Abstract P6-17-26: Care 001: multi-center randomized open-label phase II trial of neoadjuvant trastuzumab emtansine (T-DM1) in combination with lapatinib and nab-paclitaxel compared with paclitaxel, trastuzumab and pertuzumab in HER2-neu over-expressed breast cancer patients (TEAL study)

Background: We conducted a multicenter, randomized open-label phase II neoadjuvant study of trastuzumab-emtansine (T-DM1), Lapatinib (L) and Nab Paclitaxel (Nab-P) compared to standard of care (SOC) Paclitaxel (Pac), Trastuzumab (T), and Pertuzumab (P) in patients with HER2 over-expressed breast cancer.

Methods: Patients in the experimental arm received a biologic window of targeted therapies alone for 6 weeks (T-DM1 and L) followed by T-DM1 3.0 mg/kg Q3W, L 750mg oral daily and Nab-P 80 mg/m2 weekly (QW) X 12 weeks. Patients in SOC arm received targeted therapies alone for 6 weeks (T and P) followed by Pac 80mg/m2QW, T 2mg/kg QW, and P 420mg Q3W X 12 weeks. The primary objective was to evaluate the proportion of patients with residual cancer burden (RCB) 0 or 1. Key secondary objectives included correlative assessments of PIK3CA mutations, PTEN expression, and HER2 subtypes which are being reported.

Results: Thirty of the 33 enrolled patients were evaluable. Patient demographics were well balanced. HER2 subtypes and altered PIK3CA (low PTEN or PIK3CA mutations) pathway were not statistically different between both arms. We have previously reported that all patients achieved RCB 0 & I in the T-DM1, L and Nab-P arm, compared to SOC (100% vs. 62.5%, p 0.0035). In the SOC arm, the 6 week change in tumor size on breast MRI during targeted biologic window treatment is significantly different between the responders and non-responders based on two-sided Wilcoxon rank-sum test (p =0.0065). Consistent with literature, among ER positive patients treated with SOC, PTEN low expressers were less likely to respond (0%, 0 of 2) than PTEN high expressers (67%, 2 of 3). In the experimental arm, all patients responded regardless of PTEN. There was only 1 PIK3CA mutation on the experimental arm where all responded.

Table 1:Breast MRI Tumor Size Standard of Care ArmResponseNMeanStandard Deviation95% CL MeanMinimumMaximumNo6-0.13330.4457-0.60110.3344-1.00.3Yes52.58001.88330.24154.91850.24.9Sixteen patients total were present in standard of care arm but 5 had incomplete imaging data.

Conclusions: TDM1 plus L and Nab-P therapy was well tolerated with noteworthy responses in all patients, including in PTEN low expressers. Change in tumor size at 6 weeks of biologic therapies was significant between responders and non-responders and can be evaluated as a surrogate for future studies.

Citation Format: Creamer SL, Patel TA, Ensor JE, Rodriguez AA, Niravath PA, Darcourt JG, Kaklamani VG, Meisel JL, Li X, Zhao J, Kuhn JG, Rosato RR, Qian W, Belcheva A, Boone T, Chang J. Care 001: multi-center randomized open-label phase II trial of neoadjuvant trastuzumab emtansine (T-DM1) in combination with lapatinib and nab-paclitaxel compared with paclitaxel, trastuzumab and pertuzumab in HER2-neu over-expressed breast cancer patients (TEAL study) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-17-26.

Modulation of the activated protein C pathway in severe haemophilia A patients: The effects of thrombomodulin and a factor V-stabilizing fab

INTRODUCTION

The thrombomodulin (TM)/activated protein C (APC) system is a key regulator of haemostasis, limiting amplification and propagation of the formed blood clot to the injury site. Dampening APC's inhibition of factor V (FV) and factor VIII (FVIII) may be a future strategy in developing next-generation therapeutic targets for haemophilia treatment.

AIMS

To determine ex vivo the respective concentration-dependent effects of TM and a FV-stabilizing Fab on the APC regulatory pathway in severe FVIII-deficient blood and plasma.

METHODS

Ten severe haemophilia A subjects and one healthy control were enrolled. Blood was spiked with TM (0, 1, 2.5, 5, 10, 20.0 nmol/L) and FV-stabilizing Fab (0, 3, 15, 65, 300 nmol/L). The respective effects were compared to FVIII concentrations of 3- and 10% using rotational thromboelastometry clotting time (CT) and thrombin generation analysis (TGA).

RESULTS

With 1 and 2.5 nmol/L TM, 5% FVIII resulted in CT similar to the absence of TM, suggesting it completely reversed the effect of APC. Increasing TM concentrations also reduced peak thrombin generation and ETP. The addition of 300 nmol/L FV-stabilizing Fab returned CT to nearly baseline, but for most subjects was less than the effects of 3- or 10% FVIII. The FV-stabilizing Fab produced similar or greater thrombin generation compared to samples with 3- or 10% FVIII.

CONCLUSIONS

The FV-stabilizing Fab resulted in enhanced CT and TGA parameters consistent with FVIII levels of 3- and 10%. Additional studies need to further characterize how modulating the APC pathway may prove beneficial in developing new haemophilia drug targets.

Abstract P6-13-07: The taccalonolides are novel microtubule stabilizers that covalently bind tubulin and have in vivo efficacy in drug resistant tumors

Some of the most effective drugs used in the treatment of breast cancer are microtubule stabilizers. However, there are limitations to their clinical efficacy, including inherent and acquired drug resistance. All microtubule stabilizers that are currently approved for clinical use bind within the taxane pocket on β-tubulin in a reversible manner. The taccalonolides are a novel class of microtubule stabilizers that have a similar profile of microtubule stabilization as the taxanes, but circumvent drug resistance mediated by expression of drug efflux pumps, mutations in the taxane binding site, or overexpression of the βIII isotype of tubulin. We have shown that one important difference between the taccalonolides and clinically approved microtubule stabilizers is that the taccalonolides form a covalent bond to β-tubulin. This distinct interaction allows for irreversible binding, which explains their ability to avoid drug efflux mechanisms and likely belies their exquisite potency in in vivo antitumor models which allows for delivery in aqueous solvents. Serum stability and binding studies, microsomal clearance and pharmacokinetic analysis were performed with both taccalonolides AF and AJ to more fully understand the properties of this class of compounds. We found that both taccalonolides had low microsomal intrinsic clearance rates with no evidence of serum binding and had half-lives similar to paclitaxel in vivo. Like other microtubule targeted agents, taccalonolide AF has a narrow therapeutic window with antitumor effects accompanied by body weight loss. Interestingly, direct injection of taccalonolide AF into a xenograft tumor was highly effective with no associated toxicities at low doses, indicating that targeted delivery to the tumor would greatly increase the efficacy and decrease toxicities. To this end, efforts to promote the targeted delivery of taccalonolide AF to the tumor are being evaluated.

Citation Format: Risinger AL, Li J, Benavides R, Kuhn JG, Mooberry SL. The taccalonolides are novel microtubule stabilizers that covalently bind tubulin and have in vivo efficacy in drug resistant tumors. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-13-07.

Coated platelets and severe haemophilia A bleeding phenotype: Is there a connection?

INTRODUCTION

Coated platelets are a subpopulation of platelets that possess highly prothrombotic properties. Previous observational data suggest that bleeding phenotype in severe haemophilia A is associated with coated platelet levels. Haemophilia A patients with higher coated platelet levels may have a mild bleeding phenotype; those with lower levels may have a more severe bleeding phenotype.

AIM

The aim of the study was to test the hypothesis that coated platelet levels are correlated with clinical bleeding phenotype.

METHODS

This cross-sectional, observational study enrolled 20 severe haemophilia A patients, including 15 with severe and five with a mild bleeding phenotype, and a control group of 12 healthy volunteers. The haemophilia bleeding phenotype was determined by the patient's medical history and haemophilia treatment centre records. Blood was obtained from each patient by venipuncture and platelets were analysed by flow cytometry.

RESULTS

Patients categorized as having a severe bleeding phenotype experienced a median eight bleeds per year compared to one bleed annually in the mild bleeding phenotype group. Both groups had similar total platelet counts and fibrinogen levels. There was no difference in coated platelet percentage between severe and mild bleeding phenotype (17 and 16% respectively), however, both groups had significantly lower % coated platelets compared to controls (44%, P < 0.0001).

CONCLUSION

Coated platelet levels were not associated with bleeding phenotype in this study; however, these data may suggest coated platelet levels are lower in haemophilia patients relative to healthy volunteers.

Monitoring rFVIII prophylaxis dosing using global haemostasis assays

Secondary factor VIII (FVIII) prophylaxis converts severe haemophiliacs (FVIII:C < 1 IU dL(-1)) to a moderate phenotype (FVIII:C ≥ 1 IU dL(-1)), however, plasma FVIII:C is a poor predictor of bleeding risk. This study used thromboelastography (TEG) and thrombin generation assay (TGA) to quantify coagulation across a 48 h rFVIII prophylaxis period. 10 severe haemophiliacs with varying clinical bleeding phenotypes received their standard rFVIII prophylaxis dose and blood samples were obtained over 48 h. Measured parameters included FVIII:C, TEG and TGA at each time point. FVIII:C pharmacokinetics (PK) and correlation between global assay parameters was performed. The FVIII:C PK parameters were consistent with previous literature. There was significant correlation between FVIII:C and TEG R-time and aPTT (both P < 0.001). Significant correlations existed between FVIII:C and TGA peak, ETP and velocity parameters (all P < 0.001). At 24 h the TEG parameters were sub-therapeutic despite median FVIII:C of 13.0 IU dL(-1). TGA was sensitive to FVIII:C below 1 IU dL(-1). Those with the severest bleeding phenotype had the lowest TGA parameters. There was significant correlation between FVIII:C and TEG and TGA. TEG lost sensitivity at 48 h, but not TGA. Prospective studies are needed to determine whether these data can be used to design individualized rFVIII prophylaxis regimens.

