Metastatic pancreatic ductal adenocarcinoma: diagnosis and treatment with a view to the future

Gemcitabine and Paclitaxel Versus Gemcitabine Alone After 5-Fluorouracil, Oxaliplatin, and Irinotecan in Metastatic Pancreatic Adenocarcinoma: A Randomized Phase III PRODIGE 65-UCGI 36-GEMPAX UNICANCER Study

PURPOSE

GEMPAX was an open-label, randomized phase III clinical trial designed to assess the efficacy and tolerability of gemcitabine plus paclitaxel versus gemcitabine alone as second-line treatment for patients with metastatic pancreatic ductal adenocarcinoma (mPDAC) who previously received 5-fluorouracil, oxaliplatin, and irinotecan.

METHODS

Patients with histologically or cytologically confirmed mPDAC were randomly assigned (2:1) to receive GEMPAX (paclitaxel 80 mg/m2 + gemcitabine 1,000 mg/m2; IV; once at day (D) 1, D8, and D15/arm A) or gemcitabine (arm B) alone once at D1, D8, and D15 every 28 days until progression, toxicity, or patient's decision. The primary end point was overall survival (OS). Secondary end points included progression-free survival (PFS), objective response rate (ORR), quality of life, and safety.

RESULTS

Overall, 211 patients (median age, 64 [30-86] years; 62% male) were included. After a median study follow-up for alive patients of 13.4 versus 13.8 months in arm A versus arm B, the median OS (95% CI) was 6.4 (5.2 to 7.4) versus 5.9 months (4.6 to 6.9; hazard ratio [HR], 0.87 [0.63 to 1.20]; P = 0.4095), the median PFS was 3.1 (2.2 to 4.3) versus 2.0 months (1.9 to 2.3; HR, 0.64 [0.47 to 0.89]; P = 0.0067), and the ORR was 17.1% (11.3 to 24.4) versus 4.2% (0.9 to 11.9; P = 0.008) in arm A versus arm B, respectively. Overall, 16.7% of patients in arm A and 2.9% in arm B discontinued their treatment because of adverse events (AEs). One grade 5 AE associated with both gemcitabine and paclitaxel was reported in arm A (acute respiratory distress), and 58.0% versus 27.1% of patients experienced grade ≥3 treatment-related AEs in arm A versus arm B, among which 15.2% versus 4.3% had anemia, 15.9% versus 15.7% had neutropenia, 19.6% versus 4.3% had thrombocytopenia, 10.1% versus 2.9% had asthenia and 12.3% versus 0.0% had neuropathy.

CONCLUSION

While GEMPAX did not meet the primary end point of OS versus gemcitabine alone in patients with mPDAC in the second-line setting, both PFS and ORR were significantly improved.

Genomic alterations drive metastases formation in pancreatic ductal adenocarcinoma cancer: deciphering the role of CDKN2A and CDKN2B in mediating liver tropism

Metastases are often the direct cause of death from pancreatic ductal adenocarcinoma (PDAC). The role of genomic alterations (GA) in mediating tropism and metastasis formation by PDAC cells is currently unknown. We aimed to identify GAs predisposing colonization of PDAC cells to the liver and decipher mechanisms enabling this process. In order to reveal specific genes, we studied the frequency of GA in 8,880 local and 7,983 metastatic PDAC samples. We observed differential pattern of GA in the local tumor and specific metastatic sites, with liver metastases characterized by deletion of CDKN2A/B (encoding p16/p15, respectively). The role of CDKN2A/B in promoting liver metastasis was evidenced by enhanced tumorigenic phenotype of p15/p16-deleted PDAC cells when exposed to hepatocytes conditioned media. The liver is characterized by high-ammonia low-glutamine environment and transcriptomic assays indicated unique adaptation of PDAC cells to these conditions, including regulation of genes leading to reduced glutaminolysis, like overexpression of GLUL and reduction in GLS2. Furthermore, metabolic assays indicated an increase in glutamate derived from [U-13C]-glucose in p15/p16-deleted cells. Importantly, these cells thrived under high ammonia condition. These data suggest a unique role for genomic alterations in mediating tropism of PDAC. Among these alterations, p15/16 deletion was identified as a promoter of liver metastases. Further studies indicated a unique role for p15/16 in regulating glutaminolysis. These findings reveal vulnerabilities in PDAC cells, which may pave the way for the development of novel therapeutic strategies aiming at the prevention of liver metastases formation.

Phase 1b study of a small molecule antagonist of human chemokine (C-C motif) receptor 2 (PF-04136309) in combination with nab-paclitaxel/gemcitabine in first-line treatment of metastatic pancreatic ductal adenocarcinoma

Background In pancreatic ductal adenocarcinoma (PDAC), the chemokine (C-C motif) ligand 2 (CCL2)/chemokine (C-C motif) receptor 2 (CCR2) axis plays a key role in immunosuppressive properties of the tumor microenvironment, patient prognosis, and chemoresistance. This phase Ib study assessed the effects of the orally administered CCR2 inhibitor PF-04136309 in combination with nab-paclitaxel and gemcitabine in patients with previously untreated metastatic PDAC. Methods Patients received PF-04136309 twice daily (BID) continuously plus nab-paclitaxel (125 mg/m2) and gemcitabine (1000 mg/m2) administered on days 1, 8, and 15 of each 28-day cycle. The primary objectives were to evaluate safety and tolerability, characterize dose-limiting toxicities (DLTs), and determine the recommended phase II dose (RP2D) of PF-04136309. Results In all, 21 patients received PF-04136309 at a starting dose of 500 mg or 750 mg BID. The RP2D was identified to be 500 mg BID. Of 17 patients treated at the 500 mg BID starting dose, three (17.6%) experienced a total of four DLTs, including grade 3 dysesthesia, diarrhea, and hypokalemia and one event of grade 4 hypoxia. Relative to the small number of patients (n = 21), a high incidence (24%) of pulmonary toxicity was observed in this study. The objective response rate for 21 patients was 23.8% (95% confidence interval: 8.2-47.2%). Levels of CD14 + CCR2+ inflammatory monocytes (IM) decreased in the peripheral blood, but did not accumulate in the bone marrow. Conclusions PF-04136309 in combination with nab-paclitaxel plus gemcitabine had a safety profile that raises concern for synergistic pulmonary toxicity and did not show an efficacy signal above nab-paclitaxel and gemcitabine. ClinicalTrials.gov identifier: NCT02732938.