The value, qualification, and regulatory use of surrogate end points in drug development.

The acceptance and use of either surrogate end points (SEPs) or efficient clinical end points are associated with greater and more rapid availability of new medicines as compared with disease situations for which clinical end points are inefficient or no surrogates exist. This review of the history of the development, qualification, and acceptance of key SEPs shows that both successes and failures had three key characteristics: (i) apparent biologic plausibility, (ii) prognostic value for the outcome of the disease, and (iii) an association between changes in the SEP and changes in outcome with therapeutic intervention--the three factors recommended for SEPs in the International Conference on Harmonisation's "Statistical Principles for Clinical Trials." We recommend that only prognostic value be an absolute prerequisite for surrogacy, because therapeutic interventions may not exist a priori, and biological plausibility can be subjective. Ideally, all three of these factors would be traded off against one another in a consistent and transparent risk-management process.

A prototypical process for creating evidentiary standards for biomarkers and diagnostics.

A framework for developing evidentiary standards for qualification of biomarkers is a key need identified in the Food and Drug Administration's Critical Path Initiative. This article describes a systematic framework that was developed by Pharmaceutical Research and Manufacturers of America (PhRMA) committees and tested at a workshop in collaboration with the Food and Drug Administration and academia. With some necessary refinements, this could be applied to create an appropriately individualized evidentiary standard for any biomarker purpose.

An NCIC-CTG phase I dose escalation pharmacokinetic study of the matrix metalloproteinase inhibitor BAY 12-9566 in combination with doxorubicin.

BACKGROUND: This phase I study was performed to evaluate the safety, tolerability, and efficacy of the oral matrix metalloproteinase inhibitor BAY 12-9566 in combination with doxorubicin in patients with advanced solid tumours, and to identify the maximum tolerated dose of these agents in combination and the dose for use in subsequent studies. PATIENTS AND METHODS: 14 patients were entered onto 3 dose levels consisting of escalating doses of doxorubicin (50 mg/m(2), 60 mg/m(2) and 70 mg/m(2)) with 800 mg po bid BAY 12-9566. At all three dose levels, patients received doxorubicin alone in cycle one on day 1. Daily oral dosing with BAY 12-9566 was started on day 8 of cycle 1, and thus doxorubicin was given concurrently with BAY 12-9566 in cycle 2. Patients were continued on treatment until a dose limiting toxicity or tumour progression occurred. RESULTS: Pharmacokinetic studies from cycles 1 and 2 from the patients treated in the first three dose levels demonstrated that the addition of BAY 12-9566 increased the AUC(0-12h) levels of doxorubicin by a median of 48%. No effects were seen on the BAY 12-9566 pharmacokinetic values. Two dose limiting toxicities were seen at the third dose level. One patient experienced grade 3 stomatitis in cycle 2, and another patient experienced grade 4 granulocytopenia in cycle 1 and grade 4 thrombocytopenia in cycle 2. Thus the maximum tolerated dose of 60 mg/m(2) was declared. These toxicities were those that would have been expected from doxorubicin alone. CONCLUSIONS: BAY 12-9566 can be safely administered with full doses of doxorubicin without evidence of clinical interaction. The recommended dose of doxorubicin to be combined with BAY 12-9566 800 mg po b.i.d is 60 mg/m(2), however, further development of BAY 12-9566 has been abandoned.

Phase I study to determine the safety and pharmacokinetics of the novel Raf kinase and VEGFR inhibitor BAY 43-9006, administered for 28 days on/7 days off in patients with advanced, refractory solid tumors.

