A phase II study of the HSP90 inhibitor AUY922 in chemotherapy refractory advanced pancreatic cancer

OBJECTIVES

AUY922 is a novel heat shock protein inhibitor with preclinical activity in pancreatic cancer. This phase II study evaluated the efficacy of AUY922 in patients with advanced pancreatic cancer previously treated with chemotherapy.

METHODS

In this single-arm, Simon two-stage phase II trial, patients with metastatic or locally advanced pancreatic ductal adenocarcinoma who had progressed on at least one line of chemotherapy and were of good performances status (ECOG 0 or 1) were treated with AUY922 at a dose of 70 mg/m(2) IV weekly. The primary endpoint was disease control rate (objective response and stable disease ≥16 weeks).

RESULTS

Twelve patients were accrued, all of whom received treatment. At least possibly related ≥grade 3 adverse events included fatigue (8 %) and AST elevation (8 %). Ten patients were evaluable for response with 1 (10 %) having stable disease and 9 (90 %) progressive disease. The median progression-free survival was 1.6 months, and the median overall survival was 2.9 months.

CONCLUSIONS

AUY922 was not associated with significant efficacy in previously treated patients with advanced pancreatic cancer.

Overall survival and clinical characteristics of pancreatic cancer in BRCA mutation carriers

Background:

The BRCA1/2 proteins are involved in regulation of cellular proliferation by DNA damage repair via homologous recombination. Therefore, BRCA1/2 mutation carriers with pancreatic cancer may have distinct biologic outcomes.

Methods:

Patients with BRCA1/2-associated pancreatic ductal adenocarcinoma (PDAC) diagnosed between January 1994 and December 2012 were identified from databases at three participating institutions. Clinical data were collected. Disease-free survival and overall survival (OS) were analysed.

Results:

Overall, 71 patients with PDAC and BRCA1 (n=21), BRCA2 (n=49) or both (n=1) mutations were identified. Mean age at diagnosis was 60.3 years (range 33–83), 81.7% (n=58) had any family history of malignancy; 30% (n=21) underwent primary resection. Out of 71 participants, 12 received experimental therapy; one patient had missing data, these 13 cases were excluded from OS analysis. Median OS for 58 patients was 14 months (95% CI 10–23 months). Median OS for patients with stage 1/2 disease has not been reached with 52% still alive at 60 months. Median OS for stage 3/4 was 12 months (95% CI 6–15). Superior OS was observed for patients with stage 3/4 treated with platinum vs those treated with non-platinum chemotherapies (22 vs 9 months; P=0.039).

Conclusion:

Superior OS was observed for advanced-disease BRCA-associated PDAC with platinum exposure.

A phase II study of erlotinib in gemcitabine refractory advanced pancreatic cancer

BACKGROUND

Erlotinib induced skin toxicity has been associated with clinical benefit in several tumour types. This phase II study evaluated the efficacy of erlotinib, dose escalated to rash, in patients with advanced pancreatic cancer previously treated with gemcitabine.

METHODS

Erlotinib was given at an initial dose of 150 mg/day, and the dose was escalated by 50mg every 2 weeks (to a maximum of 300 mg/day) until >grade 1 rash or other dose limiting toxicities occurred. Erlotinib pharmacokinetics were performed, and baseline tumour tissue was collected for mutational analysis and epidermal growth factor receptor (EGFR) expression. The primary end-point was the disease control rate (objective response and stable disease >8 weeks).

RESULTS

Fifty-one patients were accrued, and 49 received treatment. Dose-escalation to 200-300 mg of erlotinib was possible in 9/49 (18%) patients. The most common ⩾ grade 3 adverse events included fatigue (6%), rash (4%) and diarrhoea (4%). Thirty-seven patients were evaluable for response, and the best response was stable disease in 12 patients (32% (95% confidence interval (CI) 17-47%)). Disease control was observed in nine patients (24% (95% CI: 10-38%)). Median survival was 3.8 months, and 6 month overall survival rate was 32% (95% CI 19-47%). Mutational analysis and EGFR expression were performed on 29 patients, with 93% having KRAS mutations, none having EGFR mutations, and 86% expressing EGFR. Neither KRAS mutational status nor EGFR expression was associated with survival.

CONCLUSIONS

Erlotinib dose escalated to rash was well tolerated but not associated with significant efficacy in non-selected patients with advanced pancreatic cancer.

Induction gemcitabine plus concurrent gemcitabine and radiotherapy for locally advanced unresectable or resected pancreatic cancer

AIMS

To determine the efficacy of induction gemcitabine followed by biweekly gemcitabine concurrent with radiotherapy for locally advanced pancreatic cancer.

MATERIALS AND METHODS

Between March 2001 and August 2009, 90 patients with unresectable (78) or resected (12) pancreatic cancer were treated with a standard treatment policy of induction gemcitabine (seven doses of weekly gemcitabine at 1000 mg/m(2)) followed by concurrent radiotherapy (52.5 Gy) and biweekly gemcitabine (40 mg/m(2)).

RESULTS

After induction gemcitabine, 17.8% of patients did not proceed to chemoradiotherapy, due to either disease progression, performance status deterioration or gemcitabine toxicity. Of the patients who received chemoradiotherapy, 68.9% completed the course of 52.5 Gy, whereas 79.7% received more than 45 Gy. Chemoradiotherapy was stopped early due to treatment toxicity in 22.9% of patients. On intention to treat analysis, the median overall survival was 12.7 months in the locally advanced group and 18.2 months in the resected group. On multivariate analysis for the unresectable patients, a larger gross tumour volume was a significant poor prognostic factor for overall survival and local progression-free survival.

CONCLUSION

This large series confirms, in a standard practice setting, similar efficacy and tolerability of treatment as previously reported in our phase I-II study. The benefit to patients with a gross tumour volume >48 cm(3) may be limited.

Eastern Canadian colorectal cancer consensus conference: application of new modalities of staging and treatment of gastrointestinal cancers

The annual Eastern Canadian Colorectal Cancer Consensus Conference was held in Ottawa, Ontario, October 22-23, 2010. Health care professionals involved in the care of patients with colorectal cancer participated in presentation and discussion sessions for the purpose of developing the recommendations presented here. This consensus statement addresses current issues in the management of colorectal cancer, such as the use of epidermal growth factor inhibitors in metastatic colon cancer, the benefit of calcium and magnesium with oxaliplatin chemotherapy, the role of microsatellites in treatment decisions for stage II colon cancer, the staging and treatment of rectal cancer, and the management of colorectal and metastatic pancreatic cancers.

