Abstract P2-05-12: Effects of de-escalated bisphosphonate therapy on bone turnover or metastasis markers and their correlation with risk of skeletal related events – A biomarker analysis in conjunction with the REFORM study

Background: Despite variability in an individual's risk of skeletal related events (SREs) from bone metastases (BM), all patients are treated using a similar dose and schedule (q3-4 wk) of IV bisphosphonate (BP). The REFORM trial (Amir et al., Am J Clin Oncol, in press) was a pilot randomised study evaluating the efficacy of de-escalated (q12 wk) versus standard (q3-4 wk) pamidronate in maintaining C-telopeptide (CTx) levels in the low risk range (<600ng/L) in patients with BM from breast cancer. Here we report a biomarker substudy, where additional biomarkers of bone turnover and BM behaviour were measured and correlated with SRE risk.

Methods: Eligible patients with BM, who had received ≥ 3 months of q3-4 wk IV BP and no systemic treatment change within 4 wks of study entry were enrolled. Serum & urine obtained at baseline and at 12 wks were assessed for urinary N-telopeptide (uNTx), serum procollagen type I amino-terminal propeptide (P1NP), transforming growth factor (TGF)-β, activinA and bone sialoprotein (BSP) by ELISA. Levels were correlated with number of SREs using linear regression analysis. Changes in biomarkers from baseline to 12 wks were used to calculate odds ratios for coming off study (due to either elevated CTx or SRE) or having an SRE alone using logistic regression analysis.

Results: REFORM randomized 19 patients to each treatment arm, and found that the SRE rate at 1 year in both arms was the same (n = 2). Although the mean level of the standard bone turnover marker CTx decreased slightly from baseline to wk 12 in the q3-4 wk group (240±50ng/L to 206±46ng/L), and slightly increased in the q12 wk treated group (263±65ng/L to 313±71ng/L), these changes were not statistically significant (p = 0.8). Mean activinA levels were slightly increased in both treatment arms from baseline to wk 12 (730±93pg/ml to 875±148pg/ml in q3-4 wk group vs 445±35pg/ml to 582±61pg/ml in q12 wk group) but did not quite reach statistical significance (p = 0.1). Levels of TGF-β from baseline to 12 wks in both groups was similar (22±1.6ng/ml to 22±2.3ng/ml for q3-4 wk vs 23±2.2ng/ml to 24±2.4ng/ml for q12 wk group, p = 0.8). Although the number of SREs was small, mean CTx levels at wk 12 were statistically different between patients who experienced SREs vs those that did not (615±72ng/L, n=4 vs 190±26ng/L, n=19, p < 0.0001). Although it did not reach statistical significance, mean activinA levels at wk 12 were also higher in patients who had SREs than those that did not (1069±358pg/ml, n=3 vs 681±83pg/ml, n=18, p = 0.12). Results of NTx, BSP and P1NP and correlations with more mature clinical data will also be presented.

Conclusions: In patients with BM from breast cancer with low levels of bone resorption markers, CTx predicted and activinA trended to predict SRE risk. However the non-significant trends in increasing CTx in de-escalated BP treatment, together with the observation that activinA levels are similar regardless of dosing regimen, suggest that analysis of conventional and experimental biomarkers of SRE risk requires further examination in other larger patient cohorts comparing de-escalated therapy.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P2-05-12.

Use of serum and tissue biomarker analysis embedded in a phase II clinical trial of cytarabine in castration-refractory prostate cancer to investigate prostate cancer biology

59

Background: Other than the androgen receptor, the TMPRSS2-ERG genomic aberrations in prostate cancer provide the first recent opportunity to target therapy in castration refractory prostate cancer (CRPC). We initiated a phase II clinical trial of cytarabine in docetaxel refractory CRPC on the basis of microarray, in vitro and case report evidence that cytarabine may be particularly effective in men harbouring abnormalities of the ERG oncogenes. Embedded in this clinical trial was the first use of blood mRNA levels of prostate cancer related genes as biomarkers of response and prognosis.

Methods: Patients with docetaxel refractory progressive CRPC received intravenous cytarabine at doses between 1g/m2-0.25 g/m2 q3 weekly. Responses were defined according to PCWG2C. 10 patients were enrolled between June 2007 and January 2010. TMPRSS2:ERG, PSA and PCA3 mRNA copies in whole blood collected with PAXgene tubes at the beginning of each cycle and at trial termination were quantified using transcription-mediated amplification assays. The prototype TMPRSS2:ERG assay detects the gene fusion isoform TMPRSS2 exon1 to ERG exon4.