Monitoring rFVIIa 90 μg kg⁻¹ dosing in haemophiliacs: comparing laboratory response using various whole blood assays over 6 h

Recombinant FVIIa is a haemostatic agent administered to patients with severe FVIII or FIX deficiency with inhibitors. Although rFVIIa is effective at stopping bleeding, a reliable assay to monitor its effect is lacking. To characterize the pharmacokinetics and global coagulation effects of rFVIIa for 6 h following a IV dose of 90 μg kg⁻¹. Ten non-bleeding subjects with severe FVIII or FIX deficiency were infused with a single-dose of rFVIIa 90 μg k⁻¹ body weight and blood was collected before and at 0.5, 1, 2, 4 and 6 h postdose. Global haemostasis was characterized throughout the study utilizing whole blood analyses (Hemodyne HAS, TEG, ROTEM). The clearance and half-life of factor FVII:C was estimated as 39.0 ± 8.8 mL h⁻¹ kg⁻¹ and 2.1 ± 0.2 h respectively. There was good inter-assay agreement with respect to clot initiation parameters (R, CT and FOT) and these parameters all fell to a mean of approximately 9 min following rFVIIa dosing. The platelet contractile force (PCF) and clot elastic modulus (CEM) were positively correlated to FVII:C (P < 0.0001), and these parameters were dynamic throughout the 6-h period. The MA and MCF did not correlate to FVII:C nor did they significantly change during the study. Prothrombin F1 + 2 significantly increased following rFVIIa dosing (P < 0.001), but remained steady throughout the study. There was no change in D-dimer concentrations over time. The FOT, R and CT characterized clot initiation following rFVIIa dosing. The PCF and CEM were correlated to FVII:C and characterized the dynamics of platelet function and clot strength over the rFVIIa dosing interval. The clinical significance of these findings needs additional study.

Interaction between sorafenib and erlotinib

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Background: The combination of sorafenib plus erlotinib was evaluated in patients with recurrent glioblastoma (GBM). In addition to defining the maximum tolerated dose (MTD), pharmacokinetics (PKs) for single agent and combination were determined. Methods: Adults with recurrent GBM with the usual phase I inclusion/exclusion criteria were eligible. No enzyme inducing anti-epileptic agents were allowed. Starting doses for erlotinib and sorafenib were 100mg PO QD and 200 mg PO BID, respectively, for 28 days (a cycle). For cycle 1 PKs, erlotinib was started on day 1 followed on day 2 by sorafenib. Eight plasma samples were collected over 24hrs on days 1, 15 and 28. Sorafenib and its metabolite (N-oxide) were analyzed by HPLC and erlotinib and OSI-420 by LC/MS. PK parameters were characterized by standard non-compartmental methods. Results: The MTD was sorafenib 200 mg PO BID and erlotinib 100 mg PO QD. The PKs for erlotinib (OSI) are displayed below. Conclusions: The PKs for sorafenib are in agreement with previous reports and not affected by the co-administration of erlotinib. However, there is an apparent affect of sorafenib on the PKs of erlotinib. The expected accumulation of erlotinib's Cmax and AUC at steady-state was not observed. This interaction results in at least a 2+ fold decrease in exposure to erlotinib and its active metabolite. The interaction does not appear to be the classical enzyme induction due to the rapidity of the onset/offset. This same phenomenon has been reported with the co-administration of sorafenib with gefitinib (Clin Cancer Res 13:2684,2007). Increasing the maximal velocity (Vmax) of CYP3A4, not the quantity of enzyme, is suggested as a testable hypothesis (J Pharmacol Exp Ther 290:1.1998). The clinical relevance of this interaction with regard to toxicity and efficacy warrants further evaluation.

[Table: see text]

No significant financial relationships to disclose.

Effect of recombinant factor VIIa variant (NN1731) on platelet function, clot structure and force onset time in whole blood from healthy volunteers and haemophilia patients

NN1731 is a novel variant of recombinant factor VIIa (rFVIIa) that binds to activated platelets, but has greater enzymatic activity than rFVIIa in generating FXa and thrombin. The effect of NN1731 on clot structure and platelet function was characterized ex vivo in whole blood from healthy volunteers and haemophilic patients. Blood samples from six healthy volunteers, nine haemophilia A patients with and without inhibitors and one acquired haemophilia A patient, were spiked with increasing concentrations (0.32, 0.64 and 1.28 microg mL(-1)) of rFVIIa and NN1731. Platelet contractile force (PCF) or platelet function, clot elastic modulus (CEM) or clot structure, and force onset time (FOT) or the thrombin generation time (TGT) were determined using the Hemodyne Hemostasis Analysis System (HAS). Baseline PCF, CEM and FOT values in patients were abnormal compared to healthy volunteers' baseline values. Overall, haemophilia blood samples with or without inhibitors spiked with NN1731 had significantly greater PCF, CEM and shorter FOT values relative to samples spiked with corresponding doses of rFVIIa. The variability in response to treatment between patients was greater with rFVIIa compared to NN1731. At 1.28 microg mL(-1) (90 microg kg(-1)), NN1731 normalized PCF, CEM and FOT in nine of 10 patients, while rFVIIa normalized these parameters in four of 10 patients. Increasing in vitro concentrations of NN1731 normalized platelet function, clot structure and thrombin generation consistently in haemophilia blood with or without inhibitors. NN1731 may be a promising haemostatic agent for patients with bleeding disorders. These results should be confirmed in an in vivo study.

Phase I/II dose-escalation trial of amonafide for treatment of advanced solid tumors: Genotyping to optimize dose based on polymorphic metabolism

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Background: Amonafide (AMF), a synthetic imide derivative of naphthalic acid, is a topoisomerase II inhibitor and is subject to polymorphic metabolism based on acetylation genotype. AMF is extensively metabolized by N-acetyltransferase 2 (NAT2) to N- acetylamonafide (AAMF) which has activity nearly equipotent to AMF. In our phase I evaluation, we observed a correlation between NAT2 genotype, AMF/AAMF pharmacokinetics and toxicity (J Clin Oncol 22 [14S]: 2023, 2004). Patients (pts) with slow (S) acetylator genotype tolerated higher doses than those with rapid/intermediate (R/I) acetylator genotype. The present Phase II portion was designed to prospectively determine the dose of AMF based on NAT2 genotype and focused on selected tumor types. Methods: NAT2 genotyping of genomic DNA from blood samples was done prospectively to determine acetylator status of each pt. AMF was administered IV weekly x 3 q4wk, escalation range 320 to 400 mg/m2 for R/I and 400 to 500 mg/m2 for S acetylators. Primary endpoints: safety, MTD, tumor measurements or sustained decreases in tumor markers. Results: Total 47 pts (21 M/26 F), median 66 yr, PS 0–2, acetylator status R/I (26), S (21) with ovarian (11) or prostate (9), breast (8), colon (4) cancers (CA) and other common tumors refractory to therapy were treated; 30 of 47 pts were dosed based on prospective genotyping. Of these 30 pts, 17 were R/I acetylators: no toxicity at 320 mg/m2 AMF in 7/11 pts and manageable myelosuppresion in 4/11 pts observed days 15–21 of cycle but not dose-limiting (DLT); DLT in 3/6 pts at 400 mg/m2. In the 13 S acetylators: at 400 mg/m2 no DLT in 8 pts; DLT in 2/5 pts treated at 500 mg/m2. Other side effects included nausea/vomiting, fatigue and anemia. Of all 47 pts, biologic activity was seen in 6 pts: 3/9 prostate CA (decreased PSA), 2/11 ovarian CA (decreased CA125) and 1/1 GIST (decreased lymph nodes). Conclusions: MTD determined to be 320 mg/m2 in R/I and 400mg/m2 weekly x 3q 4 weeks in S acetylators, respectively, supporting hypothesis that AMF dosing based on prospective NAT2 genotyping may allow for dose optimization based on drug metabolism and result in better tolerance. Phase II assessments at the MTD dose levels are currently ongoing for prostate cancer.

No significant financial relationships to disclose.

Percutaneous liver biopsy in adult haemophiliacs with hepatitis C virus: safety of outpatient procedure and impact of human immunodeficiency virus coinfection on the spectrum of liver disease

Both HCV and HIV are common in haemophiliacs previously treated with non-viral-inactivated clotting factor concentrates. Because of increased bleeding risks, little data are available on the safety of percutaneous outpatient liver biopsy (LBx) and impact of HIV coinfection in this population. This study aims at reporting our experience with percutaneous LBx in a cohort of haemophiliacs infected with HCV and describe the spectrum of disease and impact of HIV coinfection. A retrospective review of consecutive patients with haemophilia and HCV who underwent percutaneous LBx was performed. All patients were positive for HCV RNA by commercial assay and received factor concentrate prior to biopsy. A total of 29 male patients (mean age 36, 24 haemophilia A, five haemophilia B, and 44% coinfected with HIV) underwent successful outpatient percutaneous LBx without bleeding complication. Histologic activity index was 6.44 with advanced fibrosis (bridging fibrosis/cirrhosis) in 31%. When patients were stratified by HIV positive (n = 13) vs. HIV negative (n = 16), coinfected patients had higher fibrosis scores and higher proportion advanced fibrosis (54% vs. 12%; P = 0.0167) with no differences in age, demographic or other laboratory parameters. Multivariate logistic regression found that HIV positivity was independently associated with advanced fibrosis (OR = 3.7; 95% CI: 1.17-11.8; P = 0.026). Outpatient percutaneous LBx can be safely performed in patients with haemophilia. Despite similar age, HIV coinfection was an independent predictor of advanced fibrosis. These data support the hypothesis that HIV accelerates fibrosis progression in those coinfected with HCV and highlights the importance of liver histology in this population.

Genotypic and allelic frequencies of SULT1A1 polymorphisms in women receiving adjuvant tamoxifen therapy

Human sulfotransferase 1A1 (SULT1A1) is involved in the metabolism of a number of substances including 4-hydroxytamoxifen. It has been shown that patients who are homozygous for the variant SULT1A1 *2/*2 have lower catalytic activity. Previous data has suggested that patients with this particular genotype may be at a greater risk of developing breast cancer or not responding to tamoxifen therapy. To date, there is no data within the Hispanic population on the genotypic and allelic frequencies of the SULT1A1 gene. Two hundred and ninety-six patients were genotyped by either restriction fragment length polymorphism (RFLP) or Pyrosequencing for the SULT1A1 exon 7 polymorphism. The genotypic frequency was 0.47 (*1/*1), 0.40 (*1/*2) and 0.13 (*2/*2) in Caucasians and 0.37 (*1/*1), 0.45 (*1/*2) and 0.18 (*2/*2) in Hispanics. Although Hispanics have a higher genotypic frequency of variant genotypes this difference was not statistically significant (p=0.26). SULT1A1 genotype did not correlate with any prognostic or predictive markers associated with breast cancer. Future evaluations will assess the functional significance of this polymorphism on survival.

