Distinct genomic landscapes of gastroesophageal adenocarcinoma depending on PD-L1 expression identify mutations in RAS-MAPK pathway and TP53 as potential predictors of immunotherapy efficacy.

BACKGROUND: The impact of molecular alterations on programmed death-ligand 1 (PD-L1) combined positive score (CPS) is not well studied in gastroesophageal adenocarcinomas (GEAs). We aimed to characterize genomic features of tumors with different CPSs in GEAs. PATIENTS AND METHODS: Genomic alterations of 2518 GEAs were compared in three groups (PD-L1 CPS ≥ 10, high; CPS = 1-9, intermediate; CPS < 1, low) using next-generation sequencing. We assessed the impact of gene mutations on the efficacy of immune checkpoint inhibitors (ICIs) and tumor immune environment based on the Memorial Sloan Kettering Cancer Center and The Cancer Genome Atlas databases. RESULTS: High, intermediate, and low CPSs were seen in 18%, 54% and 28% of GEAs, respectively. PD-L1 positivity was less prevalent in women and in tissues derived from metastatic sites. PD-L1 CPS was positively associated with mismatch repair deficiency/microsatellite instability-high, but independent of tumor mutation burden distribution. Tumors with mutations in KRAS, TP53, and RAS-mitogen-activated protein kinase (MAPK) pathway were associated with higher PD-L1 CPSs in the mismatch repair proficiency and microsatellite stability (pMMR&MSS) subgroup. Patients with RAS-MAPK pathway alterations had longer overall survival (OS) from ICIs compared to wildtype (WT) patients [27 versus 13 months, hazard ratio (HR) = 0.36, 95% confidence interval (CI): 0.19-0.7, P = 0.016] and a similar trend was observed in the MSS subgroup (P = 0.11). In contrast, patients with TP53 mutations had worse OS from ICIs compared to TP53-WT patients in the MSS subgroup (5 versus 21 months, HR = 2.39, 95% CI: 1.24-4.61, P = 0.016). CONCLUSIONS: This is the largest study to investigate the distinct genomic landscapes of GEAs with different PD-L1 CPSs. Our data may provide novel insights for patient selection using mutations in TP53 and RAS-MAPK pathway and for the development of rational combination immunotherapies in GEAs.

The hard road to data interpretation: 3 or 6 months of adjuvant chemotherapy for patients with stage III colon cancer?

Background: Six months of adjuvant oxaliplatin-based chemotherapy is standard for patients with stage III colon cancer following surgery. However, oxaliplatin is associated with peripheral neurotoxicity which worsens over treatment duration. Consequently, a shorter treatment duration, if equally effective, would be extremely beneficial. A pooled analysis of data for 12 834 stage III colon cancer patients, from six randomised phase III trials of adjuvant therapy, the International Duration Evaluation of Adjuvant chemotherapy study, was carried out and the results presented at the ASCO Annual Meeting 2017. To clarify the potential impact of these results on clinical practice, ESMO decided to sponsor a special session at their 2017 Annual Meeting dedicated to achieving a more meaningful interpretation of the results. Methods: Medical oncologists from Europe, the United States and Asia selected for their involvement in the trials, together with an independent statistician and an independent clinician, were invited to provide their independent interpretations of the results and contribute to a moderated panel discussion. The pooled analysis evaluated the non-inferiority of 3 versus 6 months of adjuvant FOLFOX/CAPOX therapy but not the non-inferiority of 3 months CAPOX versus 6 months FOLFOX therapy. Results: There was strong evidence of an interaction between the choice of regimen (CAPOX or FOLFOX) and duration of treatment. Patients were classified as either 'fighters' or 'fatalists', and 3-month CAPOX was considered standard for patients classified as fatalists even if they had high-risk disease. However, patients classified as 'fighters' would only receive 3 months of CAPOX if they had low-risk disease but would always receive 6 months of CAPOX/FOLFOX if they had T4 disease. The panel was split on whether they would advocate 3 or 6 months CAPOX therapy based on high-risk N2 disease. Conclusions: The main drivers of the duration of treatment were choice of regimen and patient attitude, with risk, based mainly on T4 stage, having less influence.

