits topoisomerase I, an enzyme that relaxes supercoiled DNA for replication and transcription. DS-7300a induced apoptosis in cancer cells in vitro and showed potent antitumor activity in xenograft models of various types of solid tumors in vivo. Methods: This phase 1/2, multicenter, nonrandomized, open-label, first-in-human study of DS-7300a is ongoing in the United States and Japan in patients with selected advanced solid tumors (NCT04145622). This study has 2 parts: dose escalation (part 1) and dose expansion (part 2). Primary objectives are to evaluate the safety, tolerability, and antitumor activity of DS-7300a and to determine the maximum tolerated dose or recommended dose for the expansion part. Secondary objectives include the pharmacokinetic characterization of DS-7300a, determination of the total levels of anti–B7-H3 antibody and the drug component (DXd), and assessment of the incidence of anti-drug antibodies against DS-7300a. Key inclusion criteria are age ≥ 18 years (United States) or ≥ 20 years (Japan), an ECOG performance status of 0 or 1, ≥ 1 measurable lesion according to RECIST 1.1 as assessed by the investigator, and consent to provide pre- and on-treatment tissue samples (mandatory if clinically allowed and not contraindicated). Key exclusion criteria include prior treatment with orlotamab, enoblituzumab, other B7-H3–targeted agents, or an antibody-drug conjugate that is conjugated with a topoisomerase I inhibitor. Dose expansion will start with 3 cohorts, including patients with selected advanced solid tumors. In both parts, DS-7300a will be administered intravenously on day 1 of each 21-day cycle. During dose escalation, the starting dose of DS-7300a is 0.8 mg/kg. This trial is currently in the dose-escalation part. Clinical trial information: NCT04145622 .

Phase 1 study of napabucasin, a cancer stemness inhibitor, in patients with advanced solid tumors

PURPOSE

Napabucasin is a cancer stemness inhibitor that targets a number of oncogenic pathways, including signal transducer and activator of transcription 3 (STAT3). Phase 1/2 studies suggest tolerability and anti-tumor activity in various types of cancer; a Phase 3 study of napabucasin plus standard therapy in colorectal cancer is ongoing. This is a Phase 1 dose-escalation study in patients with advanced solid tumors, and the first study of napabucasin in Japanese patients.

METHODS

Patients received napabucasin 480, 960, or 1440 mg daily in 28-day cycles until disease progression or intolerable toxicity. Primary objectives were to determine dose-limiting toxicities (DLTs), maximum tolerated dose (MTD), and the pharmacokinetic (PK) profile of napabucasin. Blood samples were taken for PK analysis on Days 1, 2, 8, and 15 of Cycle 1, and Days 29 and 30 of Cycle 2. Secondary objectives were to assess napabucasin antitumor activity, and the relationship between biomarkers and antitumor activity. JapicCTI-No: JapicCTI-132152.

RESULTS

Enrolled were 14 patients (480 mg [n = 3], 960 mg [n = 4], 1440 mg [n = 7]). One patient experienced a DLT (Grade 3, anorexia). MTD was 1440 mg/day. Most common drug-related adverse events were diarrhea (n = 9), nausea (n = 4), vomiting (n = 3), and anorexia (n = 3). Napabucasin showed a similar PK profile to previous studies and no abnormal accumulation was observed. Following treatment, two patients had stable disease; the remaining 12 had progressive disease.

CONCLUSION

Napabucasin was well-tolerated at doses up to 1440 mg/day in Japanese patients with advanced solid tumors; the PK profile was comparable to that reported previously.

Phase I Study of the Bifunctional Fusion Protein Bintrafusp Alfa in Asian Patients with Advanced Solid Tumors, Including a Hepatocellular Carcinoma Safety-Assessment Cohort

Lessons Learned

Bintrafusp alfa had a manageable safety profile and demonstrated preliminary clinical activity in heavily pretreated patients with solid tumors (including hepatocellular carcinoma) with no or limited treatment options.

Findings from this study suggest bintrafusp alfa may be a novel therapeutic approach for patients with advanced solid tumors.

Additional trials are needed to further explore safety and efficacy of bintrafusp alfa in specific tumor types.

Background

Bintrafusp alfa is a first‐in‐class bifunctional fusion protein composed of the extracellular domain of transforming growth factor‐β (TGF‐β) RII receptor (a TGF‐β “trap”) fused to a human immunoglobulin (Ig) G1 antibody blocking programmed death‐ligand 1 (PD‐L1). Bintrafusp alfa is designed to neutralize TGF‐β signaling by “trapping” and sequestering all TGF‐β isoforms, and this trap function is physically linked to PD‐L1 blockade in the tumor microenvironment.

Methods

NCT02699515 was a phase I, open‐label, dose‐escalation study of bintrafusp alfa (3, 10, and 20 mg/kg every 2 weeks) in Asian patients with advanced solid tumors, including a hepatocellular carcinoma (HCC) safety‐assessment cohort. The primary objective was safety and tolerability; the secondary objective is best overall response.