Relationship between CYP2D6 and estrogen receptor alpha polymorphisms on tamoxifen metabolism in adjuvant breast cancer treatment

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Background: Tamoxifen (TAM) and its metabolites display large inter-individual variation with profound implications for breast cancer outcomes. Tamoxifen is hydroxylated to the potent metabolites, 4-hydroxytamoxifen (4-OH TAM) and endoxifen, by various cytochrome P450 (CYP450) genes including CYP2C9 and CYP2D6. The SULT1A1 gene is involved in the conjugation of 4-OH TAM. Tamoxifen’s binding site is the estrogen receptor (ER). Methods: Clinical data and blood samples were collected for 301 patients (299 female, 2 male) receiving at least 8 weeks of adjuvant tamoxifen therapy. HPLC analysis assessed TAM, N-desmethyltamoxifen (N-DMT), and 4-OH TAM levels. Genotyping of the CYP2C9 (*2,*3), CYP2D6 (*2, *3, *4, *6, *7, *8, *14) and SULT1A1 (*2) genes was determined by Pyrosequencing. CYP2D6 genotypes were subdivided into poor (PM), intermediate (IM), and extensive (EM) metabolizers. Genotyping of ER alpha polymorphisms, Pvu II and Xba I, utilized a Taqman Allelic Discrimination Assay. The Wilcoxon Rank Sum test was used to test associations of genotype and quantitative metabolite levels, within genotype associations, and ethnicity. Results: The majority of our patients were Caucasian (68%) and Hispanic (26%). The mean (± SD) levels for TAM, 4-OH TAM and N-DMT were 111.7 (± 58.4 ng/ml), 2.2 (± 1.5 ng/ml) and 204.7 (± 104.1 ng/ml), respectively. The CYP2D6 genotype was statistically associated with 4-OH TAM levels (p=0.0002). Differences were detected between EM and PM (p=0.0001) and IM and PM (p=0.0029). ER alpha Pvu II genotypes were shown to influence TAM levels (p=0.02). Significant differences were identified between the PP and Pp genotypes (p=0.0064) and between PP and pp genotypes (p=0.03). Hispanics had significantly higher levels of TAM (p=0.02) and 4-OH TAM (p=0.007) than Caucasians. Conclusions: Genotype and ethnicity are significantly associated with levels of TAM and 4-OH TAM and may explain clinical variation in response to TAM treatment.

No significant financial relationships to disclose.

The Spectrum of Myositis Ossiticans in Haemophilia

Myositis ossificans (MO) refers to non-neoplastic heterotopic soft tissue ossification that can have several aetiologies. Broadly it can be classified into three categories based on aetiology [1]. MO traumatica, the most common form occurs secondary to acute or chronic trauma. MO can also be associated with neurological disorders and in rare cases is congenital. The latter (progressive MO) is a genetic disorder in which congenital osseous abnormalities are associated with progressive soft tissue calcification. Despite an increased tendency to soft tissue bleeds, MO has been rarely reported in haemophilia. We treated three adolescents with haemophilia and MO of varying degrees of severity and outcome.

Onset of force development as a marker of thrombin generation in whole blood: the thrombin generation time (TGT)

Prothrombin activation requires the direct interplay of activated platelets and plasma clotting factors. Once formed, thrombin causes profound, irreversible activation of platelets and reinforces the platelet plug via fibrin formation. Delayed or deficient thrombin production increases bleeding risk. Commonly employed coagulation assays, the prothrombin and partial thromboplastin times, use clot formation as a surrogate marker of thrombin generation. These assays routinely utilize platelet-poor plasma and completely miss the effects of platelets. Other markers of thrombin generation, prothrombin fragment 1 + 2 (F1 + 2) and thrombin-antithrombin complex, are typically measured after the fact. We report a simple assay, which employs the onset of platelet contractile force (PCF) as a surrogate marker of thrombin generation. PCF generation occurs concomitant with the burst of F1 + 2 release. The time between assay start and PCF onset is termed the thrombin generation time (TGT). TGT is prolonged in clotting factor deficiencies and in the presence of direct and indirect thrombin inhibitors. TGT shortens to normal with clotting factor replacement and shortens with administration of recombinant factor VIIa. TGT is short in thrombophilic states such as coronary artery disease, diabetes and thromboangiitis obliterans and prolongs toward normal with oral and intravenous anticoagulants.

Phase I dose-finding and pharmacokinetic trial of irinotecan (CPT-11) administered every two weeks

OBJECTIVES

This trial was performed to determine the maximum tolerated dose (MTD), dose-limiting toxicity (DLT), and pharmacokinetic profile of irinotecan (CPT-11) when administered on a once-every-2-week schedule.

PATIENTS AND METHODS

CPT-11 was administered to successive cohorts of patients at progressively increasing starting doses ranging from 125 to 350 mg/m2. The MTD and DLTs were determined both for CPT-11 alone and for CPT-11 followed by filgrastim (G-CSF). Plasma samples were obtained during the first 24 hours after initial dosing to determine the total concentrations (lactone + carboxylate forms) of CPT-11; of the active metabolite SN-38; and of SN-38 glucuronide (SN-38G).

RESULTS

Neutropenic fever was the DLT for CPT-11 at the 300 mg/m2 dose level. When G-CSF was added, dose escalation beyond 350 mg/m2 could not be achieved due to grade 2-3 toxicities that prevented on-time retreatment with CPT-11. Severe, late diarrhea was uncommon on this schedule. Peak plasma concentrations of SN-38 and SN-38G were approximately 2.5% and 4.2% of the corresponding peak plasma concentration for CPT-II, respectively The harmonic mean terminal half-lives for CPT-11, SN-38, and SN-38G were 7.1 hours, 13.4 hours, and 12.7 hours, respectively. No predictive correlation was observed between CPT-11 or SN-38 peak concentration or AUC and first-cycle diarrhea, neutropenia, nausea, or vomiting. Across the range of doses studied, mean CPT-11 clearance was 14.0 +/- 4.0 l/h/m2 and volume of distribution was 146 +/- 45.9 l/m2.

CONCLUSIONS

When administered every two weeks, the recommended phase II starting dose of CPT-11 is 250 mg/m2 when given alone and 300 mg/m2 when supported by G-CSF. This every-two-week regimen offers a tolerable and active alternative to weekly or every-three-week single-agent CPT-11 therapy.

Effects of hydroxyurea on extrachromosomal DNA in patients with advanced ovarian carcinomas

PURPOSE

In vitro low concentrations of hydroxyurea eliminate double-minute chromosomes (dmins) containing amplified drug-resistance genes and oncogenes from cancer cells. This clinical trial investigated whether a noncytotoxic dose of oral hydroxyurea could reduce the number of dmins in cancer cells in patients with advanced ovarian carcinomas.

EXPERIMENTAL DESIGN

The high frequency of ascites associated with ovarian cancer facilitated the monitoring of cytogenetic variations with minimal discomfort in patients who required frequent abdominal paracentesis. Sixteen patients with advanced ovarian carcinomas resistant to conventional cisplatin-based and/or paclitaxel chemotherapy and with ascites requiring frequent abdominal paracentesis were entered in this study. A course of treatment consisted of a single oral dose of 80 mg/kg hydroxyurea every 3 days for 6 weeks. Blood and i.p. levels of hydroxyurea were determined. We monitored the variations of dmins in tumor cells taken from serial abdominal paracenteses.

RESULTS

The median number of courses administered to the patients was 1 (range, 1--9). In ascites, hydroxyurea concentrations were 610.3 +/- 76.3, 219.8 +/- 85.6, and 86.1 micromol/liter at 4, 24, and 30 h after oral administration, respectively. Eleven (78.6%) of 14 patient specimens contained dmins before therapy. The number of spreads with tumor cells containing dmins were reduced by more than 50% in 5 (45%) of 11 and 3 (60%) of 5 patients at the completion of the first and second course of chemotherapy, respectively. Using tumor cells taken directly from the patients and grown in soft agar, we documented that concentrations of hydroxyurea in ascites were too low to have any cytotoxic effects. No grade 3--4 hydroxyurea-related toxicities nor any objective responses were observed. However, despite the utilization of a low noncytotoxic dose of hydroxyurea, two patients had prolonged stabilization of their disease for 6 and 10 months, respectively, with concomitant decreases in the number of dmins that remained until progression.

CONCLUSIONS

This study showed that, in some circumstances, a noncytotoxic dose of hydroxyurea given to patients with ovarian cancer can decrease the number of metaphase spreads containing dmins in cancer cells.

Pharmacokinetic and phase I studies of brequinar (DUP 785; NSC 368390) in combination with cisplatin in patients with advanced malignancies

Brequinar (DUP 785; NSC 368390) is a quinoline carboxylic acid derivative that inhibits pyrimidine synthesis at the level of dihydro-orotate dehydrogenase and revealed synergy with cisplatin in preclinical models. In this study investigating the pharmacokinetic and toxicity of brequinar in combination with cisplatin, patients were initially treated with weekly brequinar, in combination with an every-three-week administration of cisplatin. Due to toxicity, the schedule was modified to a 28-day cycle with brequinar given on days 1, 8, 15, and cisplatin on day 1. A total of 24 patients (16 male, 8 female; median age 57; median performance status 1) received 69 courses of therapy. Six dose levels were explored, with cisplatin/ brequinar doses, respectively, of 50/500, 50/650, 50/860, 60/860, 75/650, and 75/860 mg/m2. The serum concentration versus time curves for brequinar were biphasic. A comparison of the pharmacokinetic results after the first and third doses of brequinar indicate that the presence of 50, 60, and 75 mg/m2cisplatin did not change the protein binding and the pharmacokinetics of brequinar in any of the three brequinar-dose groups. Total cisplatin plasma pharmacokinetic followed a triphasic-shape curve and unbound cisplatin decayed at a very rapid rate. Since pharmacokinetic parameters for total cisplatin in this study were similar to those reported in the literature, the presence of brequinar is unlikely to alter the pharmacokinetics of cisplatin. Main dose-limiting toxicities included myelosuppression (including neutropenia and thrombocytopenia) and mucositis. Cisplatin/brequinar doses of 50/500, 50/650, 50/860, 60/860, 75/650, and 75/860 mg/m2, were associated with dose limiting toxicity in 0/3, 1/3, 1/3, 1/3, 2/4, 2/5, and 4/6 patients, respectively. This study shows that co-administration of brequinar and cisplatin does not affect the pharmacokinetic properties of either drug and that the MTDs of cisplatin/brequinar combinations are 60/860 mg/m2 or 75/650 mg/m2. From this study, we conclude that full dose of 75 mg/m2 cisplatin (day 1) can be administered with 650 mg/m2 brequinar (days 1, 8 and 15) without significant modifications of individual drug pharmacokinetic parameters.