Higher capecitabine AUC in elderly patients with advanced colorectal cancer (SWOGS0030).

BACKGROUND: The aging process is accompanied by physiological changes including reduced glomerular filtration and hepatic function, as well as changes in gastric secretions. To investigate what effect would aging have on the disposition of capecitabine and its metabolites, the pharmacokinetics between patients ≥70 years and <60 years were compared in SWOG0030. METHODS: Twenty-nine unresectable colorectal cancer patients were stratified to either ≥70 or <60 years of age, where the disposition of capecitabine and its metabolites were compared. RESULTS: Notable increase in capecitabine area under the curve (AUC) was accompanied by reduction in capecitabine clearance in ≥70 years patients (P<0.05). No difference in 5'-deoxy-5-fluorocytidine, 5'-deoxy-5-fluorouridine (DFUR), and 5-fluorouracil (5FU) AUCs between the two age groups, suggesting that carboxylesterase and cytidine deaminase (CDA) activity was similar between the two age groups. These results suggest that metabolic enzymes involved in converting capecitabine metabolites are not altered by age. An elevation in capecitabine Cmax and reduction in clearance was seen in females, where capecitabine AUC was 40.3% higher in women. Elevation of DFUR Cmax (45%) and AUC (46%) (P<0.05) was also noted, suggesting that CDA activity may be higher in females. CONCLUSION: Increases in capecitabine Cmax and AUC was observed in patients ≥70 years when compared with younger patients who were >60 years.

A phase II study of bevacizumab, oxaliplatin, and docetaxel in locally advanced and metastatic gastric and gastroesophageal junction cancers.

BACKGROUND: Bevacizumab has demonstrated antitumor activity in multiple diseases. This phase II study was undertaken to determine the effects of adding bevacizumab to a regimen of docetaxel and oxaliplatin in patients with advanced adenocarcinoma of the stomach or gastroesophageal junction. PATIENTS AND METHODS: Previously untreated patients with locally advanced or metastatic disease and a performance status (PS) of 0-1 were eligible for this study. Patients received bevacizumab at 7.5 mg/kg, docetaxel at 70 mg/m(2), and oxaliplatin at 75 mg/m(2) administered on day 1 of a 21-day cycle. The primary end point of the study was progression-free survival (PFS). RESULTS: A total of 38 eligible patients (median age 57 years, 45% gastric, 55% PS 0) were enrolled on to the study. Median PFS was 6.6 months [95% confidence interval (CI) 4.4-10.5] and median survival 11.1 months (95% CI 8.2-15.3). Complete responses were documented in 2 (5%) patients, partial responses in 14 (37%), and stable disease in 14 (37%). No treatment-related deaths were observed. The most commonly reported grade 3-4 toxicity was neutropenia (34%), and gastrointestinal perforation occurred in three patients (8%). CONCLUSION: The combination of bevacizumab, docetaxel, and oxaliplatin has promising activity for further evaluation in randomized trials.

Phase II study of gemcitabine, cisplatin, and infusional fluorouracil in advanced pancreatic cancer.

PURPOSE: This phase II study was undertaken to determine the efficacy of adding infusional fluorouracil (FU) to the chemotherapy doublet of gemcitabine and cisplatin in patients with advanced pancreatic cancer. PATIENTS AND METHODS: The eligibility criteria included histologically or cytologically confirmed adenocarcinoma of the pancreas that was either unresectable or metastatic. No prior gemcitabine therapy was allowed. Patients received a combination of gemcitabine 1000 mg/m2 intravenously (IV) on days 1, 8, and 15; cisplatin 50 mg/m2 IV on days 1 and 15; and FU 175 mg/m2/d from days 1 to 15 by continuous IV infusion. Cycles were repeated every 28 days. Objective tumor response and toxicity were evaluated according to the World Health Organization criteria. RESULTS: A total of 47 patients (median age, 57 years; males, 59%) were enrolled. Sixteen patients had locally advanced (LA) disease, and 31 patients had metastatic disease. A total of 183 cycles of chemotherapy were administered. In patients with metastatic disease (n = 31), the probability of survival at 6 and 12 months was 66% and 34%, respectively. Objective partial response or stable disease was observed in 26% (90% confidence interval [CI], 0.14 to 0.41) and 61% (90% CI, 0.45 to 0.74) of patients, respectively. In patients with LA disease (n = 16), there were three partial responses (19%; 90 CI, 0.07 to 0.39). One patient in this group was successfully resected after FU-based radiotherapy. The most common grade 3 to 4 toxicities were neutropenia (60%), thrombocytopenia (42%), and anemia (26%). Thirteen patients were hospitalized for treatment-related complications. CONCLUSION: The combination of gemcitabine, cisplatin, and infusional FU has significant activity in patients with advanced pancreatic cancer.