Results: No patients demonstrated a serum PSA response (PCWG2C). The average number of cycles administered was 2.6. Significant toxicities including grade 3-4 thrombocytopenia (2) and grade 3-4 neutropenia (3). These toxicities necessitated several dose reductions in the protocol, however most patients were removed from trial for serum PSA progression alone. PCA3 and PSA mRNAs were detectable in 8/10 and 9/10 cases, respectively; there was no correlation between serum PSA and PCA3 or PSA mRNA copy levels in blood. Testing for TMPRSS2:ERG in blood was able to predict the presence or absence of the TMPRSS2-ERG rearrangement in 9/10 cases when compared to 3 colour FISH carried out on baseline biopsies/ prostatectomies (2/10 positive for Exon 4:Exon 1 deletion).

Conclusions: Cytarabine administation is ineffective in docetaxel refractory CRPC. Blood mRNA levels of prostate cancer genes reveal novel aspects of prostate cancer biology and have implications for the understanding of circulating tumour cells.

[Table: see text]

Association between radiographic response and overall survival in men with metastatic castration-resistant prostate cancer receiving chemotherapy

118

Background: In men with metastatic castration resistant prostate cancer (CRPC),the association of measurable tumor responses with overall survival (OS) is unknown. We retrospectively evaluated the TAX327 phase III trial to study this relationship.

Methods: Eligible patients for this analysis included those with WHO-defined measurable metastatic disease randomized to receive either docetaxel or mitoxantrone. OS was estimated using the Kaplan-Meier method and the prognostic relationship of WHO-defined radiologic response with OS was performed using Cox proportional hazards regression. Landmark analyses evaluated survival from baseline and 2, 3, 4 and 6 months after baseline.

Results: Four hundred and twelve patients enrolled on the TAX327 trial had measurable tumors. Thirty-seven patients exhibited a complete or partial objective response (CR/PR, 9.0%), 116 had stable disease (SD, 28.2%), 99 had progressive disease (PD,24%) and 160 (38.8%) did not have a post-baseline objective assessment. Partial responders demonstrated longer median OS (29.0 months) than patients with SD (22.1 months), or those with PD (10.8 months) or those who were not assessed (12.7 months). These results remained after landmark analysis. We found a significant association between ≥30% PSA declines and radiologic response, with ≥30% PSA declines occurring in all patients with CR/PR, 79.8% of patients with SD and 34.4% with PD. Radiologic response remained a significant but modest post-treatment prognostic factor for OS after adjusting for treatment, pain-response and ≥30% PSA-decline (p=0.009).

Conclusions: In men with metastatic CRPC and measurable disease receiving chemotherapy, objective tumor response was prognostic for OS, and appears to complement PSA assessment.

[Table: see text]

Mature results of a randomized phase II study of OGX-011 in combination with docetaxel/prednisone versus docetaxel/prednisone in patients with metastatic castration-resistant prostate cancer

5012

Background: Clusterin is a cytoprotective chaperone protein associated with CRPC progression. OGX is a 2'-methoxyethyl antisense that potentiates chemotherapy in xenografts and inhibits clusterin expression at doses of <640 mg. Methods: Pts with CRPC and chemo-naive received docetaxel (DOC) 75mg/m2 q3w + OGX 640mg IV weekly + prednisone (Arm A) or DOC + prednisone (Arm B) in a single stage randomized phase II design. Primary endpoint was PSA response rate (RR). Progression-free survival (PFS) and overall survival (OS) were secondary endpoints. Planned sample size was 40/arm: Arm A the hypotheses (PSA RR<40% vs. >60%) could be tested at 10% β and 10% α, Arm B the true PSA RR could be estimated with half-width of the 90% CI<13% if PSA RR=40%. Results: 82 pts (41 Arm A, 41 Arm B) were randomized from 09/05–12/06. At this analysis time, all pts are off therapy and 49 have died. One pt was ineligible but included in ITT survival analysis. Baseline characteristics were similar: median age 69 (49–87), PSA >100 μg/L in 51%, Hgb ≥100 g/L in 98%, alk phos >ULN in 44%, LDH >ULN in 36%, ECOG performance status (PS) 0:1 in 51%:49%, bone/lymph node/visceral metastases in 69%/50%/28%. Median cycles for Arm A and B was 9 and 7. Adverse events associated with OGX included fatigue, fever, rigors, diarrhea and rash. Mean serum clusterin change on day 1 cycle 2 was -18% in Arm A and +8% in Arm B (p = 0.0005). PSA RR was 58% (Arm A) and 54% (Arm B). PSA declines at 12 weeks of any/>30%/>50% was observed in 87%/65%/45% (Arm A) and 68%/58%/34% (Arm B). PSA/objective disease progression as best response occurred in 0%/4% (Arm A), and 3%/17% (Arm B). PFS for Arms A and B was 7.3 (5.3–8.8) and 6.1 months (3.7–8.6). Median OS for Arms A and B was 27.5 (19.2-∞) and 16.9 months (12.7–26.0) (unadjusted HR = 0.60 [0.34–1.06], p = 0.07). Variables predictive of OS on multivariate analysis: PS 0 vs 1 (p = 0.0002), presence of visceral metastasis (p = 0.006) and treatment assignment (HR = 0.54 [0.29–0.97], p = 0.04). Conclusions: The PSA RR in both arms met criterion for further study. OGX reduced serum clusterin and OS appears superior with DOC/OGX. This combination warrants further evaluation. Supported by a grant from the NCI-Canada/Canadian Cancer Society.