A Phase II study of paclitaxel in patients with recurrent malignant glioma using different doses depending upon the concomitant use of anticonvulsants: a North American Brain Tumor Consortium report

BACKGROUND

The primary objective of the current study was to determine the response rate of paclitaxel in patients with recurrent malignant glioma by using different doses dependent on the concomitant use of anticonvulsants. Secondary objectives were to determine the time period to treatment failure, to evaluate toxicities, and to obtain pharmacokinetic data.

METHODS

Adult patients who had recurrent malignant glioma were treated with paclitaxel. Patients were treated at different doses depending on the concomitant use of anticonvulsants known to induce the p450 hepatic enzyme system. Patients on such agents were treated at a dose of 330 mg/m2, whereas those not on these anticonvulsants were treated at a dose of 210 mg/m2. Tumor response was assessed at 6-week intervals. Treatment was continued until documented tumor progression or unacceptable toxicity occurred, or a total of 12 paclitaxel infusions was completed.

RESULTS

From January 1997 to June 1997, 23 patients were treated with paclitaxel. Four patients were ineligible for the current study. Of the 19 eligible patients, there were no responses seen. Four (21%) had stabilization of disease. Median time to treatment failure was 1 month (95% confidence interval [CI], 1-2 mos) and median survival was 7 months (95% CI, 6-10 mos). Three patients were removed from the current study because they had toxicity. Pharmacokinetic studies demonstrated that drug levels and clearance values were consistent with previously reported findings.

CONCLUSION

Even though higher doses were administered to patients who had recurrent malignant glioma and who were on concomitant anticonvulsants, there were no objective responses to paclitaxel. Time to tumor progression was 1 month. Further testing of paclitaxel at this dose schedule does not appear to be warranted in this patient population.

Fluorouracil and the new oral fluorinated pyrimidines

OBJECTIVE

To briefly review the biotransformation and bioavailability of fluorouracil (5-FU); discuss the effects of dihydropyrimidine dehydrogenase (DpD) on the efficacy and toxicity profiles of 5-FU; and review a new class of drugs known collectively as the oral fluorinated pyrimidines, which inhibit or circumvent DpD activity and, when administered with 5-FU, alter its pharmacokinetic and pharmacodynamic properties.

DATA SOURCES

A MEDLINE literature search was conducted (1966-March 1999) using the search terms fluoropyrimidines, fluorouracil, 5-FU, fluorinated pyrimidines, capecitabine, eniluracil, uracil-tegafur, uracil-ftorafur, UFT, S1, BMS-247616, and BOF-A2. Reference lists, bibliographies of pertinent articles, and abstracts from the American Society of Clinical Oncology and the San Antonio Breast Cancer Symposium annual meetings were also identified and reviewed. Both preclinical and clinical literature were reviewed and analyzed.

DATA SYNTHESIS

The new oral fluorinated pyrimidines appear to produce antitumor activity equivalent or superior to that of intravenously administered 5-FU by achieving higher intratumoral 5-FU concentrations or sustained 5-FU exposure. These agents are generally associated with manageable and non-life-threatening toxicities. The oral route of administration facilitates ease of administration and may reduce total healthcare costs associated with 5-FU-sensitive tumors. More studies are needed to assess the therapeutic and economic benefits of the oral fluorinated pyrimidines.

CONCLUSIONS

The bioavailability, efficacy, and toxicity of 5-FU depend on its catabolic rate-limiting enzyme, The new oral fluorinated pyrimidines inhibit or circumvent DpD activity and, when combined with 5-FU, increase 5-FU's bioavailability and cytotoxic effects and decrease its toxicities. Results of Phase I and II studies in patients with a variety of malignancies suggest positive outcomes, including greater efficacy, less drug-related toxicity, lower costs related to drug administration, and greater patient convenience.

A Phase II study of paclitaxel in patients with recurrent malignant glioma using different doses depending upon the concomitant use of anticonvulsants: a North American Brain Tumor Consortium report

BACKGROUND

The primary objective of the current study was to determine the response rate of paclitaxel in patients with recurrent malignant glioma by using different doses dependent on the concomitant use of anticonvulsants. Secondary objectives were to determine the time period to treatment failure, to evaluate toxicities, and to obtain pharmacokinetic data.

METHODS

Adult patients who had recurrent malignant glioma were treated with paclitaxel. Patients were treated at different doses depending on the concomitant use of anticonvulsants known to induce the p450 hepatic enzyme system. Patients on such agents were treated at a dose of 330 mg/m2, whereas those not on these anticonvulsants were treated at a dose of 210 mg/m2. Tumor response was assessed at 6-week intervals. Treatment was continued until documented tumor progression or unacceptable toxicity occurred, or a total of 12 paclitaxel infusions was completed.

RESULTS

From January 1997 to June 1997, 23 patients were treated with paclitaxel. Four patients were ineligible for the current study. Of the 19 eligible patients, there were no responses seen. Four (21%) had stabilization of disease. Median time to treatment failure was 1 month (95% confidence interval [CI], 1-2 mos) and median survival was 7 months (95% CI, 6-10 mos). Three patients were removed from the current study because they had toxicity. Pharmacokinetic studies demonstrated that drug levels and clearance values were consistent with previously reported findings.

CONCLUSION

Even though higher doses were administered to patients who had recurrent malignant glioma and who were on concomitant anticonvulsants, there were no objective responses to paclitaxel. Time to tumor progression was 1 month. Further testing of paclitaxel at this dose schedule does not appear to be warranted in this patient population.

Phase I and pharmacokinetic study of irofulven, a novel mushroom-derived cytotoxin, administered for five consecutive days every four weeks in patients with advanced solid malignancies

PURPOSE

To evaluate the toxicity and pharmacologic behavior of the novel mushroom-derived cytotoxin irofulven administered as a 5-minute intravenous (IV) infusion daily for 5 days every 4 weeks to patients with advanced solid malignancies.

PATIENTS AND METHODS

In this phase I trial, 46 patients were treated with irofulven doses ranging from 1.0 to 17.69 mg/m(2) as a 5-minute IV infusion (two patients received a 1-hour infusion) daily for 5 days every 4 weeks. The modified continual reassessment method was used for dose escalation. Pharmacokinetic studies were performed on days 1 and 5 to characterize the plasma disposition of irofulven.

RESULTS

Forty-six patients were treated with 92 courses of irofulven. The dose-limiting toxicities on this schedule were myelosuppression and renal dysfunction. At the 14.15-mg/m(2) dose level, renal dysfunction resembling renal tubular acidosis occurred in four of 10 patients and was ameliorated by prophylactic IV hydration. The 17.69-mg/m(2) dose level was not tolerated because of grade 4 neutropenia and renal toxicity, whereas the 14.15-mg/m(2) dose level was not tolerable with repetitive dosing because of persistent thrombocytopenia. Other common toxicities included mild to moderate nausea, vomiting, facial erythema, and fatigue. One partial response occurred in a patient with advanced, refractory metastatic pancreatic cancer lasting 7 months. Pharmacokinetic studies of irofulven revealed dose-proportional increases in both maximum plasma concentrations and area under the concentration-time curve, while the agent exhibited a rapid elimination half-life of 2 to 10 minutes.

CONCLUSION

Given the results of this study, the recommended dose of irofulven is 10.64 mg/m(2) as a 5-minute IV infusion daily for 5 days every 4 weeks. The preliminary antitumor activity documented in a patient with advanced pancreatic cancer and the striking preclinical antitumor effects of irofulven observed on intermittent dosing schedules support further disease-directed evaluations of this agent on the schedule evaluated in this study.

9-cis-Retinoic acid suppresses mammary tumorigenesis in C3(1)-simian virus 40 T antigen-transgenic mice

Retinoids have been investigated as potential agents for the prevention and treatment of human cancers. These compounds play an important role in regulating cell growth, differentiation, and apoptosis. 9-cis-Retinoic acid (9cRA) is a naturally occurring ligand with a high affinity for both the retinoic acid receptors and the retinoid X receptors. We hypothesized that treatment with 9cRA would prevent mammary tumorigenesis in transgenic mice that spontaneously develop mammary tumors. To test this hypothesis, C3(1)-SV40 T antigen (Tag) mice, which develop mammary tumors by the age of 6 months, were treated daily p.o. with vehicle or two different dose levels of 9cRA (10 or 50 mg/kg) from 5 weeks to 6 months of age. Tumor size and number were measured twice each week, and histological samples of normal and malignant tissue were obtained from each mouse at time of sacrifice. Our results demonstrate that 9cRA suppresses mammary tumorigenesis in C3(1)-SV40 Tag-transgenic mice. Time to tumor development was significantly delayed in treated mice; median time to tumor formation for vehicle-treated mice was 140 days versus 167 days for mice treated with 50 mg/kg 9cRA (P = 0.05). In addition, the number of tumors per mouse was reduced by >50% in mice treated with 9cRA (3.43 for vehicle, 2.33 for 10 mg/kg 9cRA, and 1.13 for 50 mg/kg 9cRA, P < or = 0.002). Histological analysis of the mammary glands from vehicle and treated mice demonstrated that 9cRA treatment also did not affect normal mammary gland development. Immunohistochemical staining of normal and malignant breast tissue and Western blot analysis demonstrated that SV40 Tag expression was not affected by treatment with retinoids. Single doses of 10 and 50 mg/kg resulted in peak plasma concentrations of 3.4 and 6.71 microM, respectively. Daily doses of 9cRA for 28 days resulted in plasma concentrations of 0.86 and 1.68 microM, respectively, concentrations consistent with that seen in humans treated with 9cRA in clinical trials. These results demonstrate that 9cRA suppresses mammary carcinogenesis in transgenic mice without any major toxicity and suggest that retinoids are promising agents for the prevention of human breast cancer.

A phase I trial of 1,3-bis(2-chloroethyl)-1-nitrosourea plus temozolomide: a North American Brain Tumor Consortium study

The North American Brain Tumor Consortium conducted a phase I trial of the combination 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) and temozolomide. Eligibility included a patient with a cancer type that was considered refractory to standard therapy. Prior nitrosourea treatments were not permitted. There were parallel dose escalations in two treatment schedules. Forty-five patients were enrolled during an 18-month period. The maximum tolerated doses (MTDs) when temozolomide followed BCNU (Arm A) were temozolomide at 550 mg/m2/p.o. and BCNU at 150 mg/m2/i.v.), whereas the MTD when temozolomide preceded BCNU (Arm B) was temozolomide at 400 mg/m2/p.o. and BCNU at 100 mg/m2/i.v. Toxicity was predominantly hematologic, although there were three instances of pulmonary toxicity, which in one case could have represented potentiation of nitrosourea-induced pulmonary fibrosis. The half-life of temozolomide was 1.86 (+/-0.31) h. There was a moderate relationship between dose and peak concentration and a strong relationship between dose and plasma concentration time curve. Pharmacokinetic parameters of temozolomide were unaffected by the treatment schedule, so the difference in MTD between the schedules is likely due to a biologic rather than a pharmacokinetic sequence interaction. There were 9 partial responses among 43 patients evaluable for response, including 5 of 25 with a histologic diagnosis of glioblastoma. The recommended dose and schedule for phase II trials of this regimen are BCNU 150 mg/m2/i.v. followed in 2 h by temozolomide 550 mg/m2/p.o. repeated every 6 weeks. We are also recommending screening and periodic pulmonary function testing during treatment to assess the possible potentiation of nitrosourea-induced pulmonary fibrosis.