Developments in the systemic therapy of pancreatic cancer.

Pancreatic adenocarcinoma is the fourth leading cause of cancer mortality in the United States of America. Progress in the treatment of this disease in the past several decades has been very modest. Several new agents with activity against pancreatic cancer have been identified. Of these, gemcitabine is the most promising agent when used in combination with other drugs. Pilot phase II studies combining gemcitabine with 5-flourouracil, irinotecan, docetaxel, or cisplatin show improved outcomes in objective response rates and survival that need to be confirmed in larger randomized studies. Advancement in the understanding of the molecular biology of neoplasia in recent years has helped identify several molecular targets for future new drug development in pancreatic cancer. Assessment of response to therapy of pancreatic cancer has been a difficult challenge. Functional imaging with techniques such as positron emission tomography (PET) may yield a more precise and timely objective evaluation of response to treatment.

A single-institution experience with concurrent capecitabine and radiation therapy in gastrointestinal malignancies.

PURPOSE: We report our clinical experience with 32 patients receiving concurrent irradiation and capecitabine. METHODS AND MATERIALS: Medical records of patients with gastrointestinal malignancies treated with radiation and capecitabine therapy were reviewed. RESULTS: The population consisted of 20 males and 12 females, with a median age of 67.5 years (45-84 years) and adequate hepatic and bone marrow function. Histology was adenocarcinoma in all patients, except two with esophageal squamous carcinoma. Twenty-one patients received the regimen as adjuvant therapy, three received preoperative therapy, and 8 patients received therapy for palliation. The median dose of capecitabine was 1600 mg/m(2)/day (1200-2500 mg/m(2)/day) orally for 5 days per week for the duration of radiation therapy. Thirty patients received a total dose ranging from 45 Gy to 64 Gy over 4-6 weeks. Two previously radiated patients received total doses of 29.9 Gy and 46 Gy. Grade 3/4 toxicities observed were neutropenia in 3 patients and diarrhea, thrombocytopenia, fatigue, and myocardial infarction in 1 patient each. No treatment-related mortality was observed. Twenty of 21 patients (95.2%) who received adjuvant therapy continue to be in complete remission. Four of 11 (36%) evaluable patients demonstrated a response. CONCLUSION: Concurrent capecitabine and radiation were very well tolerated and warrant further investigation in prospective trials.

Expression of inflammatory modulator COX-2 in pancreatic ductal adenocarcinoma and its relationship to pathologic and clinical parameters.

Despite the exceedingly poor prognosis of pancreatic cancer, it is often histologically well to moderately differentiated. The apparent resistance to conventional therapeutic modalities is poorly understood and may be related to the molecules involved in its progression or its propensity for perineurial invasion. Cyclooxygenase-2 (COX-2) is an inducible enzyme homologous to COX-1 that is responsible for production of prostaglandins at sites of inflammation. It is activated by a variety of growth factors and tumor promoters, and it has been implicated in cancer progression. It may also have a role in the resistance to therapy. Anti-COX-2 agents have been documented to have antitumor activity, and some are now being tested in the therapy for various cancers, including those of the pancreas. Experience regarding the rate of COX-2 expression in pancreatic cancer and its relationship to the clinical and biologic parameters is very limited. In this study, immunohistochemical stains for COX-2 have been performed on 120 cases of pancreatic ductal adenocarcinoma. The stains were scored according to the percentage (0: no staining, 1: < 10%, 2: 10-50%, and 3: >50% of the cells staining) and intensity (0 for no staining, 1 for mild staining, and 2 for dark staining) of staining. Based on the combined score for each case, they were divided into low expressors (percentage and intensity < or =1) and high expressors (percentage or intensity >1). In addition to global scoring for each case, the glandular and solid (poorly differentiated) components, when present, were scored separately. The global scores were correlated with clinical and biologic parameters. Seventy-four percent of the cases exhibited expression of COX-2 and 53% were high expressors. No significant association was observed when comparing the global COX-2 expression to survival, tumor size, stage, and vascular invasion. Increased perineural invasion was found to be significantly associated with COX-2 expression (p < 0.05). Increased expression was also more common in the glandular component as compared with the solid component of the tumors (68% versus 35%, p < 0.05). Of the 34 patients who received radiotherapy, 9 were low expressor (median survival 19.5 months) and 25 were high expressors (median survival 14 months). The difference in survival was not statistically significant.

