Paclitaxel Protein Bound Plus Cisplatin Plus Gemcitabine and Paricalcitol for Pancreatic Adenocarcinoma (NABPLAGEMD)

Pancreatic cancer continues to be a highly lethal disease with an overall 5 year survival of only 8%. Since 2004, the incidence of pancreatic cancer has been increasing by 1.5% per year and it is estimated that there will be 53,670 new cases diagnosed in the United States in 2017, with 43,090 expected deaths. Pancreatic cancer is the third most common cause of cancer-related deaths in both men and women, and the incidence is about equal in both sexes. Of all types of pancreatic cancers, pancreatic ductal adenocarcinoma (PDA) is by far the most common, representing 80% of cases. Due to lack of adequate screening techniques, greater than 80% of patients at the time of diagnosis present with unresectable, advanced disease. Standard treatment options for inoperable patients with locally advanced and metastatic PDA have been quite limited. Gemcitabine monotherapy, approved by the Food and Drug Administration (FDA) in 1996, demonstrated a median survival of 5.7 months, and has been the mainstay in treating patients with PDA. The first combination regimen to demonstrate any survival benefit compared with gemcitabine alone was gemcitabine plus erlotinib, with median survival of 6.24 months versus 5.91 months for single agent gemcitabine. A meta-analysis of randomized trials by Heinemann and colleagues showed that patients with advanced pancreatic cancer and a good performance status may benefit from combination chemotherapy with gemcitabine plus a platinum agent or a fluoropyrimidine. Multiple combination regimens are being utilized. Recently, the regimen of 5-fluorouracil/leucovorin/irinotecan/oxaliplatin (FOLFIRINOX) compared with gemcitabine demonstrated improvement in both progression-free survival (PFS, 6.4 vs. 3.3 months) and overall survival (OS, 11.1 vs. 6.8 months) for patients with a good performance status. FOLFIRINOX, however, is associated with substantial grade 3 and 4 toxicities, including diarrhea, nausea, vomiting, fatigue, neutropenia and febrile neutropenia, and cannot be given to patients \>76 years of age or in some cases patients with head of the pancreas tumors. An international phase III trial comparing paclitaxel protein bound (now called paclitaxel protein bound) plus gemcitabine to gemcitabine single agent demonstrated a statistically significant improvement in OS (8.5 vs. 6.7 months) for advanced pancreatic cancer patients using the gemcitabine and paclitaxel protein bound over gemcitabine alone. A recently completed phase Ib/II trial of the combination of paclitaxel protein bound plus gemcitabine plus cisplatin in previously untreated stage IV pancreatic adenocarcinoma patients was presented at the 2017 Gastrointestinal Cancer Symposium. In 24 patients with stage IV pancreatic cancer they reported 8.3% complete response (CR), 62.5% partial response (PR), 16.7% stable disease and 12.5% progressive disease. The rationale for adding cisplatin to paclitaxel protein bound and gemcitabine is that in a study of 1,029 patients whose pancreatic cancer tumors underwent molecular profiling, 57% of these tumors were negative for expression of the excision repair cross-complementation group 1 (ERCC1), indicating sensitivity to a platinum anti-tumor agent. In addition to the above, in our whole genome/transcriptome sequencing analysis, we found that abnormal repair pathways were a feature of all of the pancreatic cancers that were sequenced. Cisplatin prevents cellular deoxyribonucleic acid (DNA) repair by binding to and causing crosslinking of DNA, triggering apoptosis. Cisplatin has been used in other combination regimens to treat patients with PDA. For example, the cisplatin, epirubicin, 5-fluorouracil and gemcitabine (PEFG) regimen had an acceptable toxicity profile and was associated with a 24% partial response rate, 5 month PFS and 8.3 month OS as second line therapy. Most recently, a study showed that Vitamin D can change the pancreatic tumor microenvironment from an immunologically suppressive (tumor promoting) one to an immunologically hostile one (e.g. decreased IL-6, decreased CXCL12 etc.). In addition, in the same study, the vitamin D ligand calcipotriol decreased production of collagen, decreased myeloid derived suppressor cells (MDSCs) and decreased regulatory T cells. Remarkably, in clinical practice, the vitamin D analogue paricalcitol was observed to reverse chemotherapy resistance. Two individuals with pancreatic adenocarcinoma who were receiving paclitaxel protein bound and gemcitabine based combination chemotherapy developed progressive disease which was reversed by the addition of paricalcitol. Based upon these promising clinical and pre-clinical data we are initiating a clinical trial combining paclitaxel protein bound, gemcitabine, and cisplatin for patients with metastatic PDA. When these patients develop progressive disease the vitamin D analog paricalcitol will be added to the regimen. The treatment will continue until further disease progression.