[Table: see text]

Declines in physical function from androgen deprivation therapy (ADT) in men with nonmetastatic prostate cancer: A matched cohort study

9526

Background: Although prolonged use of ADT is hypothesized to adversely affect physical function, few studies have examined this relationship longitudinally using objective measures of physical function. Methods: Men age 50+ with non-metastatic prostate cancer (PC) starting continuous ADT were enrolled in this prospective longitudinal matched cohort study. Physical function was assessed with the six-minute walk test (6MWT), grip strength, and the Timed Up and Go (TUG) test, representing endurance, upper extremity strength, and lower extremity strength, respectively. Self-reported physical function was measured with the Medical Outcomes Study SF-36. Assessments were done at baseline, 3 months, 6 months, and 12 months. Two control groups, matched on age, education, and baseline function were also enrolled. One control group had PC but did not receive ADT, and the other group did not have PC. Linear mixed effects regression models were fitted adjusting for baseline covariates. Results: 85 patients on ADT, 86 PC controls, and 86 healthy controls were enrolled. All 3 groups were similar in age (mean age 69.1 y, range 50–87) and physical function (all ANOVA p>0.05). The 6MWT distance improved in both control groups (p=0.05 and 0.05 for PC and healthy controls, respectively) but remained stable in the ADT group (p=0.96)). Grip strength declined in the ADT group (p=0.04), remained stable in the PC control group (p=0.31), and improved in the healthy control group (p=0.008). TUG scores remained stable over time and across groups (p>0.10). SF-36 physical function declined in the ADT group (p<0.001) but increased in both control groups (p<0.001). Negative effects on outcomes were noted within 3–6 months of starting ADT and were larger with older age. Conclusions: Endurance, upper extremity strength, and self-reported physical function are affected within 3–6 months of starting ADT, particularly in older men. Declines persist at 12 months after adjustment for baseline function and covariates. Exercise intervention studies to counteract these losses are warranted.

No significant financial relationships to disclose.

A randomized phase II study of OGX-011 in combination with docetaxel and prednisone or docetaxel and prednisone alone in patients with metastatic hormone refractory prostate cancer (HRPC)

5069

Background: Clusterin, a cytoprotective chaperone protein that promotes cell survival, is associated with androgen independent progression and overexpressed in HRPC. OGX-011 (OGX, developed by OncoGenex Technologies/Isis Pharmaceuticals) is a 2’- methoxyethyl modified phosphorothioate antisense that inhibits clusterin expression in humans at doses of ≤640 mg and potentiates chemotherapy activity in prostate xenografts. The objective of this study was to determine the anti-tumor activity of OGX in combination with docetaxel (DOC) in patients (pts) with HRPC. Methods: Chemo-naive pts with metastatic HRPC were randomized to receive DOC 75mg/m2 q3 weeks + OGX 640mg weekly as a 2-hour IV infusion (Arm A) + prednisone or DOC + prednisone (Arm B). Serum levels of clusterin were assessed serially. A single stage randomized phase II design was employed with PSA response rate (RR) as the primary endpoint (Bubley et al, J Clin Oncol 1999;17:3461). Planned sample size was 40 per arm: Arm A the hypotheses (H0:PSA RR<40% vs. H1:PSA RR>60%) could be tested at 10% β and 10% a, Arm B the true PSA RR could be estimated with half-width of the 90% confidence interval <13% if observed PSA RR was 40%. Results: 82 pts (41/arm) were enrolled from September 2005 to December 2006 at 12 centers. Baseline characteristics are similar in both arms (available to date for 63 pts): median age 67 (range: 49–84), PSA 110 μg/L (5.6–1261), hemoglobin 128 g/L (96–158), alkaline phosphatase 133 U/L (47–1294), LDH 193 U/L (120–741). ECOG performance status was 0 in 49% and 1 in 51%; 67% had bone/nodal disease only and 33% had other metastatic sites. To date, 56 pts have received ≥2 cycles. Toxicity due to OGX included grade 1/2 fevers and rigors in 37% and 67% pts respectively, but other adverse events were similar in both arms. PSA response has occurred in 43%, progression in 9%, and 48% have not yet met criteria for response or progression. Conclusions: Combined docetaxel and OGX is well tolerated in pts with metastatic HRPC and PSA responses have been observed. Pt treatment, follow-up and analysis of serum clusterin levels continue. Results by arm will be available by June 2007. Supported by a grant from the NCI-Canada/Canadian Cancer Society.

No significant financial relationships to disclose.