Phase II study of gemcitabine and cisplatin in the treatment of patients with advanced pancreatic carcinoma.

BACKGROUND: Pancreatic carcinoma is considered among the most chemoresistant of human malignancies. The most commonly used cytotoxic single agents, 5-fluorouracil and 2'-deoxy-2',2'-difluorocytidine (gemcitabine), have objective response rates of less than 10% in large studies. Hypothesizing noncross resistance and a synergistic interaction between gemcitabine and cisplatin, early clinical studies have demonstrated significant activity with this combination in patients with several types of malignant disease. A Phase II study was undertaken to determine the efficacy of gemcitabine in combination with cisplatin in patients with locally advanced and metastatic pancreatic carcinoma based on these considerations. METHODS: The eligibility criteria included histologically confirmed, locally advanced, unresectable or metastatic exocrine carcinoma of the pancreas with no prior gemcitabine therapy; prior adjuvant therapy was allowed provided the last day of therapy was at least 6 months prior to starting treatment; clinically measurable or evaluable disease; a Southwest Oncology Group scale performance status of 0-2; a life expectancy of > 12 weeks; and adequate bone marrow, hepatic, and renal function. A total of 42 patients, 4 patients with locally advanced, unresectable disease and 38 patients with metastatic disease, were treated and received a total of 211 cycles of therapy between May 1997 to March 1999. The median age of patients was 61.5 years. The patients were treated in the outpatient setting with a combination of gemcitabine 1,000 mg/M(2) intravenously over 30 minutes administered on Days 1, 8, and 15 of each cycle and cisplatin 50 mg/M(2) intravenously administered after gemcitabine infusion on Days 1 and 15 with adequate prehydration accompanied by adequate urinary output. Cycles were repeated every 28 days. Response and toxicity were assessed according to World Health Organization and standard criteria. RESULTS: The complete and partial response rate among all 42 registered patients was 11 of 42 patients (26%; 95% confidence interval, 0.14-0.42). Stabilization of disease was seen in 15 patients (38%). Two additional patients with metastatic disease who achieved major responses to chemotherapy were rendered free of disease surgically, achieving a complete response status. The median overall survival was 7.1 months (95% confidence interval [CI], 6.3-9.1 months), with 64% of patients alive at 6 months and 19% of patients alive at 12 months. The median time to disease progression was 5.4 months (range, 0.9-20.8 months). Major toxicities were neutropenia and thrombocytopenia, with one episode of neutropenic fever. CONCLUSIONS: The combination of gemcitabine and cisplatin appeared to have significantly greater activity than single-agent gemcitabine in this Phase II study, with tolerable toxicity. The antitumor activity of this combination needs to be confirmed in multi-institutional or comparative trials.

Phase II study of liposomal doxorubicin in patients with advanced colorectal cancer.