High interstitial fluid pressure (IFP) and hypoxia as biomarkers of cisplatin chemoradiation response in advanced cervix cancer

5584

Background: Chemoradiotherapy (CRT) has been shown to improve survival compared to RT alone for locally advanced cervix cancer. The tumour microenvironment in cervix cancer is also known to influence disease progression and response to treatment. In this prospective study, pre-treatment tumour hypoxia and interstitial fluid pressure (IFP) were examined as potential biomarkers of improved treatment effectiveness in a cohort of patients treated with definitive radiation alone, or with the addition of concurrent cisplatin CRT. Methods: Between April 1994 and January 2006, 309 eligible patients with cervix cancer were entered into a prospective study of hypoxia and IFP prior to definitive treatment. Patients accrued between 1994 and 1999 (n = 115) were treated with RT alone, and those accrued between 2000 and 2006 (n = 194) received RT and concurrent weekly cisplatin CRT. Clinical characteristics were similar between the two cohorts except pelvic lymph node metastases were more frequent in the CRT cohort (42% vs. 19%, p = 0.0005), likely due to changes in definition of positive nodes on CT or MR imaging. The median follow-up was 3.6 years (2.9 years for CRT and 7.8 years for RT). Results: The use of CRT improved outcome in hypoxic tumors compared to RT (57% 3-yr DFS vs. 42%, p = 0.045) with a trend to improved DFS in patients with high IFP tumors (57% 3-yr DFS vs. 44% for RT alone, p = 0.056). A strong interaction was identified between IFP and treatment (CRT vs. RT, p = 0.007). After correcting for the effects of clinical prognostic factors, cisplatin significantly improved DFS in the high IFP group (p = 0.02), and showed a trend towards improved DFS in those with hypoxia (p = 0.1). In patients with both high IFP and hypoxia a similar benefit of cisplatin was seen. Conclusions: Patients with high IFP and hypoxic tumours may selectively benefit from the addition of concurrent cisplatin CRT to their treatment regimen. This observation is contrary to an effect of high IFP on impaired drug delivery, but may reflect reduced DNA repair under hypoxic conditions, which could facilitate cell killing with both radiation and cisplatin chemotherapy.

No significant financial relationships to disclose.

A phase II study of Halichondrin B analog eribulin mesylate (E7389) as second-line therapy for patients with advanced pancreatic cancer

e15634

Background: Eribulin mesylate is a halichondrin B analog that inhibits microtubule dynamics by a mechanism that is distinct from other tubulin-targeted agents. Preclinical studies suggest that Eribulin may be effective in pancreatic cancer. The primary objective of this study was to determine the objective response rate (complete and partial) to Eribulin in patients with advanced, pancreatic adenocarcinoma that had progressed after gemcitabine based therapy. Methods: Eligibility criteria included histologically confirmed pancreatic adenocarcinoma; measurable locally advanced, or metastatic disease; disease progression after gemcitabine; and ECOG performance status 0–2. Patients (pts) received Eribulin mesylate 1.4 mg/m2 IV on days 1 and 8. Treatment was repeated every 3 weeks in the absence of disease progression or unacceptable toxicity. Response was assessed by CT scans every 6 weeks while on treatment. Initially 12 pts were to be accrued, if 1 or more pt(s) had an objective response the accrual would increase to a total of 37. Results: 15 pts were accrued,14 received treatment and 12 were evaluable for response. Median age 61; M:F = 8:7; ECOG 1:2 = 11:4; Median number of cycles 2 (1–15). Grade 3+ adverse events included neutropenia (29%), fatigue (14%), peripheral neuropathy (7%) and thrombosis (7%). There were no complete or partial responses, and therefore the study was closed at the first accrual cut off. The best response was stable disease (SD) in 5/12 (42%) pts. Of these 5 pts, 3 (42%) had SD for 12 cycles or greater. Survival data is pending. Conclusions: Eribulin was well tolerated and did not result in any objective responses in refractory pancreatic cancer. However, 42% of pts had stable disease and for 3 pts this was maintained for more than 9 months. Further studies of eribulin in pancreatic cancer may be warranted.

No significant financial relationships to disclose.

Phase II trial of erlotinib in advanced pancreatic cancer (PC)

4609

Background: The epidermal growth factor receptor (EGFR) is a potentially important target in PC. Benefit from erlotinib (Tarceva), an oral EGFR tyrosine kinase inhibitor has been associated with the presence of a skin rash. The purpose of this study was to determine the efficacy of erlotinib, dosed to achieve a rash, in patients (pts) with PC. Methods: Erlotinib was given at an initial dose of 150 mg/day to eligible pts with locally advanced (LA) or metastatic PC who had progressed or were unable to tolerate gemcitabine-based chemotherapy. The dose of erlotinib was increased by 50mg every 2 weeks (maximum 300 mg/day) until > grade 1 rash (CTCAE v 3.0) or other dose-limiting toxicities occurred. Erlotinib pharmacokinetic (PK) studies were performed. Baseline tumor tissue was collected for analysis of Kras mutations, EGFR by IHC and FISH. The primary endpoint of this two- stage phase II trial was prolonged disease control (PR + SD > 8 wks) with a rate of >20% assumed to be significant . Results: Fifty pts were accrued (median age 61, M:F = 25:25, ECOG 0:1:2 = 5:41:4, LA:Metastatic = 5:45, prior gemcitabine none:adjuvant:palliative = 2:16:35). 47 and 40 pts were evaluable for toxicity and response, respectively. Dose-escalation to 200–300 mg of erlotinib was possible in 9 pts. Most common treatment adverse events (TAEs) of any grade were: rash (35 pts, 74.5%), diarrhea (18 pts, 38.3 %), and fatigue (8 pts, 17%). Grade 3+ TAEs were rash in 2 pts and diarrhea in 2 pts. Best response was SD in 14 pts, 0.35 (95% CI: 0.2–0.5). Prolonged disease control (SD > 8 wks) was observed in 10/40 evaluable pts, 0.25 (95% CI: 0.12–0.38), which met the primary study endpoint. Median TTP was 1.6 mo (95% CI:1.6–2.1), mOS 4.1 mo (95% CI:3.2–7.3), and 6 mo OS rate was 39% (95%CI: 24–61%). PK and correlative data are being analyzed and will be presented. Conclusions: Erlotinib is associated with prolonged stable disease in a subset of pts with advanced refractory PC. Dose escalation in the absence of toxicity is feasible and safe.

