Concurrent chemoradiotherapy with gemcitabine and cisplatin for pancreatic cancer: from the laboratory to the clinic

A Pharmacokinetic and Pharmacodynamic Evaluation of the Anti-Hepatocellular Carcinoma Compound 4-N-Carbobenzoxy-gemcitabine (Cbz-dFdC)

Gemcitabine (dFdC) demonstrates significant effectiveness against solid tumors in vitro and in vivo; however, its clinical application is limited because it tends to easily undergo deamination metabolism. Therefore, we synthesized 4-N-carbobenzoxy-gemcitabine (Cbz-dFdC) as a lead prodrug and conducted a detailed pharmacokinetic, metabolic, and pharmacodynamic evaluation. After intragastric Cbz-dFdC administration, the C_max of Cbz-dFdC and dFdC was 451.1 ± 106.7 and 1656.3 ± 431.5 ng/mL, respectively. The T_max of Cbz-dFdC and dFdC was 2 and 4 h, respectively. After intragastric administration of Cbz-dFdC, this compound was mainly distributed in the intestine due to low carboxylesterase-1 (CES1) activity. Cbz-dFdC is activated by CES1 in both humans and rats. The enzyme kinetic curves were well fitted by the Michaelis–Menten equation in rats’ blood, plasma, and tissue homogenates and S9 of the liver and kidney, as well as human liver S9 and CES1 recombinase. The pharmacodynamic results showed that the Cbz-dFdC have a good antitumor effect in the HepG2 cell and in tumor-bearing mice, respectively. In general, Cbz-dFdC has good pharmaceutical characteristics and is therefore a good candidate for a potential prodrug.

Second-line chemotherapy for advanced pancreatic cancer: Which is the best option?

Despite recent biological insight and therapeutic advances, the prognosis of advanced pancreatic cancer still remains poor. For more than 15 years, gemcitabine monotherapy has been the cornerstone of first-line treatment. Recently, prospective randomized trials have shown that novel upfront combination regimens tested in prospective randomized trials have resulted in improved patients' outcome increasing the proportion of putative candidate to second-line therapy. There is no definite standard of care after disease progression. A novel formulation in which irinotecan is encapsulated into liposomal-based nanoparticles may increase the efficacy of the drug without incrementing its toxicity. NAPOLI-1 was the first randomized trial to compare nanoliposomal irinotecan and fluorouracil-leucovorin (5-FU/LV) to 5-FU/LV alone after a gemcitabine-based chemotherapy. This review focuses on the current data for the management of second-line treatment for metastatic pancreatic adenocarcinoma, presents the most interesting ongoing clinical trials and illustrates the biologically-driven future options beyond disease progression.

Chemotherapeutic agents for GI tumor chemoradiotherapy overview of chemotherapeutic agents to be combined with radiotherapy in the GI tract and their potential as radiosensitizers

In the treatment of gastrointestinal tumors, simultaneous radiochemotherapy plays an important role. It is one of the principles of simultaneous radiochemotherapy, applying only chemotherapeutic agents simultaneously to radiation, which are primarily effective in the treated tumor entity, therefore a lot of different agents, like antimetabolites, mostly 5-fluorouracil, platinum derivates (mostly cisplatinum and oxaliplatin), mitomycin C and taxanes are used in simultaneous radiochemotherapy. Most of these have also radiation-intensifying effects. The mechanisms and interactions with ionizing radiation are presented in the article.

Inhibition of RAC1 GTPase sensitizes pancreatic cancer cells to γ-irradiation

Radiation therapy is a staple treatment for pancreatic cancer. However, owing to the intrinsic radioresistance of pancreatic cancer cells, radiation therapy often fails to increase survival of pancreatic cancer patients. Radiation impedes cancer cells by inducing DNA damage, which can activate cell cycle checkpoints. Normal cells possess both a G1 and G2 checkpoint. However, cancer cells are often defective in G1 checkpoint due to mutations/alterations in key regulators of this checkpoint. Accordingly, our results show that normal pancreatic ductal cells respond to ionizing radiation (IR) with activation of both checkpoints whereas pancreatic cancer cells respond to IR with G2/M arrest only. Overexpression/hyperactivation of Rac1 GTPase is detected in the majority of pancreatic cancers. Rac1 plays important roles in survival and Ras-mediated transformation. Here, we show that Rac1 also plays a critical role in the response of pancreatic cancer cells to IR. Inhibition of Rac1 using specific inhibitor and dominant negative Rac1 mutant not only abrogates IR-induced G2 checkpoint activation, but also increases radiosensitivity of pancreatic cancer cells through induction of apoptosis. These results implicate Rac1 signaling in the survival of pancreatic cancer cells following IR, raising the possibility that this pathway contributes to the intrinsic radioresistance of pancreatic cancer.

Cisplatin-induced non-apoptotic death of pancreatic cancer cells requires mitochondrial cyclophilin-D-p53 signaling

The pancreatic cancer remains a fatal disease for the majority of patients. Cisplatin has displayed significant cytotoxic effects against the pancreatic cancer cells, however the underlying mechanisms remain inconclusive. Here, we found that cisplatin mainly induced non-apoptotic death of the pancreatic cancer cells (AsPC-1 and Capan-2), which was associated with a significant p53 activation (phosphorylation and accumulation). Further, activated p53 was found to translocate to mitochondria where it formed a complex with cyclophilin D (Cyp-D). We provided evidences to support that mitochondrial Cyp-D/p53 complexation might be critical for cisplatin-induced non-apoptotic death of pancreatic cancer cells. Inhibition of Cyp-D by its inhibitor cyclosporine A (CsA), or by shRNA-mediated knockdown suppressed cisplatin-induced pancreatic cancer cell death. Both CsA and Cyp-D knockdown also disrupted the Cyp-D/p53 complex formation in mitochondria. Meanwhile, the pancreatic cancer cells with p53 knockdown were resistant to cisplatin. On the other hand, HEK-293 over-expressing Cyp-D were hyper-sensitive to cisplatin. Interestingly, camptothecin (CMT)-induced pancreatic cancer cell apoptotic death was not affected CsA or Cyp-D knockdown. Together, these data suggested that cisplatin-induced non-apoptotic death requires mitochondria Cyp-D-p53 signaling in pancreatic cancer cells.

Can drugs enhance hypofractionated radiotherapy? A novel method of modeling radiosensitization using in vitro data

PURPOSE

Hypofractionated radiotherapy (hRT) is being explored for a number of malignancies. The potential benefit of giving concurrent chemotherapy with hRT is not known. We sought to predict the effects of combined modality treatments by using mathematical models derived from laboratory data.

METHODS AND MATERIALS

Data from 26 published clonogenic survival assays for cancer cell lines with and without the use of radiosensitizing chemotherapy were collected. The first three data points of the RT arm of each assay were used to derive parameters for the linear quadratic (LQ) model, the multitarget (MT) model, and the generalized linear quadratic (gLQ) model. For each assay and model, the difference between the predicted and observed surviving fractions at the highest tested RT dose was calculated. The gLQ model was fitted to all the data from each RT cell survival assay, and the biologically equivalent doses in 2-Gy fractions (EQD2s) of clinically relevant hRT regimens were calculated. The increase in cell kill conferred by the addition of chemotherapy was used to estimate the EQD2 of hRT along with a radiosensitizing agent. For comparison, this was repeated using conventionally fractionated RT regimens.