Doxil is a liposomal preparation of doxorubicin that results in prolonged pharmacologic exposure in vivo to the active agent. We sought to test the hypothesis that this new formulation would result in improved efficacy in patients with colorectal cancer. Patients with advanced colorectal cancer who had received prior therapy were eligible for the trial. Treatment consisted of Doxil 45 mg/m2 intravenously every 3 weeks. Seventeen patients entered the trial and they received a median of two cycles of treatment. None of the patients had a partial response to treatment. Stable disease was the best response, and one patient received therapy for 17 cycles before her disease progressed. The therapy was well tolerated, with only two patients having the dose decreased because of hand-foot syndrome. Four patients experienced allergic reactions during the infusion, but with appropriate premedication and slowing of the infusion, treatment was able to be resumed without difficulty. No greater than grade I neutropenia or thrombocytopenia developed in any patient. Although Doxil was well tolerated at this dose and schedule, it was not an active agent in this group of patients. Doxil alone or in combination with other agents is worthy of further study in cancers responsive to doxorubicin.

A phase II trial of bryostatin 1 in the treatment of metastatic colorectal cancer.

Current chemotherapy for patients with advanced colorectal cancer is relatively ineffective and may be associated with significant toxicity. Bryostatin 1 (bryo 1) influences cell proliferation, intracellular metabolism and signaling, differentiation, and apoptosis in human cancer cell lines via modulation of protein kinase C (PKC) activity. This trial investigates the efficacy and toxicity of bryo 1 as a novel therapeutic agent for patients with advanced colorectal cancer who have had previous 5-fluorouracil therapy. The primary end point was tumor response to bryo 1. Toxicity was also assessed. Twenty-eight patients with advanced colorectal cancer were enrolled. The mean age was 59 years (range, 38-76), with 16 men and 12 women, and good minority representation (11 African-Americans). The first 10 patients initially received 25 microg/m2 of bryo 1 weekly as a 24-h infusion for 3 weeks of every 4-week cycle, with dose escalation to 35 microg/m2 starting with the second cycle. The remaining patients were started at 35 microg/m2 and escalated to 40 microg/m2, if toxicity was minimal. Twenty-five patients were evaluable for objective tumor response, and complete data on toxicity were collected on 26 patients. No partial or complete tumor responses were observed. All 25 patients had disease progression within four cycles. Myalgia was the most common toxicity. Myelosuppression was not seen. bryo 1 as a weekly 24-h continuous infusion lacks single-agent antitumor activity in advanced colorectal cancer. Toxicity differs from that of traditional chemotherapeutic drugs.

Cost analysis of pancreatic carcinoma treatment.

BACKGROUND: Pancreatic carcinoma is a major health issue and financial burden to society. To improve the quality and efficiency of care delivered, it is essential for health care providers to have a good understanding of the cost of treatment. METHODS: The authors examined the facility-based costs and survival of 103 patients with pancreatic carcinoma who were treated at the Karmanos Cancer Institute between January 1992 and September 1998. Longitudinal cost data for each patient were obtained, and from those data, 6-month, 1-year, and lifetime total treatment costs were calculated. RESULTS: The average 6-month, 1-year, and lifetime total treatment costs were $37,327, $42,218, and $48,803, respectively, and the median survival was 7 months. In univariate analyses, the disease stage at diagnosis was a highly significant predictor of total cost. Patients with metastatic disease had the lowest cost, and patients with resectable disease had the highest cost. In multivariate analyses controlling for disease stage, treatment strategies and dual insurance coverage were also important predictors of costs but patient age, race, and gender were not predictive. Disease stage also was highly predictive of survival. In a multivariate analysis controlling for disease stage, chemotherapy and radiation therapy were correlated with longer survival, whereas resection and palliative bypass surgery were not. CONCLUSIONS: The costs of treating patients with pancreatic carcinoma are considerable, even though survival duration typically is short. Disease stage was the most dominating factor determining costs and survival. After controlling for disease stage, chemotherapy, surgery, and dual insurance coverage were also significantly associated with higher cost of care. However, in survival analyses, only chemotherapy and radiation therapy were associated with a significant increase in patient survival.

Cisplatin, cytarabine, caffeine, and continuously infused 5-fluorouracil (PACE) in the treatment of advanced pancreatic carcinoma: a phase II study.