The Prostate Cancer Clinical Trials Working Group (PCCTWG) consensus criteria for phase II clinical trials for castration-resistant prostate cancer

5057

Background: The clinical manifestations of castration-resistant metastatic prostate cancer pose challenges to the design of phase 2 trials. In 1999, PSAWG issued a consensus report to standardize phase 2 design and endpoint definitions. A reassessment is reported. Methods: At 4 meetings, and using electronic communication, PCCTWG is seeking consensus on the design and analysis of phase 2 trials that can inform decisions about proceeding to phase 3. Results: PCCTWG recognizes that trial objectives, and details of design and analysis depend on the agent under study. PCCTWG recommends: (i) A standard disease assessment that includes prior treatment history, bone scan, and CT of the chest, abdomen and pelvis; (ii) Revision of eligibility criteria to lower PSA thresholds and serum testosterone levels; (iii) Emphasis on time-to-event endpoints including clinical, biochemical (e.g. PSA) or radiologic progression, recognizing that molecular targeted agents may delay progression without influencing initial response. (iv) Independent reporting of biochemical, radiographic, and clinical outcomes, avoiding grouped categorizations of complete or partial response, or stable disease. (v) Treating for a minimum of 12 weeks before assessing disease status, as the onset of PSA declines are often delayed, verifying that an agent does not influence release of PSA from cells. (vi) RECIST criteria are appropriate for changes in measurable disease, separating nodal and visceral sites. (vii) Changes in bone scan should be reported as “new lesions” or “no new lesions”, confirming findings of progression on a second scan. (viii) Pain and analgesic intake should be assessed using validated scales. (ix) Due to inherent variability, randomization to experimental and control groups is preferred, and innovative designs, e.g. expanding selected arms of randomized phase 2 trials to phase 3. Conclusions: PCCTWG recommends increasing emphasis on time to event endpoints as decision aids in proceeding from phase 2 to phase 3 trials. The recommendations will evolve as data are generated from phase 3 studies on the ability of intermediate endpoints to predict for clinical benefit. Support: MSKCC SPORE (CA 92629), Prostate Cancer Foundation.

No significant financial relationships to disclose.

Analysis of prostate-specific antigen decline as a surrogate for overall survival in metastatic hormone-refractory prostate cancer (HRPC)

5009

Background: A 30% PSA decline following initiation of cytotoxic chemotherapy has been identified as a potential surrogate for overall survival in metastatic HRPC. We sought to examine whether various levels of PSA decline were surrogates for overall survival in TAX327, a randomized trial of q3w docetaxel and prednisone (DP), q1w DP, and q3w mitoxantrone and prednisone (MP). Methods: In this trial of 1006 men with HRPC, 943 men had sufficient data on 3-month post-treatment PSA decline for analysis, and 646 had sufficient data for analysis for a change in PSA kinetics with therapy. Surrogacy was examined for a range of PSA decline from 0% to 90% and PSA normalization, and for post-treatment changes in PSA kinetics. We investigated the Prentice Criteria for surrogacy using Cox proportional hazards models and calculated the proportion of treatment effect explained (PTE) by each surrogate marker. Results: In this analysis, a 30% or greater PSA decline with therapy was identified as the optimal cutoff that correlated with overall survival, based on the highest PTE point estimate (0.66, 95% CI 0.23–1.0), with 1.0 being a perfect surrogate. A 30% decline in PSA in the first 3 months after treatment occurred in 65% of subjects receiving q3w DP, 67% q1w DP, and 44% q3w MP, despite the significant survival benefits seen only with q3w DP. A 30% PSA decline was associated with a hazard ratio (HR) of 0.43 (95% CI 0.36–0.51) for overall survival after adjusting for treatment effect, while treatment effect itself lost significance, indicating surrogacy. Additionally, PSA normalization, changes in PSA kinetics, and pain response were significant prognostic variables, yet were only modest surrogates for the survival benefit seen with q3w DP therapy. Conclusions: In this trial of two schedules of DP as compared to MP for HRPC, a PSA decline of 30% in the first three months following initiation of cytotoxic chemotherapy was found to have the highest degree of surrogacy for overall survival, thus confirming data from the SWOG 9916 trial. However, given that the confidence interval for the estimate of this surrogate effect is wide, overall survival should remain the preferred endpoint for phase III trials of cytotoxic agents in HRPC.

No significant financial relationships to disclose.