RESULTS

At a mean RT dose of 8.0 Gy, the average errors for the LQ, MT, and gLQ models were 1.63, 0.83, and 0.56 log units, respectively, favoring the gLQ model (p < 0.05). Radiosensitizing chemotherapy increased the EQD2 of hRT schedules by an average of 28% to 82%, depending on disease site. This increase was similar to the gains predicted for the addition of chemotherapy to conventionally fractionated RT.

CONCLUSIONS

Based on published in vitro assays, the gLQ equation is superior to the LQ and MT models in predicting cell kill at high doses of RT. Modeling exercises demonstrate that significant increases in biologically equivalent dose may be achieved with the addition of radiosensitizing agents to hRT. Clinical study of this approach is warranted.

Gemcitabine alone versus gemcitabine plus radiotherapy in patients with locally advanced pancreatic cancer: an Eastern Cooperative Oncology Group trial

PURPOSE

The purpose of this trial was to evaluate the role of radiation therapy with concurrent gemcitabine (GEM) compared with GEM alone in patients with localized unresectable pancreatic cancer.

PATIENTS AND METHODS

Patients with localized unresectable adenocarcinoma of the pancreas were randomly assigned to receive GEM alone (at 1,000 mg/m(2)/wk for weeks 1 to 6, followed by 1 week rest, then for 3 of 4 weeks) or GEM (600 mg/m(2)/wk for weeks 1 to 5, then 4 weeks later 1,000 mg/m(2) for 3 of 4 weeks) plus radiotherapy (starting on day 1, 1.8 Gy/Fx for total of 50.4 Gy). Measurement of quality of life using the Functional Assessment of Cancer Therapy-Hepatobiliary questionnaire was also performed.

RESULTS

Of 74 patients entered on trial and randomly assigned to receive GEM alone (arm A; n = 37) or GEM plus radiation (arm B; n = 34), patients in arm B had greater incidence of grades 4 and 5 toxicities (41% v 9%), but grades 3 and 4 toxicities combined were similar (77% in A v 79% in B). No statistical differences were seen in quality of life measurements at 6, 15 to 16, and 36 weeks. The primary end point was survival, which was 9.2 months (95% CI, 7.9 to 11.4 months) and 11.1 months (95% CI, 7.6 to 15.5 months) for arms A and B, respectively (one-sided P = .017 by stratified log-rank test).

CONCLUSION

This trial demonstrates improved overall survival with the addition of radiation therapy to GEM in patients with localized unresectable pancreatic cancer, with acceptable toxicity.

The deaminated metabolite of gemcitabine, 2',2'-difluorodeoxyuridine, modulates the rate of gemcitabine transport and intracellular phosphorylation via deoxycytidine kinase

Gemcitabine (dFdC) is a chemotherapeutic nucleoside analog that undergoes uptake via equilibrative nucleoside transporters (hENT) followed by sequential phosphorylation to the active triphosphate moiety (dFdCTP). Its deaminated metabolite, 2',2'-difluorodeoxyuridine (dFdU), competes with the parent compound for cellular entry via hENTs, but over time dFdU increases the net intracellular accumulation of dFdC by a currently unknown mechanism. In this study, we investigated whether dFdU affects intracellular phosphorylation of gemcitabine by modulating the activity of deoxycytidine kinase (dCK). We report here that coincubation of dFdU with dFdC significantly increases intracellular levels of dFdCTP. dFdCTP was not identified as a substrate for hENTs, suggesting that dFdU affects the formation rather than elimination of the triphosphate. To further characterize the disposition of dFdC in the presence of dFdU, the net intracellular radioactivity of [5-(3)H]dFdC and corresponding metabolic profile were evaluated in HeLa cells transfected with dCK-targeting small interfering RNA. Intracellular radioactivity significantly decreased in cells with compromised intracellular phosphorylation, which was mainly due to a loss in dFdCTP. Although dFdU increased the net intracellular radioactivity of [5-(3)H]dFdC at 24 h in control cells, this increase was abolished in the absence of dCK activity, strongly suggesting that the interaction between dFdU and dFdC occurs via modulation of both transport and metabolism. In conclusion, we have demonstrated that the intracellular distribution of dFdC is dependent on both transport and metabolic processes, and that by affecting the rate at which dFdC enters the cell, the presence of dFdU may be altering the metabolic fate of the parent compound (dFdC).

Gemcitabine/cisplatin versus 5-fluorouracil/mitomycin C chemoradiotherapy in locally advanced pancreatic cancer: a retrospective analysis of 93 patients

Background

Despite of a growing number of gemcitabine based chemoradiotherapy studies in locally advanced pancreatic cancer (LAPC), 5-fluorouracil based regimens are still regarded to be standard and the debate of superiority between the two drugs is going on. The aim of this retrospective analysis was to evaluate the effect of two concurrent chemoradiotherapy regimens using 5-fluorouracil or gemcitabine to compare their effect and tolerance.

Methods

We have performed a single centre retrospective analysis of 93 patients treated with conventionally fractionated radiotherapy of 55.8 Gray using either concurrent 5-fluorouracil, 1 g/m² on days 1-5 and 29-33 of radiotherapy and 10 mg/m² of mitomycin C on day 1, 29 of radiotherapy (FM group, 35 patients) versus gemcitabine (300 mg/m²) and cisplatin, (30 mg/m²) on days 1, 8, 22, and 29 (GC group, 58 patients). Primary endpoint was the median overall survival (OS) rate.

Results

The median OS rate was 12.7 months in the GC group and 9.7 months in the FM group. The 1-year OS rate was 53% versus 40%, respectively (p = 0.009). GC led to more grade 3 leukocytopenia and thrombocytopenia than FM, but not to more grade 4 myelosuppression. Thrombocytopenia was the most frequently observed grade 4 toxicity in both groups (11% after FM versus 12% after GC). No grade 3/4 febrile neutropenia was observed. Grade 3 nausea was more common in the FM group (20% versus 9%) and grade 4 nausea was observed in one patient per group only.

Conclusions

GC was superior to FM for overall survival and both regimens were similar in terms of tolerance. We conclude that GC leads to encouraging results and that the use of FM for chemoradiotherapy in LAPC cannot be recommended without concerns.

