Safety, Efficacy, and Biomarker Results from a Phase Ib Study of the Anti-DKK1 Antibody DKN-01 in Combination with Pembrolizumab in Advanced Esophagogastric Cancers.

Therapeutic combinations targeting innate and adaptive immunity and predictive biomarkers of response in esophagogastric cancer (EGC) are needed. We assessed safety and clinical utility of DKN-01 (a novel DKK1-neutralizing IgG4 antibody) combined with pembrolizumab and retrospectively determined DKK1 tumoral expression as a biomarker. Patients with advanced EGC received intravenous DKN-01 (150 or 300 mg) on days 1 and 15 with pembrolizumab 200 mg on day 1 in 21-day cycles. Clinical response was assessed by RECIST v1.1. Association of tumoral DKK1 mRNA expression (H-score: high ≥ upper-tertile, low < upper-tertile) with response was assessed with PD-L1 levels as a covariate. Sixty-three patients received DKN-01 150 mg (n = 2) or 300 mg (n = 61) plus pembrolizumab. Common adverse events were fatigue, anemia, blood alkaline phosphatase elevation, aspartate aminotransferase elevation, and hyponatremia. Among evaluable anti-PD-1/PD-L1-naïve patients receiving DKN-01 300 mg and pembrolizumab, objective response rate (ORR) was 11.4% (5/44) and 18.5% (5/27) in patients with gastroesophageal junction or gastric cancer (GEJ/GC). Among response-evaluable anti-PD-1/PD-L1-naïve patients with GEJ/GC and known tumoral DKK1 expression, ORR was 50% in DKK1-high and 0% in DKK1-low patients, median PFS was 22.1 vs. 5.9 weeks (HR, 0.24; 95% CI, 0.08-0.67), respectively, and median OS was 31.6 weeks vs. 17.4 weeks (HR, 0.41; 95% CI, 0.16-1.07), respectively. Association of DKK1 expression with PFS was independent of PD-L1 expression (adjusted HR, 0.21; 95% CI, 0.06-0.69). DKN-01 combined with pembrolizumab was well tolerated with no new safety signals. Antitumor activity was enriched in anti-PD-1/PD-L1-naïve patients with GEJ/GC whose tumors expressed high DKK1.

Motixafortide and Pembrolizumab Combined to Nanoliposomal Irinotecan, Fluorouracil, and Folinic Acid in Metastatic Pancreatic Cancer: The COMBAT/KEYNOTE-202 Trial.

PURPOSE: Pancreatic ductal adenocarcinoma (PDAC) is largely unresponsive to checkpoint inhibitors. Blockade of the CXCR4/CXCL12 axis increases intratumoral trafficking of activated T cells while restraining immunosuppressive elements. This study evaluates dual blockade of CXCR4 and PD1 with chemotherapy in PDAC. PATIENTS AND METHODS: Multicenter, single-arm, phase II study to evaluate the safety and efficacy of motixafortide and pembrolizumab combined with chemotherapy in patients with de novo metastatic PDAC and disease progression on front-line gemcitabine-based therapy (NCT02826486). Subjects received a priming phase of motixafortide daily on days 1-5, followed by repeated cycles of motixafortide twice a week; pembrolizumab every 3 weeks; and nanoliposomal irinotecan, fluorouracil, and leucovorin every 2 weeks (NAPOLI-1 regimen). The primary objective was objective response rate (ORR). Secondary objectives included overall survival (OS), progression-free survival (PFS), disease control rate (DCR), safety, and tolerability. RESULTS: A total of 43 patients were enrolled. The ORR according to RECISTv1.1 was 21.1% with confirmed ORR of 13.2%. The DCR was 63.2% with median duration of clinical benefit of 5.7 months. In the intention-to-treat population, median PFS was 3.8 months and median OS was 6.6 months. The triple combination was safe and well tolerated, with toxicity comparable with the NAPOLI-1 regimen. Notably, the incidence of grade 3 or higher neutropenia and infection was 7%, lower than expected for this chemotherapy regimen. CONCLUSIONS: Triple combination of motixafortide, pembrolizumab, and chemotherapy was safe and well tolerated, and showed signs of efficacy in a population with poor prognosis and aggressive disease.

Pembrolizumab plus GX-188E therapeutic DNA vaccine in patients with HPV-16-positive or HPV-18-positive advanced cervical cancer: interim results of a single-arm, phase 2 trial.