BACKGROUND: BAY 43--9006, an oral multi-kinase inhibitor, targets serine-threonine kinases and receptor tyrosine kinases, and affects the tumor and vasculature in preclinical models. Based on its pharmacologic effect, it may be a useful cancer treatment. This study determined the maximum tolerated dose (MTD) of BAY 43-9006 in 42 patients with advanced, refractory metastatic or recurrent solid tumors. Dose-limiting toxicities (DLTs), safety, pharmacokinetics and tumor response were also evaluated. PATIENTS AND METHODS: In this open-label, phase I, dose-escalation study, BAY 43--9,006 was administered orally in repeated cycles of 35 days (28 days on/7 days off). Eight doses were investigated: from 50 mg every fourth day to 600 mg twice daily. Treatment continued until unacceptable toxicity, tumor progression or death. RESULTS: The MTD was 400 mg twice daily. BAY 43-9006 was well tolerated, with mild to moderate toxicities; only six patients discontinued study therapy due to adverse events. DLTs consisted of hand-foot skin reaction in three of seven patients receiving 600 mg twice daily. Stable disease was achieved in 22% of patients; median duration of stable disease was 7.2 months. Consistent with its observed half-life of approximately 27 h, BAY 43-9, 006 accumulated on multiple dosing. Increases in exposure were less than proportional to the increases in dose. CONCLUSIONS: Results indicate that further clinical investigation of BAY 43--9006 is warranted, and suggest it could be a promising future therapy for patients with cancer.

An NCIC CTG phase I/pharmacokinetic study of the matrix metalloproteinase and angiogenesis inhibitor BAY 12-9566 in combination with 5-fluorouracil/leucovorin.

BACKGROUND: This phase I study was performed to evaluate the safety, tolerability, and efficacy of the oral matrix metalloproteinase inhibitor BAY 12-9566 in combination with 5-fluorouracil/leucovorin in patients with advanced solid tumours, and to identify the maximum tolerated dose and the dose for use in future studies. PATIENTS AND METHODS: BAY 12-9566 and 5-fluorouracil/leucovorin were administered to 17 patients in 3 cohorts. Each patient served as his/her own control, with 5-fluorouracil being given alone on days 1-5 of cycle 1. In cohort 1, BAY 12-9566 at 800 mg p.o. b.i.d. was given with 350 mg/m2 5-fluorouracil/20 mg/m2 leucovorin x 5 days q28 days. In cohort 2, the BAY 12-9566 dose was reduced to 400 mg p.o. b.i.d., with the 5-fluorouracil/leucovorin doses remaining unchanged. Finally, in cohort 3, BAY 12-9566 400 mg bid was given with 5-fluorouracil 400 mg/m2/day. Patients were continued on therapy until unacceptable toxicity or tumour progression occurred. Pharmacokinetic analyses for both BAY 12-9566 and 5-fluorouracil were performed. RESULTS: The maximum tolerated dose was 400 mg p.o. b.i.d. BAY 12-9566 plus 5-fluorouracil/leucovorin at 400 mg/m2/day and 20 mg/m2/day, respectively. Thrombocytopenia necessitated a decrease of the dose of BAY 12-9566 by 50% from cohort 1 to cohort 2. Two dose-limiting toxicities occurred in cohort 3 consisting of neutropenic fever, and ileitis, causing severe diarrhea. Of 17 patients treated on study, 7 of 14 patients evaluable for response achieved stable disease. Pharmacokinetic analysis suggested there was no interaction between BAY 12-9566 and 5-fluorouracil. CONCLUSIONS: BAY 12-9566 400 mg bid and 5-fluorouracil 350 mg/m2 plus leucovorin 20 mg/m2 can be co-administered. Although there is some evidence of a clinical interaction, there is no apparent pharmacokinetic interaction. Future studies with these 2 types of agents administered in combination are warranted.

A phase I and pharmacokinetic study of BAY59: a novel taxane.

PURPOSE: To determine the maximum tolerated dose (MTD), the dose limiting toxicities (DLT) and the pharmacokinetics of BAY59, a novel taxane given as a 1-hour intravenous infusion every 3 weeks in patients with advanced refractory solid tumors. EXPERIMENTAL DESIGN: Initially, 15 patients with previously treated (median of 4 prior chemotherapy regimens) refractory cancers, but with normal marrow, hepatic and renal function were treated with BAY59 at doses of 15, 30, 50, 75 and 100 mg/m2 using a standard dose escalation design. Subsequently, 11 patients were treated, 5 at 90 mg/m2 and 6 who had had prior oxaliplatin at 75 mg/m2. RESULTS: At 75 mg/m2, grade 4 neutropenia was noted in 2/6 patients, of whom 1 had grade 4 neutropenia lasting more than 5 days (DLT). At 100 mg/m2, 2/2 patients had febrile neutropenia, with 1 fatality. At 90 mg/m2, 2/5 patients had DLTs, including grade 3 neuropathy, severe lower extremity pain, dehydration and grade 4 neutropenia. The MTD was determined to be 75 mg/m2. A cohort of 6 patients, previously exposed to oxaliplatin, were enrolled at the MTD to evaluate the incidence of neurotoxicity. While DLTs (grade 3 arthralgia, grade 4 neutropenia) were noted in 3/6 patients, there was no increase in the incidence of neurotoxicity. There were no responses. Pharmacokinetics of BAY59 was linear over the doses studied, with a median terminal half-life of 21 h. CONCLUSIONS: The recommended phase II dose for BAY59 is 75 mg/m2.

