Activating oxidative phosphorylation by a pyruvate dehydrogenase kinase inhibitor overcomes sorafenib resistance of hepatocellular carcinoma

Background:

Sorafenib is the only drug approved for the treatment of hepatocellular carcinoma (HCC). The bioenergetic propensity of cancer cells has been correlated to anticancer drug resistance, but such correlation is unclear in sorafenib resistance of HCC.

Methods:

Six sorafenib-naive HCC cell lines and one sorafenib-resistant HCC cell line (Huh-7R; derived from sorafenib-sensitive Huh-7) were used. The bioenergetic propensity was calculated by measurement of lactate in the presence or absence of oligomycin. Dichloroacetate (DCA), a pyruvate dehydrogenase kinase (PDK) inhibitor, and siRNA of hexokinase 2 (HK2) were used to target relevant pathways of cancer metabolism. Cell viability, mitochondrial membrane potential, and sub-G1 fraction were measured for in vitro efficacy. Reactive oxygen species (ROS), adenosine triphosphate (ATP) and glucose uptake were also measured. A subcutaneous xenograft mouse model was used for in vivo efficacy.

Results:

The bioenergetic propensity for using glycolysis correlated with decreased sorafenib sensitivity (R²=0.9067, among sorafenib-naive cell lines; P=0.003, compared between Huh-7 and Huh-7 R). DCA reduced lactate production and increased ROS and ATP, indicating activation of oxidative phosphorylation (OXPHOS). DCA markedly sensitised sorafenib-resistant HCC cells to sorafenib-induced apoptosis (sub-G1 (combination vs sorafenib): Hep3B, 65.4±8.4% vs 13±2.9% Huh-7 R, 25.3± 5.7% vs 4.3±1.5% each P<0.0001), whereas siRNA of HK2 did not. Sorafenib (10 mg kg⁻¹ per day) plus DCA (100 mg kg⁻¹ per day) also resulted in superior tumour regression than sorafenib alone in mice (tumour size: −87% vs −36%, P<0.001).

Conclusion:

The bioenergetic propensity is a potentially useful predictive biomarker of sorafenib sensitivity, and activation of OXPHOS by PDK inhibitors may overcome sorafenib resistance of HCC.

Use of plasma angiogenesis-related factors to investigate the association of interleukin 8 and interleukin 6 levels with efficacy of sorafenib-based antiangiogenic therapy in patients with advanced hepatocellular carcinoma (HCC)

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Background: Anti-angiogenic agents have become the most important class of therapy for patients (pts) with advanced HCC. However, biomarkers predictive of the efficacy of anti-angiogenic therapy remain lacking.

Methods: Advanced HCC pts, enrolled in a phase II study (Hsu et al: J Hepatol 2010) and its extended cohort, were treated with sorafenib plus metronomic oral tegafur/uracil until disease progression. Plasma samples were collected before treatment and 4 weeks after the start of treatment. The levels of IL-6, IL-8, IL-13, CXCL10, PDGF and VEGF-A were analyzed by multiplexed bead suspension arrays (Bio-Rad, Hercules, CA, US). Levels of VEGF-C, VEGF-D, PlGF, fibroblast growth factor 2 (FGF2), SDF1-alpha and soluble VEGF receptor 2 were determined by ELISA. The baseline levels and post-treatment changes of these plasma factors were analyzed for their associations with treatment outcomes.

Results: Among 68 pts treated with the protocol treatment, 64 were enrolled to this study. There were 4 partial responder (PR) and 33 patients with stable disease (SD) according to RECIST 1.0. The disease control rate (PR+SD) was 58%. The median PFS and OS were 3.7 and 7.4 months, respectively. Patients with progressive disease, compared to those with disease control, had significant increase of post- treatment IL-6 (p = 0.016) and IL-8 (p = 0.021), borderline significant increase of post-treatment FGF2 (p = 0.078) and significant decrease of post-treatment CXCL-10 (p = 0.046). High baseline IL-8 was significantly associated with poorer PFS and OS (p = 0.002 and 0.001, respectively). More increase of post-treatment IL-6 was associated with poorer PFS and OS (p = 0.087 and 0.018, respectively). By multivariate analysis, high baseline IL-8 and more post-treatment increase of IL-6 remained independent predictors for poorer PFS and OS.

Conclusions: High baseline IL-8 and more post-treatment increase of IL-6 in plasma were associated with poor treatment outcomes in advanced HCC pts treated with sorafenib-based anti-angiogenic therapy. This study was supported by the grant of NSC 98-3112-B-002-038.

No significant financial relationships to disclose.