BACKGROUND: Survival outcomes for patients with recurrent or advanced cervical cancer are poor. Pembrolizumab has been approved for the treatment of recurrent or metastatic cervical cancer, with an overall response rate of 14·3%. GX-188E vaccination has been shown to induce human papillomavirus (HPV) E6-specific and E7-specific T-cell responses and cervical lesion regression in patients with cervical precancer. We aimed to investigate whether a combination of GX-188E therapeutic DNA vaccine plus pembrolizumab showed antitumour activity against recurrent or advanced cervical cancer. METHODS: In this open-label, single-arm, phase 2 trial, patients with recurrent or advanced, inoperable cervical cancer, who were aged 18 years or older with Eastern Cooperative Oncology Group performance status of 0 or 1 and histologically confirmed recurrent or advanced HPV-positive (HPV-16 or HPV-18) cervical cancer, and who had progressed after available standard-of-care therapy were recruited from seven hospitals in South Korea. Patients received intramuscular 2 mg GX-188E at weeks 1, 2, 4, 7, 13, and 19, with one optional dose at week 46 that was at the investigator's discretion, and intravenous pembrolizumab 200 mg every 3 weeks for up to 2 years or until disease progression. The primary endpoint was the overall response rate within 24 weeks assessed by the investigator using Response Evaluation Criteria in Solid Tumors version 1.1 in patients who received at least 45 days of treatment 45 days of treatment with at least one post-baseline tumour assessment, and this is the report of a planned interim analysis. This trial is registered with ClinicalTrials.gov, NCT03444376. FINDINGS: Between June 19, 2018, and March 20, 2020, 36 patients were enrolled and received at least one dose of the study treatment. 26 patients were evaluable for interim activity assessment, with at least one post-baseline tumour assessment at week 10. At the data cutoff date on March 30, 2020, median follow-up duration was 6·2 months (IQR 3·5-8·1). At 24 weeks, 11 (42%; 95% CI 23-63) of 26 patients achieved an overall response; four (15%) had a complete response and seven (27%) had a partial response. 16 (44%) of 36 patients had treatment-related adverse events of any grade and four (11%) had grade 3-4 treatment-related adverse events. Grade 3 increased aspartate aminotransferase, syncope, pericardial effusion, and hyperkalaemia, and grade 4 increased alanine aminotransferase were reported in one patient each. No treatment-related deaths were reported. INTERPRETATION: Treatment with GX-188E therapeutic vaccine plus pembrolizumab for patients with recurrent or advanced cervical cancer was safe and treatment-related adverse events were manageable. This combination therapy showed preliminary antitumour activity in this interim analysis, which could represent a new potential treatment option for this patient population. This trial is ongoing. FUNDING: National OncoVenture.

BL-8040, a CXCR4 antagonist, in combination with pembrolizumab and chemotherapy for pancreatic cancer: the COMBAT trial.

Programmed cell death 1 (PD-1) inhibitors have limited effect in pancreatic ductal adenocarcinoma (PDAC), underscoring the need to co-target alternative pathways. CXC chemokine receptor 4 (CXCR4) blockade promotes T cell tumor infiltration and is synergistic with anti-PD-1 therapy in PDAC mouse models. We conducted a phase IIa, open-label, two-cohort study to assess the safety, efficacy and immunobiological effects of the CXCR4 antagonist BL-8040 (motixafortide) with pembrolizumab and chemotherapy in metastatic PDAC (NCT02826486). The primary outcome was objective response rate (ORR). Secondary outcomes were overall survival (OS), disease control rate (DCR) and safety. In cohort 1, 37 patients with chemotherapy-resistant disease received BL-8040 and pembrolizumab. The DCR was 34.5% in the evaluable population (modified intention to treat, mITT; N = 29), including nine patients (31%) with stable disease and one patient (3.4%) with partial response. Median OS (mOS) was 3.3 months in the ITT population. Notably, in patients receiving study drugs as second-line therapy, the mOS was 7.5 months. BL-8040 increased CD8+ effector T cell tumor infiltration, decreased myeloid-derived suppressor cells (MDSCs) and further decreased circulating regulatory T cells. In cohort 2, 22 patients received BL-8040 and pembrolizumab with chemotherapy, with an ORR, DCR and median duration of response of 32%, 77% and 7.8 months, respectively. These data suggest that combined CXCR4 and PD-1 blockade may expand the benefit of chemotherapy in PDAC and warrants confirmation in subsequent randomized trials.

Assessment of Clinical Activity of PD-1 Checkpoint Inhibitor Combination Therapies Reported in Clinical Trials.

Importance: Because cancer drugs given in combination have the potential for increased tumor-cell killing, finding the best combination partners for programmed cell death 1 (PD-1) checkpoint inhibitors could improve clinical outcomes for patients with cancer. Objective: To identify optimal strategies for combining PD-1 immune checkpoint inhibitors with other cancer therapies. Design, Setting, and Participants: This cross-sectional study compiled 319 results from 98 clinical trials testing PD-1 pathway inhibitors alone or in combination with other agents among 24 915 patients with metastatic cancer. All clinical trials had a primary completion date before September 16, 2018. Data analysis was conducted from November 2018 to August 2019. Exposures: Patients with metastatic cancer were treated with PD-1 immune checkpoint inhibitors alone or with other cancer therapies. Main Outcomes and Measures: Clinical activity was measured as objective response rates (ORRs). Combination measures included fold change from monotherapy to combination ORR, comparison of observed combination ORRs with estimated combination ORRs based on independent additivity, and a computational model to assess clinical synergy. To assess whether the ORRs of various combinations may be greater than the independent contribution of each agent, a Bliss independent activity model was used to analyze observed combination ORRs, and a Z score, measuring the difference between observed and calculated ORRs, was generated. Results: In 319 results from 98 clinical trials among 24 915 patients, ORRs for monotherapy were compared with combination data by indication and line of therapy, demonstrating an increased ORR in 105 of 127 results (82.7%) where ORRs were available for both PD-1 pathway inhibitor monotherapy and combination therapy. A few combinations showed increases above the Bliss-estimated activity, possibly identifying limited clinical synergy. The mean (SD) Z score for all trials was 0.0430 (0.0243). The mean (SD) Z score was 0.0923 (0.0628) for platinum chemotherapy regimen combinations, 0.0547 (0.0821) for vascular endothelial growth factor or vascular endothelial growth factor receptor tyrosine kinase inhibitor combinations, 0.0893 (0.086) for indoleamine 2,3-dioxygenase inhibitor combinations, and 0.0558 (0.0849) for cytotoxic T-lymphocyte-associated protein 4 inhibitor combinations. Conclusions and Relevance: In this cross-sectional study, most combination trials showed the expected benefit of combining 2 active anticancer agents, but few combination trials showed clinical synergy according to the Bliss independent activity model.