Pharmacokinetics and tolerability of a new intravenous immunoglobulin preparation, IGIV-C, 10% (Gamunex, 10%).

BACKGROUND AND OBJECTIVES: A new intravenous immunoglobulin (IGIV) process has been developed that integrates efficient inactivation of enveloped virus, using caprylate, with immunoglobulin G (IgG) purification and caprylate removal by column chromatography. Two clinical studies were conducted to compare the pharmacokinetics of the new product, IGIV-C, 10% (Gamunex, 10%), formulated with glycine, with the licensed solvent-detergent (SD)-treated intravenous immunoglobulin IGIV-SD, 10% (Gamimune N, 10%), formulated with glycine, and IGIV-C, 5%, formulated with 10% maltose. MATERIALS AND METHODS: Both studies were randomized, multicentre crossover trials of 18 and 20 (respectively) adult patients with primary humoral immune deficiency in which patients received one IGIV product for three consecutive periods (3-4 weeks) before crossing over to the other product. Pharmacokinetic parameters were determined after the third infusion of each product. RESULTS: IGIV-C, 10% was bioequivalent to IGIV-SD, 10%, with half-lives (t1/2) of 35 and 34 days, respectively. IGIV-C, 5%, was bioequivalent to IGIV-C, 10%, with t1/2 of 35 and 36 days, respectively. The products had comparable safety profiles. CONCLUSIONS: The pharmacokinetic profiles observed in these trials indicate that IGIV-C, 10% may replace, and be administered in a manner similar to, IGIV-SD, 10%.

Effect of age and gender on the safety, tolerability, and pharmacokinetics of BAY 12-9566 in healthy subjects.

The impact of age and gender on the single-dose pharmacokinetics, safety, and tolerability of BAY 12-9566 was evaluated in healthy subjects. Volunteers were grouped according to age and gender (13 young males, 11 elderly males, and 12 elderly females) and then randomized in a 2:1 ratio to receive a single oral 50 mg dose of BAY 12-9566 or placebo. Serial plasma samples were collected up to 336 hours postdose and assayed for BAY 12-9566. Peak plasma concentration, time to reach peak plasma concentration, the area under the concentration-time curve, oral clearance, volume of distribution, and elimination half-life were calculated. BAY 12-9566 was well tolerated in all treatment groups, and no serious adverse events occurred during the study. Substantial age- or gender-related differences were not observed for any of the pharmacokinetic parameters tested. Based on these pharmacokinetic and tolerability profiles, age- or gender-related dose adjustments were not required for BAY 12-9566.

Distribution of [14C]suramin in tissues of male rats following a single intravenous dose.

PURPOSE: Suramin has been shown to have efficacy in treatment of prostate cancer. In the present study we evaluated distribution of [14C]suramin in tissues over time following a single intravenous dose. METHODS: Male rats were given a single IV dose of 300 mg/kg [14C]suramin and sacrificed at 1 or 6 hours, or at 1, 7, 14, 28, 56, or 84 days postdose. Radioactivity remaining in tissues was measured by quantitative whole body autoradiography. RESULTS: At one hour highest tissue activity was found in blood vessel walls and caecum, followed by lung, blood, skin, preputial, thyroid, brown fat, heart, kidney, lymph nodes, liver, salivary, adrenal, Harder's and lacrimal glands, prostate, and spleen. Considerable activity was present in membranes surrounding muscle groups, bone and other organs. Relatively low activity was found in brain tissue although persistent concentration was evident in choroid plexus. High levels were present in bladder and caecum contents. Activity declined in blood but continued to increase in many tissues at later time points. Kidney reached maximum levels at 7 days postdose and retained concentration considerably higher than other tissues over the course of the study. Concentrations in tissues were persistent and considerable activity remained at 84 days postdose. Terminal elimination half life in tissues was prolonged, approximately 39 days in blood and 91 and 102 days in kidney and spleen, respectively. Uptake in prostate was highest in membranous structures separating secretory lobules. CONCLUSION: Suramin is widely distributed to tissues and appears to have particular affinity for boundary membranes surrounding organs and other structural tissue elements, possibly due to uptake by glycosaminoglycans. Antitumor activity may be related to inhibition of growth factors associated with these elements.

