Gemcitabine, Docetaxel, Capecitabine, Cisplatin, Irinotecan as First-line Treatment for Metastatic Pancreatic Cancer

Purpose

Treatment of advanced pancreatic cancer with a single therapeutic at a maximal dose has been largely ineffective at increasing survival. Combination therapies are commonly studied but often limited by toxicity. We previously showed that low-dose multiagent therapy with gemcitabine, docetaxel (taxotere), capecitabine (xeloda), and cisplatin (GTX-C) was safe, well tolerated, and effective (NCT01459614). Here, we hypothesize that adding irinotecan to GTX-C may improve survival with minimal toxicity.

Experimental Design

Patients with treatment-naïve metastatic pancreatic adenocarcinoma were treated with gemcitabine, docetaxel (taxotere), capecitabine (xeloda), cisplatin, and irinotecan (GTX-CI). Treatment consisted of capecitabine 500 mg twice daily on days 1-14 and gemcitabine 300 to 500 mg/m2, docetaxel 20 mg/m2, cisplatin 15 to 20 mg/m2, and irinotecan 20 to 60 mg/m2 on days 4 and 11 of a 21-day cycle. The primary objective was 9-month overall survival (OS). Secondary objectives included response rate (RR), disease control rate (DCR), progression-free survival (PFS), and OS.

Results

The regimen was well tolerated. The recommended phase II dose was gemcitabine 500 mg/m2, docetaxel 20 mg/m2, capecitabine 500 mg po bid, cisplatin 20 mg/m2, and irinotecan 20 mg/m2. Median follow-up in phase II was 11.02 months (2.37-45.17). Nine-month OS rate was 57% [95% confidence interval (CI): (41-77)]. RR was 57% [95% CI: (37-75) 50% PR and 7% CR]. DCR was 87% [95% CI: (69-96)]. Median OS and PFS were 11.02 [95% CI: (8.54-21.09)] and 8.34 [95% CI: (6.34-NA)] months, respectively.

Conclusions

The addition of irinotecan to GTX-C was safe and well tolerated. While the study did not meet its primary objective, the responses were clinically meaningful using a well-tolerated regimen.

Significance

We aimed to optimize the previously reported efficacious regimen of low-dose multiagent therapy with GTX-C for the treatment of metastatic pancreatic ductal adenocarcinoma by adding irinotecan. The primary objective was not met, but GTX-CI was well tolerated. The RR of 57%, median PFS of 8.3 months, median OS of 11 months, and 36-month OS rate of 19% suggest clinical benefit. Further optimization of this regimen is warranted.

A platform trial of neoadjuvant and adjuvant antitumor vaccination alone or in combination with PD-1 antagonist and CD137 agonist antibodies in patients with resectable pancreatic adenocarcinoma

A neoadjuvant immunotherapy platform clinical trial allows for rapid evaluation of treatment-related changes in tumors and identifying targets to optimize treatment responses. We enrolled patients with resectable pancreatic adenocarcinoma into such a platform trial (NCT02451982) to receive pancreatic cancer GVAX vaccine with low-dose cyclophosphamide alone (Arm A; n = 16), with anti-PD-1 antibody nivolumab (Arm B; n = 14), and with both nivolumab and anti-CD137 agonist antibody urelumab (Arm C; n = 10), respectively. The primary endpoint for Arms A/B - treatment-related change in IL17A expression in vaccine-induced lymphoid aggregates - was previously published. Here, we report the primary endpoint for Arms B/C: treatment-related change in intratumoral CD8+ CD137+ cells and the secondary outcomes including safety, disease-free and overall survivals for all Arms. Treatment with GVAX+nivolumab+urelumab meets the primary endpoint by significantly increasing intratumoral CD8+ CD137+ cells (p = 0.003) compared to GVAX+Nivolumab. All treatments are well-tolerated. Median disease-free and overall survivals, respectively, are 13.90/14.98/33.51 and 23.59/27.01/35.55 months for Arms A/B/C. GVAX+nivolumab+urelumab demonstrates numerically-improved disease-free survival (HR = 0.55, p = 0.242; HR = 0.51, p = 0.173) and overall survival (HR = 0.59, p = 0.377; HR = 0.53, p = 0.279) compared to GVAX and GVAX+nivolumab, respectively, although not statistically significant due to small sample size. Therefore, neoadjuvant and adjuvant GVAX with PD-1 blockade and CD137 agonist antibody therapy is safe, increases intratumoral activated, cytotoxic T cells, and demonstrates a potentially promising efficacy signal in resectable pancreatic adenocarcinoma that warrants further study.

