Clinical and microarray analysis of breast cancers of all subtypes from two prospective preoperative chemotherapy studies.

BACKGROUND: We aimed to analyse clinical and gene expression profiles to predict pathologic complete response and disease-free survival using two consecutive, prospective, preoperative chemotherapy trial cohorts. METHODS: Clinicopathological and gene expression data were evaluated in a cohort from two consecutive phase II preoperative studies that included patients with stage IIA-IIIC breast cancer of all subtypes. Analysed specimens were obtained before preoperative chemotherapy, and cDNA microarray analyses were performed using the Affymetrix Gene Chip U133 plus 2.0. RESULTS: Between December 2005 and December 2010, 122 patients were analysed. The pathologic complete response rate was significantly higher in HER2+ and HR-/HER2- cancers. Age, pathologic complete response, HR-/HER2- status, and lymph node positivity (⩾4) were significant poor prognostic factors for disease-free survival. For the cDNA microarray analyses, sufficient tumour samples were available from 78 of the 107 patients (73%). An 8-gene signature predictive of pathologic complete response and a 17-gene signature predictive of prognosis were identified. Patients were categorised into low-risk (n=45) and high-risk groups (n=33) (HR 70.0, P=0.004). CONCLUSIONS: This study yielded preliminary data on the expression of specific genes predicting pathologic complete response and disease-free survival in a cohort of chemonaïve breast cancer patients. Further validation may distinguish those who would benefit most from perioperative chemotherapy as well as those needing further intervention.

Activated PI3K/AKT and MAPK pathways are potential good prognostic markers in node-positive, triple-negative breast cancer.

BACKGROUND: Triple-negative breast cancer (TNBC) patients are a poor prognostic subgroup, and currently, there is no biomarker for targeted therapy. PATIENTS AND METHODS: Tissue samples were obtained from 75 TNBC patients with lymph-node metastases who had received adjuvant chemotherapy. We examined 11 biomarkers, including PIK3CA and AKT1mutation, with regard to event-free survival (EFS) and overall survival (OS) of patients. RESULTS: In the tumor tissues, phospho-AKT (pAKT) expression was significantly related to HER4 expression. Expression of each of these biomarkers was significantly related to longer EFS (P = 0.024 and 0.03, respectively). pERK expression was also a good prognostic factor regarding EFS and OS in TNBC (P = 0.002 and 0.006, respectively). We also identified a correlation between epidermal growth factor receptor positivity and insulin-like growth factor receptor type 1 positivity (P = 0.001). pERK and T-stage (1-3 versus >3) were independent good prognostic factors by multivariate analysis. CONCLUSIONS: We determined that tumors expressing pAKT or pERK are a good prognostic subtype in node-positive TNBC. Different targeted therapies may be necessary for TNBC that involves activation of PI3K/AKT or MAPK pathways.

Clinical impact of pentraxin family expression on prognosis of pancreatic carcinoma.

BACKGROUND: Inflammatory mediators may have decisive roles at different stages of tumour development. Mediators within the pentraxin family may be used as strong biomarkers in prognosis of advanced pancreatic carcinoma patients. METHODS: Using pancreatic carcinoma cell lines and gene transfectant, we measured long pentraxin (PTX3) level in culture solution and carried out cellular migration assay in vitro. In vivo study of the treatment-naive patients with advanced pancreatic carcinoma assigned to undergo gemcitabine therapy was prospectively conducted to measure and investigate the role of plasma PTX3, C-reactive protein (CRP), and eight inflammatory mediators by using collected clinical data. RESULTS: Elevated PTX3 production was observed in several cell lines, and a direct relationship between migratory activity and PTX3 level was identified in vitro. High PTX3 level (117 days) was significantly less than that of patients with low PTX3 level (357 days, P<0.001). Multivariate analysis of the pancreatic carcinoma revealed a strong correlation between pentraxin family member expression and prognosis of pancreatic carcinoma. The relationship between PTX3 expression and the expression of other pro-inflammatory mediators indicated that PTX3 level is positively correlated with levels of CRP, interleukin-6, and macrophage-inhibitory factor. CONCLUSION: Pentraxin family members, especially PTX3, may be used as promising biomarkers in the prognosis of pancreatic carcinoma patients.