Radiosensitization by gemcitabine fixed-dose-rate infusion versus bolus injection in a pancreatic cancer model

It has recently been shown that fixed-dose-rate (gemcitabine) infusion may be superior to bolus gemcitabine in the treatment of metastatic pancreas cancer. We wished to compare the radiosensitizing effects of fixed-dose-rate gemcitabine infusion to standard bolus injection. We measured weight loss and mouse intestinal crypt survival to determine equally toxic concentrations of gemcitabine administered through a 3-hour fixed-dose-rate infusion versus bolus injection in combination with fractionated radiation. To measure the effect of fixed-dose-rate gemcitabine infusion or bolus injection on radiosensitization, we treated mice bearing Panc-1 xenografts with equally toxic concentrations of gemcitabine (100 mg/kg fixed-dose-rate infusion or 500 mg/kg bolus injection) and fractionated radiation and monitored tumor growth. We found that 100 mg/kg gemcitabine through fixed-dose-rate infusion produced the same weight loss and intestinal crypt toxicity as the 500 mg/kg bolus injection. In nude mice bearing Panc-1 xenografts, fixed-dose-rate gemcitabine infusion produced greater radiosensitization than bolus injection with tumor doubling times of 44 +/- 5 versus 29 +/- 3 days, respectively (*P < .05). Fixed-dose-rate gemcitabine infusion produced enhanced radiosensitization without additional normal tissue toxicity compared to bolus gemcitabine injection. These data support an ongoing clinical trial using fixed-dose-rate gemcitabine infusion combined with conformal radiation in the treatment of locally advanced pancreatic cancer.

Radiotherapy combined with gemcitabine and oxaliplatin in pancreatic cancer cells

Clinical evidence suggests that gemcitabine (Gem) plus oxaliplatin (Ox) is superior to gemcitabine alone in advanced pancreatic carcinoma. The addition of radiation to gemcitabine improves response and is a standard treatment for locally advanced disease. We investigated the effect of oxaliplatin on gemcitabine-based chemoradiation by determining whether gemcitabine and oxaliplatin produced synergistic cytotoxicity using median effect analysis and radiosensitization using clonogenic survival assays. We analyzed the effects of gemcitabine and oxaliplatin on cell cycle distribution by DNA content and on radiation-induced DNA damage repair by phosphorylated H2AX (gamma-H2AX). Gemcitabine and oxaliplatin produced schedule-dependent synergistic cytotoxicity in BxPC-3 and Panc-1 cells (combination indices: 0.76 +/- 0.05, 0.61 +/- 0.11). In BxPC-3 cells, oxaliplatin did not affect gemcitabine-mediated radiosensitization (Gem 1.99 +/- 0.27; Gem + Ox 2.38 +/- 0.30). In Panc-1 cells, oxaliplatin significantly enhanced gemcitabine-mediated radiosensitization (Gem 1.31 +/- 0.05; Gem + Ox 2.90 +/- 0.31). Radiosensitization by gemcitabine was accompanied by early S-phase arrest and induction/persistence of gamma-H2AX protein, which were unaltered by oxaliplatin. Addition of oxaliplatin to gemcitabine produces radiosensitization equal to or greater than gemcitabine alone, supporting our clinical investigation of oxaliplatin with gemcitabine-radiation in pancreatic cancer aimed at improving systemic disease control while maintaining local tumor radiosensitization.

A phase 2 trial of gemcitabine, 5-fluorouracil, and radiation therapy in locally advanced nonmetastatic pancreatic adenocarcinoma : cancer and Leukemia Group B (CALGB) 80003

BACKGROUND

The purpose of this study was to assess the efficacy and safety of 5-fluorouracil (5FU) and gemcitabine administered concurrently with radiation in patients with locally advanced, nonmetastatic pancreatic cancer.

METHODS

Eligible patients had histologically confirmed pancreatic adenocarcinoma deemed locally unresectable without evidence of metastatic disease. In addition, all patients underwent laparoscopy or laparotomy before study entry to rule out peritoneal carcinomatosis. Patients received radiation therapy (50.4 Gy) with concurrent infusional 5FU (200 mg/m(2) 5 days/week) and weekly gemcitabine (200 mg/m(2) ). After a 3-week break, patients received weekly gemcitabine at 1000 mg/m(2) for 3 of 4 weeks, for 4 cycles. The primary endpoint of the trial was the proportion of patients surviving 9 months from study entry. Secondary endpoints included objective tumor response, CA19-9 response, overall survival (OS) time to progression (TTP), and toxicity.

RESULTS

Between November 2001 and October 2004, 81 patients were enrolled, 78 of whom were eligible for analysis. With a median follow-up of 55.2 months, the median OS was 12.2 months (95% confidence interval [CI], 10.9-14.9) and the median TTP was 10 months (95% CI, 6.4-12.0). An objective tumor response was seen in 19 patients (25%), and among 56 patients with an elevated CA19-9 at baseline, 29 (52%) had a sustained CA19-9 response. Overall, 41% of patients had grade 3 or greater treatment-related gastrointestinal adverse events.

CONCLUSIONS

The combination of 5FU, gemcitabine, and radiation is well tolerated. Survival is comparable with the best results of other recent studies of 5FU and radiation or gemcitabine and radiation.

Pancreatic cancer cells resistance to gemcitabine: the role of MUC4 mucin

Background:

A major obstacle to the successful management of pancreatic cancer is to acquire resistance to the existing chemotherapeutic agents. Resistance to gemcitabine, the standard first-line chemotherapeutic agent for advanced and metastatic pancreatic cancer, is mainly attributed to an altered apoptotic threshold in the pancreatic cancer. The MUC4 transmembrane glycoprotein is aberrantly overexpressed in the pancreatic cancer and recently, has been shown to increase pancreatic tumour cell growth by the inhibition of apoptosis.

Methods:

Effect of MUC4 on pancreatic cancer cells resistance to gemcitabine was studied in MUC4-expressing and MUC4-knocked down pancreatic cancer cell lines after treatment with gemcitabine by Annexin-V staining, DNA fragmentation assay, assessment of mitochondrial cytochrome c release, immunoblotting and co-immunoprecipitation techniques.

Results:

Annexin-V staining and DNA fragmentation experiment demonstrated that MUC4 protects CD18/HPAF pancreatic cancer cells from gemcitabine-induced apoptosis. In concert with these results, MUC4 also attenuated mitochondrial cytochrome c release and the activation of caspase-9. Further, our results showed that MUC4 exerts anti-apoptotic function through HER2/extracellular signal-regulated kinase-dependent phosphorylation and inactivation of the pro-apoptotic protein Bad.

Conclusion:

Our results elucidate the function of MUC4 in imparting resistance to pancreatic cancer cells against gemcitabine through the activation of anti-apoptotic pathways and, thereby, promoting cell survival.

Single postoperative instillation of gemcitabine in patients with non-muscle-invasive transitional cell carcinoma of the bladder: a randomised, double-blind, placebo-controlled phase III multicentre study

BACKGROUND

Recurrence prophylaxis with intravesical gemcitabine (GEM) was effective and safe in patients with non-muscle-invasive bladder cancer (NMIBC); efficacy as single-shot instillation remains to be proved.

OBJECTIVE

To compare the efficacy of a single GEM instillation versus placebo (PBO) immediately after transurethral resection (TUR) of tumour in patients with histologically confirmed NMIBC (pTa/pT1,G1-3).

DESIGN, SETTING, AND PARTICIPANTS

This was a double-blind, randomised, PBO-controlled study in patients with clinical evidence of primary or recurrent NMIBC (Ta/T1,G1-3). Of 355 patients randomised at 24 urologic centres, 328 underwent TUR and received instillation (92.4%; GEM/PBO: 166/162). In case of nonmalignancy, carcinoma in situ (CIS), > or = pT2 disease, or intraoperative complications, patients were discontinued.