[Table: see text]

Flow cytometric measurement of intracellular pH

A number of fundamentally important biological processes, such as cell signaling and the initiation of mitosis, are accompanied by a change in intracellular pH. Flow cytometric measurement of pH is a generally straightforward procedure that can be done with any instrument equipped with a 488-nm argon laser. The overall approach is similar to that for calcium: generation of a calibration curve by imparting known changes in pH and interpolation of the test sample pH. This unit presents the traditional calibration method using high-potassium buffers and the proton ionophore nigericin and a more recently developed technique, the pseudo null method, which involves resuspension of cells in defined mixtures of weak acids and weak bases.

A single agent, phase I pharmacodynamic study of nimotuzumab (TheraCIM-h-R3) in patients with advanced refractory solid tumors

14030

Background: Nimotuzumab (N) is a humanized mAb against the EGFR extracellular ligand binding domain. Although well tolerated when combined with radiotherapy in previous studies and lacking usual toxicities of EGFR-targeting agents, the pharmacodynamics (PD) of N has not been elucidated. This phase I study was designed to evaluate the safety, tolerability and PD of N. Methods: Eligibility criteria included advanced solid tumors refractory to standard therapy and ECOG PS = 0 - 2. IV N was administered weekly x 6 and then every other week (6 weeks = 1 treatment cycle). Tumor, skin and liver biopsies obtained pre- and 2 and 7 weeks post-treatment were evaluated using computer-based, whole mount assessment of immunohistochemical staining. Results: Accrual was completed 21/09/06, 17 patients (11m/6f, median age 63, 13 colorectal cancer, ECOG 0:1:2 = 6:10:1, prior therapy 1:2:3+ = 2:6:9) were registered and 16 patients were treated on 4 dose levels (100, 200, 400 and 800 mg) for a total of 43 treatment cycles (1 patient deemed ineligible after registration did not receive study therapy). Treatment was well tolerated. One dose-limiting toxicity was observed (dose level 1 - grade 3 fatigue possibly attributable to N) . Skin toxicity was mild (Gr 1/2 in 7/1 patients). Confirmed stable disease was seen in 6 patients, a confirmed partial response in 1 patient with prolonged progression-free status observed in 3 patients for 5.8, 14.1 and 18.7 months (the latter two remain on study). Baseline and week 2 biopsies of tumor/skin/liver were evaluable in 12/13/7 pts. Week 7 tumor/skin/liver biopsies in initially responding or stable patients were evaluable in 6/8/6 pts. Post treatment (week 2), EGFR staining decreased in 8/12 matched tumor [mean ratio (post/pre): 0.79 range: (0.37, 1.91)], 8/13 skin [0.96 (0.40, 1.31)] and 5/7 liver [0.88 (0.62, 1.17)] biopsies. No significant relationship was detected between pre/post-treatment EGFR expression with either response or toxicity. Evaluation of downstream targets of EGFR (in tumor, skin and liver) is ongoing and will be presented. Conclusions: Overall nimotuzumab was well tolerated and exhibits mild skin toxicity. Prolonged progression free-survival was observed in 3/16 of these heavily pre-treated patients.

No significant financial relationships to disclose.

A phase II clinical and pharmacodynamic study of temsirolimus in advanced neuroendocrine carcinomas

Standard cytotoxic treatments for neuroendocrine tumours have been associated with limited activity and remarkable toxicity. A phase II study was designed to evaluate the efficacy, safety and pharmacodynamics of temsirolimus in patients with advanced neuroendocrine carcinoma (NEC). Thirty-seven patients with advanced progressive NEC received intravenous weekly doses of 25 mg of temsirolimus. Patients were evaluated for tumour response, time to progression (TTP), overall survival (OS) and adverse events (AE). Twenty-two archival specimens, as well as 13 paired tumour biopsies obtained pretreatment and after 2 weeks of temsirolimus were assessed for potential predictive and correlative markers. The intent-to-treat response rate was 5.6% (95% CI 0.6–18.7%), median TTP 6 months and 1-year OS rate 71.5%. The most frequent drug-related AE of all grades as percentage of patients were: fatigue (78%), hyperglycaemia (69%) and rash/desquamation (64%). Temsirolimus effectively inhibited the phosphorylation of S6 (P=0.02). Higher baseline levels of pmTOR (phosphorylated mammalian target of rapamycin) (P=0.01) predicted for a better response. Increases in pAKT (P=0.041) and decreases in pmTOR (P=0.048) after treatment were associated with an increased TTP. Temsirolimus appears to have little activity and does not warrant further single-agent evaluation in advanced NEC. Pharmacodynamic analysis revealed effective mTOR pathway downregulation.

Phase II study of erlotinib (OSI-774) in patients with metastatic colorectal cancer

Erlotinib (Tarceva™, OSI-774), a potent epidermal growth factor receptor tyrosine kinase inhibitor (EGFR), was evaluated in a phase II study to assess its activity in patients with metastatic colorectal cancer. In all, 38 patients with metastatic colorectal cancer were treated with erlotinib at a continuous daily oral dose of 150 mg. Radiological evaluation was carried out every 8 weeks and tumour biopsies were performed before treatment and on day 8. Of 31 evaluable patients, 19 (61%) had progressive disease and 12 (39%) had stable disease (s.d.). The median time to progression for those patients having s.d. was 123 days (range 108–329 days). The most common adverse events were rash in 34 patients and diarrhoea in 23 patients. Correlative studies were conducted to investigate the effect of erlotinib on downstream signalling. Tumour tissue correlations were based on usable tissue from eight match paired tumour samples pre- and on therapy, and showed a statistically significant decrease in the median intensity of both pEGFR (P=0.008) and phospho-extracellular signal-regulated kinase (ERK) (P=0.008) a week after commencement of treatment. No other statistically significant change in tumour markers was observed. Erlotinib was well tolerated with the most common toxicities being rash and diarrhoea. More than one-third of evaluable patients had s.d. for a minimum of 8 weeks. Correlative studies showed a reduction in phosphorylated EGFR and ERK in tumour tissue post-treatment.