Encouraging results using cisplatin, cytarabine, and caffeine for the treatment of pancreatic carcinoma prompted a phase II study using these agents and adding continuous intravenous infusion (CI) 5-fluorouracil (5-FU) (PACE). Patients with advanced pancreatic adenocarcinoma who had not received prior cytotoxic therapy were eligible. Treatment consisted of the following: on day 1, the administration of cisplatin 100 mg/m2 IV, cytarabine 2 g/m2 IV every 12 hours x 2 doses, and caffeine 400 mg/m2 subcutaneously after each cytarabine dose; and on days 3 to 21, 5-FU 250 mg/m2/day given by CI. Cycles were repeated every 28 days. Thirty eligible patients were entered in the study. The median number of cycles received was three. Grade IV neutropenia and thrombocytopenia occurred in 53% and 27% of patients, respectively. Among 30 treated patients, complete remission (CR) was seen in 2 patients and partial remission (PR) in 3 patients, for an overall response rate of 16.7% (95% confidence interval 6.8-32.4%). The median survival was 5.0 months (range: 0.3-32.4 months) and 16.7% and 10% of patients were alive at 1 and 2 years. respectively. Changes in the serum level of CA 19-9 provided an early marker of response which translated in differences in survival. Those with increasing or decreasing/stable levels of CA 19-9 after the first cycle of therapy had median survivals of 1.7 and 8.3 months, respectively (p = 0.0002). Although PACE chemotherapy produced durable responses in pancreatic cancer, the toxicity was substantial. A modification of this regimen with newer, less toxic drugs may provide better results and reduced toxicity. Also, the monitoring of the serum CA 19-9 level may provide a means to assess response and predict survival.

Characterizing tumors using metabolic imaging: PET imaging of cellular proliferation and steroid receptors.

Treatment decisions in oncology are increasingly guided by information on the biologic characteristics of tumors. Currently, patient-specific information on tumor biology is obtained from the analysis of biopsy material. Positron emission tomography (PET) provides quantitative estimates of regional biochemistry and receptor status and can overcome the sampling error and difficulty in performing serial studies inherent with biopsy. Imaging using the glucose metabolism tracer, 2 -deoxy-2- fluoro-D-glucose (FDG), has demonstrated PET's ability to guide therapy in clinical oncology. In this review, we highlight PET approaches to imaging two other aspects of tumor biology: cellular proliferation and tumor steroid receptors. We review the biochemical and biologic processes underlying the imaging, positron-emitting radiopharmaceuticals that have been developed, quantitative image-analysis considerations, and clinical studies to date. This provides a basis for evaluating future developments in these promising applications of PET metabolic imaging.

Radiosynthesis of 3'-deoxy-3'-[(18)F]fluorothymidine: [(18)F]FLT for imaging of cellular proliferation in vivo.

A reliable radiosynthesis of 3'-deoxy-3'-[(18)F]fluorothymidine ([(18)F]FLT) has been developed based on [(18)10 mCi (370 MBq) of radiochemically pure [(18)1 Ci/micromol (37 GBq/micromol) at EOS within 100 min and in 13% radiochemical yield (end of bombardment (EOB); 7% end of synthesis (EOS)). [(18)F]FLT has been designed as a new positron emission tomography imaging agent for visualizing cellular proliferation in vivo based on the metabolism of thymidine.

Kinetic analysis of 2-[11C]thymidine PET imaging studies: validation studies.