INTERVENTION

We used a single, postoperative 30-40-min instillation of GEM (2000 mg/100 ml of saline) or PBO (100 ml of saline) followed by continuous bladder irrigation for > or = 20 h. A second TUR (no instillation) and adjuvant bacillus Calmette-Guérin (BCG) instillations were allowed.

MEASUREMENTS

Primary outcome was recurrence-free survival (RFS). Secondary outcomes included type of recurrence and adverse events. To detect a difference in RFS, 191 recurrences were required (80% power, log-rank-test, alpha = 0.050).

RESULTS AND LIMITATIONS

Two hundred forty-eight patients (69.9%, GEM, PBO: 124, 124) had histologically confirmed pTa/pT1 G1-3 Gx tumour and were eligible for efficacy (GEM: 76.6% male; median age: 65 yr; PBO: 83.1% male; median age: 67 yr). Treatment groups were balanced (pTa: 75.0%, 71.0%; G1-G2: 85.5%, 87.9%; recurrent tumour: 24.2%, 21.0%; BCG: 10.5%, 16.9%). After a median follow-up of 24 mo, there were only 94 recurrences and 11 deaths. The study was terminated early based on predefined decision criteria. RFS was high in both groups (12-mo RFS [95% confidence interval (CI)]: GEM: 77.7% [68.8-84.3]; PBO: 75.3% [66.3-82.3]). There was no significant group difference (hazard ratio [HR]: 0.946 [0.64-1.39], log-rank test, p=0.777).

CONCLUSIONS

In this study of NMIBC, the immediate single instillation of GEM 2000 mg/100 ml of saline after TUR was not superior to PBO in terms of RFS. Rigid continuous irrigation and improved TUR/cystoscopy techniques may have contributed to the high RFS in both groups.

Improving gemcitabine-mediated radiosensitization using molecularly targeted therapy: a review

In the last three decades, gemcitabine has progressed from the status of a laboratory cytotoxic drug to a standard clinical chemotherapeutic agent and a potent radiation sensitizer. In an effort to improve the efficacy of gemcitabine, additional chemotherapeutic agents have been combined with gemcitabine (both with and without radiation) but with toxicity proving to be a major limitation. Therefore, the integration of molecularly targeted agents, which potentially produce less toxicity than standard chemotherapy, with gemcitabine radiation is a promising strategy for improving chemoradiation. Two of the most promising targets, described in this review, for improving the efficacy of gemcitabine radiation are epidermal growth factor receptor and checkpoint kinase 1.

The combination of epidermal growth factor receptor inhibitors with gemcitabine and radiation in pancreatic cancer

PURPOSE

Gemcitabine-radiotherapy is a standard treatment for locally advanced pancreatic cancer. Clinical data have shown that gemcitabine plus erlotinib is superior to gemcitabine alone for advanced pancreatic cancer. Therefore, we investigated the effects of the combination of epidermal growth factor receptor inhibitors with gemcitabine and radiation on a pancreatic cancer model.

EXPERIMENTAL DESIGN

EGFR signaling was analyzed by measuring phosphorylated EGFR (pEGFR(Y845, (Y1173)) and AKT (pAKT(S473)) protein levels in pancreatic cancer cell lines and tumors. The effects of scheduling on gemcitabine-mediated cytotoxicity and radiosensitization combined with erlotinib were determined by clonogenic survival. In vivo, the effects of cetuximab or erlotinib in combination with gemcitabine-radiation on the growth of BxPC-3 tumor xenografts were measured.

RESULTS

We found in vitro that gemcitabine induced phosphorylation of EGFR at Y845 and Y1173 that was blocked by erlotinib. Treatment of BxPC-3 cells with gemcitabine before erlotinib enhanced gemcitabine-mediated cytotoxicity without abrogating radiosensitization. In vivo, cetuximab or erlotinib in combination with gemcitabine-radiation inhibited growth compared with gemcitabine-radiation (time to tumor doubling: gemcitabine + radiation, 19 +/- 3 days; cetuximab + gemcitabine + radiation, 30 +/- 3 days; P < 0.05, erlotinib + gemcitabine + radiation 28 +/- 3 days; P < 0.1). Cetuximab or erlotinib in combination with gemcitabine-radiation resulted in significant inhibition of pEGFR(Y1173) and pAKT(S473) early in treatment, and pEGFR(Y845), pEGFR(Y1173), and pAKT(S473) by the end of treatment. This study shows a novel difference pEGFR(Y845) and pEGFR(Y1173) in response to EGFR inhibition.

CONCLUSIONS

These results show that the EGFR inhibitors cetuximab and erlotinib increase the efficacy of gemcitabine-radiation. This work supports the integration of EGFR inhibitors with gemcitabine-radiation in clinical trials for pancreatic cancer.

Interleukin-4 cytotoxin therapy synergizes with gemcitabine in a mouse model of pancreatic ductal adenocarcinoma

Targeting cell surface receptors with cytotoxins or immunotoxins provides a unique opportunity for tumor therapy. Here, we show the efficacy of the combination therapy of gemcitabine with an interleukin-4 (IL-4) cytotoxin composed of IL-4 and truncated Pseudomonas exotoxin in animal models of pancreatic ductal adenocarcinoma (PDA). We have observed that 42 of 70 (60%) tumor samples from patients with PDA express moderate- to high-density surface IL-4 receptor (IL-4R), whereas normal pancreatic samples express no or low-density IL-4R. IL-4 cytotoxin was specifically and highly cytotoxic [50% protein synthesis inhibition (IC50) ranging from >0.1 to 13 ng/mL] to six of eight pancreatic cancer cell lines, whereas no cytotoxicity (IC50>1,000 ng/mL) was observed in normal human pancreatic duct epithelium cells, fibroblasts, and human umbilical vein endothelial cells (HUVEC). We also showed that IL-4 cytotoxin in combination with gemcitabine exhibited synergistic antitumor activity in vitro. To confirm synergistic antitumor activity in vivo and monitor precise real-time disease progression, we used a novel metastatic and orthotopic mouse model using green fluorescent protein-transfected cancer cells and whole-body imaging system. The combination of both agents caused complete eradication of tumors in 40% of nude mice with small established PDA tumors. In addition, combined treatment significantly prolonged the survival of nude mice bearing day 14 advanced distant metastatic PDA tumors. Similar results were observed in mice xenografted with PDA obtained from a patient undergoing surgical resection. These results indicate that IL-4 cytotoxin combined with gemcitabine may provide effective therapy for the treatment of patients with PDA.

Treatment with an oral fluoropyrimidine, S-1, plus cisplatin in patients who failed postoperative gemcitabine treatment for pancreatic cancer: a pilot study

BACKGROUND

This study set out to evaluate, in patients with gemcitabine-resistant pancreatic cancer, the response rate and toxicity of S-1 plus cisplatin (CDDP).

METHODS

Seventeen patients with histologically diagnosed invasive ductal pancreatic cancer were enrolled in this study. All patients had growing recurrent pancreas cancer despite the administration of gemcitabine. Thirteen patients underwent pancreatectomy, and 2 underwent choledochojejunostomy and gastrojejunostomy without pancreatectomy. S-1 (80 mg/m(2) per day) was orally administered for 21 consecutive days, followed by a 14-day rest period. CDDP (40 mg/m(2)) in 500 ml saline was administered by intravenous drip on day 8. This schedule was repeated every 5 weeks until the occurrence of disease progression, unacceptable toxicities, or the patient's refusal to continue.