Long-term results of concurrent gemcitabine (G) and radiotherapy (GRT) for locally advanced (LA) or high-risk resected (R) pancreatic cancer

4101

Background: G is active against pancreatic carcinoma and is a potent radiosensitizer. We present extended follow up data from a phase I/II study of patients treated with combination GRT. Methods: Eligible patients had either LA or high-risk resected [R] pancreatic cancer [positive nodes or positive margin]. 28 were enrolled in a Phase I study of increasing doses of radiotherapy (35 Gy [n = 7]/43.75 Gy [n = 11]/52.5 Gy [n = 10] given over 4, 5 or 6 weeks, respectively in 1.75 Gy fractions) concurrently with 40 mg/m2 gemcitabine biweekly. Subsequently 35 were treated with induction gemcitabine (G) 1000 mg/m2 7/8 weeks followed by concurrent bi-weekly gemcitabine (40 mg/m2) with 52.5 Gy (30 fractions of 1.75 Gy over 6 weeks). In total there were 63 patients (31 LA and 32 R) treated between March 1999–July 2001. Results: In the LA population the best response observed was CR - 1, PR - 2, SD - 10, PD - 10. GRT was not delivered to 8 patients due to progression on G alone (n = 5) or patient request (n = 3). By intent to treat analysis, the median survival in LA disease was 15.1 months and the 2 year survival was 19%. In the resected population the median time to progression was 14.3 months, the median survival was 17.9 months and the 5 year survival was 19%. The treatment was generally well tolerated during both the induction G and the GRT ( Table ). Conclusion: Survival for both LA and HR patients with this concurrent gemcitabine radiotherapy regimen is promising and warrants further investigation.

[Table: see text]

No significant financial relationships to disclose.

Molecular correlates associated with a phase II study of temsirolimus (CCI-779) in patients with metastatic or recurrent endometrial cancer—NCIC IND 160

3003

Background: PTEN is a tumor suppressor gene and mutations in PTEN causing loss of protein expression/function may play a significant role in the pathogenesis of EC. Loss of PTEN protein expression has been reported in 26–80% of EC and leads to deregulated PI3K/Akt/mTOR signalling which may give neoplastic cells a survival advantage by enhancing angiogenesis, protein translation and cell cycle progression. Inhibition of mTOR, a protein kinase downstream of the PI3K/Akt pathway and target of rapamycins, inhibits proliferation of EC cell lines and formation of EC in PTEN−/+ heterozygous mice. We have evaluated temsirolimus (T) an ester derivative of rapamycin that inhibits mTOR given the frequent loss of PTEN in human EC. Methods: A two stage, phase II study has been conducted to evaluate single agent activity of T in women with recurrent or metastatic EC (chemotherapy naïve, upto 1 prior line of hormonal therapy). Treatment was 25mg i.v. weekly. One cycle is defined as 4 weeks of therapy. Thirty one patients (pts) have been registered; 23 are evaluable for toxicity and 19 for response. Results: Preliminary results have demonstrated encouraging activity and the trial fulfilled predefined criteria for activity. Of 19 pts evaluable for response, 5 have had a confirmed partial response (PR) (26%) and 12 have stable disease (SD) as best response (63%). Two pts had progressive disease (PD) (11%). PTEN, phosphorylated (p) mTOR and p-S6 protein (immunohistochemistry) results are available on 9 pts to date. The preliminary results indicate that responses and stable disease are seen in pts irrespective of PTEN status. Loss of p-mTOR was evident in tumor cells from all pts (range 75–99% loss) and did not correlate with response. Phosphorylated S6 was low in tumor cells in the one pt who had PD (5%), and levels were higher in pts with PR and SD (mean and median 30%). Conclusions: We conclude that Temsirolimus has encouraging single agent activity for in recurrent and metastatic EC, and the findings indicate this is irrespective of PTEN status. We are currently evaluating activity of T in pts previously treated with chemotherapy and molecular correlates in additional specimens.

No significant financial relationships to disclose.

Post-operative radiochemotherapy for gastric cancer: adoption and adaptation

AIMS

Intergroup study 0116 (INT-0116) showed an 11% absolute improvement in 3-year survival with post-operative radiochemotherapy for gastric cancer, but reported 33% severe acute GI toxicity using conventional simulation with large fields. We adapted the treatment using conformal radiotherapy techniques and assessed toxicity and outcome in 20 consecutive patients.

METHODS

A conformal radiotherapy technique previously developed for gastric lymphoma was adapted to treat the target volume defined in INT-0116. The five-field plan used a large anterior field, plus asymmetrically matched upper AP:PA fields and lower lateral fields. Consecutive patients with ECOG PS 0-2 and stage IB-IV non-metastatic gastric cancer were treated with 5-FU (425 mg/m2 daily x 5 days) and leucovorin (20 mg/m2 daily x 5 days) for one cycle prior to and two cycles following concurrent radiation (45 Gy/25 fractions) with identical drug dosages on the first 4 and last 3 days of radiation. Acute toxicity was prospectively recorded weekly using RTOG and NCI common toxicity criteria. Patient charts were reviewed in November 2003 and late toxicity and outcome were recorded.

RESULTS

Nineteen of 20 patients completed radiotherapy and 14 completed all chemotherapy cycles. One patient died of neutropenic sepsis. Maximum acute toxicity [grade (number)] was: 5(1), 4(0), 3(4), 2(10), 1(4), 0(1). There were two grade 1 late toxicities. Two-year overall survival is 70% (95% confidence interval: 50-90).

CONCLUSIONS

Conformal radiotherapy may improve acute toxicity (25% grade 3 or greater toxicity as compared with 41% reported in INT-0116). Survival is comparable to that achieved in the INT-0116 treatment arm (approximately 60% at 2 years). INT-0116 results can be achieved outside a study setting; however, further efforts to improve treatment efficacy and minimize toxicity are warranted.

Gemcitabine concurrent with continuous infusional 5-fluorouracil in advanced biliary cancers: a review of the Princess Margaret Hospital experience

BACKGROUND

Unresectable biliary tract cancer has a very poor prognosis. A combination of weekly gemcitabine plus continuous infusional 5-fluorouracil (5-FU) (GEM/CVI 5-FU) was evaluated as therapy for this cancer.

PATIENTS AND METHODS

The charts of 27 patients with advanced biliary tract adenocarcinoma treated with GEM/CVI 5-FU at the Princess Margaret Hospital were evaluated for response, survival and toxicity. The treatment consisted of a 30-min infusion of gemcitabine at 900 mg/m(2) on days 1, 8 and 15 of a 28-day cycle plus 5-FU given via a peripherally inserted central line at 200 mg/m(2)/day continuously for 21 days, every 28 days.