A multivariate prognostic nomogram incorporating PSA kinetics in hormone-refractory metastatic prostate cancer (HRPC)

5058

Background: To develop a prognostic model and nomogram using baseline clinical variables to predict death among men with metastatic hormone-refractory prostate cancer (HRPC). Methods: TAX 327 was a clinical trial that randomized 1,006 men with metastatic HRPC to receive 3-weekly or weekly docetaxel or mitoxantrone, each with prednisone. Of these, 635 men had baseline data that included PSA kinetics, with 518 mortality events recorded as of November 2006. We developed a multivariate Cox model and nomogram to predict survival at two, three, and five years. Results: Ten independent prognostic factors were identified in multivariate analysis and include: 1) presence of liver metastases (HR 1.64, p=0.02), 2) number of metastatic sites (HR 1.58 if =2 sites, p=0.001), 3) clinically significant pain at baseline (HR 1.46, p<0.0001), 4) Karnofsky Performance Status (HR 1.42 if =70, p=0.01), 5) type of progression at baseline (HR 1.40 for measurable disease progression and 1.28 for bone scan progression, p=0.002 and 0.014 respectively), 6) pretreatment PSA doubling time (PSADT, HR 1.20 if <55 days, p=0.048), 7) baseline PSA (HR 1.17 per log rise, p<0.0001), 8) tumor grade (HR 1.18 for high grade, p=0.076), 9) alkaline phosphatase (HR 1.26 per log rise, p<0.0001), and 10) hemoglobin (HR 1.10 per unit decline, p=0.006). A PSADT <55 days (median value for this dataset) was associated with other adverse prognostic factors, but was independently associated with shortened overall survival. Men with a PSA less than the median of 114 ng/ml and longer PSADT (=55 days) had a median survival of 24.7 months, while those with higher PSA and shorter PSADT had a median survival of 13.8 months. A nomogram was developed based on this Cox multivariate model and validated internally using bootstrap methods, with a concordance index of 0.69. Conclusions: This multivariate model identified several prognostic factors in men with metastatic HRPC including PSADT, and led to the successful development of a clinically applicable nomogram. External prospective validation may support the wider use of this prognostic baseline model for men with HRPC treated with chemotherapy.

No significant financial relationships to disclose.

The transition from phase II to phase III studies

6514

Background: Phase II trials are performed to detect potential anti-tumor effects of a new treatment and should be used to decide whether to proceed to a phase 3 trial or not. However, many phase 2 trials never lead to a phase 3 trial despite encouraging results. Here we sought to determine how often (i) positive phase 2 trials have led to phase 3 trials, and (ii) how often phase 2 trials were designed to lead to a phase 3 trial. Methods: We reviewed 200 phase 2 trials, presented at ASCO meetings in 1995–1996, and 2006, selecting randomly 20 abstracts with encouraging results for 5 cancer sites (breast, lung, GI, GU, Gyn) in each time period. For those presented in 1995–1996, we searched systematically for subsequent randomized studies where one treatment arm was similar to that in the phase 2 study. For those presented in 2006, a questionnaire was sent to authors asking whether they recommend evaluating the regimen in a phase 3 trial, whether a phase 3 trial is planned and whether resources (budget, patients, drugs) are available to conduct a phase 3 trial. Results: Ten years after presenting phase 2 trials with positive results, only 13 regimens have been evaluated in a phase 3 trial. Of 100 investigators who presented a phase 2 trial in 2006, 42 returned the questionnaire, 36 confirmed that the results met criteria of efficacy and 25 thought the regimen should be evaluated in a phase 3 trial. Only 10 investigators plan to undertake a phase 3 trial, and 8 stated they had resources to do so. Reasons for not planning a phase 3 study included insufficient efficacy (7), insufficient access to patients (5) or financial support (5), lack of interest from colleagues (6), and lack of support from the company (8). Conclusions: Few (∼13%) phase 2 trials with promising activity are followed by phase 3 trials and this is not increasing with time. Reasons include lack of resources such as money, drugs and patients. Many of these limitations are known when planning the phase 2 study, implying that many phase 2 trials are not planned as precursors of phase 3 trials. Resources spent on such trials would be better applied to practice-changing phase 3 trials.

No significant financial relationships to disclose.

Is physical function affected by androgen deprivation therapy (ADT) in men with non-metastatic prostate cancer?

4615

Background: Although prolonged use ofADT is hypothesized to adversely affect physical function, only a few small studies have examined this relationship and it remains unclear if self-reported weakness represents a decline in actual physical performance or is related to fatigue. Loss of physical function may be particularly important to older men who already have limited functional reserves. Methods: Men age 50 or older with non-metastatic prostate cancer who were starting continuous ADT were enrolled in this prospective longitudinal study. Physical function was tested using a Jamar dynamometer (grip strength), the Timed Up and Go (TUG) test, and the six-minute walk test (6MWT), representing upper extremity strength, lower extremity strength, and endurance, respectively. Assessments were done at baseline (prior to ADT), 3 months, 6 months, and 12 months. Results: 42 patients on ADT have been enrolled to date (mean age 74.8 y). There was a gradual but steady decline in grip strength from baseline (39.2 kg) to 3 months (38.1 kg), 6 months (37.9 kg), and 12 months (35.3 kg) (p < 0.05 for all comparisons). On average, patients took 7.3 seconds to complete the TUG and walked 1507 feet during the 6MWT at baseline. TUG and 6MWT scores did not worsen over time (p > 0.05). Conclusions: Preliminary data suggest that 3–12 months of ADT is associated with worsening upper extremity strength but lower extremity strength and endurance are relatively unaffected. A larger sample size is needed to determine if all aspects of physical function or only upper extremity strength deteriorate with ADT use. Additionally, most patients in our study reported excellent health and functional status at baseline and our results may not adequately reflect the impact of ADT in more frail older men.

