A phase II multi-institutional trial of low-dose N-(phosphonacetyl)-L-aspartate and high-dose 5-fluorouracil as a short-term infusion in the treatment of adenocarcinoma of the pancreas. A Southwest Oncology Group study

Evaluation of Phase II Trial Design in Advanced Pancreatic Cancer

OBJECTIVES

We evaluated how well phase II trials in locally advanced and metastatic pancreatic cancer (LAMPC) meet current recommendations for trial design.

METHODS

We conducted a systematic review of phase II first-line treatment trial for LAMPC. We assessed baseline characteristics, type of comparison, and primary end point to examine adherence to the National Cancer Institute recommendations for trial design.

RESULTS

We identified 148 studies (180 treatment arms, 7505 participants). Forty-seven (32%) studies adhered to none of the 5 evaluated National Cancer Institute recommendations, 62 (42%) followed 1, 31 (21%) followed 2, and 8 (5%) followed 3 recommendations. Studies varied with respect to the proportion of patients with good performance status (range, 0%-80%) and locally advanced disease (range, 14%-100%). Eighty-two (55%) studies concluded that investigational agents should progress to phase III testing; of these, 24 (16%) had documented phase III trials. Three (8%) phase III trials demonstrated clinically meaningful improvements for investigational agents. One of 38 phase II trials that investigated biological investigational agents was enriched for a biomarker.

CONCLUSIONS

Phase II trials do not conform well to current recommendations for trial design in LAMPC.

Treatment of metastatic pancreatic adenocarcinoma: a comprehensive review

The current standard therapy for metastatic pancreatic adenocarcinoma is the single-agent gemcitabine, by the increasingly used fixed rate infusion of 10 mg/m2/min. There is strong reason to anticipate that additional benefits will accrue with gemcitabine-based combination chemotherapy. Gemcitabine and CPT-11 are synergistic with many drugs and non-cross-resistant with each other. Rigorous clinical investigations will be performed in an effort to identify optimal drug sequence and schedules for these novel combinations.

Late onset of CAD gene amplification in unamplified PALA resistant Chinese hamster mutants

In rodent cells, resistance to PALA (N-phosphonacetyl-L-aspartate) has always been found associated with amplification of the CAD gene (carbamyl-P synthetase, aspartate transcarbamylase, dihydro-orotase). We describe two PALA resistant Chinese hamster mutant cell lines in which amplification of the CAD gene was not present. The PALA resistant phenotype was stable when the cells were grown in non-selective medium. However, after prolonged growth in the presence of the same drug concentration used for selection, cells with increased CAD gene copy number and higher levels of resistance overrode the original population. In these cell populations, a heterogeneous organization of the CAD genes was revealed by fluorescence in situ hybridization on mitotic chromosomes indicating that the additional copies of the gene were generated in several ways, such as non-disjunction and breakage-fusion-bridge cycles. The clastogenic effect of PALA, evidenced as chromosomal aberrations in the cells grown in the presence of the drug, could have favored the late onset of the amplified mutants. It is tempting to speculate that, during the expansion of tumor populations, different drug resistance mechanisms, including gene amplification, could occur in succession and lead to the generation of cells highly resistant to chemotherapeutic agents.

CPT-11 in gastrointestinal cancer

Colorectal, gastric and pancreatic cancers are major health problems worldwide. Although surgery is a curative option in 50% of patients with colorectal cancer, it is much less effective in gastric cancer (< 20% of patients) and virtually ineffective in pancreatic cancer. These three cancer types also respond poorly to chemotherapy. CPT-11 (irinotecan), a novel cytotoxic drug, is now available in many countries as a single agent for second-line therapy in metastatic colorectal cancer. The response rate in the pivotal European study of metastatic colorectal cancer patients was 14%, with a median duration of response of 8.5 months. There was also a high rate of disease stabilisation (44%), with a median duration of 4.8 months. Median survival time was 10.4 months. The dose-limiting toxicities (DLT) for CPT-11 are delayed diarrhoea and neutropenia, both of which are schedule dependent and non-cumulative. These encouraging data in second-line therapy support the further study of CPT-11 as first-line therapy for colorectal cancer in combination with other agents. Four Japanese trials of CPT-11 as first- and/or second-line single-agent therapy for advanced gastric cancer report response rates of 18-43%. The median durations for response and survival time in the late phase II trial were 2.3 months and 5.8 months, respectively. These results are in the range of those reported for sequential high-dose methotrexate and 5-fluorouracil (5-FU)/doxorubicin (FAMTX), etoposide/leucovorin/5-FU (ELF) or cisplatin/5-FU therapy in gastric cancer. Data are currently available from five phase II studies of CPT-11 in advanced pancreatic cancer: four Japanese and one European. The response rates ranged from 9 to 19%. The median duration of survival for all treated patients in the European study was 5.2 months. CPT-11 in combination with 5-FU is currently being investigated in Japan, the U.S.A. and Europe in patients with gastrointestinal tumours. CPT-11 is also being evaluated in combination with each of the following agents: oxaliplatin, docetaxel, raltitrexed, etoposide and mitomycin C. Japanese studies of CPT-11 plus cisplatin in patients with gastric cancer have produced response rates of 48-59%. These encouraging data highlight the potential for CPT-11 in combination therapy for gastrointestinal tumours.