RESULTS

Objective responses were observed in nine patients (33%; 95% confidence interval 17% to 54%). An additional eight patients (30%) achieved stable disease for a median of 4 months (range 2.3-11). Median time to progression and overall survival were 3.7 and 5.3 months, respectively. Direct chemotherapy-related toxicity was mild, with only 11% grade > or =3 myelosuppression. Central venous catheter complications were common (26%). There were no treatment-related deaths.

CONCLUSIONS

This study shows that GEM/CVI 5-FU is active and well tolerated in advanced and metastatic biliary tract cancers.

The palliative benefit of irinotecan in 5-fluorouracil-refractory colorectal cancer: its prospective evaluation by a Multicenter Canadian Trial

Most patients with colorectal cancer (CRC) who have failed initial 5-fluorouracil (5-FU) chemotherapy have worsening of disease-related symptoms (DRS) and quality of life (QOL). Irinotecan has a reported response rate of 10%-20% in such patients. The aim of this phase II trial was to prospectively determine the palliative benefit of irinotecan utilizing DRS as primary endpoints of response. Patients had advanced CRC refractory to 5-FU with at least 1 DRS defined as (1) Karnofsky performance status (KPS) 60%-80%, (2) baseline analgesic use > or = 10 mg morphine/day (or equivalent), or (3) disease-related pain score > 1 cm on a 10-cm linear analogue self-assessment (LASA) scale. Patients received irinotecan 125 mg/m2 weekly for 4 weeks on an every-6-weeks schedule. The primary endpoint was palliative response defined as > or = 50% decrease in pain score or analgesic usage, or 10% increase in KPS, from baseline for 4 weeks. QOL was assessed by the European Organization for Research and Treatment of Cancer Quality-of-Life Questionnaire Core 30 (EORTC QLQ-C30) version 2 instrument. A total of 65 patients were entered onto the study. Median baseline parameters were KPS 70%, analgesic score 11 mg/day, and pain score 2.4 cm. A palliative response was achieved in 27 patients (42%), improvement in pain score predominated. LASA and EORTC QLQ-C30 instruments showed parallel changes in DRS. The radiological response rate was 11% (complete responses and partial responses, n = 46); 23 patients achieved stable disease. Median overall survival was 7.2 months. Irinotecan provides a rate of palliative benefit higher than the radiological response rate. Patients-oriented palliative endpoints can be useful in assessing the benefit of agents in early-phase clinical trials.

Tumor hypoxia has independent predictor impact only in patients with node-negative cervix cancer

PURPOSE

This prospective clinical study was begun in 1994 to validate the independent prognostic impact of tumor hypoxia in patients with cervix cancer treated with definitive radiation therapy.

PATIENTS AND METHODS

Between May 1994 and January 1999, 106 eligible patients with epithelial cervix cancer had tumor oxygen pressure (PO(2)) measured using the Eppendorf probe. Oxygenation data are presented as the hypoxic proportion, defined as the percentage of PO(2) readings less than 5 mm/Hg (abbreviated as HP(5)) and the median PO(2).

RESULTS

The median HP(5) in individual patients was 48%, and the median PO(2) was HP(5). Progression-free survival (PFS) for patients with hypoxic tumors (HP(5) > 50%) was 37% at 3 years versus 67% in those patients with better oxygenated tumors (P =.004). In multivariate analysis, only tumor size (risk ratio [RR], 1.33; P =.0003) and evidence of pelvic nodal metastases on imaging studies (RR, 2.52; P =.0065) were predictive of PFS. However, an interaction between nodal status and oxygenation was observed (P =.006), and further analysis indicated that HP(5) was an independent predictor of outcome in patients with negative nodes on imaging (P =.007). There was a significant increase in the 3-year cumulative incidence of distant metastases in the hypoxic group (41% v 15% in those with HP(5) < 50%; P =.0023), but not in pelvic relapse (37% v 27%; P =.12).

CONCLUSION

Tumor hypoxia is an independent predictor of poor PFS only in patients with node-negative cervix cancer, in addition to tumor size. Its impact appears to be related to an increased risk of distant metastases rather than to an effect on pelvic control.

Interstitial fluid pressure predicts survival in patients with cervix cancer independent of clinical prognostic factors and tumor oxygen measurements

The purpose of this study was to determine the independent prognostic significanceof interstitial fluid pressure (IFP) measurements in cervix cancer. A total of 102 patients with newly diagnosed cervix cancer were accrued to this prospective study. There were 31 International Federation of Gynecology and Obstetrics stage IB or IIA tumors, 40 IIB tumors, and 31 IIIB tumors. The median size was 5 cm (range, 2-10 cm). Pelvic lymphadenopathy was identified radiographically in 20 patients. IFP was measured at examination under anesthesia using a wick-in-needle technique. Multiple measurements were made in each tumor. The mean IFP in individual tumors ranged from -3 to 48 mm Hg, and the median for the entire cohort was 19 mm Hg. Treatment consisted of external beam and intracavitary radiation without chemotherapy. Median follow-up was 2.5 years. The 3-year disease-free survival of all of the patients was 53%. Disease-free survival was 34% in patients with IFP >19 mm Hg, and 68% in those with lower IFP (P = 0.002). To evaluate rigorously the independent prognostic significance of IFP measurements relative to established clinical factors, a multivariate model was first developed using stepwise selection of clinical covariates. Tumor size (P = 0.0003) and pelvic lymph node status (P = 0.0016) comprised the clinical model. IFP, when added to this model, provided additional independent prognostic information (P = 0.0013). IFP was also significant (P = 0.0027) when the clinical factors and hypoxic proportion as determined with the Eppendorf electrode were analyzed together. Patients with high IFP were more likely to recur both locally and at distant sites. This study is the first to document a strong, independent prognostic importance of pretreatment IFP measurements in cervix cancer. Patients with high IFP are significantly more likely than those with low IFP to recur after radiotherapy and die of progressive disease, independent of clinical prognostic factors and the results of tumor oxygen measurements.