No significant financial relationships to disclose.

Phase II study of troxacitabine (BCH-4556) in patients with advanced and/or metastatic renal cell carcinoma: a trial of the National Cancer Institute of Canada-Clinical Trials Group

PURPOSE

A multi-institution phase II study was undertaken by National Cancer Institute of Canada-Clinical Trials Group to evaluate the efficacy and toxicity of intravenous troxacitabine (Troxatyl; Shire Pharmaceuticals Plc, Laval, Quebec, Canada), in patients with renal cell carcinoma.

PATIENTS AND METHODS

Between June 1999 and March 2000, 35 patients (24 male) with a mean age of 60 years who had advanced and/or metastatic disease were treated with troxacitabine given as an intravenous infusion over 30 minutes at a dose of 10 mg/m2 intravenously, once every 3 weeks.

RESULTS

Of the 33 of 35 patients evaluable for response, there were two confirmed partial responses, 21 patients had stable disease (median duration, 4.4 months), and 10 patients had progressive disease. Eight patients remained stable for more than 6 months, of whom six remain free of progression. The most common drug-related nonhematologic toxicities observed were skin rash (77.1%), hand-foot syndrome (68.6%), alopecia (51.4%), fatigue (51.4%), and nausea (57.1%). Out of a total of 145 cycles of treatment, 98 were given without steroid premedication, whereas 47 cycles were given with steroid premedication. Without premedication, skin rash occurred in 37% of cycles compared with 26% when steroids were given prophylactically.

CONCLUSION

Troxacitabine given at a dose of 10 mg/m2 once every 3 weeks was well tolerated in patients with metastatic renal cell cancer, with common toxicities being a moderate to severe granulocytopenia and skin rash. Steroid premedication may reduce the frequency and severity of the skin rash. Our current study suggests that the nucleoside analog troxacitabine may have modest activity against renal cell carcinoma; however, larger studies are required to confirm this.

A National Cancer Institute of Canada clinical trials group phase II study of eniluracil (776C85) and oral 5-fluorouracil in patients with advanced squamous cell head and neck cancer

BACKGROUND/PATIENTS AND METHODS: Thirty-two patients with recurrent head and neck cancer (HNC) following radiotherapy and/or surgery were treated with eniluracil (10 mg/m2) and 5-fluorouracil (5-FU) (1 mg/m2) (E5F) orally twice daily for 28 days followed by a seven-day treatment free period. Thirty-five-day cycles were repeated until disease progression, unacceptable toxicity or patient refusal. Doses were modified for toxicity. Standard toxicity and response criteria were used.

RESULTS

Thirty-two patients were accrued; thirty-two and twenty-eight patients were evaluable for toxicity and response, respectively. Twelve patients received three or more cycles of E5F. Drug related toxicities were usually grade 1-2 intensity and included lethargy, nausea or diarrhea (> or = 25% of patients), and anorexia, rash or itch, stomatitis or vomiting (12%-24% of patients). Hematologic toxicity was generally mild; two patients experienced grade 3-5 leukopenia or thrombocytopenia. No significant biochemical toxicity was seen. One patient was withdrawn (severe nausea and vomiting) and one patient died because of drug related toxicity (thrombocytopenia). In the final analysis there were one complete and four partial responses for a 15.6% overall response.

CONCLUSIONS

E5F demonstrates activity in chemotherapy naïve patients with advanced HNC cancer with acceptable toxicity profile. Further investigation of E5F with other active agents is warranted in HNC.

Long-term follow-up of a phase III intergroup study of cisplatin alone or in combination with methotrexate, vinblastine, and doxorubicin in patients with metastatic urothelial carcinoma: a cooperative group study

PURPOSE

A previously reported randomized intergroup trial demonstrated that combination chemotherapy with methotrexate, vinblastine, doxorubicin, and cisplatin (M-VAC) was superior to single-agent cisplatin in patients with advanced urothelial carcinoma. We conducted a long-term analysis of patients included in the intergroup trial to examine factors associated with long-term survival.

PATIENTS AND METHODS

Two-hundred fifty-five assessable patients with urothelial carcinoma were randomized to receive either single-agent cisplatin (70 mg/m2 on day 1) or combination chemotherapy with methotrexate (30 mg/m2 on days 1, 15, and 22), vinblastine (3 mg/m2 on days 2, 15, and 22), doxorubicin (30 mg/m2 on day 2), and cisplatin (70 mg/m2 on day 2). Courses were repeated every 28 days. The association between patient characteristics and survival was assessed using Cox proportional hazards models.