A phase I evaluation of multitargeted antifolate (MTA, LY231514), administered every 21 days, utilizing the modified continual reassessment method for dose escalation

PURPOSE

To determine toxicities, maximally tolerated dose (MTD), pharmacokinetic profile, and potential antitumor activity of MTA, a novel antifolate compound which inhibits the enzymes thymidylate synthase (TS), glycinamide ribonucleotide formyltransferase (GARFT), and dihydrofolate reductase (DHFR).

METHODS

Patients with advanced solid tumors were given MTA intravenously over 10 min every 21 days. Dose escalation was based on the modified continual reassessment method (MCRM), with one patient treated at each minimally toxic dose level. Pharmacokinetic studies were performed in all patients.

RESULTS

A total of 37 patients (27 males, 10 females, median age 59 years, median performance status 90%) were treated with 132 courses at nine dose levels, ranging from 50 to 700 mg/m(2). The MTD of MTA was 600 mg/m(2), with neutropenia and thrombocytopenia, and cumulative fatigue as the dose-limiting toxicities. Hematologic toxicity correlated with renal function and mild reversible renal dysfunction was observed in multiple patients. Other nonhematologic toxicities observed included mild to moderate fatigue, anorexia, nausea, diarrhea, mucositis, rash, and reversible hepatic transaminase elevations. Three patients expired due to drug-related complications. Pharmacokinetic analysis during the first course of treatment at the 600 mg/m(2) dose level demonstrated a mean harmonic half-life, maximum plasma concentration (Cpmax), clearance (CL), area under the curve (AUC), and apparent volume of distribution at steady state (Vdss) of 3.08 h, 137 microg/ml, 40.0 ml/min per m(2), 266 microg. h/ml, and 7.0 l/m(2), respectively. An average of 78% of the compound was excreted unchanged in the urine. Partial responses were achieved in two patients with advanced pancreatic cancer and in two patients with advanced colorectal cancer. Minor responses were obtained in six patients with advanced colorectal cancer.

CONCLUSIONS

The MTD and dose for phase II clinical trials of MTA when administered intravenously over 10 min every 21 days was 600 mg/m(2). MTA is a promising new anticancer agent.

Phase I and pharmacologic study of the tyrosine kinase inhibitor SU101 in patients with advanced solid tumors

PURPOSE

To evaluate the clinical feasibility and pharmacologic behavior of the platelet-derived growth factor (PDGF) tyrosine kinase inhibitor SU101, administered on a prolonged, intermittent dosing schedule to patients with advanced solid malignancies.

PATIENTS AND METHODS

Twenty-six patients were treated with SU101 doses ranging from 15 to 443 mg/m(2) as a 24-hour continuous intravenous (IV) infusion weekly for 4 weeks, repeated every 6 weeks. Pharmacokinetic studies were performed to characterize the disposition of SU101 and its major active metabolite, SU0020. Immunohistochemical staining of PDGF-alpha and -beta receptors was performed on malignant tumor specimens obtained at diagnosis.

RESULTS

Twenty-six patients were treated with 52 courses (187 infusions) of SU101. The most common toxicities were mild to moderate nausea, vomiting, and fever. Two patients experienced one episode each of grade 3 neutropenia at the 333 and 443 mg/m(2) dose levels. Dose escalation of SU101 above 443 mg/m(2)/wk was precluded by the total volume of infusate required, 2.5 to 3.0 L. Individual plasma SU101 and SU0020 concentrations were described by a one-compartment model that incorporates both first-order formation and elimination of SU0020. SU101 was rapidly converted to SU0020, which exhibited a long elimination half-life averaging 19 +/- 12 days. At the 443 mg/m(2)/wk dose level, trough plasma SU0020 concentrations during weeks 2 and 4 ranged from 54 to 522 micromol/L. Immunohistochemical studies revealed PDGF-alpha and -beta receptor staining in the majority (15 of 19) of malignant neoplasms.

CONCLUSION

SU101 was well tolerated as a 24-hour continuous IV infusion at doses of up to 443 mg/m(2)/wk for 4 consecutive weeks every 6 weeks. Although further dose escalation was precluded by infusate volume constraints, this SU101 dose schedule resulted in the achievement and maintenance of substantial plasma concentrations of the major metabolite, SU0020, for the entire treatment period.

Phase II study of phenylacetate in patients with recurrent malignant glioma: a North American Brain Tumor Consortium report

PURPOSE

To determine the response rate, time to treatment failure, and toxicity of phenylacetate in patients with recurrent malignant glioma and to identify plasma concentrations achieved during repeated continuous infusion of this agent.

PATIENTS AND METHODS

Adult patients with recurrent malignant glioma were treated with phenylacetate. The schedule consisted of a 2-week continuous, intravenous infusion followed by a 2-week rest period (14 days on, 14 days off). A starting dose of 400 mg/kg total body weight per day of phenylacetate was initially used and subsequently changed to 400 mg/kg/d based on ideal body weight. Intrapatient dose escalations were allowed to a maximum of 450 mg/kg ideal body weight/d. Tumor response was assessed every 8 weeks. The National Cancer Institute common toxicity criteria were used to assess toxicity. Plasma concentrations achieved during the patients' first two 14-day infusions were assessed.

RESULTS

Forty-three patients were enrolled between December 1994 and December 1996. Of these, 40 patients were assessable for toxicity and response to therapy. Reversible symptoms of fatigue and somnolence were the primary toxicities, with only mild hematologic toxicity. Thirty (75%) of the 40 patients failed treatment within 2 months, seven (17.5%) had stable disease, and three (7.5%) had a response defined as more than 50% reduction in the tumor. Median time to treatment failure was 2 months. Thirty-five patients have died, with a median survival of 8 months. Pharmacokinetic data for this dose schedule showed no difference in the mean plasma concentrations of phenylacetate between weeks 1 and 2 or between weeks 5 and 6.

CONCLUSION

Phenylacetate has little activity at this dose schedule in patients with recurrent malignant glioma. Further studies with this drug would necessitate an evaluation of a different dose schedule.

Phase I and pharmacokinetic trial of oral irinotecan administered daily for 5 days every 3 weeks in patients with solid tumors

PURPOSE

We conducted a phase I dose-escalation trial of orally administered irinotecan (CPT-11) to characterize the maximum-tolerated dose (MTD), dose-limiting toxicities (DLTs), pharmacokinetic profile, and antitumor effects in patients with refractory malignancies.

PATIENTS AND METHODS

CPT-11 solution for intravenous (IV) use was mixed with CranGrape juice (Ocean Spray, Lakeville-Middleboro, MA) and administered orally once per day for 5 days every 3 weeks to 28 patients. Starting dosages ranged from 20 to 100 mg/m2/d.

RESULTS

Grade 4 delayed diarrhea was the DLT at the 80 mg/m2/d dosage in patients younger than 65 years of age and at the 66 mg/m2/d dosage in patients 65 or older. The other most clinically significant toxicity of oral CPT-11 was neutropenia. A linear relationship was found between dose, peak plasma concentration, and area under the concentration-time curve (AUC) for both CPT-11 and SN-38 lactone, implying no saturation in the conversion of irinotecan to SN-38. The mean metabolic ratio ([AUC(SN-38 total) + AUC(SN-38G total)]/AUC(CPT-11 total)) was 0.7 to 0.8, which suggests that oral dosing results in presystemic conversion of CPT-11 to SN-38. An average of 72% of SN-38 was maintained in the lactone form during the first 24 hours after drug administration. One patient with previously treated colorectal cancer and liver metastases who received oral CPT-11 at the 80 mg/m2/d dosage achieved a confirmed partial response.

CONCLUSION

The MTD and recommended phase II dosage for oral CPT-11 is 66 mg/m2/d in patients younger than 65 years of age and 50 mg/m2/d in patients 65 or older, administered daily for 5 days every 3 weeks. The DLT of diarrhea is similar to that observed with IV administration of CPT-11. The biologic activity and favorable pharmacokinetic characteristics make oral administration of CPT-11 an attractive option for further clinical development.

A Phase I and pharmacological study of the glutamine antagonist acivicin with the amino acid solution aminosyn in patients with advanced solid malignancies

Acivicin is a glutamine analogue antimetabolite that inhibits several glutamate-dependent synthetic enzymes. Previous studies of this agent administered on a 72-h continuous i.v. infusion schedule every 3 weeks demonstrated a high rate of severe, albeit reversible, central nervous system (CNS) toxicity at the 30 mg/m2/day dose level. Animal studies have shown that the CNS toxicity of acivicin can be prevented by a concomitant infusion of amino acids postulated to block drug uptake in the CNS by a saturable transport system that is common to endogenous amino acids. This study evaluated the feasibility of escalating acivicin doses in cancer patients by administering acivicin with a concomitant 96-h i.v. infusion of a mixture of 16 amino acids (Aminosyn, 10%). Twenty-three patients with advanced malignancies were treated with acivicin on a 72-h continuous infusion schedule at doses ranging from 25 to 60 mg/m2/day every 3 weeks. Reversible, dose-limiting CNS toxicity, characterized by lethargy, confusion, and decreased mental status, occurred in the two patients enrolled at the 60 mg/m2/day dose level, precluding further dose escalation. The maximum tolerated dose (MTD) and recommended dose for additional evaluation of acivicin on this schedule is 50 mg/m2/day. Other toxicities observed were dose-related neutropenia that was grade 4 in four patients (four courses), complicated with fever in three of those patients, and grade 3-4 thrombocytopenia in three patients (three courses). Pharmacokinetics studies performed in 15 patients revealed that the acivicin plasma Css increased from 0.44 microg/ml (range, 0.28-0.59 microg/ml) at the 25 mg/m2/day to 1.06 microg/ml (0.64-1.5 microg/ml) at the 50 mg/m2/dose level. Acivicin Css at the MTD was not significantly higher than previously reported values with single-agent acivicin on the same schedule of administration at the MTD of 25 mg/m2/day dose level (0.60 microg/ml; range, 0.43-0.81 microg/ml). Neurotoxicity did not correlate with acivicin Css, but relationships between exposure to acivicin and the occurrence of both neutropenia and thrombocytopenia were well described by a sigmoidal Emax model. This trial demonstrated that concomitant infusions of amino acid can prevent acivicin-induced CNS toxicity, which allows the dose of acivicin to be escalated 2-fold above previously tolerable doses; however, this effect did not translate in a significant increment in acivicin Css.