RESULTS

Five (29.4%) patients achieved a partial response and 2 (11.8%) had stable disease. In 5 of 15 patients (33.3%) who had elevated serum carbohydrate antigen (CA)19-9 levels at the start of treatment the CA19-9 was reduced by more than 50%. The median survival time was 10 months (range, 20 months), with 63.7% and 31.9% of patients alive at 6 and 12 months, respectively. Major adverse reactions in the 15 patients included gastrointestinal toxicities of grade 1 or 2. Only one patient (5.9%) developed grade 3 leucopenia.

CONCLUSION

S-1 with CDDP has a promising effect against gemcitabine-resistant pancreatic cancer, with easily manageable toxicities. Further investigation of this regimen is warranted in patients with pancreatic cancer, especially in comparison with gemcitabine.

Everolimus and mycophenolate mofetil sensitize human pancreatic cancer cells to gemcitabine in vitro: a novel adjunct to standard chemotherapy?

BACKGROUND/AIMS

Gemcitabine improves survival in pancreatic adenocarcinoma. A variety of drugs have been tested to potentiate gemcitabine treatment for pancreatic cancer cells. Two major immunosuppressive drugs, mycophenolate mofetil (MMF) and everolimus (RAD001) have been shown to exert an anti-tumoral effect, but their ability to sensitize human pancreatic cell lines during gemcitabine treatment remains unclear. We examined the effects of everolimus and MMF on gemcitabine-treated MiaPaCa and Panc-1 cell lines.

METHODS

MiaPaCa and Panc-1 human pancreatic tumor cell lines were subjected to everolimus (0.001-1 microg/ml) or MMF (0.1-100 microg/ml) treatment in combination with gemcitabine (1-10(6) nM). Western blot analysis was performed for Panc-1 cells in the presence or absence of TGF-beta1 and different treatments: 0.1-100 muicro/ml MMF and 0.1-100 microg/ml everolimus. The antiproliferative effect of the treatment was assessed by BrdU test. The results were evaluated by two-way analysis of variance followed by post-hoc tests, and nonlinear regression analysis for dose-response rates.

RESULTS

As expected, standard treatment doses of gemcitabine decreased proliferation dose-dependently. Everolimus increased the actual EC(50) response to gemcitabine treatment (1-10(3) nM) to as much as 83.1 and 82.1% in MiaPaCa and Panc-1 cell lines, respectively. Likewise, concomitant administration with MMF altered the EC(50) of gemcitabine treatment in MiaPaCa cell lines to values between 76.8 and 85.2% for doses of >or=1 microg/ml. Even the minor dose of MMF (0.1 microg/ml) increased the antiproliferative effect of gemcitabine by 43.5% for MiaPaCa and 42.4% for Panc-1 cells. In addition, treatment of Panc-1 cells with MMF (0.1-100 microg/ml) dose-dependently inhibited TGF-beta1-induced collagen expression.

CONCLUSION

We found an overadditive antiproliferative effect of both MMF and everolimus in gemcitabine-treated MiaPaCa and Panc-1 cells in vitro, and an additional inhibitory effect of MMF on TGF-beta1-induced collagen type I expression. Interestingly, both the sensitizing effect of pancreatic cancer cells to gemcitabine treatment and the inhibition of collagen type I expression could be achieved by clinically feasible doses of everolimus and MMF. The use of these drugs is promising as a novel adjunct to standard chemotherapy.

Gemcitabine, cisplatin, and radiotherapy for patients with locally advanced pancreatic adenocarcinoma: results of the North Central Cancer Treatment Group Phase II Study N9942

PURPOSE

A phase II study was conducted to determine the efficacy and toxicity of radiotherapy with concomitant gemcitabine and cisplatin for patients with locally advanced pancreatic adenocarcinoma.

PATIENTS AND METHODS

Forty-eight patients with locally advanced pancreatic adenocarcinoma received gemcitabine (30 mg/m2) and cisplatin (10 mg/m2) twice weekly during the first 3 weeks of radiotherapy. The radiation dose to the primary tumor and regional nodes was 45 Gy in 25 fractions, and the gross tumor volume received an additional 5.4 Gy in three fractions. Four weeks after radiotherapy, patients received gemcitabine (1,000 mg/m2) once weekly every 3 of 4 weeks for a 12-week period. The primary end point was survival at 12 months. Secondary end points were time to progression, toxicity, and quality of life.

RESULTS

Survival at 1 year was 40% for 47 eligible patients. The median survival was 10.2 months. Confirmed responses were observed for 8.5% (two partial, two complete), and median time to progression was 7.3 months. Grade 4 or higher toxicity was observed for 31% and consisted primarily of hematologic and GI toxicity. There was a trend toward improved overall quality of life, measured by the Symptom Distress Scale (P = .06), with significant improvements in domains of insomnia, pain, and outlook.

CONCLUSION

The combination of radiotherapy, gemcitabine, and cisplatin was well tolerated. Survival results were similar to those achieved with other treatment regimens for patients with locally advanced pancreatic cancer but did not meet our predefined criteria for additional evaluation of this regimen.

A preclinical evaluation of pemetrexed and irinotecan combination as second-line chemotherapy in pancreatic cancer

Gemcitabine (GEM)-based chemotherapy is regarded as the standard treatment of pancreatic adenocarcinoma, but yields a very limited disease control. Very few studies have investigated salvage chemotherapy after failure of GEM or GEM-containing chemotherapy and preclinical studies attempting to widen the therapeutic armamentarium, not including GEM, are warranted. MIA PaCa2, CFPAC-1 and Capan-1 pancreatic cancer cell lines were treated with GEM, fluouracil (5-FU), docetaxel (DCT), oxaliplatin (OXP), irinotecan (CPT-11), pemetrexed (PMX) and raltitrexed (RTX) as single agent. Pemetrexed, inducing apoptosis with IC50s under the Cmax in the three lines tested, appeared the most effective drug as single agent. Based on these results, schedule- and concentration-dependent drug interactions (assessed using the combination index) of PMX/GEM, PMX/DCT and PMX-CPT-11 were evaluated. The combinatory study clearly indicated the PMX and CPT-11 combination as the most active against pancreatic cancer. To confirm the efficacy of PMX-CPT-11 combination, we extended the study to a panel of 10 pancreatic cancer cell lines using clinically relevant concentrations (PMX 10 microM; CPT-11 1 microm). In eight of 10 lines, the PMX-CPT-11 treatment significantly reduced cell recovery and increased both the subG1 and caspase 3/7 fraction. After a 5-day wash out period, an increased fraction of subG1 and caspase3/7 persisted in PMX-CPT-11-pretreated cell lines and a significant reduction in the clonogenicity capacity was evident. Finally, in vivo, the PMX/CPT-11 combination showed the ability to inhibit xenograft tumours growth as second-line therapy after GEM treatment. The PMX and CPT-11 combination displays a strong schedule-independent synergistic cytotoxic activity against pancreatic cancer, providing experimental basis for its clinical testing as salvage chemotherapy in pancreatic cancer patients.