UNLABELLED: 2-[11C]thymidine has been tested as a PET tracer of cellular proliferation. We have previously described a model of thymidine and labeled metabolite kinetics for use in quantifying the flux of thymidine into DNA as a measure of tumor proliferation. We describe here the results of studies to validate some of the model's assumptions and to test the model's ability to predict the time course of tracer incorporation into DNA in tumors. METHODS: Three sets of studies were conducted: (a) The uptake of tracers in proliferative tissues of normal mice was measured early after injection to assess the relative delivery of thymidine and metabolites of thymidine catabolism (thymine and CO2) and calculate relative blood-tissue transfer rates (relative K1s). (b) By using sequential injections of [11C]thymidine and [11C]thymine in normal human volunteers, the kinetics of the first labeled metabolite were measured to determine whether it was trapped in proliferating tissue such as the bone marrow. (c) In a multitumor rat model, 2-[14C]thymidine injection, tumor sampling and quantitative DNA extraction were performed to measure the time course of label uptake into DNA for comparison with model predictions. RESULTS: Studies in mice showed consistent relative delivery of thymidine and metabolites in somatic tissue but, as expected, showed reduced delivery of thymidine and thymine in the normal brain compared to CO2. Thymine studies in volunteers showed only minimal trapping of label in bone marrow in comparison to thymidine. This quantity of trapping could be explained by a small amount of fixation of labeled CO2 in tissue, a process that is included as part of the model. Uptake experiments in rats showed early incorporation of label into DNA, and the model was able to fit the time course of uptake. CONCLUSION: These initial studies support the assumptions of the compartmental model and demonstrate its ability to quantify thymidine flux into DNA by using 2-[11C]thymidine and PET. Results suggest that further work will be necessary to investigate the effects of tumor heterogeneity and to compare PET measures of tumor proliferation to in vitro measures of proliferation and to clinical tumor behavior in patients undergoing therapy.

Phase II study of CI-958 in colorectal cancer.

PURPOSE: We completed a phase II trial of CI-958 (NSC 635371) in patients with advanced colorectal cancer given at a dose of 700 mg/m2 every 21 days. METHODS: All 15 patients had metastatic disease and had been previously treated with one 5-fluorouracil-based regimen in an adjuvant (six) or metastatic (nine) setting. RESULTS: None of the patients treated with CI-958 had an objective response to treatment. Median survival was 4.8 months after the start of treatment. Leukopenia was the major toxicity, but no patient experienced febrile neutropenia. An acute febrile reaction was seen after infusion in four of the first nine patients treated. This was abrogated by pretreatment with dexamethasone in the remaining patients. CONCLUSIONS: CI-958 was not effective at this dose and schedule in patients with previously treated advanced colorectal cancer.

Imaging proliferation in vivo with [F-18]FLT and positron emission tomography.

Positron emission tomography (PET) is now regularly used in the diagnosis and staging of cancer. These uses and its ability to monitor treatment response would be aided by the development of imaging agents that can be used to measure tissue and tumor proliferation. We have developed and tested [F-18]FLT (3'-deoxy-3'-fluorothymidine); it is resistant to degradation, is retained in proliferating tissues by the action of thymidine kinase 1 (TK), and produces high-contrast images of normal marrow and tumors in canine and human subjects.

Carbon-11-thymidine and FDG to measure therapy response.

UNLABELLED: This study was performed to determine if PET imaging with 11C-thymidine could measure tumor response to chemotherapy early after the initiation of treatment. Imaging of deoxyriboneucleic acid biosynthesis, quantitated with 11C-thymidine, was compared with measurements of tumor energetics, obtained by imaging with 18F-fluorodeoxyglucose (FDG). METHODS: We imaged four patients with small cell lung cancer and two with high-grade sarcoma both before and approximately 1 wk after the start of chemotherapy. Thymidine and FDG studies were done on the same day. Tumor uptake was quantified by standardized uptake values (SUVs) for both tracers by the metabolic rate of FDG and thymidine flux constant (K(TdR)) using regions of interest placed on the most active part of the tumor. RESULTS: In the four patients with clinical response to treatment, both thymidine and FDG uptake markedly declined 1 wk after therapy. Thymidine measurements of SUV and K(TdR) declined by 64% +/- 15% and 84% +/- 33%, respectively. FDG SUV and the metabolic rate of FDG declined by 51% +/- 9% and 63% +/- 23%, respectively. In the patient with metastatic small cell lung cancer who had disease progression, the thymidine SUV decreased by only 8% (FDG not done). In a patient with abdominal sarcoma and progressive disease, thymidine SUV was essentially unchanged (declined by 3%), whereas FDG SUV increased by 69%. CONCLUSION: Images show a decline in both cellular energetics and proliferative rate after successful chemotherapy. In the two patients with progressive disease, thymidine uptake was unchanged 1 wk after therapy. In our limited series, K(TdR) measurements showed a complete shutdown in tumor proliferation in patients in whom FDG showed a more limited decrease in glucose metabolism.