A phase I and pharmacokinetic trial of terephthalamidine (NSC 57155) as a 120-hour continuous infusion

In this phase I study, terephthalamidine was administered as a 120-hour continuous infusion repeated every 21 days. Thirteen patients received 27 courses of terephthalamidine at four dose levels ( 14, 28, 46, and 70 mg/m2/day). Dose-limiting toxicity consisted of profound and intractable anorexia, weight loss and prostration in all patients. Toxicity was delayed and accompanied by hyponatremia and hypokalemia. No hematologic or other toxicity was documented. One patient with adenocarcinoma of the lung had a 40% decrease in mediastinal lymph nodes and resolution of a pleural effusion lasting 2 months. Pharmacokinetic analysis by HPLC was performed in all patients during their first course. The harmonic mean terminal half-life for terephthalamidine was 23 hours with a plasma clearance of 1.7 1/hr/m2. Both plasma concentrations achieved during infusion (r2 = 0.9) and area under the curve (AUC) (r2 = 0.8) were proportional to increase in dose (p < 0.002). Renal excretion accounted for 64% of the total cumulative dose, with an average renal clearance of 1.16 1/hr/m2. Due to the unacceptable toxicity seen at all doses with this schedule, no further studies are recommended unless the mechanism of toxicity is better understood and can be prevented.

Alternative dosing schedules for irinotecan

Most of the clinical experience with irinotecan (CPT-11 [Camptosar]) has been with either a weekly or an every-3-week schedule. Recent phase I trials have explored new routes and schedules of administration. One approach attempts to maximize dose frequency and intensity by giving irinotecan every 2 weeks. A phase I trial of this approach is now complete and has led to a phase II trial in patients with recurrent colorectal cancer. Data suggest that smaller doses of a topoisomerase I inhibitor administered repeatedly may result in greater antitumor activity than large doses administered intermittently. A phase I trial has been performed in adults in which irinotecan was administered daily for 5 consecutive days, followed by 2 days off, for 2 weeks out of 3. Similar trials are under way in children. Oral administration, another strategy that has undergone phase I testing, has several theoretical advantages:(1) The acidic pH of the stomach favors maintenance of irinotecan in the active lactone ring form. (2) Irinotecan is more rapidly and extensively converted to SN-38 by tissue carboxylesterases found in high concentrations in the gut and liver. (3) Low doses can be delivered over a protracted period. (4) The oral route enhances patient convenience. These alternative dosing schedules may facilitate integration of irinotecan into combination chemotherapy and combined-modality treatment regimens.

Pharmacology of irinotecan

Irinotecan (CPT-11 [Camptosar]), a semisynthetic derivative of the plant alkaloid camptothecin, is bioactivated by carboxylesterases (EC3.1.1-) to the topoisomerase I inhibitor SN-38, a minor metabolite. Bioactivation of intravenously administered irinotecan by carboxylesterases occurs predominantly in the liver. Two human carboxylesterase isoforms responsible for SN-38 formation have been characterized. At relevant hepatic irinotecan concentrations up to 12 micrograms/mL, a low-Km isoform is responsible for irinotecan bioactivation. High concentrations of drugs commonly coadministered with irinotecan do not inhibit carboxylesterase activity. Intestinal carboxylesterases can also generate SN-38, followed by subsequent oral absorption. A second major polar metabolite of irinotecan, aminopentanecarboxylic acid (APC), is the product of CYP3A4-mediated oxidation of the terminal piperidine ring. APC is 100-fold less active than SN-38 as a topoisomerase I inhibitor and is a relatively weak inhibitor of acetylcholinesterase. SN-38 is eliminated mainly through conjugation by hepatic uridine glucuronosyltransferase (UGT*1.1), the same isoezyme responsible for glucuronidation of bilirubin. Grade 4 irinotecan-related toxicity (ie, neutropenia, diarrhea) has recently been reported in two patients with deficient UGT*1.1 activity. SN-38 glucuronide (SN-38G), which has only 1/100th the antitumor activity of SN-38, is actively secreted into the bile by a canalicular multispecific organic anion transporter. Deconjugation of SN-38G to SN-38 by beta-glucuronidase produced by the intestinal flora may contribute to enterohepatic recirculation of SN-38 and delayed intestinal toxicity.

Evaluation of the linearity of docetaxel pharmacokinetics

The taxanes, paclitaxel and docetaxel, have favorable response rates in patients with breast, gynecologic, and lung cancers and have demonstrated activity against a variety of malignancies. In human trials, paclitaxel pharmacokinetics are nonlinear and are best fit by a three-compartment model with nonlinear distribution into the second compartment as well as nonlinear elimination. This finding is important for patients receiving paclitaxel at high doses or as a short infusion, as it results in disproportionately high peak concentrations and delayed elimination. The presence of nonlinear processes in docetaxel pharmacokinetics has not previously been examined. Therefore, plasma concentration data obtained from 53 patients receiving docetaxel at 55-115 mg/m2 over 1-24 h as part of phase I studies were modeled using the nonlinear three-compartment model found most suitable for paclitaxel and the results were compared with those obtained using the linear version. Docetaxel disposition was best described by the three-compartment nonlinear model in 28 of 53 data sets (53%). However, the difference in curve fit observed between the two models was modest (did not improve Akaike criteria) and unlikely to be of relevance. This study suggests that nonlinear processes in docetaxel pharmacokinetics may exist, but, unlike the case of paclitaxel, they are not likely to have a significant impact at the dose and administration schedule used in routine clinical practice (60-100 mg/m2 given over 1 h by infusion). The presence of nonlinear docetaxel pharmacokinetics at doses above 115 mg/m2 will have to be determined in case of further dose escalation.

Phase I study of paclitaxel in patients with recurrent malignant glioma: a North American Brain Tumor Consortium report

PURPOSE

To determine the maximum-tolerated dose (MTD) of paclitaxel administered as a 3-hour infusion in patients with recurrent malignant glioma.

PATIENTS AND METHODS

Patients were stratified by starting dose of paclitaxel and concurrent anticonvulsant (AC) use and were treated in cohorts of three patients. The starting dose was 240 mg/m2 administered intravenously with escalations of 30 mg/m2 until the MTD was established. Pharmacokinetic data were obtained for each patient for the first infusion. Tumor response was assessed at 6-week intervals and treatment was continued until documented tumor progression, unacceptable toxicity, or a total of 12 paclitaxel infusions.

RESULTS

From April 1995 to December 1996, 34 patients were treated; 27 patients in the AC group and seven patients in the non-AC group. The MTD for patients who received ACs was established at 360 mg/m2 and the dose-limiting toxicity (DLT) was central neurotoxicity, characterized as transient encephalopathy and seizures. In contrast, the MTD for patients who did not receive ACs was 240 mg/m2, and myelosuppression, gastrointestinal toxicity, and fatigue were the DLTs. Pharmacokinetic data confirmed that the plasma drug levels and clearance rates were similar for patients in both groups at the respective dose levels that produced DLTs.

CONCLUSION

The pharmacokinetics of paclitaxel are altered by ACs, and significantly larger doses of the drug can be administered to patients with brain tumors on AC therapy. The toxicity profile is different for patients on AC therapy treated at these higher doses. A phase II study has been initiated that uses a dose of 330 mg/m2 for patients on AC therapy and 210 mg/m2 for patients not on AC therapy.

A phase I and translational study of sequential administration of the topoisomerase I and II inhibitors topotecan and etoposide

Because topoisomerase (topo) I- and topo II-targeting agents exert their principal effects on the two major classes of enzymes involved in regulating DNA topology in the cell, there has been considerable interest in evaluating combinations of these classes of agents. In preclinical studies of inhibitors of topo I and topo II in combination, drug scheduling and sequencing have been critical determinants of antitumor activity, with a greater magnitude of cytotoxicity generally occurring when treatment with the topo I inhibitor precedes treatment with the topo II-targeting agent. The underlying mechanism that has been proposed to explain this schedule dependency is compensatory up-regulation of topo II and, therefore, enhanced cytotoxicity of topo II inhibitors in cells treated initially with topo I inhibitors. The feasibility of sequentially administering the topo I inhibitor topotecan (TPT) followed by the topo II inhibitor etoposide to patients with advanced solid malignancies was evaluated in this Phase I and translational laboratory study. Fifty patients with solid neoplasms were treated with TPT doses ranging from 0.17 to 1.05 mg/m2/day as a 72-h continuous (i.v.) infusion on days 1-3 followed by etoposide, 75 or 100 mg/m2/day as a 2-h i.v. infusion daily on days 8-10. The combined rate of severe neutropenia and thrombocytopenia was unacceptably high above the TPT (mg/m2/day)/etoposide (mg/m2/day) dose levels of 0.68/100 and 0.68/75 in minimally and heavily pretreated patients, respectively, and these dose levels are recommended for further disease-directed evaluations of TPT/etoposide on this administration schedule. Successive biopsies of accessible tumors were obtained for quantitation of topo I and II levels prior to and immediately after treatment with TPT and prior to and immediately after treatment with etoposide in seven patients. The results of these limited studies in tumors did not fully support the proposed mechanistic rationale favoring the development of this particular sequential TPT/etoposide regimen, because only two of the six patients' tumors in whom topo I was successively measured had either modest or substantial decrements in topo I levels following treatment with TPT, and the principal effect of interest, up-regulation of topo II following treatment with TPT, was clearly documented in the tumors of only one of six subjects in whom successive measurements of topo I were performed. Even in view of the notable objective antitumor activity in three subjects, including a complete response in a patient with colorectal carcinoma and partial responses in one patient each with non-small cell lung and gastric carcinomas, the toxicity and ancillary laboratory results do not provide substantial evidence that sequential treatment with TPT and etoposide might be more advantageous than either TPT or etoposide administered as a single agent.