Pharmacogenetics of anticancer drug sensitivity in pancreatic cancer

Chemotherapy has produced unsatisfactory results in pancreas cancer and novel approaches, including treatment tailoring by pharmacogenetic analysis and new molecular-targeted drugs, are required. The scarcity of effective therapies may reflect the lack of knowledge about the influence of tumor-related molecular abnormalities on responsiveness to drugs. Advances in the understanding of pancreas cancer biology have been made over the past decade, including the discovery of critical mutations in oncogenes (i.e., K-Ras) as well as the loss of tumor suppressor genes, such as TP53 and p16(INK4). Other studies showed the dysregulation of the expression of proteins involved in the control of cell cycle, proliferation, apoptosis, and invasiveness, such as Bcl-2, Akt, mdm2, and epidermal growth factor receptor. These characteristics might contribute to the aggressive behavior of pancreatic cancer and influence response to treatment. Indeed, the inactivation of p53 may explain the relative resistance to 5-fluorouracil, whereas Bcl-2 overexpression is associated with reduced sensitivity to gemcitabine. However, the future challenge of pancreas cancer chemotherapy relies on the identification of molecular markers that help in the selection of drugs best suited to the individual patient. Recent pharmacogenetic studies focused on genes encoding proteins directly involved in drug activity, showing the role of thymidylate synthase and human equilibrative nucleoside transporter-1 as prognostic factor in 5-fluorouracil- and gemcitabine-treated patients, respectively. Finally, inhibitors of signal transduction and angiogenesis are under extensive investigation, and several prospective trials have been devoted to this area. Pharmacogenetics is likely to play a central role in the personalization of treatment, to stratify patients based on their likelihood of response to both standard agents (i.e., gemcitabine/nucleoside transporters) and targeted treatments (i.e., epidermal growth factor receptor gene mutations and/or amplification and tyrosine kinase inhibitors), Thus, molecular analysis should be implemented in the optimal management of the patient affected by pancreatic adenocarcinoma.

Weekly gemcitabine and cisplatin in combination with pelvic radiation in the primary therapy of cervical cancer: A phase I trial of the Puget Sound Oncology Consortium

OBJECTIVE

Define the maximum tolerated dose of weekly gemcitabine given concomitantly with standard weekly cisplatin and pelvic radiotherapy for primary treatment of cervical cancer.

METHODS

Gemcitabine at specified dose levels was given concomitantly with weekly cisplatin at 40 mg/m2 for six cycles with concurrent radiotherapy in primary therapy of stage IB-IVA cervix cancer. Radiation consisted of 4500-5000 cGy in 25 daily fractions combined with brachytherapy to take point A to > or = 8500 cGy.

RESULTS

At gemcitabine 100 mg/m2, three of six patients demonstrated a dose limiting toxicity (DLT). At gemcitabine 50 mg/m2, two of two had DLTs. DLTs consisted of severe fatigue, lymphopenia, diarrhea, and tinnitus. All patients had a clinical complete response; four pathologically confirmed. Two patients recurred outside the radiated field and seven are disease-free (median follow-up 30 months). Following the second DLT at gemcitabine 50 mg/m2, the trial was stopped according to predetermined criteria.

CONCLUSIONS

Adding low dose weekly gemcitabine to cisplatin and pelvic radiotherapy resulted in an excellent response but unacceptable toxicities. Addition of gemcitabine prior to weekly cisplatin with radiation for cervical cancer will likely require reduction of cisplatin doses.

Targeting the RNA Splicing Machinery as a Novel Treatment Strategy for Pancreatic Carcinoma

Aberrant patterns of pre-mRNA splicing have been established for many human malignancies, yet the mechanisms responsible for these tumor-specific changes remain undefined and represent a promising area for therapeutic intervention. Using immunohistochemistry, we have localized the expression of a central splicing regulator, serine-arginine protein kinase 1 (SRPK1), to the ductular epithelial cells within human pancreas and have further shown its increased expression in tumors of the pancreas, breast, and colon. Small interfering RNA-mediated down-regulation of SRPK1 in pancreatic tumor cell lines resulted in a dose-dependent decrease in proliferative capacity and increase in apoptotic potential. Coordinately, the disruption of SRPK1 expression resulted in enhanced sensitivity of tumor cells to killing by gemcitabine and/or cisplatin. A dose-dependent reduction in the phosphorylation status of specific SR proteins was detected following the down-regulation of SRPK1 and is likely responsible for the observed alterations in expression of proteins associated with apoptosis and multidrug resistance. These data support SRPK1 as a new, potential target for the treatment of pancreatic ductular cancer that at present remains largely unresponsive to conventional therapies. Furthermore, these results support the development of innovative therapies that target not only specific splice variants arising during tumorigenesis but also the splice regulatory machinery that itself may be abnormal in malignant cells.

Cellular and pharmacogenetics foundation of synergistic interaction of pemetrexed and gemcitabine in human non-small-cell lung cancer cells

Gemcitabine and pemetrexed are effective agents in the treatment of non-small-cell lung cancer (NSCLC), and the present study investigates cellular and genetic aspects of their interaction against A549, Calu-1, and Calu-6 cells. Cells were treated with pemetrexed and gemcitabine, and their interaction was assessed using the combination index. The role of drug metabolism in gemcitabine cytotoxicity was examined with inhibitors of deoxycytidine kinase (dCK), 5'-nucleotidase, and cytidine deaminase, whereas the role of pemetrexed targets, thymidylate synthase (TS), dihydrofolate reductase (DHFR), and glycinamide ribonucleotide formyltransferase (GARFT) in drug chemosensitivity was analyzed in cytotoxicity rescue studies. The effect of gemcitabine and pemetrexed on Akt phosphorylation was investigated with enzyme-linked immunosorbent assay, whereas quantitative polymerase chain reaction (PCR) was used to study target gene-expression profiles and its modulation by each drug. Synergistic cytotoxicity was demonstrated, and pemetrexed significantly decreased the amount of phosphorylated Akt, enhanced apoptosis, and increased the expression of dCK in A549 and Calu-6 cells, as well as the expression of the human nucleoside equilibrative transporter 1 (hENT1) in all cell lines. PCR demonstrated a correlation between dCK expression and gemcitabine sensitivity, whereas expression of TS, DHFR, and GARFT was predictive of pemetrexed chemosensitivity. These data demonstrated that 1) gemcitabine and pemetrexed synergistically interact against NSCLC cells through the suppression of Akt phosphorylation and induction of apoptosis; 2) the gene expression profile of critical genes may predict for drug chemosensitivity; and 3) pemetrexed enhances dCK and hENT1 expression, thus suggesting the role of gene-expression modulation for rational development of chemotherapy combinations.