The ACAT inhibitor avasimibe reduces macrophages and matrix metalloproteinase expression in atherosclerotic lesions of hypercholesterolemic rabbits.

Given the significance of cholesteryl ester (CE) accumulation in macrophage foam cell formation, we hypothesized that inhibitors of acyl-CoA:cholesterol O-acyltransferase (ACAT) would produce a histologically stable lesion by limiting macrophage enrichment and thereby a source of matrix metalloproteinases (MMPs). Male New Zealand White rabbits were sequentially fed a cholesterol/fat diet for 9 weeks, a fat-only diet for 6 weeks, and 25 mg/kg avasimibe for 7 to 8 weeks. Avasimibe had no effect on plasma total cholesterol exposure. Plasma avasimibe maximal concentration and 24-hour area-under-the-curve levels were 178 ng/mL and 2525 ng. h/mL, respectively, after 7 weeks of treatment with 25 mg/kg avasimibe. The median inhibitory concentration against human monocyte-macrophage ACAT was 12 ng/mL when determined in the absence of albumin, and aortic arch avasimibe levels were 25 ng/g of tissue wet weight. Avasimibe reduced thoracic aortic and iliac-femoral CE content by 39%, the extent of thoracic aortic lesions by 41%, aortic arch cross-sectional lesions area by 35%, and monocyte-macrophage area by 27%. The reduction in monocyte-macrophage area reflected a change in cell number and not cell size. In the iliac-femoral artery, avasimibe decreased monocyte-macrophage content by 77% and reduced the macrophage-to-lesion ratio from 0.16 to 0.05. Within the aortic arch, the catalytic activity of latent and active MMP-9 was reduced by 65% and 33%, respectively; latent and active MMP-1 and MMP-3 activity measured collectively was decreased by 52% and 60%, respectively, and MMP-2 was unchanged. Aortic arch MMP-9, tissue inhibitor of matrix metalloproteinase (TIMP)-1, and TIMP-2 mRNA levels were reduced 29% to 39%, and MMP-2 mRNA levels increased. We conclude that the bioavailable ACAT inhibitor avasimibe can directly limit macrophage accumulation, resulting in the histological appearance of mainly fibromuscular lesions, and can potentially stabilize preestablished atherosclerotic lesions by reducing MMP expression within the lesion.

Development of a chiral HPLC method to evaluate in vivo enantiomeric inversion of an unstable, polar radiosensitizer in plasma.

A chiral HPLC method to quantify in vivo enantiomeric inversion of prodrug CI-1010 (IR) or its drug IIR (PD 146923), a radiosensitizer, upon X-irradiation of dosed rats was developed. These polar enantiomers were separated only by using normal-phase chiral HPLC. A Chiralpak AS column provided the best separation. Isolation of analytes from plasma employed solid-phase extraction (SPE), and required conditions that were compatible with normal-phase HPLC. Options for SPE were restricted by the chemically reactive nature of both prodrug and drug, which produced analyte losses as high as 100%. Acceptable recoveries using SPE required evaluation of conditions for analyte chemical stability. The validated method gave a lower-limit of quantitation (LLOQ) of 200 ng/ml for each enantiomer extracted from 0.15 ml of plasma. The LLOQ of the inverted enantiomer could be detected in the presence of 10,000 ng/ml of the dosed enantiomer. Precision (RSD) ranged from 14.2 to 4.4%, and from 24.2 to 5.1% for IIS and IIR, respectively. Accuracy (RE) was +/- 13.1 and +/- 13.2%, respectively. Recoveries ranged from 44.3 to 71.4%, and from 40.7 to 67.9%, for IIS and IIR, respectively.

Validated HPLC/MS/MS assay for CI-1011 in rat plasma and a comparison with an HPLC/UV assay.