Phase I and pharmacokinetic study of GI147211, a water-soluble camptothecin analogue, administered for five consecutive days every three weeks

GI1147211 is a 7-substituted 10,11-ethylenedioxy-20(S)-camptothecin analogue that inhibits the nuclear enzyme topoisomerase I. In this Phase I and pharmacological study, 24 patients with advanced solid malignancies received a total of 72 courses of GI147211 as a 30-min infusion daily for 5 consecutive days, at doses ranging from 0.3 to 1.75 mg/m2/day. Severe neutropenia precluded dose escalation above 1.5 mg/m2/day in minimally pretreated patients, and both severe neutropenia and thrombocytopenia were dose limiting in heavily pretreated patients at doses above 1.0 mg/m2/day. These doses are, therefore, recommended for subsequent Phase II evaluations of GI147211 in patients with comparable prior therapy. Nonhematological toxicities, including nausea, vomiting, fatigue, and anorexia, were mild to moderate. The disposition of GI147211 in blood was described by a linear three-compartment model, with renal elimination accounting for only 11% of drug distribution. No relationship was observed between the pharmacological exposure to GI147211 and effects on neutrophils; however, patients who developed dose-limiting myelosuppression did experience greater exposure to both the lactone and total forms of the drug. The hydrolysis kinetics of GI147211 revealed not only a shift of the drug to the inactive carboxylate form in human serum albumin but also stabilization of the lactone in erythrocytes, perhaps accounting for the observed lactone:total area under the concentration-time curve ratio of 0.27. These results indicate that GI147211 exhibits predictable toxicities and that further studies are warranted to determine the distinct role of this compound among currently available camptothecin analogues.

A bioavailability and pharmacokinetic study of oral and intravenous hydroxyurea

Despite the widespread usage of hydroxyurea in the treatment of both malignant and nonmalignant diseases and a recent expansion in the recognition of its potential therapeutic applications, there have been few detailed studies of hydroxyurea's pharmacokinetic (PK) behavior and oral bioavailability. Parenteral administration schedules have been evaluated because of concerns about the possibility for significant interindividual variability in the PK behavior and bioavailability of hydroxyurea after oral administration. In this PK and bioavailability study, 29 patients with advanced solid malignancies were randomized to treatment with 2, 000 mg hydroxyurea administered either orally or as a 30-minute intravenous (IV) infusion accompanied by extensive plasma and urine sampling for PK studies. After 3 weeks of treatment with hydroxyurea (80 mg/kg orally every 3 days followed by a 1-week washout period), patients were crossed over to the alternate route of administration, at which time extensive PK studies were repeated. Three days later, patients continued treatment with 80 mg/kg hydroxyurea orally every 3 days for 3 weeks, followed by a 1-week rest period. Thereafter, 80 mg/kg hydroxyurea was administered orally every 3 days. Twenty-two of 29 patients had extensive plasma and urine sampling performed after treatment with both oral and IV hydroxyurea. Oral bioavailability (F) averaged 108%. Moreover, interindividual variability in F was low, as indicated by 19 of 22 individual F values within a narrow range of 85% to 127% and a modest coefficient of variation of 17%. The time in which maximum plasma concentrations (Cmax) were achieved averaged 1.22 hours with an average lag time of 0.22 hours after oral administration. Except for Cmax, which was 19. 5% higher after IV drug administration, the PK profiles of oral and IV hydroxyurea were very similar. The plasma disposition of hydroxyurea was well described by a linear two-compartment model. The initial harmonic mean half-lives for oral and IV hydroxyurea were 1.78 and 0.63 hours, respectively, and the harmonic mean terminal half-lives were 3.32 and 3.39 hours, respectively. For IV hydroxyurea, systemic clearance averaged 76.16 mL/min/m2 and the mean volume of distribution at steady-state was 19.71 L/m2, whereas Cloral/F and Voral/F averaged 73.16 mL/min/m2 and 19.65 L/m2, respectively, after oral administration. The percentage of the administered dose of hydroxyurea that was excreted unchanged into the urine was nearly identical after oral and IV administration-36. 84% and 35.82%, respectively. Additionally, the acute toxic effects of hydroxyurea after treatment on both routes were similar. Relationships between pertinent PK parameters and the principal toxicity, neutropenia, were sought, but no pharmacodynamic relationships were evident. From PK, bioavailability, and toxicologic standpoints, these results indicate that there are no clear advantages for administering hydroxyurea by the IV route except in situations when oral administration is not possible and/or in the case of severe gastrointestinal impairment.

A phase I clinical and pharmacokinetic study of the angiogenesis inhibitor, tecogalan sodium

BACKGROUND

Tecogalan sodium is an angiogenesis inhibitor isolated from a sulfated polysaccharide produced by the bacterium Arthrobacter. The antiangiogenic effect of tecogalan sodium is thought to be mediated by the inhibition of binding of basic fibroblast growth factor to cellular receptors.

PATIENTS AND METHODS

A phase I study was conducted in thirty-three patients with refractory malignancies, including AIDS-associated Kaposi's sarcoma. Patients received a single i.v. infusion every three weeks with the infusion duration ranging from one to twenty-four hours. Seven different dosage levels were studied (125, 185, 240, 300, 390, 445, and 500 mg/m2).

RESULTS

The primary dose-limiting toxicity was prolongation of the activated partial thromboplastin time with peak times being between 1.0-4.0 times the upper limit of normal. This toxicity was ameliorated at a given dose level by prolonging the infusion time. Other common toxicities included fever (40%) and rigors (31%) which were well controlled with acetominophen and meperidine. The serum half-life of tecogalan sodium was between 1-1.5 hours and < 25% of unchanged drug was excreted in the urine.

CONCLUSIONS

The recommended phase II dose of tecogalan sodium on this schedule is 390 mg/m2 over 24 hours. Other schedules including continuous administration should be investigated to maximize the efficacy of this novel angiogenesis inhibitor.

Pharmacokinetic profile of Mitoguazone (MGBG) in patients with AIDS related non-Hodgkin's lymphoma

Mitoguazone is a unique chemotherapeutic agent whose activity is believed to result primarily from the competitive inhibition of S-adenosyl-methionine decarboxylase leading to a disruption in polyamine biosynthesis. Initial clinical trials demonstrated that the dose-limiting toxicities (mucositis and myelosuppression) of Mitoguazone were both dose and schedule dependent. Early pharmacokinetic studies of Mitoguazone in man revealed a prolonged half-life. Concurrent with a recent Phase II trial of Mitoguazone in patients with AIDS related non-Hodgkin's lymphoma, the single dose pharmacokinetics of Mitoguazone were characterized. Twelve patients received 600 mg/m2 of intravenous Mitoguazone over 30 minutes on an intermittent every 2 week schedule. Blood, urine, cerebrospinal fluid (CSF), pleural fluid and tissue samples were collected and analyzed by HPLC. Mitoguazone was cleared from the plasma triexponentially with a harmonic mean terminal half-life of 175 hours and a mean residence time of 192 hours. Peak plasma levels occurred immediately post-infusion, ranged from 6.47 to 42.8 micrograms/ml, and remained (for an extended period) well above the reported concentration for inhibition of polyamine biosynthesis. Plasma clearance averaged 4.73 l/hr/m2 with a relatively large apparent volume of distribution at steady-state of 1012 l/m2 indicating tissue sequestration. Renal excretion of unchanged Mitoguazone accounted for an average of 15.8% of the dose within 48 to 72 hours post-administration. Detectable levels of drug were present in random voided samples eight days post-dose. Mitoguazone levels in CSF ranged from 22 to 186 ng/ml post-dose with CSF/plasma ratios ranging from 0.6% to 7%. The pleural fluid/plasma ratio was approximately 1. Tissue levels of Mitoguazone were highest in the liver followed by lymph node, spleen and the brain.

Phase II trial of irinotecan in patients with progressive or rapidly recurrent colorectal cancer

PURPOSE

To evaluate irinotecan (CPT-11; Yakult Honsha, Tokyo, Japan) in patients with metastatic colorectal carcinoma that had recurred or progressed following fluorouracil (5-FU)-based therapy.

PATIENTS AND METHODS

Patients were treated with irinotecan 125 to 150 mg/m2 intravenously (IV) every week for 4 weeks, followed by a 2-week rest. Forty-eight patients were entered onto the study and all were assessable for toxicity. Forty-three patients completed one full course of therapy and were assessable for response.

RESULTS

One complete and nine partial responses were observed (response rate, 23%; 95% confidence interval [CI], 10% to 36%). The median response duration was 6 months (range, 2 to 13). The median survival time was 10.4 months and the 1-year survival rate was 46% (95% CI, 39% to 53%). Grade 4 diarrhea occurred in four of the first nine patients (44%) treated on this study at the 150-mg/m2 dose level. The study was amended to reduce the starting dose of irinotecan to 125 mg/m2. At this dose, nine of 39 patients (23%) developed grade 4 diarrhea. Aggressive administration of loperamide also reduced the incidence of grade 4 diarrhea. Grade 4 neutropenia occurred in eight of 48 patients (17%), but was associated with bacteremia and sepsis in only case.

CONCLUSION

Irinotecan has significant single-agent activity against colorectal cancer that has progressed during or shortly after treatment with 5-FU-based chemotherapy. The incidence of severe diarrhea is reduced by using a starting dose of irinotecan 125 mg/m2 and by initiating loperamide at the earliest signs of diarrhea. These results warrant further clinical evaluation to define the role of irinotecan in the treatment of individuals with colorectal cancer.

Pharmacokinetic profile of recombination human insulin-like growth factor binding protein-1 in athymic mice

Neutralization of insulin-like growth factor action by insulin-like growth factor binding protein-1 inhibits the in vitro growth of breast cancer cells. We performed this study to determine the pharmacokinetic profile of recombinant human IGFBP-1 (rhIGFBP-1) in athymic mice as a prelude to testing this protein in a human tumor xenograft model. After the subcutaneous injection of 1 mg, rhIGFBP-1 migrating at 29 kDa could be detected by ligand blotting and immunoblotting. Plasma concentrations of rhIGFBP-1 were quantified by immunoassay and demonstrated a half-life was 2.49 hours with the maximal concentration of 43.5 micrograms/mL occurring at 1 hour. The area under the concentration-time curve was 78.32 micrograms x hr/mL. Plasma clearance was 12.77 mL/hr and the mean residence time was 1.96 hours. rhIGFBP-1 was also detected in some tissues and was also cleared rapidly. These results show that high plasma and tissue levels of rhIGFBP-1 can be obtained after subcutaneous injection in athymic mice, however, the short half-life of the protein may limit its therapeutic use.

Initial phase I evaluation of the novel thymidylate synthase inhibitor, LY231514, using the modified continual reassessment method for dose escalation

PURPOSE

To determine the toxicities, maximal-tolerated dose (MTD), pharmacokinetic profile, and potential antitumor activity of LY231514, a novel thymidylate synthase (TS) inhibitor.