Concurrent chemoradiotherapy with cetuximab plus twice-weekly paclitaxel and cisplatin followed by esophagectomy for locally advanced esophageal squamous cell carcinoma

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Background: We investigated the efficacy and safety of adding cetuximab into twice-weekly paclitaxel/cisplatin-based concurrent chemoradiotherapy (CCRT), followed by surgery, for patients with locally advanced esophageal squamous cell carcinoma (ESCC).

Methods: Patients with operable ESCC (T3N0-1M0 or T1-3N1M0 or M1a) were treated with paclitaxel (35 mg/m2 1 h on days 1 and 4/week), cisplatin (15 mg/m2 1 h on days 2 and 5/week), cetuximab (400 mg/m2 2 h on day -5, then 250 mg/m2 2 h on day 3/week) and radiotherapy (2 Gy on days 1-5/week). When the accumulated radiation dose reached 40 Gy, the feasibility of esophagectomy was evaluated for all patients. In patients for whom esophagectomy was not feasible, CCRT was continued to a radiation dose of 60-66 Gy.

Results: Sixty-two patients with ESCC were enrolled, and the majority had T3N1M0 or M1a tumors by endoscopic ultrasonographic staging (94%). All patients received CCRT to 40 Gy. Forty-three patients underwent surgery, and 17 patients continued definitive CCRT to 60-66 Gy. Of the scheduled doses of paclitaxel, cisplatin, and cetuximab, 80%, 79%, and 99% were given, respectively. The intent-to-treat pathological complete response rate was 24% (15/62) (95% confidence interval: 13-35%). At the median follow-up of 13.3 months, the one-year progression-free and overall survivals were 76% and 63%, respectively. The most common grade 3/4 toxic effects were leukopenia (51%), neutropenia (15%), esophagitis (19%), and infection (12%). Grade 1, 2, and 3 skin rash occurred in 59%, 36%, and 2% of patients, respectively. Grade 1, 2, 3, and 4 hypomagnesemia occurred in 14%, 5%, 0%, and 5% of patients, respectively.

Conclusions: Adding cetuximab to twice-weekly paclitaxel/cisplatin-based CCRT prior to esophagectomy is an active and tolerable treatment for locally advanced ESCC.

No significant financial relationships to disclose.

Exposure-response (E-R) analysis to facilitate phase III (P3) dose selection for AMG 479 (A479) in combination with gemcitabine (G) to treat metastatic pancreatic cancer (mPC)

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Background: A479 is an investigational, fully human monoclonal antibody against IGF1R. In a phase II study, 125 pts with mPC were randomized 1:1:1 to A479, placebo (P), or conatumumab in combination with G. Addition of A479 (12 mg/kg IV, Q2W) to G (1000 mg/m2) showed evidence of improved OS and PFS (Kindler, JCO 2010:28 abstr 4035). An E-R analysis was done to inform P3 dose selection for A479.

Methods: A population PK model of A479 was constructed using data from multiple studies. An E-R analysis was performed with pts from the A479+G and P+G arms (∼40 pts/arm). The effect of estimated steady-state area under the curve (AUCss) on OS and PFS was evaluated with a Cox proportional hazard model. Effects of potential confounding factors on OS- AUCss and PFS-AUCss associations were assessed by multivariate analysis. Exposure-safety data were analyzed with descriptive statistics and linear regression. P3 doses for A479 were explored with Monte Carlo simulations using population PK and parametric survival models.

Results: There was a positive association between OS or PFS and higher AUCss in the A479+G arm (P<0.001, <0.001) that remained even when data from the A479+G and P+G arms were combined (P=0.033, 0.022). Pts with AUCss ≥ median (19.2 mg·h/μL) had longer median OS and PFS (16.0, 7.6 months) than pts with AUCss < median (4.7, 1.9 months). OS-AUCss and PFS-AUCss associations were significant after adjusting for potential confounding factors. Sensitivity E-R analyses were done to confirm the modeling results. The incidence of most adverse events was similar between the AUCss < and ≥ median groups, although the incidence of grade ≥3 hyperglycemia, neutropenia, and thrombocytopenia trended higher in pts with AUCss ≥ median. Population PK indicated 1.7-fold higher clearance of A479 in mPC than non-mPC pts. No G-A479 PK interactions were identified. PK simulations showed similar AUCss of A479 in mPC pts at 20 mg/kg and in non-mPC pts at 12 mg/kg. Simulations projected improved OS and PFS with 20 mg/kg vs 12 mg/kg A479.

Conclusions: Increased exposure to A479 is associated with improved clinical outcomes in mPC. This supports the evaluation of 20 mg/kg A479 in P3.