Comparison of (99m)Tc-sestamibi and doxorubicin to monitor inhibition of P-glycoprotein function

P-glycoprotein (Pgp) overexpression is a well-recognized factor in resistance to chemotherapy. Doxorubicin flow cytometry is used to monitor Pgp function in haematological specimens and biopsies from other cancers, and radionuclide imaging with sestamibi has recently shown promise for non-invasive monitoring. In the present study the two methods were directly compared in single-cell suspensions of three variants of the human breast carcinoma cell line MCF7: sensitive MCF7/WT, doxorubicin-selected MCF7/AdrR, and MDR1-gene-transfected MCF7/BC19 cells with doxorubicin resistance factors of 1, 192, and 14, respectively. Accumulation of sestamibi and mean fluorescence of doxorubicin (5.5 microM) were assessed over 60 min in the presence and absence of Pgp modulators GG918 (0.01 to 0.2 microM) and PSC833 (0.05 to 2.0 microM). Accumulation curves for sestamibi and doxorubicin differed among the cell variants under control conditions, with sestamibi showing a significantly greater difference between WT and resistant cells than doxorubicin. Both GG918 and PSC833 reversed uptake deficits to WT levels for sestamibi in MCF7/BC19 cells and doxorubicin in MCF7/BC19 and MCF7/AdrR cells, but failed to show the same effect for sestamibi in MCF7/AdrR cells (approximately 30% of MCF7/WT level). Thus, both methods clearly distinguished sensitive from resistant MCF7 variants, with the radionuclide method showing greater sensitivity.

T-cell frequency analysis does not predict the incidence of graft-versus-host disease in HLA-matched sibling bone marrow transplantation

BACKGROUND

Graft-versus-host disease (GVHD) is a major and sometimes fatal complication of allogeneic bone marrow transplantation (BMT). The prediction of GVHD remains an important issue in preventing morbidity and mortality after allogeneic BMT. In the past 10 years, there has been great interest in using the frequency analysis of alloreactive helper and cytotoxic T lymphocyte precursors (HTLp and CTLp) to detect recipient-specific alloreactivity and thus predict GVHD in HLA-matched related and unrelated BMT. However, the results remain controversial. The intention of the present study was to investigate whether alloreactive HTLp and CTLp frequencies measured in donor peripheral blood before BMT would be a useful predictor for the occurrence of acute GVHD after HLA-matched sibling BMT.

METHOD

A combined limiting dilution assay was used to determine alloreactive HTLp and CTLp frequencies for 42 HLA-matched sibling patient/donor pairs. The pretransplantation host-reactive HTLp and CTLp frequencies were then correlated with post-transplantation clinical outcomes of acute GVHD. The association between HTLp/CTLp frequencies and the incidence of acute GVHD was determined using the Fisher's exact test.

RESULTS

The mean values of HTLp and CTLp frequencies for this cohort of HLA-matched sibling patient/donor pairs were 1:321,322 (range 1:71,000 to 1:1000,000) and 1:195,260 (range 1:3,717 to 1:1000,000), respectively. Acute GVHD (> or =II) was observed in one of four patients with high (>1:100,000) HTLp frequencies and 20 of 36 patients with low (<1:100,000) HTLp frequencies. Similarly, 6 of 10 patients with high (>1: 100,000) CTLp frequencies and 14 of 29 patients with low (<1:100,000) CTLp frequencies developed acute GVHD (> or =II). The overall correlation between hostreactive HTLp/CTLp frequencies and the incidence of acute GVHD in this cohort of patients was 42.5% and 53.9%, respectively. There was no significant difference in the incidence of acute GVHD between the patients with either high or low host-reactive HTLp/ CTLp frequencies (P=0.331 and 0.716, respectively). The data were also analyzed separately for the adult patient group based on GVHD prophylaxis with either cyclosporine alone or the combination of cyclosporine and methotrexate. Within these two prophylaxis groups, neither HTLp nor CTLp frequencies correlated with acute GVHD.

CONCLUSION

Host-reactive HTLp and CTLp frequency analysis did not provide informative prediction for the occurrence of acute GVHD after HLA-matched sibling BMT.

A prospective, longitudinal study of the relationship of psychological work to duration of survival in patients with metastatic cancer

This study is a prospective, longitudinal investigation of the psychological factors associated with the duration of survival in patients with metastatic cancers of various kinds who were receiving group psychotherapy. A correlative approach rather than an experimental (trials) design was used in the study because our aim was to relate the psychological attributes of each individual to survival rather than to test the efficacy of the intervention. Twenty-two patients with medically incurable metastatic cancer of various kinds received weekly group psychotherapy for up to 1 year, the great majority remaining well enough to attend the group for at least 8 months. During this time, they provided extensive verbal data, through written homework, and from notes taken by the therapists at interviews and during group sessions. These data were subjected to detailed qualitative analysis, as a result of which a number of psychological themes were defined. A quantitative rating was assigned to the data for each theme in each individual patient through team discussions. The scores for the individual themes were summed to produce a 'total psychological score', representing the degree of each patient's involvement with psychological self-help work. The values for each patient were then related to his or her survival duration. Cox regression analyses showed that this composite score, and five of six major themes, were significantly related to survival duration. These themes were: ability to act and change; willingness to initiate change; application to self-help work; relationships with others; and quality of experience. In contrast, there was no relationship between survival and four standard psychometric measures taken at the onset of therapy. However, results on a 5-point scale measuring the subject's expectancy that psychological efforts would affect the disease showed a strong relationship to survival. To control for differences in severity of disease as a factor possibly influencing psychological work, the analyses were repeated, using the survival duration predicted for each patient by a panel of oncologists as a covariate. Closely similar results were obtained. Limitations on the interpretation of the results are discussed. Within these limits, it appears that there is a strong association between longer survival and psychological factors related to the involvement of cancer patients in psychological self-help activities. While causality cannot be inferred, reasons are given for believing that this is not a result of the disease influencing the patients' psychology, but rather the converse.

A comparison in individual murine tumors of techniques for measuring oxygen levels

PURPOSE

To investigate the relationship between different techniques for measuring oxygen levels in a murine tumor model.

METHODS AND MATERIALS

Using the murine fibrosarcoma line KHT-C, five techniques of measuring oxygen levels-the Eppendorf pO2 Histograph, EF5 binding, the comet assay, a paired survival assay, and an in vivo growth delay assay-were assessed. In these experiments, three or more techniques were applied in different combinations to measure the oxygen levels in individual tumors.

RESULTS

Statistically significant correlations were observed between the hypoxic proportions calculated from the paired survival assay with those from EF5 binding. The comet assay was found to have a statistically significant correlation with the paired survival analysis and the growth delay analysis. No statistically significant correlation was found between the Eppendorf pO2 Histograph measurements and those from the other techniques, although there were weak correlations with the paired survival assay and EF5 binding. For technical reasons, a comparison was not made between EF5 binding and the growth delay assay.