PATIENTS AND METHODS

Patients with advanced solid tumors were administered LY231514 intravenously over 10 minutes, weekly for 4 weeks, every 42 days. Dose escalation was based on the modified continual reassessment method (MCRM), with one patient treated at each minimally toxic dose level. Pharmacokinetic studies were performed in all patients.

RESULTS

Twenty-five patients were administered 58 courses of LY231514 at doses that ranged from 10 to 40 mg/m2/wk. Reversible neutropenia was the dose-limiting toxicity. Inability to maintain the weekly treatment schedule due to neutropenia limited dose escalation on this schedule. Nonhematologic toxicities observed included mild fatigue, anorexia, and nausea. At the 40-mg/m2/wk dose level, the mean harmonic half-life, maximum plasma concentration, clearance, and apparent volume of distribution at steady-state were 2.02 hours, 11.20 micrograms/mL, 52.3 mL/min/m2, and 6.64 L/m2, respectively. No major antitumor responses were observed; however, minor responses were achieved in two patients with advanced colorectal cancer.

CONCLUSION

The dose-limiting toxicity, MTD, and recommended phase II dose of LY231514 when administered weekly for 4 weeks every 42 days are neutropenia, 40 mg/m2, and 30 mg/m2, respectively.

Quantitative analysis of NQO1 gene expression by RT-PCR and CE-LIF

A capillary electrophoresis-laser-induced fluorescence (CE-LIF) method to quantitate reverse transcription-polymerase chain reaction (RT-PCR) products of NAD(P)H:quinone acceptor oxidoreductase (NQO1) derived from whole blood after amplification with a reaction-specific internal standard is reported. The internal standard eliminates variability within the PCR (Hoffman-La Roche, Inc., Nutley, NJ, U.S.A.), while analysis by CE-LIF adds sensitivity and reduces variability associated with isotopic detection. Both the PCR and CE aspects of the assay are precise, with migration time precision of less than 1% and peak area ratio precisions of 9.8-15%. Future applications of this technique may include the analysis of gene therapy, oligonucleotides, and point mutations.

Deoxyspergualin: phase I clinical, immunologic and pharmacokinetic study

Deoxyspergualin (DSG) is an analog of the polyamine spergualin with preclinical evidence of activity in murine and human tumor models. This phase I study examined a 120 h continuous infusion schedule in 56 patients with refractory solid tumors at doses ranging from 80 to 2792 mg/m2/day. Dose-limiting toxicity was reversible hypotension and appeared to be associated with plasma levels of DSG > 4 micrograms/ml. Other dose-dependent effects noted were pruritus and circumoral paresthesias. Myelosuppression and gastrointestinal toxicities were mild and sporadic. Two patients with refractory head and neck cancer had minor responses. The recommended phase II dose on this schedule is 1800 mg/m2. Additional monitoring to identify immunologic properties included immunophenotyping of peripheral lymphocytes and cytotoxic activity by means of standard 51Cr-release assays. These studies revealed a non-dose-dependent increase in the number of cells expressing T cell antigens predominantly the T suppressor (CD8) phenotype posttreatment. In three patients, a mild increase in LAK activity was noted post-treatment without a consistent relationship to dose or change in cell surface antigens. Pharmacokinetic studies were completed on 26 patients ranging from doses of 80 to 2792 mg/m2. The average plasma concentration ranged from 0.07 to 7 micrograms/ml. DSG was rapidly cleared from the plasma with a mean terminal half-life of 1.9 h. Mean total body clearance was 25.24 l/h/m2. Further in vivo immunologic studies should be pursued while the agent is studied in fixed dosage phase II clinical trials.

Hepsulfam distribution in blood, plasma and cerebrospinal fluid of baboons

The alkylating agent Hepsulfam (Sulfamic acid 1,7-heptanediyl ester, NSC 329680) was developed as a more hydrophilic analog of busulfan. The objective of this study was to determine partitioning of hepsulfam between blood, plasma, and cerebrospinal fluid (CSF) in two female baboons following intravenous administration. Hepsulfam was administered at 11 mg/kg, and blood and CSF levels were determined by gas chromatography with electron capture detection. Blood levels were fairly constant between animals (17-25 and 20-23 micrograms/ml) for six hours after administration, following peak levels of 43 and 33 micrograms/ml, respectively, for the two animals. Peak plasma levels of 35 and 36 micrograms/ml were achieved, and initial plasma half-lives in baboons were similar to those seen in other species, with a t1/2 alpha of 1 h. The plasma terminal half life of 0.2 h, estimated from limited sampling times, was shorter in baboons than in mice, dogs, or humans. Baboon CSF levels decreased from 1.7 to 0.3 micrograms/ml during 6 h post infusion, and peak concentrations in CSF lagged behind plasma levels. CSF/plasma ratios ranged from 0.33 to 0.62 in one animal, whereas ratios of 0.2-0.25 were maintained in the other animal during the same period. Results from this study indicate hepsulfam will enter the CSF following intravenous administration, and the CSF/plasma ratios are lower than those obtained following oral busulfan administration.

Pharmacodynamics of daily subcutaneous recombinant human interleukin-3 in normal volunteers

Normal volunteers received subcutaneous injections of recombinant human interleukin-3 (rhIL-3) on 4 consecutive days to characterize toxicity, pharmacokinetics, and hematopoietic effects. Dosages were 2.5, 5.0, and 7.5 micrograms/kg/day (n = 6 subjects per group). Adverse effects consisted predominantly of flu-like symptoms such as fever and headache. Mean area under the serum concentration-time curve and maximum serum concentration were linearly related to dose. Serum clearance was not apparently related to dose. Clearance increased slightly but significantly between days 1 and 4. Rapid but modest elevations in neutrophil and eosinophil counts were observed during treatment. Mean platelet counts rose modestly, peaking on day 10. Increases of CD34+ cell counts were correlated with increases of colony-forming unit-granulocyte macrophage (peak, day 7).

A phase I and pharmacokinetics study of 2-chlorodeoxyadenosine in patients with solid tumors

Preclinical studies of 2-chlorodeoxyadenosine (2-CdA) against solid tumors in the human tumor cloning assay and evidence that 2-CdA is active against slow-growing or resting tumor cells have stimulated interest in the clinical activity of this agent against solid tumors. This study sought to estimate the maximum tolerated dose, dose-limiting toxicity, and plasma and urine pharmacokinetics accompanying the intravenous administration of 2-CdA by 120-h continuous infusion in patients with solid tumors. Treated patients were also assessed for other toxicities of therapy and for antitumor response. A total of 23 patients received 35 courses of treatment given at doses of 3.5, 5.3, 6.5 and 8.1 mg/m2 per day by continuous intravenous infusion for 5 days and repeated every 28 days. Blood and urine specimens were collected before, during, and after drug infusion. The dose-limiting toxicity at 8.1 mg/m2 per day manifested as granulocytopenia in 2 of 5 patients (3 of 7 courses of treatment) and as thrombocytopenia in 3 of 5 patients (3 of 7 courses of treatment). At the dose levels of 6.5 and 8.1 mg/m2 per day, recovery from thrombocytopenia was often delayed. Severe lymphocytopenia (< 1,000/microliters) was observed at all dose levels of 2-CdA. Dose-related anemia and leukopenia were observed and were infrequently severe. Non-hematological toxicities were confined to mild-to-moderate nausea, vomiting, fatigue, and anorexia. Fever of 37 degrees-40 degrees C was induced during drug infusion in 19 patients. No antitumor response was observed. Average plasma concentrations at steady-state (Cpss) ranged from 3 ng/ml at the initial dose level to 13 ng/ml at the dose level of 8.1 mg/m2 per day. Both the Cpss and the area under the plasma concentration-time curve (AUC) were proportional to the dose. A relationship was observed between the percentage of change in absolute neutrophil count and the AUC. Renal excretion accounted for only 18% of the elimination of 2-CdA over the 5-day infusion period. The maximum tolerated dose for 2-CdA given by 5-day continuous infusion was 8.1 mg/m2 per day in this study. The recommended dose on this schedule for phase II studies is 6.5 mg/m2 per day. Granulocytopenia and thrombocytopenia were dose-limiting. No antitumor activity was observed during this study. On the basis of the plasma concentrations of 2-CdA observed, it is unlikely that this schedule of drug administration will permit achievement of the concentrations consistent with antitumor activity observed in preclinical studies.

Activity of DMP 840, a new bis-naphthalimide, on primary human tumor colony-forming units

BACKGROUND

DMP 840 ((R,R)-2,2'-[1,2-ethanediylbis[imino(1-methyl-2,1-ethanediyl)]]- bis[5-nitro-1H-benz[de]-iso[quinoline-1,3(2H)-dione]dimethane- sulfonate; NSC-D640430) is one in a series of bis-naphthalimides that binds DNA with high affinity and has sequence specificity to multiple G and C bases. It is also a potent inhibitor of RNA synthesis. DMP 840 has been selected for clinical evaluation on the basis of a broad spectrum of activity (including cures) in human tumors in murine models.

PURPOSE

We evaluated DMP 840 in a human tumor clonogenic assay to estimate what plasma concentrations may be necessary for clinical cytotoxic activity and to determine what types of tumors potentially might be primary targets for initial phase II studies.

METHODS

A soft-agar cloning system assay was used to determine the in vitro effects of DMP 840 against cells from biopsy specimens of colorectal, breast, lung ovarian, renal cell, stomach, and bladder cancers and from other tumor types. A total of 260 human tumor specimens were exposed continuously during the assay to DMP 840; 103 were assessable (20 colonies or more on control plates and 30% or less survival for the positive control). An in vitro response was defined as at least a 50% decrease in tumor colony formation resulting from drug exposure compared with controls.

RESULTS

In vitro responses were seen in 10% (one of 10), 54% (55 of 101), 80% (82 of 103), and 89% (82 of 92) of specimens tested at 0.01, 0.1, 1.0, and 10.0 micrograms/mL of DMP 840, respectively. At a concentration of 0.1 microgram/mL, specific activity was seen against melanoma (80%) and against renal cell (80%), ovarian (63%), breast (54%), non-small-cell lung (42%), and colorectal cancers (33%). DMP 840 demonstrated activity in tumor specimens resistant in vitro to methotrexate (88%), doxorubicin (58%), platinum (57%), cyclophosphamide (53%), vinblastine (53%), etoposide (53%), fluorouracil (37%), and paclitaxel (36%).

CONCLUSIONS

At in vitro concentrations of 0.1 microgram/mL as a continuous exposure, DMP 840 has activity against a variety of human tumors, including a subgroup resistant in vitro to standard antineoplastic agents.

IMPLICATIONS

Further clinical development of DMP 840 is warranted.