A liquid chromatographic/mass spectrometric (LC/MS/MS) method to quantitate CI-1011 in rat plasma has been validated and compared to an LC/UV assay. The analyte and internal standard were isolated from the plasma matrix by using liquid/liquid extraction with diethyl ether. The ether layer was evaporated to dryness and the residue reconstituted in acetonitrile-water (70:30, v/v). A 2.1 x 150 mm x 5 microns Zorbax RX-C18 column with a mobile phase of acetonitrile-ammonium acetate (pH 8.0; 5 mM)-triethylamine (70:30:0.03, v/v/v) delivered at a flow rate of 0.2 ml min-1 was used for chromatography. Analyte and internal standard ion chromatograms were obtained by operating the mass spectrometer in the negative ion multiple reaction monitoring mode to detect the presence of a precursor-product ion pair for both the analyte and the internal standard. Samples were introduced into the mass spectrometer using electrospray ionization. Retention times of CI-1011 and of the internal standard (IS), [13C6]CI-1011, were approximately 4.2 min. No peaks interfering with the quantitation of CI-1011 were observed throughout the validation process. Mean recoveries of CI-1011 from rat plasma ranged from 98.2 to 105%. The recovery of the IS was 100%. Assay precision for CI-1011, based on the percent relative standard deviation of replicate quality controls, was less than or equal to 5.60% with an accuracy of +/- 8.80%. The lower limit of quantitation for CI-1011 was 0.500 ng ml-1 for a 0.2-ml sample aliquot. CI-1011 is stable in rat plasma for 24 h at room temperature and for at least 34 days at -20 degrees C. This assay has been proven suitable for routine quantitation of CI-1011 in rat plasma at concentrations from 0.500 (100 pg on-column) to 500 ng ml-1. The applicability of this method to determine CI-1011 concentrations in rat plasma is reported in this manuscript. CI-1011 concentrations, in plasma samples from cholesterol- and chow-fed rats administered single daily oral doses of CI-1011 in a CMC/Tween suspension, obtained using a validated LC/UV assay were compared to concentrations obtained using the reported LC/MS/MS assay over the concentration range 0.0806-12.3 micrograms ml-1. The concordance correlation coefficient determined for this comparison was 0.9977, suggesting that the CI-1011 concentrations obtained by the two assays are in excellent agreement.

Management of nonmatrix interfering peaks in a chiral high-performance liquid chromatographic assay produced by solid-phase extraction of rat plasma.

PD 146923, under evaluation as an alkylating radiosensitizing drug, contains one chiral center and one chemically reactive aziridine ring. A method was developed to evaluate possible in vivo enantiomeric inversion of PD 146923 in rat plasma. Normal-phase chiral HPLC was necessary to separate the enantiomers, but a typical aqueous-based solid-phase extraction (SPE) was needed to isolate the analytes from plasma. SPE at higher analyte concentrations removed all interfering peaks and gave acceptable recoveries. However, peaks (A-G) from seven new components interfering with analyte detection at lower concentrations were produced by SPE. The interfering peaks overlapped each other, so some were not observed until other, more intense interfering peaks had been managed. The low separation efficiency of the chiral column precluded management of interfering peaks by modifying chromatographic parameters. Chemical reactivity of the analytes forced the use of mild conditions for management of interfering peaks. Peaks A-F were: (A) water from the SPE cartridge; (B) SPE sorbent endcapping; (C, E and F) nonvolatile salts of the SPE elution acid reacting with bases from the injection solvent or with unidentified bases from the SPE cartridge; (D and G) analyte degradation products. This study identifies the nonmatrix peaks coeluting with the analytes, and describes how an aqueous-based SPE method was developed for isolating these very polar, highly reactive analytes in plasma for separation in a normal-phase chiral HPLC assay. Additionally, B, C, E or F probably are present in many other solid-phase extractions, but are not observed because of polarity or solubility properties.

A phase I trial and pharmacokinetic evaluation of CI-980 in patients with advanced solid tumors.