CONCLUSIONS

The correlations found between EF5 binding and the comet assay with the radiobiological assays suggest that these techniques have potential for predicting outcome following radiation treatment. The lack of correlation seen between the pO2 Histograph data and the radiobiological assays is in contrast to results from early clinical trials.

Phase I trial of sequential topotecan followed by etoposide in adults with myeloid leukemia: a National Cancer Institute of Canada Clinical Trials Group Study

Prolonged exposure to a topoisomerase I inhibitor may increase expression of topoisomerase II, making cells more susceptible inhibitors of that enzyme. This study was undertaken to establish the maximum tolerated dose (MTD) of a topotecan/topoisomerase II inhibitor sequential combination that may be active in acute leukemia, and to evaluate the effects of in vivo exposure to topotecan on topoisomerase II levels in leukemic blast cells as measured by image cytometry. Patients who were eligible for this phase I study had relapsed or refractory acute myeloid leukemia (< or = 2 prior regimens) or CML blast crisis (0 or 1 prior regimen). Topotecan was given as a 5 day continuous i.v. infusion and was to be escalated through three levels (1.5, 1.75 and 2.0 mg/m2 day), followed by etoposide at two dose levels (100 and 150 mg/m2) i.v. bolus days 6, 7 and 8. Topoisomerase IIalpha levels in leukemic blasts from bone marrow were measured by image cytometry prior to starting treatment, on day 5 of topotecan infusion and on day 28; and daily during topotecan in peripheral blood blasts. Dose-limiting toxicity was seen in two of six patients at the first dose level (topotecan 1.5 mg/m2/day, etoposide 100 mg/m2/day; > or = grade 3 mucositis in both cases). This cohort was expanded to 10 patients; no further non-hematologic dose-limiting toxicity was observed, but given the extent of toxicity seen, further dose escalation was judged not to be feasible. Topo IIalpha levels increased in peripheral blood blasts during the first 72 h of topotecan infusion and returned to near baseline by day 5, whereas levels appeared to decrease in bone marrow blasts by day 5 compared to pretreatment. One complete hematologic and cytogenetic remission in a patient with CML blast crisis was observed in the 10 patients evaluable for response. The sequential administration of topotecan 1.5 mg/m2/day continuous infusion for 5 days followed by etoposide 100 mg/m2/day x 3 is the recommended phase II dose for this schedule. Topotecan increases topo IIalpha expression in vivo in leukemia cells, but levels of the enzyme are cell cycle dependent. Pharmacodynamic evaluation of the sequential or combination administration of novel antileukemic agents may help improve treatment strategies in acute leukemia.

Heterogeneity of tumor oxygenation: relationship to tumor necrosis, tumor size, and metastasis

PURPOSE

Measurements of oxygenation in the transplanted rodent KHT-C and SCC-VII tumors demonstrate significant heterogeneity from tumor to tumor as is observed in human tumors. This finding suggests that heterogeneity in oxygenation between tumors is likely related to factors associated with tumor growth rather than to intrinsic genetic differences. In this study we examined whether measurements of the oxygenation of individual KHT-C tumors were related to necrosis in the tumors or to tumor size and whether the more hypoxic tumors gave rise to more metastases.

METHODS

Tumors were grown in the gastrocnemius muscle of C3H mice and tumor oxygenation was measured at defined sizes (approx. 0.35 g, 1.0 g, and 2.0 g) using an Eppendorf polarographic oxygen probe. Necrosis was assessed by examining histological sections cut from tumors used for the oxygen measurements. Metastasis was assessed by counting macroscopic lung nodules in mice sacrificed when their tumors reached a size of approximately 2 g.

RESULTS

Tumor oxygenation in individual KHT-C tumors became poorer and necrosis became more extensive as the tumors grew larger but, at a size of 0.3-0.4 g, there was no relationship between oxygenation and extent of necrosis. In general, measurements of tumor pO2 at a size of 0.3-0.4 g were predictive of tumor PO2 in the same tumor at a size of about 1 g, but by the time the tumors reached a size of about 2 g they were all very hypoxic. There was a trend suggesting a relationship between macroscopic metastases in the lung and degree of hypoxia in the KHT-C tumors but this was not statistically significant.

CONCLUSION

The results indicate that the heterogeneity of oxygenation seen in KHT-C tumors is not explained by different degrees of necrosis in the individual tumors. The lack of a correlation between increased metastasis formation and increased levels of hypoxia in the KHT-C tumors is not consistent with results reported for human tumors.

A phase II study of temozolomide in advanced untreated pancreatic cancer

Temozolomide (SCH 52365) is an imidazotetrazine derivative which exhibits broad spectrum activity against murine tumors and is structurally related to dacarbazine (DTIC). Temozolomide cytotoxicity is schedule dependent in vivo with a daily x 5 schedule showing the highest activity. Oral temozolomide is rapidly and completely absorbed with minimal interpatient and intrapatient variability in pharmacokinetics. Clinical studies have demonstrated activity against melanoma and glioma. The present study examined the activity of oral temozolomide against patients with pancreatic cancer. Patients with advanced pancreatic adenocarcinoma previously untreated with chemotherapy received temozolomide 200 mg/m2/day once daily orally for 5 days with cycles repeated every 28 days. There were 16 patients entered on study with 15 evaluable for response and toxicity. There were no responses seen in 15 evaluable patients with 14 manifesting progressive disease within 2 months of starting therapy. Toxicity was primarily hematological with 3 patients experiencing > or = grade 3 neutropenia and thrombocytopenia respectively. Other toxicities were relatively modest. In conclusion, temozolomide in the once daily x 5 schedule is inactive against adenocarcinoma of the pancreas.