RESULTS

With long-term follow-up evaluation, survival in the M-VAC arm continues to be superior to cisplatin (P = .00015, log-rank test). Predictors of survival include performance status, histology, and the presence of liver or bone metastasis. Only 3.7% of the patients randomized to M-VAC are alive and continuously disease-free at 6 years.

CONCLUSION

Long-term follow-up evaluation of the intergroup trial confirms that M-VAC is superior to single-agent cisplatin in patients with advanced urothelial carcinoma; however, durable progression-free survival is rare. Patients with non-transitional-cell histology, poor performance status, and/or bone or visceral involvement fare poorly and are unlikely to benefit significantly from M-VAC chemotherapy.

Pharmacokinetic studies of amiloride and its analogs using reversed-phase high-performance liquid chromatography

We have studied the pharmacokinetics of amiloride and its analogs. A high-performance liquid chromatographic method has been adapted for the measurement of amiloride, 5-(N-ethyl-N-isopropyl)amiloride (EIPA) and 5-(N, N-hexamethylene)amiloride (HMA) in mouse plasma, kidney, liver and tumor tissues. The method uses a C8 preparative solid-phase column, followed by separation using a reversed-phase C18 column (250 x 4 mm I.D., 5 microns particle size) with detection by ultraviolet absorption at 365 nm. Reversed-phase separations were performed at ambient temperature using a non-linear gradient method with two different mobile phases: mobile phase A was 100% acetonitrile while mobile phase B was 0.15 M perchloric acid at pH 2.20 (flow-rate was 1.2 ml/min). The retention times for amiloride, benzamil (used as an internal standard), EIPA and HMA are 13.4, 19.5, 21.8 and 23.5 min, respectively. The calibration curves are linear over the range of 0.1-50 microM in plasma and in tissues. The half-lives of amiloride, EIPA and HMA (and their confidence intervals) in plasma after intraperitoneal injection of drugs into mice were 68.8 +/- 0.2, 31.2 +/- 2.5 and 39.3 +/- 7.9 min, respectively. Amiloride was detected as a metabolite of EIPA but not of HMA. When EIPA was injected at a dose of 10 micrograms/g body weight, it was cleared rapidly from liver, but concentrations > 1 microM were sustained for at least 2 h in murine kidney and in a transplantable tumor.

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.

Studies with glycolysis-deficient cells suggest that production of lactic acid is not the only cause of tumor acidity

Solid tumors have been observed to develop an acidic extracellular environment, which is believed to occur as a result of lactic acid accumulation produced during aerobic and anaerobic glycolysis. Experiments using glycolysis-deficient ras-transfected Chinese hamster lung fibroblasts have been performed to test the hypothesis that lactic acid production within solid tumors is responsible for the development of tumor acidity. The variant cells have defects in glucose transport and in the glycolytic enzyme phosphoglucose isomerase with 1% activity compared to parental cells. Consequently, the in vitro rate of lactic acid production by variant cells was < 4% compared to parental cells. An in vitro correlation between lactic acid production and acidification of exposure medium was observed for parental and variant cells. Implantation of both cell lines into nude mice led to tumors with minimal difference in growth rate. As expected, variant cells died when exposed to hypoxic conditions in culture, and parental tumors were observed to have a larger fraction of cells resistant to radiation due to hypoxia (27%) than variant tumors (2%). Using pH microelectrodes, parental (n = 12) and variant (n = 12) tumors were observed to have extracellular pH (pHe) values of 6.65 +/- 0.07 and 6.78 +/- 0.04 (mean +/- SE, P = 0.13), respectively, whereas normal muscle had a pHe of 7.29 +/- 0.06 (P < 0.0001 for both cell lines). The lactic acid content of variant tumors was found to be similar to that in serum, whereas parental tumors had lactic acid content that was higher than in serum (P < 0.0001). We conclude that there was no correlation between lactic acid content and acidosis for these tumors derived from ras-transfected fibroblasts. These results provide evidence that the production of lactic acid via glycolysis is not the only mechanism responsible for the development of an acidic environment within solid tumors.

Goals of palliative cancer therapy

The major conclusions of the Workshop on Goals of Palliative Cancer Therapy are as follows: 1. The goals of any cancer therapy should be stated explicitly. 2. If the goal of treatment is palliation, this should be documented according to one of the established and validated methods for assessment of quality of life. Several validated methods are available, and although imperfect, have been shown to give reliable information. 3. The use of simple measures of quality of life (eg, symptom checklists, pain assessment cards) should become routine in oncology practice. The act of introducing such measures improves palliation. 4. Measures of cost-effectiveness should be used more widely in clinical decision making to ensure the appropriate deployment of resources. 5. There must be improved education of all health professionals with regard to the multiple methods for provision of palliative treatment to cancer patients and the assessment of palliation.