Activity-dependent depression of neuronal sodium channels by the general anaesthetic isoflurane

BACKGROUND

The mechanisms by which volatile anaesthetics such as isoflurane alter neuronal function are poorly understood, in particular their presynaptic mechanisms. Presynaptic voltage-gated sodium channels (Na(v)) have been implicated as a target for anaesthetic inhibition of neurotransmitter release. We hypothesize that state-dependent interactions of isoflurane with Na(v) lead to increased inhibition of Na(+) current (I(Na)) during periods of high-frequency neuronal activity.

METHODS

The electrophysiological effects of isoflurane, at concentrations equivalent to those used clinically, were measured on recombinant brain-type Na(v)1.2 expressed in ND7/23 neuroblastoma cells and on endogenous Na(v) in isolated rat neurohypophysial nerve terminals. Rate constants determined from experiments on the recombinant channel were used in a simple model of Na(v) gating.

RESULTS

At resting membrane potentials, isoflurane depressed peak I(Na) and shifted steady-state inactivation in a hyperpolarizing direction. After membrane depolarization, isoflurane accelerated entry (τ(control)=0.36 [0.03] ms compared with τ(isoflurane)=0.33 [0.05] ms, P<0.05) and slowed recovery (τ(control)=6.9 [1.1] ms compared with τ(isoflurane)=9.0 [1.9] ms, P<0.005) from apparent fast inactivation, resulting in enhanced depression of I(Na), during high-frequency stimulation of both recombinant and endogenous nerve terminal Na(v). A simple model of Na(v) gating involving stabilisation of fast inactivation, accounts for this novel form of activity-dependent block.

CONCLUSIONS

Isoflurane stabilises the fast-inactivated state of neuronal Na(v) leading to greater depression of I(Na) during high-frequency stimulation, consistent with enhanced inhibition of fast firing neurones.

A phase II trial of low-dose multiagent chemotherapy with gemcitabine, docetaxel, capecitabine, and cisplatin (GTX-C) in patients with metastatic pancreatic cancer

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Background: Multiagent chemotherapy with three agents has been shown to delay the emergence of resistance and extend survival in patients with metastatic pancreatic adenocarcinoma. Four drug regimens, even at low doses, may further improve survival by simultaneously targeting multiple non-redundant oncogenic pathways. Methods: A phase II study of GTX-C (capecitabine 500 mg bid on days 1-14, and the combination of gemcitabine 500 mg/m2 (10 mg/m2/min), docetaxel 20 mg/m2 and cisplatin 20 mg/m2 on days 4 and 11) was initiated in newly diagnosed untreated metastatic pancreatic cancer patients. The primary endpoint was progression-free survival rate at 6 months; the regimen would be considered active if the 6-month PFS rate was >75% and inactive if < 50%. Results: Twenty-nine patients were enrolled and 10 patients remain on GTX-C treatment at the time of this report. All patients were ECOG 0 or 1. Eighty-six percent of patients had evidence of liver metastases and 25% had biliary stents in place at time of study enrollment. Median CA19-9 was 6,159 U/mL (37-154,323 U/mL). Median length of follow-up was 9.0 months. Grade 3/4 related adverse events included: nausea/vomiting (7%), transaminitis (10%), anemia (14%), thrombocytopenia (24%), and neutropenia (55%). However, febrile neutropenia occurred in only 3 patients (10%) and not until cycles 6, 14, and 15. PFS rate at 6 months was 76.4% (95% CI: 54.6% - 88.7%). The partial response (PR) rate was 50%, stable disease (SD) rate was 39% and the disease control rate (DCR) was 89%. CA19-9 declines of >80% occurred in 77% of patients with measurable levels. Estimated median PFS was 8.4 months (95% CI: 6.1-10.6 months) and OS was 13.9 months (95% CI: 10.0-17.2 months) at the time of this submission. Updated results will be reported at GI ASCO 2014. Conclusions: GTX-C is highly active and well-tolerated in patients with metastatic pancreatic cancer and should be tested in a larger, comparative study. Clinical trial information: NCT01459614.