A rationale for expanding the endpoints for clinical trials in advanced pancreatic carcinoma

BACKGROUND

Using classical endpoints, such as response rate and survival, as the sole measures of benefit, little progress has been made in the treatment of advanced pancreatic carcinoma in the past 30 years. We challenge the assumption that response rate and survival are the only appropriate endpoints for clinical trials in this disease setting.

METHOD

A review of the literature and roundtable discussion were undertaken.

RESULTS

Using current imaging techniques, it is inherently difficult to distinguish pancreatic tumor from normal pancreas, inflammatory tissue, local fibrosis, and unopacified bowel. As a result, objective tumor measurements are often imprecise, unreliable, and irreproducible. This difficulty may explain the wide variation in response rates reported in clinical trials even when the same therapies are used. Tumor-related symptoms, such as anorexia, weight loss, severe pain (requiring opioid analgesia), and impaired functional status, are prevalent and debilitating characteristics of this disease. Tools that can assess these symptoms in a consistent fashion over time have been developed and have been integrated into clinical trials to evaluate new drugs in this setting.

CONCLUSIONS

Systematic assessment of the impact of a new therapy on tumor-related symptoms may provide a sensitive and accurate way to identify useful new treatments for patients with advanced pancreatic carcinoma. Such analyses can be a useful complement to the classical endpoints of response rate and survival.

Chemotherapy for patients with adenocarcinoma of the pancreas

Adenocarcinomas of the pancreas are diagnosed at an advanced, non-curable stage in most patients. In addition to local relapse or progression, distant metastases determine the poor prognosis, resulting in a median survival of less than 6 months in most studies of patients with locally advanced or metastatic pancreatic cancer. None of the cytotoxic drugs available show impressive activity in treatment of this disease. Therefore, chemotherapy is not recommended in pancreatic cancer. In selected cases, 5-fluorouracil-based therapy - with or without simultaneous radiation - may result in tumor responses. With a once-a-week outpatient protocol of folinic acid and 5-fluorouracil, we observed a progression-free period from 15 to 42 weeks in nine of 19 patients treated without any serious adverse effects, confirming reports of the weak, but well-tolerated activity of this combination. To alter the prognosis for patients with advanced adenocarcinomas of the pancreas, new drugs with more activity have to be developed and tested in well-designed trials.

Evaluating the role of photodynamic therapy in the management of pancreatic cancer

BACKGROUND AND OBJECTIVE

Cancer of the pancreas constitutes one of the major causes of cancer related death throughout the world. A 5-year survival rate of only 2% and a maximum of 20 months median survival in multi modality treatment studies dealing with the most favorable patients only, has been demonstrated. This review analyzes the principal treatments and available experimental data in view of a clinical application of photodynamic therapy (PDT) for the treatment of pancreatic cancer.

STUDY DESIGN/MATERIALS AND METHODS

On the basis of published results, we examined the palliation of pancreatic cancer by chemotherapy alone; radiation alone and multimodality schedules (radiation and chemotherapy). Radical tumor resection was examined as attempted curative treatment.

RESULTS

In reported therapeutic procedures, palliative or potentially curative, median survival was below 2 years. The GTSG reported survival time increases from 10.9 to 21.0 months when surgery is followed by adjuvant chemotherapy and radiation. This combination postoperatively does not increase mortality, but adds 30% morbidity. Photodynamic therapy has been demonstrated in preclinical studies to have a selective effect on malignant versus the normal pancreas.

CONCLUSION

PDT is highly effective in eliciting the destruction of experimental pancreatic tumors with the lack of significant effect on the normal pancreas. The poor prognosis for patients with this disease, especially those patients with advanced disease, warrants closer examination of PDT for the treatment of pancreatic cancer.