Combined Modality Therapy of Gemcitabine and Radiation

The combination of gemcitabine and radiotherapy is a promising combined modality therapy. However, the clinical application of this combination has to be implemented carefully because of an increased toxicity to normal tissues. A body of experimental evidence shows that gemcitabine is a potent radiosensitizer in vitro and in vivo. The observations so far indicate that various mechanisms are responsible for the radiosensitizing effect. Although it is often difficult to transfer experimental data to the clinic, these studies offer the possibility to develop an improved schedule of administration for patient treatment, based on rational evidence in tumor biology. In the current review, the preclinical data that support the use of gemcitabine as a radiosensitizing agent and the clinical trials that have been conducted to date are summarized.

Synergistic cytotoxicity and pharmacogenetics of gemcitabine and pemetrexed combination in pancreatic cancer cell lines

PURPOSE

Gemcitabine is an inhibitor of ribonucleotide reductase (RR) and DNA synthesis and is an effective agent in the treatment of pancreas cancer. The present study investigates whether the multitargeted antifolate pemetrexed would be synergistic with gemcitabine against MIA PaCa-2, PANC-1, and Capan-1 pancreatic cancer cell lines.

EXPERIMENTAL DESIGN

Cells were treated with gemcitabine and pemetrexed, and the type of drug interaction was assessed using the combination index. Cytotoxicity of gemcitabine was examined with inhibitors of (a) deoxycytidine kinase (dCK), which activates gemcitabine by phosphorylation, and (b) 5'-nucleotidase (drug dephosphorylation) and cytidine deaminase (drug deamination), the main inactivating enzymes. The effects of gemcitabine and pemetrexed on cell cycle were analyzed by flow cytometry, and apoptosis was examined by fluorescence microscopy. Finally, quantitative, real-time PCR was used to study the pharmacogenetics of the drug combination.

RESULTS

Synergistic cytotoxicity and enhancement of apoptosis was demonstrated, mostly with the sequence pemetrexed-->gemcitabine. Pemetrexed increased cells in S phase, the most sensitive to gemcitabine, and a positive correlation was found between the expression ratio of dCK:RR and gemcitabine sensitivity. Indeed, pemetrexed significantly enhanced dCK gene expression (+227.9, +86.0, and +135.5% in MIA PaCa-2, PANC-1, and Capan-1 cells, respectively), and the crucial role of this enzyme was confirmed by impairment of gemcitabine cytotoxicity after dCK saturation with 2'-deoxycytidine.

CONCLUSIONS

These data demonstrate that the gemcitabine and pemetrexed combination displays schedule-dependent synergistic cytotoxic activity, favorably modulates cell cycle, induces apoptosis, and enhances dCK expression in pancreatic cancer cells.

Adjuvant therapy in pancreatic cancer: Phase I trial of radiation dose escalation with concurrent full-dose gemcitabine

PURPOSE

To determine the maximal tolerated dose of radiation delivered to the primary tumor bed, in combination with full-dose gemcitabine (1000 mg/m(2) weekly x 3), after resection of pancreatic cancer.

METHODS AND MATERIALS

Patients with resected pancreatic carcinoma and poor prognostic features, a positive resection margin, or involved lymph nodes were eligible. Radiotherapy (RT) was directed at the preoperative tumor volume with a conformal technique. Regional lymph node basins were not included. The initial starting radiation dose was 24 Gy in 1.6-Gy fractions. Escalation was achieved by increasing the fraction size in 0.2-Gy increments, keeping the duration of RT to 3 weeks. Gemcitabine was given i.v. for 30-40 min at a dose of 1000 mg/m(2) before RT on Days 1, 8, and 15 of a 28-day cycle. After completion of RT and chemotherapy, an additional cycle of gemcitabine was delivered.

RESULTS

Between November 1997 and October 2001, 32 patients were entered: 30 after Whipple resection (positive margins in 2, positive nodes in 22, and both in 6), 1 after distal pancreatectomy, and 1 after incomplete resection of a tumor involving the body (both patients with positive margins and nodes). Treatment was well tolerated. Of the 32 patients, 27 completed all protocol therapy and 29 maintained their pretreatment weight within 5%. Five patients experienced dose-limiting toxicity, four with Grade 3 vomiting requiring hospitalization and one fatal toxicity secondary to pneumonia/sepsis. At the final radiation dose level (42 Gy), 2 patients experienced GI dose-limiting toxicity. At the 39-Gy-dose level, 5 of 6 patients were without dose-limiting toxicity. Isolated local or regional progression was documented in 1 patient. Distant progression was documented in 26 of 32 patients (6 with concurrent local or regional progression). The median survival was 16.5 months (95% confidence interval 12.3-19.9)

CONCLUSION

The results of our study indicate that the maximal tolerated radiation dose, administered using conformal techniques targeted to the tumor bed, is 39 Gy. In this high-risk population, data on locoregional control suggest that the reduction in radiation dose and field size minimizes toxicity and does not result in excess failures at these sites.

In vitro and in vivo evaluation of novel antitumor prodrugs of 5-fluoro-2′-deoxyuridine activated by hypoxic irradiation

PURPOSE

We previously developed a novel antitumor prodrug that has a 2-oxopropyl substituent at the N(1) position of 5-fluorouracil (5-FU) and releases 5-FU via one-electron reduction on hypoxic irradiation. Although the compound was effective in vivo, its activity against murine tumors was not high enough to warrant clinical studies. Therefore, we developed a similar family of radiation-activated prodrugs of 5-fluoro-2'-deoxyuridine (FdUrd), which is generally more potent than 5-FU, and investigated their radiation chemical reactivity and in vitro and in vivo effects.

METHODS AND MATERIALS

Compounds bearing various 2-oxoalkyl substituents at the N(3) position of FdUrd were synthesized and investigated. After aerobic or hypoxic irradiation to the prodrugs dissolved in water or culture medium, release of FdUrd was measured using high-performance liquid chromatography. To investigate in vitro cytotoxicity, SCCVII and EMT6 cells in culture were irradiated in the presence of the prodrug under aerobic or hypoxic conditions, and then kept with the compound for 24 h. Cell survival was then measured using a colony assay. To investigate in vivo effects, the drug was injected intraperitoneally at a dose of 100 or 300 mg/kg into Balb/c mice bearing EMT6 tumors 30 min before irradiation. The tumor growth delay-time was then assessed.

RESULTS

In vitro, the prodrugs released FdUrd at G-values (molar numbers of molecules produced by 1 J of radiation energy) of 1.6-2.0 x 10(-7) mol/J after hypoxic irradiation. The G-values for FdUrd release with hypoxic irradiation were about 100-fold greater than those with aerobic irradiation. Among the prodrugs tested, OFU106 bearing a 2-oxocyclopentyl substituent released the highest amount of FdUrd in the culture medium, and it was subjected to further in vitro and in vivo assays. Although OFU106 administered alone showed no cytotoxicity up to a concentration of 0.2 mM, it produced an enhanced cytotoxic effect when administered before hypoxic irradiation and kept with the cells for 24 h. The enhancement ratios calculated at the surviving fraction of 1% were 1.35-1.4 at 0.04 mM and 1.45-1.5 at 0.2 mM. In vivo, however, administration of OFU106 (100 or 300 mg/kg) before 20 Gy of irradiation did not produce marked growth delays compared with 20 Gy of radiation alone.