[Table: see text]

Geographic difference in safety and efficacy of systemic chemotherapy for advanced gastric or gastroesophageal carcinoma: A meta-regression approach

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Background: The standard of chemotherapy regimens for patients with advanced or metastatic gastric cancer vary and the clinical outcome were heterogeneous in Asian vs. non-Asian countries.

Methods: Treatment group-based meta-analysis and meta-regression were performed to analyze results of randomized trials published since 2005 for advanced or metastatic gastric cancer patients who received systemic chemotherapy as first-line treatment. Data were extracted and synthesized according to the Cochrane guidelines.

Results: Among the 24 trials (totally 6,502 patients) eligible for meta-analysis, Asian trials reported lower percentage of gastroesophageal junctional carcinoma, higher percentage of diffuse-type histology, and more frequent use of second-line chemotherapy. Meta- regression analyses indicate that, after controlling other patient or treatment factors, Asian trials are associated with 22.7% (95% CI: 19.5-26.0%, p<0.0001) lower incidence of grade 3-4 neutropenia and 3.5% (95% CI: 2.1-4.9%, p<0.0001) lower incidence of grade 3-4 diarrhea, which were the most commonly reported toxicity. The use of high-dose infusional 5-fluorouracil, compared with other fuoropyrimidine regimens, reported 16.6% lower incidence of neutropenia (95% CI: 13.3-19.9%, p<0.0001). Higher percentage of patients with gastroesophageal junction carcinoma and patients with 2 or more organs involved predicted poor progression-free survival. The use of second-line chemotherapy predicts better 1-year overall survival, which will increase by 9% (95% CI: 8-10%) for every 10 percent increase in patients who received second-line chemotherapy.

Conclusions: Geographic region (Asian vs. non-Asian) plays an important role in the heterogeneity of gastric cancer clinical trials and is an independent predictor of safety in systemic therapy for gastric cancer.

No significant financial relationships to disclose.

Phase II study of weekly low-dose everolimus plus weekly 24-hour infusions of cisplatin and high-dose 5-fluorouracil and leucovorin for first-line treatment in patients with advanced gastric cancers

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Background: Cisplatin-HDFL, consisting of weekly 24-hour infusions of cisplatin and high-dose 5-fluorouracil (5-FU) and leucovorin (LV), is an effective and low-toxicity regimen for patients with advanced gastric cancer (GC) in Taiwan (J Clin Oncol. 1994;12(4):875; J Clin Oncol. 2006;24(18S):A14063). Everolimus (RAD001), a derivative of rapamycin, is an orally bioavailable mTOR inhibitor. We have demonstrated that low-dose everolimus (0.5-5.0 nM) sensitizes cytotoxic effects of cisplatin and 5-FU in GC cells (Proc Am Assoc Cancer Res. 2007;48:A4043).

Methods: Patients who had pathologically confirmed chemonaive advanced GC, at least 1 measurable lesion, a fasting serum triglyceride level > 70 mg/dl, ECOG PS 0-2, and adequate organ functions were treated with everolimus 10 mg po on days 1, 8, and 15 concurrently with the initiation of chemotherapy; cisplatin 35 mg/m2 iv 24h infusion on days 1 and 8; 5-FU 2,000 mg/m2 and LV 300 mg/m2 (HDFL) iv 24h infusion on days 1, 8, and 15, in a every 28-day cycle. Response assessment was performed every 2 cycles. The primary endpoint was confirmed objective response rate (RR) by RECIST.

Results: Between March 2008 and July 2010, 24 patients (M:11, F:13) with a median age of 53 (range: 33-69) were evaluable for response. The overall RR was 50% (95% CI: 29-71%) with 12 partial responders. Among a total of 162 cycles (median: 7, range: 1-13) given, grade (Gr) 3/4 toxicities included neutropenia (4.3%), infection (2.5%), nausea (3.1%) and vomiting (3.1%). Gr 1/2 nausea, vomiting, stomatitis, and diarrhea developed in 19.2%, 15.4%, 14.8%, and 5.5% of cycles, respectively. Skin rash and hand-foot syndrome were mild. One patient developed reversible HDFL-related hyperammonemic encephalopathy. Median progression-free survival was 8.4 months (range: 1.3-15.4+) and median overall survival was 14.8 months (range: 4.0-21.6+).

Conclusions: Weekly low-dose everolimus plus weekly cisplatin-HDFL is an effective first-line regimen for patients with advanced GC. Addition of weekly low-dose everolimus to infusional cisplatin-HDFL did not add gastrointestinal toxicities.

No significant financial relationships to disclose.