Results

As of August 24, 2018, 23 patients (including 9 in the HCC cohort) received bintrafusp alfa. Eight patients experienced treatment‐related adverse events (TRAEs). Three patients had grade 3 TRAEs (13.0%; hypoacusis, hyponatremia, hypopituitarism, increased blood creatine phosphokinase, and intracranial tumor hemorrhage); one had grade 4 hyponatremia (4.3%). No treatment‐related deaths occurred. In the dose‐escalation cohort, two patients had a confirmed partial response, and 3 had stable disease (SD), for an overall response rate of 14.3% and a disease control rate (DCR) of 35.7%. In the HCC cohort, one patient had SD (DCR, 11.1%). A dose‐proportional pharmacokinetics profile was observed at doses of >3 mg/kg.

Conclusion

Bintrafusp alfa had a manageable safety profile and preliminary efficacy in heavily pretreated patients with advanced solid tumors, including HCC.

Pembrolizumab for the treatment of programmed death-ligand 1-positive advanced carcinoid or pancreatic neuroendocrine tumors: Results from the KEYNOTE-028 study

BACKGROUND

Despite a protracted disease course and multiple available therapies, patients with well-differentiated neuroendocrine tumors (NETs) inevitably experience disease progression. Programmed death-ligand 1 (PD-L1) has been associated with NET progression and prognosis. The multicohort, phase 1 KEYNOTE-028 study (ClinicalTrials.gov identifier NCT02054806) evaluated the activity and safety of the anti-programmed cell death protein 1 immunotherapy pembrolizumab in patients with well-differentiated or moderately-differentiated NETs.

METHODS

Patients with PD-L1-positive, locally advanced or metastatic carcinoid or well-differentiated or moderately-differentiated pancreatic NETs (pNETs) were enrolled into separate cohorts and received pembrolizumab at a dose of 10 mg/kg every 2 weeks for up to 2 years. The objective response rate was the primary endpoint (as per Response Evaluation Criteria in Solid Tumors version 1.1, by investigator review). Safety was a secondary endpoint.

RESULTS

Of 170 and 106 patients, respectively, who had evaluable samples among those screened for the carcinoid and pNET cohorts, 21% and 25%, respectively, had PD-L1-positive tumors; of these, 25 and 16 patients, respectively, were eligible and treated. The median follow-up was 20 months (range, 2-35 months) and 21 months (range, 5-32 months), respectively. The objective response rate was 12.0% (95% CI, 2.5%-31.2%) and 6.3% (95% CI, 0.2%-30.2%), respectively; 3 partial responses occurred among the carcinoid cohort and 1 among the pNET cohort. The median duration of response in the carcinoid cohort was 9.2 months (range, 6.9-11.1 months), and was not reached in the pNET cohort. No complete responses occurred. Treatment-related adverse events occurred in 68% and 69% of patients, respectively, most often diarrhea (7 patients in the carcinoid cohort and 4 patients in the pNET cohort) and fatigue (6 patients in each cohort). Hypothyroidism was the most common immune-mediated adverse event (5 patients in the carcinoid cohort and 2 patients in the pNET cohort).

CONCLUSIONS

Pembrolizumab demonstrated antitumor activity in a subset of patients with NETs and was well-tolerated.

Safety and Tolerability of Bintrafusp Alfa, a Bifunctional Fusion Protein Targeting TGFβ and PD-L1, in Asian Patients with Pretreated Recurrent or Refractory Gastric Cancer

PURPOSE

Patients with advanced gastric/gastroesophageal junction cancer (GC/GEJC) have limited treatment options after first-line therapy. Bintrafusp alfa is a first-in-class bifunctional fusion protein composed of the extracellular domain of the TGFβRII receptor (a TGFβ "trap") fused to a human IgG1 antibody against programmed death ligand 1 (PD-L1), potentially offering a new treatment approach for these patients. We report results for bintrafusp alfa in GC/GEJC.

PATIENTS AND METHODS

Asian patients with recurrent GC/GEJC for whom standard therapy does not exist or for whom standard therapy has failed enrolled in this expansion cohort of an ongoing phase I trial and received bintrafusp alfa 1,200 mg once every 2 weeks until disease progression, unacceptable toxicity, or withdrawal. The primary objective was to assess safety/tolerability.

RESULTS

By July 23, 2018, 31 heavily pretreated patients received bintrafusp alfa for a median of 10.1 weeks; 3 patients remained on treatment. Six patients (19%) experienced grade 3 treatment-related adverse events (AE); no grade 4 events occurred. One on-treatment death occurred (sudden death); rupture of a preexisting thoracic aortic aneurysm was the suspected cause. Ten patients (32%) had immune-related AEs. The confirmed objective response rate per independent review committee was 16%; disease control rate was 26%. Median duration of response was 8.7 months (range, 2.4-12.4+). Responses occurred irrespective of PD-L1 expression or microsatellite instability status and appeared to correlate with high tumor TGFB1 levels.

CONCLUSIONS

In this first evaluation in Asian patients with heavily pretreated advanced GC/GEJC, bintrafusp alfa demonstrated a manageable safety profile and clinical activity.