CONCLUSION

On hypoxic irradiation in vitro, the prodrugs of FdUrd were activated as efficiently as were the prodrugs of 5-FU, but marked in vivo effects could not be detected. This strategy of prodrug design should be used in further development of radiation-activated prodrugs of more potent anticancer agents.

Phase I Trial Using a Time-to-Event Continual Reassessment Strategy for Dose Escalation of Cisplatin Combined With Gemcitabine and Radiation Therapy in Pancreatic Cancer

Purpose

The primary objective of this study was to determine the maximum-tolerated dose of cisplatin that could be added to full-dose gemcitabine and radiation therapy (RT) in patients with pancreatic cancer.

Patients and Methods

Nineteen patients were treated. Gemcitabine 1,000 mg/m2 was administered over 30 minutes on days 1, 8, and 15 of a 28-day cycle. Cisplatin followed gemcitabine on days 1 and 15. The initial dose level of cisplatin was 30 mg/m2, escalated to a targeted dose of 50 mg/m2 using Time-to-Event Continual Reassessment Method. RT was initiated on cycle 1, day 1, in 2.4 Gy fractions to a total dose of 36 Gy. A second cycle of chemotherapy was planned following a 1-week rest.

Results

Four of eight patients experienced acute dose limiting toxicity at the 50 mg/m2 cisplatin dose level. Patients treated at 30 and 40 mg/m2 cisplatin dose level tolerated therapy without dose-limiting toxicity. Median survival was 10.7 months (95% CI, 5.4 to 18.2) for all patients, and 12.9 months (95% CI, 7.4 to 21.2) for those without metastasis.

Conclusion

Cisplatin at doses up to 40 mg/m2 may be safely added to full-dose gemcitabine and conformal RT. The Time-to-Event Continual Reassessment Method trial design allowed rapid completion of the study and confidence in the conclusion about the maximum tolerated dose, but accrued more patients to a dose level above the maximum tolerated dose than the typical phase I design. Local and systemic disease control and survival in this study cohort supports further investigation of gemcitabine-based RT and combination chemotherapy in this disease.

Intensity modulated radiation therapy and chemotherapy for locally advanced pancreatic cancer: Results of feasibility study

AIM: To explore whether intensity modulated radiation therapy (IMRT) in combination with chemotherapy could increase radiation dose to gross tumor volume without severe acute radiation related toxicity by decreasing the dose to the surrounding normal tissue in patients with locally advanced pancreatic cancer.

METHODS: Twenty-one patients with locally advanced pancreatic cancer were evaluated in this clinical trial. Patients would receive the dose of IMRT from 21 Gy to 30 Gy in 7 to 10 fractions within two weeks after conventional radiotherapy of 30 Gy in 15 fractions over 3 wk. The total escalation tumor dose would be 51, 54, 57, 60 Gy, respectively. 5-fluororacil (5-FU) or gemcitabine was given concurrently with radiotherapy during the treatment course.

RESULTS: Sixteen patients who had completed the radiotherapy plan with doses of 51 Gy (3 cases), 54 Gy (3 cases), 57 Gy (3 cases) and 60 Gy (7 cases) were included for evaluation. The median levels of CA19-9 prior to and after radiotherapy were 716 U/mL and 255 U/mL respectively (P < 0.001) in 13 patients who demonstrated high levels of CA19-9 before radiotherapy. Fourteen patients who suffered from pain could reduce at least 1/3-1/2 amount of analgesic intake and 5 among these patients got complete relief of pain. Ten patients improved in Karnofsky performance status (KPS). The median follow-up period was 8 mo and one-year survival rate was 35%. No patient suffered more than grade III acute toxicities induced by radiotherapy.

CONCLUSION: Sixty Gy in 25 fractions over 5 wk with late course IMRT technique combined with concurrent 5-FU chemotherapy can provide a definitely palliative benefit with tolerable acute radiation related toxicity for patients with advanced pancreatic cancer.

Gemcitabine in cervical cancer

OBJECTIVE

Recurrent and advanced cervical cancers are associated with high mortality and a lack of effective treatment options, especially for women who are poor candidates for surgery or radiation therapy. The broad clinical effectiveness and low toxicity of gemcitabine in other human malignancies suggest that it might be useful in treating cervical tumors.

METHODS

Fifteen phase I/II clinical trials on the use of gemcitabine, both as a single agent and in combination with cisplatin, in patients with recurrent or advanced carcinoma of the cervix were reviewed. Data from studies in which gemcitabine was used in combination with radiotherapy for induction therapy and with cisplatin for neoadjuvant chemotherapy were also evaluated.

RESULTS

Although single-agent gemcitabine was generally inferior to cisplatin, when used concurrently with cisplatin and/or radiation therapy, objective response rates were high and survival was prolonged. The drug also showed promise when used with cisplatin as neoadjuvant therapy.

CONCLUSIONS

Initial studies suggest that gemcitabine may be useful in the management of recurrent or advanced cervical cancer when used concurrently with cisplatin. Accordingly, a large phase III study will compare cisplatin/gemcitabine with the current standard, and further evaluation of gemcitabine appears to be warranted in conjunction with radiotherapy and in the neoadjuvant setting.

A phase I study of radiation therapy and twice-weekly gemcitabine and cisplatin in patients with locally advanced pancreatic cancer

PURPOSE

In vitro studies suggest that low-dose gemcitabine sensitizes cells to radiation therapy and that this effect persists for 48 h after drug exposure. Cisplatin is a radiation sensitizer and is also synergistic with gemcitabine in some in vitro tumor systems. Gemcitabine's radiosensitizing properties can theoretically be exploited by twice-weekly administration. This study assessed toxicity in patients with pancreatic cancer treated with radiation therapy, gemcitabine, and cisplatin.

METHODS AND MATERIALS

Patients with locally advanced pancreatic or gastric cancer were eligible. Gemcitabine and cisplatin were given twice weekly for 3 weeks during radiation therapy (50.4 Gy in 28 fractions). The starting dose of gemcitabine was 5 mg/m(2) i.v. The starting dose for cisplatin was 5 mg/m(2). Chemotherapy doses escalated every 3 to 6 patients according to a standard Phase I study design.

RESULTS

Twenty-four evaluable patients, all with pancreatic cancer, were treated on this protocol. Grade 3 neutropenia occurred in 2 patients, Grade 3 thrombocytopenia occurred in 2, and Grade 4 lymphopenia occurred in 1. There was no clear relationship between chemotherapy dose and hematologic toxicity. The most common Grade 3-4 nonhematologic toxic responses were vomiting (7 patients) and nausea (7 patients). Dose-limiting toxicity consisting of Grade 4 nausea and vomiting occurred in 2 of 3 patients at dose Level 6 (gemcitabine 45 mg/m(2) i.v. and cisplatin 10 mg/m(2) i.v.). Six patients were treated at dose Level 5 (gemcitabine 30 mg/m(2) i.v. and cisplatin 10 mg/m(2) i.v.) without dose-limiting toxicity.

CONCLUSION

Gemcitabine 30 mg/m(2) i.v. twice weekly and cisplatin 10 mg/m(2) i.v. twice weekly may be given concurrently with radiation therapy (50.4 Gy in 28 fractions) with acceptable toxicity.