Effects of agents which inhibit the regulation of intracellular pH on murine solid tumours

Cell killing can be achieved in an acidic environment in tissue culture (medium pH less than 7.0) by agents (nigericin, carbonylcyanide-3-chlorophenylhydrazone (CCCP)) which transport protons from the extracellular space into the cytoplasm. Cell killing is enhanced when these agents are used in combination with compounds (amiloride, 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS)) which inhibit the membrane-based exchangers responsible for the regulation of intracellular pH (pHi). We describe experiments which assess the ability of these agents to kill tumour cells in spheroids and in vivo. Both nigericin and CCCP were observed to penetrate tissue based on their ability to kill tumour cells in spheroids. The mean extracellular pH (pHe) of the KHT fibrosarcoma and the EMT-6 sarcoma were observed to be 0.21 and 0.32 pH units more acidic than the mean pHe in muscle tissue. Intraperitoneal (i.p.) administration of the vasodilator hydralazine (10 mg kg-1) caused a reduction of the mean pHe of the KHT but not the EMT-6 tumour. Nigericin (2.5 mg kg-1, i.p.) plus amiloride (10 mg kg-1, i.p.) followed 30 min later by hydralazine (10 mg kg-1, i.p.) reduced the surviving fraction of cells in the KHT and EMT-6 tumours, but had minimal effects on growth delay. When KHT tumours were treated with 15 Gy X-rays followed immediately by nigericin plus amiloride and hydralazine a reduced surviving fraction as well as an increase in tumour growth delay was observed compared to radiation alone. The administration of nigericin (2.5 mg kg-1, i.p.) or the combination of nigericin (2.5 mg kg-1, i.p.) followed by hydralazine (10 mg kg-1, intravenous (i.v.)) resulted in reductions of tumour pHi of 0.27 and 0.29 pH units respectively as determined by 31P magnetic resonance spectroscopy (MRS). Our results show that the combination of nigericin and hydralazine (with or without amiloride) can kill cells in rodent solid tumours and that cell killing is associated with a reduction in the mean pHi of tumour cells.

A randomized comparison of cisplatin alone or in combination with methotrexate, vinblastine, and doxorubicin in patients with metastatic urothelial carcinoma: a cooperative group study

PURPOSE

A prospective randomized trial was performed to determine if the addition of methotrexate, vinblastine, and doxorubicin to cisplatin (M-VAC) imparted a response rate or a survival advantage over single-agent cisplatin in patients with advanced urothelial carcinoma.

PATIENTS AND METHODS

From October 1984 through May 1989, 269 patients with advanced urothelial carcinoma were entered onto this international intergroup trial and randomized to receive intravenous (IV) cisplatin (70 mg/m2) alone or with methotrexate (30 mg/m2 on days 1, 15, 22), vinblastine (3 mg/m2 on days 2, 15, 22) plus doxorubicin (30 mg/m2 on day 2). Cycles were repeated every 28 days until tumor progression or a maximum of six cycles. There were 246 fully assessable patients of whom 126 were randomized to cisplatin alone and 120 were randomized to the M-VAC regimen.

RESULTS

As expected, the M-VAC regimen was associated with a greater toxicity, especially leukopenia, mucositis, granulocytopenic fever, and drug-related mortality. Response rates were superior for the M-VAC regimen compared with single-agent cisplatin (39% v 12%; P less than .0001). Similarly, the progression-free survival (10.0 v 4.3 months) and overall survival (12.5 v 8.2 months) were significantly greater for the combined therapy arm.

CONCLUSION

Although a more toxic regimen, we found M-VAC to be superior to single-agent cisplatin with respect to response rate, duration of remission, and overall survival in patients with advanced urothelial carcinoma.

Chemotherapy for recurrent or metastatic carcinoma of the nasopharynx. A review of the Princess Margaret Hospital experience

There is little information about the ability of chemotherapy to achieve palliation for patients with recurrent or metastatic carcinoma of the nasopharynx. Therefore, the authors reviewed the records of all patients who had received chemotherapy for this disease at the Princess Margaret Hospital between 1970 and 1989. Seventy patients were identified who had measurable disease and had not received prior systemic therapy. Forty patients received single agents or nonaggressive drug combinations, most of them before 1980. There were three complete responses (CR) and seven partial responses (PR) among this group for a response rate of 25% (95% confidence limits, 13% to 41%). Thirty patients received either drug combinations that were active in aggressive lymphomas or cisplatin-based combinations. There were 7 CR and 14 PR among this group for a response rate of 70% (95% confidence limits, 51% to 85%). Two patients who were treated aggressively are still alive and in complete remission at 3 and 12 years. This type of retrospective review cannot exclude bias caused by patient selection. However, in the absence of randomized trials, the authors suggest the following: (1) carcinoma of the nasopharynx should be considered a malignant neoplasm that is distinct from squamous cell cancer in other sites of the head and neck; and (2) selected patients with recurrent or metastatic carcinoma of the nasopharynx should receive aggressive combination chemotherapy.