Phase I trial of low dose N-phosphonacetyl-L-aspartic acid and high dose 5-fluorouracil administered concomitantly with radiation therapy for unresectable localized adenocarcinoma of the pancreas

BACKGROUND

Preclinical and clinical data suggest that N-phosphonacetyl-L-aspartic acid (PALA) can augment the cytotoxic effects of 5-fluorouracil (5-FU). In addition, the combination of 5-FU and radiation therapy has been used with success in prolonging survival and providing palliation of symptoms in patients with advanced unresectable pancreatic carcinoma. This Phase I study was undertaken to determine the feasibility and evaluate the qualitative and quantitative toxicities of PALA and escalating doses of 5-FU administered concomitantly with radiation therapy in patients with locally advanced nonmetastatic pancreatic adenocarcinoma.

METHODS

Ten previously untreated patients with advanced nonmetastatic adenocarcinoma of the pancreas were treated with 250 mg/m2 of PALA given as an intravenous bolus followed 24 hours later by 5-FU, which was given by continuous 24-hour infusion every week. The 5-FU doses were assigned according to a Phase I drug escalation (1000 mg/m2, 1300 mg/m2, and 1700 mg/m2). Radiation therapy was delivered concurrently with chemotherapy at a dose of 180 cGy per fraction (900 cGy per week) over 6 1/2 weeks. PALA and 5-FU were continued weekly after the end of radiation therapy, with disease assessments made every 8 weeks. Chemotherapy was continued until the disease progressed.

RESULTS

All 10 patients were evaluable. The maximum tolerated dose (MTD) of 5-FU was 1300 mg/m2. Two of the four patients treated at the 1700 mg/m2 dose level experienced dose-limiting toxicities, nausea/vomiting and mucositis, respectively. Toxicities were mild to moderate at the 1000 mg/m2 and 1300 mg/m2 dose levels. Two patients treated with 5-FU at the 1300 mg/m2 dose level had complete responses, and one patient treated at the 1700 mg/m2 dose level had a partial response. The median survival was 12.5 months, and four patients survived more than 1 year.

CONCLUSIONS

PALA and 5-FU administered concomitantly with radiation therapy is an active regimen in locally advanced, unresectable pancreatic cancer. Dose-limiting toxicities are nausea/vomiting and mucositis. The MTD of 5-FU is 1300 mg/m2. The regimen is well tolerated and administered in an outpatient setting.

Phase II trial of PALA and 6-methylmercaptopurine riboside (MMPR) in combination with 5-fluorouracil in advanced pancreatic cancer

The biochemical modulators PALA, an inhibitor of aspartate transcarbamylase which depletes uridine nucleotide pools, and 6-methylmercaptopurine riboside (MMPR) which inhibits purine metabolism, selectively potentiate the antitumor activity of 5-fluorouracil (5-FU) in preclinical models. Based on a phase I trial of this combination, we performed a phase II trial in patients with advanced pancreatic cancer. PALA 250 mg/m2 was administered i.v. on day 1, followed 24h later by MMPR 150 mg/m2 as a bolus i.v. injection, and 5-FU 2300 mg/m2 by 24h infusion. Treatments were repeated weekly. Seventeen patients, all previously untreated with chemotherapy, were entered, of whom 14 are evaluable for response. Toxicity > or = grade 2 included nausea (6/17), vomiting (4/17), diarrhea (3/17), stomatitis (5/17), and neurotoxicity (2/17). Among 14 evaluable patients there were no partial responses, and two patients with stable disease. Pretreatment with PALA and MMPR is insufficient to enhance the activity of 5-FU in pancreatic cancer.

Phase II trial of PALA in combination with 5-fluorouracil in advanced pancreatic cancer

Phosphonacetyl-L-aspartate (PALA), in inhibitor of aspartate transcarbamylase that depletes uridine nucleotide pools, selectively potentiates the antitumor activity of 5-fluorouracil (5-FU) in preclinical models. Due to the promising results we obtained using PALA/5-FU in colorectal cancer, we performed a phase II trial in patients presenting with advanced pancreatic cancer. PALA was given intravenously at 250 mg/m2 on day 1, followed 24 h later by 2,600 mg/m2 5-FU given by 24-h infusion. Treatments were repeated weekly. A total of 41 patients who had not previously undergone chemotherapy were entered in the trial; of these, 35 were evaluable for response. Toxicity was generally mild to moderate; neurotoxicity (13/35) and diarrhea (8/35) predominated. Among the 35 patients, 1 achieved a complete response and 4, a partial remission, for an overall response rate of 14%. The median survival was 5.1 months. Pretreatment with PALA alone was not sufficient to enhance the activity of 5-FU in pancreatic cancer.