Phase II study of dexverapamil plus anthracycline in patients with metastatic breast cancer who have progressed on the same anthracycline regimen

The purpose of this study is to evaluate whether metastatic breast cancer that has progressed on an anthracycline-containing drug regimen will subsequently respond to that identical regimen if dexverapamil, a modulator of P-glycoprotein-mediated drug resistance, is given concomitantly. Eligible patients received 180 mg/m2 dexverapamil every 6 h for 15 doses with the anthracycline administered 30 min after the seventh dose. Blood for dexverapamil levels was drawn before and 30 min after this dose. When possible, biopsies were obtained to measure mdr-1 expression by reverse transcription-PCR and by image cytometry. Of the 21 patients entered onto the trial, 20 were evaluable for response. There were two partial responses (10%) that both lasted for 6 months, and two additional patients had stable disease. Seven patients had asymptomatic cardiotoxicity consisting of hypotension (24%), bradycardia (5%), or prolongation of the P-R interval (14%). Two patients developed acute congestive heart failure, one on dexverapamil and one 10 days after stopping it. Dexverapamil did not seem to increase anthracycline toxicity. The median trough dexverapamil plus norverapamil level on day 3 was 1110 ng/ml (range, 186-3385 ng/ml), and the median peak level was 2164 ng/ml (range, 964-8382 ng/ml). There was poor correlation between reverse transcription-PCR and image cytometry for the level of mdr-1 expression. Because dexverapamil has been shown to affect doxorubicin pharmacokinetics subsequent to the initiation of this trial, it cannot be concluded that the responses seen were necessarily due to P-glycoprotein inhibition. Additional studies are necessary to determine whether mdr-1 modulators can reverse clinical drug resistance in breast cancer patients. The intrinsic cardiotoxicity of dexverapamil makes it less suitable for such studies than several other available agents.

Flow cytometric calibration of intracellular pH measurements in viable cells using mixtures of weak acids and bases

We describe a new method for calibrating intracellular pH (pH1) measurements by flow cytometry, based on the null point method proposed originally by Eisner et al. (Pflügers Arch 413:553-558, 1989). The method involves suspending cells loaded with pH-sensitive dyes, such as SNARF-1 or BCECF, in defined mixtures of the weak acid butyric acid and the weak base trimethylamine. Only the uncharged forms of these agents freely permeate the plasma membrane. The weak acid donates protons intracellularly, whereas the weak base accepts them. In accordance with the Henderson-Hasselbalch equation, when cells are exposed to these mixtures, the steady-state pHi is displaced, and the fluorescence signal reflects this new pHi. The null point method described by Eisner et al. derives pHi by determining the molar ratio of acid to base that produces no change in fluorescence signal. In this paper, we show that it is not necessary to obtain the true null point, because a calibration curve can be derived from "pseudo null" values whose pHi is defined by the equation pHi = pHe -0.5 log [(AT)/(BT)], where pHe is the extracellular pH, and (AT) and (BT) are the total concentrations of weak acid and base in the suspension. We refer to this as the "pseudo null calibration method." It is rapid, technically simple, and reproducible. Compared with the widely used nigericin calibration method, it is not influenced by the intracellular potassium concentration; therefore, it may give a more reliable estimate of the absolute value of pHi.

Flow cytometric determination of glutathione in clinical samples

Glutathione-based processes are believed to be important determinants of resistance to cancer chemotherapy, and measurement of glutathione (GSH) in tumor tissue is therefore of clinical relevance. Flow cytometric methods have been developed for measuring cellular GSH content that appear to correlate well with biochemical determinations. These flow cytometric techniques are rapid, allow tumor cells to be distinguished from stromal elements, and show considerable intratumoral heterogeneity in human tumor cell GSH content. Although large prospective studies are required to determine the correlations between GSH content and treatment outcome in cancer patients, this approach is a powerful alternative to standard biochemical assays for GSH.

Flow cytometric measurement of lipid peroxidation in vital cells using parinaric acid

A method for measuring lipid peroxidation using time resolved flow cytometry is described. Because of its chemical nature, the naturally fluorescent fatty acid cis-parinaric acid is readily consumed in lipid peroxidation reactions. It could be loaded into Chinese hamster ovary cells in a time and concentration dependent manner at 37 degrees C, with 5 microM for 60' giving consistent, bright fluorescence without evidence of cytotoxicity. Examination of cells by fluorescence microscopy showed diffuse staining of surface and internal membranes. Cells were maintained at 37 degrees C while being examined in an Epics Elite flow cytometer equipped with a 325 nm HeCd laser, and parinaric acid fluorescence at 405 nm was measured over time. Addition of the oxidant tert-butyl hydroperoxide resulted in a burst of intracellular oxidation, shown by simultaneously loading the cells with dichlorofluorescein, and loss of parinaric fluorescence over time. This was followed by cell death, indicated by loss of forward light scatter and uptake of propidium iodide. Pretreatment of the cells with the antioxidant alpha-tocopherol, 200 microM, reduced the rate of loss of parinaric acid fluorescence and delayed the onset of cell death. Simultaneous biochemical determination of the lipid peroxidation breakdown product malondialdehyde confirmed a close temporal relationship with loss of parinaric acid fluorescence, both with and without alpha-tocopherol pretreatment and suggested that the flow cytometric assay for lipid peroxidation is of comparable sensitivity. The mitochondrial stain dodecyl acridine orange and the cyanine dye DiOC(6)3 were combined with cis-parinaric acid staining and could be excited by the latter using resonance energy transfer.(ABSTRACT TRUNCATED AT 250 WORDS)

The hypothermic response of mice to delta-9-tetrahydrocannabinol is enhanced by chlorpromazine, thioxanthenes, alpha-adrenoceptor antagonists and pentolinium but not by SCH 23390 or sulpiride

Chlorpromazine, given either subcutaneously (0.375 mg/kg) or unilaterally into the preoptic/anterior hypothalamic area through a chronically implanted cannula (20 micrograms), was found to enhance the hypothermic response to delta-9-tetrahydrocannabinol (THC; 5 mg/kg i.p.) in unrestrained adult male MF1 mice, kept at 22 degrees C. In mg/kg terms, chlorpromazine was no more potent when injected into the preoptic/anterior hypothalamic area than when given subcutaneously. Phentolamine (54 micrograms) had no significant effect on hypothermia induced by THC when injected into the hypothalamus although it did enhance this response when given subcutaneously (15 mg/kg). Hypothermia induced by THC was also enhanced by flupentixol (0.375 mg/kg s.c.), piflutixol (23.4 micrograms/kg s.c.), pentolinium (5 mg/kg s.c.), prazosin (0.1875 mg/kg s.c.) and indoramin (6 mg/kg s.c.) but not by SCH 23390 (6 mg/kg s.c.) or sulpiride (40 mg/kg s.c.). When taken together with the results from a previous study, these data support the hypothesis that chlorpromazine enhances hypothermia induced in mice by THC by antagonizing alpha-adrenoceptors so as to decrease the capacity of the animals to minimise peripheral blood flow by vasoconstriction. The present data also support the hypothesis that flupentixol and piflutixol interacted with THC not by antagonizing dopamine at D1 or D2 receptors but rather by blocking alpha-adrenoceptors.