Phase Ib study of eprenetapopt (APR-246) in combination with pembrolizumab in patients with advanced or metastatic solid tumors

Background

We conducted a phase I, multicenter, open-label, dose-finding, and expansion study to determine the safety and preliminary efficacy of eprenetapopt (APR-246) combined with pembrolizumab in patients with advanced/metastatic solid tumors (ClinicalTrials.gov NCT04383938).

Patients and methods

For dose-finding, requirements were non-central nervous system primary solid tumor, intolerant to/progressed after ≥1 line of treatment, and eligible for pembrolizumab; for expansion: (i) gastric/gastroesophageal junction tumor, intolerant to/progressed after first-line treatment, and no prior anti-programmed cell death receptor-1 (PD-1)/programmed death-ligand 1 (PD-L1) therapy; (ii) bladder/urothelial tumor, intolerant to/progressed after first-line cisplatin-based chemotherapy, and no prior anti-PD-1/PD-L1 therapy; (iii) non-small-cell lung cancer (NSCLC) with previous anti-PD-1/PD-L1 therapy. Patients received eprenetapopt 4.5 g/day intravenously (IV) on days 1-4 with pembrolizumab 200 mg IV on day 3 in each 21-day cycle. Primary endpoints were dose-limiting toxicity (DLT), adverse events (AEs), and recommended phase II dose (RP2D) of eprenetapopt.

Results

Forty patients were enrolled (median age 66 years; range 27-85) and 37 received eprenetapopt plus pembrolizumab. No DLTs were reported and the RP2D for eprenetapopt in combination was 4.5 g/day IV on days 1-4. The most common eprenetapopt-related AEs were dizziness (35.1%), nausea (32.4%), and vomiting (29.7%). AEs leading to eprenetapopt discontinuation occurred in 2/37 patients (5.4%). In efficacy-assessable patients (n = 29), one achieved complete response (urothelial cancer), two achieved partial responses (NSCLC, urothelial cancer), and six patients had stable disease.

Conclusions

The eprenetapopt plus pembrolizumab combination was well tolerated with an acceptable safety profile and showed clinical activity in patients with solid tumors.

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Eprenetapopt in combination with pembrolizumab was well tolerated with an acceptable safety profile.

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Eprenetapopt plus pembrolizumab demonstrated clinical activity in heavily pre-treated patients with solid tumors.

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This is the first clinical trial evaluating the combination of a p53 reactivator with immuno-oncology therapy.

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This work informs the development of treatment combining immunotherapy with agents targeting specific pathways such as p53.

Epidermal growth factor receptor overexpression in resected pancreatic cancer

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Background: The effect of overexpression of epidermal growth factor receptor (EGFR) in pancreatic carcinoma is uncertain. In this study, we examine the association between EGFR overexpression (membrane and cytoplasmic) and histopathologic features and clinical outcomes in patients post resection.

Methods: Seventy three patients underwent curative resection for pancreatic cancer from 4/08 to 4/10. Tumor EGFR expression was determined immunohistochemically using EGFR pharmDxTM kit. Cytoplasmic overexpression was considered positive if EGFR expression was seen in the cytoplasm in ≥10% of cells. Cell membrane staining scores were assigned: 0 (no membrane staining), 1+ (incomplete membrane staining in ≥ 10% of cells, 2+ (complete weak/moderate membrane staining in ≥ 10% of cells) and 3+ (complete heavy staining in ≥ 10% of cells). A score of 2+ and 3+ were considered as membrane overexpression. Comparisons between EGFR overexpression and clinicopathologic features were assessed by chi-square test with p-value < 0.05 as statistically significant. Proportional hazard regression was used to estimate progression free survival and overall survival.

Results: Out of 73 patients, 43 (59%) and 50 (68%) patients had membrane and cytoplasmic EGFR overexpression respectively. AJCC stages were: stage I: 8, stage II: 63, stage III: 1 and stage IV: 1 patient. There was statistically significant correlation between cell membrane EGFR overexpression and lymph node positivity (p=0.04). Membrane EGFR overexpression was not significantly associated with local invasion, margin positivity, vascular invasion, perineural invasion, histologic grade or stage. Cytoplasmic EFGR overexpression was significantly associated with margin positivity (p=0.01) only. The hazard ratios (95% CI) for PFS and OS in patients with membrane EGFR overexpression was 1.37 (0.72-2.60) and 1.27 (0.62-2.61) respectively. The corresponding values for patients with cytoplasmic overexpression were 1.65 (0.80-3.37) and 1.25 (0.58-2.71) respectively.

Conclusions: Membrane EGFR overexpression was associated with lymph node status and cytoplasmic EFGR overexpression with margin positivity. There was no association of EFGR expression and clinical outcomes.

No significant financial relationships to disclose.

Gemcitabine, oxaliplatin, and bevacizumab (GEMOX-B): A promising regimen for the treatment of advanced biliary tract cancers

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Background: Biliary-tract cancers (BTCs) arise from the epithelium of the gallbladder and bile ducts and are relatively rare, affecting 9-12,000 people in the United States annually. Peak incidence is in the seventh decade of life. Prognosis of advanced BTCs is poor with median overall survival of approximately 10 months. There has been no standard treatment regimen because of lack of randomized clinical trials data. Phase II trials have demonstrated the efficacy of the combination of gemcitabine and oxaliplatin with the response rate of ∼50%. In a recently published phase II trial, the addition of bevacizumab to this regimen (GEMOX-B) resulted in 63% progression-free survival (PFS) at 6 months. In this retrospective study, we evaluated the efficacy of GEMOX-B in patients with advanced biliary tract cancers treated at Thomas Jefferson University.

Methods: All patients received treatment on day 1 and 15 of 28-day cycle: bevacizumab 10 mg/kg, followed by gemcitabine 1000 mg/m2 and oxaliplatin 85 mg/m2. All patients were administered diphenhydramine, dexamethasone, and ondansetron prior to chemotherapy. Response was assessed using the RECIST criteria. PFS was measured from start of chemotherapy to disease progression or death.

Results: A total of 6 patients with BTCs were treated with GEMOX-B. One patient was male and 5 were female. The median age was 45 years (40-64 years). All patient had ECOG performance score 0-1. Three patients had progressed on prior therapy. A total of 65 cycles were administered with the median being 9 (range: 7-21) cycles. Two patients (33%) had partial response and 4 patients (66%) had stable disease. One patient progressed after 6.4 months of therapy. One patient died due to pneumonia but had stable disease at time of death. One patient developed encephalopathy, likely due to bevacizumab. Two patients are still receiving treatment. The median PFS has not been reached (range: 6-42 months).

Conclusions: This retrospective study further suggests that GEMOX-B is an active regimen in BTCs. Additional studies are needed to further evaluate the toxicity and efficacy of this regimen and understand molecular pathways governing sensitivity to chemotherapy.

No significant financial relationships to disclose.