CI-980 is a synthetic mitotic inhibitor that binds to the colchicine binding site of tubulin. It demonstrates broad activity against human and murine tumor models and shows no cross resistance with tumor models whose mechanism of resistance is mediated by P-glycoprotein (MDR-1). A phase I study was completed in 25 patients with solid tumors using a 24-hour infusion schedule, with courses repeated every 3 weeks. Eight dose levels were tested between 1.2 and 15.6 mg/m2. The maximum tolerated dose was 14.4 mg/m2. Neutropenia was dose-related but not dose-limiting; thrombocytopenia was infrequent. CNS toxicities were dose-limiting and consisted of dizziness, headache, loss of coordination, loss of consciousness, nervousness, and other symptoms. These events occurred near the end of the infusion and were reversible, usually within 24 hours. One patient who was to be treated at dose level 8 (intended dose was 19.2 mg/m2; actual dose was 15.6 mg/m2) became encephalopathic prior to completion of the infusion. Other adverse events included gastrointestinal toxicities (nausea, vomiting, anorexia, constipation, stomatitis, dyspepsia, bleeding, cheilitis), IV site erythema, fever, and fatigue. A partial response was observed in one patient with colon cancer and reductions in CA-125 levels were observed in 2 patients with ovarian cancer. Pharmacokinetics were linear and dose-proportional. Results indicate high systemic clearance and wide tissue distribution. Mean pharmacokinetic parameter values: T1/2 = 5.52 hours, plasma clearance 1163 mL/min/m2, and Vdss 376 L/m2.

An HPLC assay utilizing solid-phase extraction for CI-1010, an alkylating radiosensitizer, in rat plasma.

CI-1010, a 2-nitroimidazole, is a chiral prodrug for the active moiety PD 146923 and is under development as an alkylating radiosensitizer to be used as an adjuvant to radiotherapy. Because CI-1010 has an estimated half-life < or = 2 min under physiological conditions its metabolites/degradation products PD 146415, an inactive moiety, and PD 146923 were assayed to support rat toxicology studies. The method involves the processing of plasma samples through phenyl solid-phase extraction cartridges followed by chromatography on CN columns with UV detection at 325 nm. The assay appears linear over the range 0.050-100 micrograms ml-1 for both PD 146415 and PD 146923. Interrun accuracy and precision estimates for PD 146415 and PD 146923 were within +/- 6.50 and < or = 3.27%, respectively, and +/- 12.8 and < or = 4.06%, respectively, for quality controls containing nominal concentrations of 0.400, 4.00 and 40.0 micrograms ml-1. The absolute recovery of CI-1010, PD 146415 and internal standard, PD 126675, were approximately 40, 96 and 95%, respectively. The recovery of PD 146923 appeared concentration dependent and ranged from 68 to 92%. PD 146415 and PD 146923 were both stable in rat plasma at 4 degrees C and -77 degrees C for at least 7 h and 154 days, respectively. CI-1010 was not stable in rat plasma at 4 degrees C. CI-1010, PD 146415 and PD 126675 were stable for at least 63 days in 10 mM phosphate buffer at pH 3.0 and 4 degrees C. Under identical conditions PD 146923 was stable for only 8 days. The applicability of this method to determine concentrations of PD 146415 and PD 146923 in rat plasma is reported in this paper.

Pharmacokinetic evaluation of zeniplatin in humans.

Zeniplatin, a more water-soluble organoplatinum than cisplatin, was evaluated for clinical pharmacology in the context of a phase II trial in previously treated patients with ovarian carcinoma. A total of 12 patients were given zeniplatin at 120 mg/m2 by rapid intravenous infusion over 90 min, with both blood and urine being sampled. All platinum moieties were analyzed in whole blood, plasma, plasma ultrafiltrate, and urine by atomic absorption, and free zeniplatin was analyzed in plasma ultrafiltrate by specific high-performance liquid chromatography (HPLC). In a comparison of the platinum-time concentration curve, AUC (area under the curve) values indicated that approximately 90% of platinum moieties were bound to circulating plasma proteins. There was no evidence of drug accumulation after repetitive dosing. The terminal half-life (t1/2) of this drug in plasma ultrafiltrate (3.7-7.2 h.) as measured by HPLC was slightly longer than that of carboplatin, whereas total platinum moieties in plasma displayed a long t1/2 (124-154 h). Approximately 60% of platinum moieties could be recovered in the urine within 24 h. These findings suggest that zeniplatin has a pharmacokinetic profile similar to that of carboplatin.