Phase 1 study of lenvatinib combined with carboplatin and paclitaxel in patients with non-small-cell lung cancer.

BACKGROUND: This dose-finding study evaluated lenvatinib, an oral multitargeted receptor tyrosine kinase inhibitor, in combination with carboplatin/paclitaxel in chemotherapy-naïve non-small-cell lung cancer (NSCLC) patients. PATIENTS AND METHODS: Patients received lenvatinib twice daily (BID) with carboplatin (area under the curve 6 mg ml(-1) min(-1), day 1)/paclitaxel (200 mg m(-2), day 1) every 3 weeks. The initial dose of lenvatinib was 6 mg BID. The primary end point was maximum tolerated dose (MTD) of lenvatinib. At the MTD, the cohort was expanded by 16 patients. Safety, pharmacokinetics, pharmacodynamics, and antitumor effects were evaluated. RESULTS: Twenty-eight patients were treated. At 6 mg BID, dose-limiting toxicities (DLTs) included febrile neutropenia/gingival infection (n=2). No DLTs occurred with 4 mg BID, the recommended MTD for the expansion. Common grade 3/4 toxicities included neutropenia, leukopenia, hypertension, and thrombocytopenia. The combination had no significant impact on individual drug pharmacokinetics. Response rate and median progression-free survival were 68% and 9.0 months, respectively, with 4 mg BID. In the plasma biomarker analysis, stromal cell-derived factor 1α, stem cell factor, and granulocyte colony-stimulating factor correlated with antitumor activity. CONCLUSION: The MTD for lenvatinib with carboplatin/paclitaxel is 4 mg BID in advanced NSCLC patients. This regimen demonstrated manageable tolerability and encouraging antitumor activity.

Simultaneous determination of dextromethorphan, dextrorphan and doxylamine in human plasma by HPLC coupled to electrospray ionization tandem mass spectrometry: application to a pharmacokinetic study.

In the present study, a fast, sensitive and robust method to quantify dextromethorphan, dextrorphan and doxylamine in human plasma using deuterated internal standards (IS) is described. The analytes and the IS were extracted from plasma by a liquid-liquid extraction (LLE) using diethyl-ether/hexane (80/20, v/v). Extracted samples were analyzed by high performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). Chromatographic separation was performed by pumping the mobile phase (acetonitrile/water/formic acid (90/9/1, v/v/v) during 4.0min at a flow-rate of 1.5 mL min⁻¹ into a Phenomenex Gemini® C18, 5 µm analytical column (150 × 4.6 mm i.d.). The calibration curve was linear over the range from 0.2 to 200 ng mL⁻¹ for dextromethorphan and doxylamine and 0.05 to 10 ng mL⁻¹ for dextrorphan. The intra-batch precision and accuracy (%CV) of the method ranged from 2.5 to 9.5%, and 88.9 to 105.1%, respectively. Method inter-batch precision (%CV) and accuracy ranged from 6.7 to 10.3%, and 92.2 to 107.1%, respectively. The run-time was for 4 min. The analytical procedure herein described was used to assess the pharmacokinetics of dextromethorphan, dextrorphan and doxylamine in healthy volunteers after a single oral dose of a formulation containing 30 mg of dextromethorphan hydrobromide and 12.5mg of doxylamine succinate. The method has high sensitivity, specificity and allows high throughput analysis required for a pharmacokinetic study.

FGFR2 gene amplification and clinicopathological features in gastric cancer.

BACKGROUND: Frequency of FGFR2 amplification, its clinicopathological features, and the results of high-throughput screening assays in a large cohort of gastric clinical samples remain largely unclear. METHODS: Drug sensitivity to a fibroblast growth factor receptor (FGFR) inhibitor was evaluated in vitro. The gene amplification of the FGFRs in formalin-fixed, paraffin-embedded (FFPE) gastric cancer tissues was determined by a real-time PCR-based copy number assay and fluorescence in situ hybridisation (FISH). RESULTS: FGFR2 amplification confers hypersensitivity to FGFR inhibitor in gastric cancer cell lines. The copy number assay revealed that 4.1% (11 out of 267) of the gastric cancers harboured FGFR2 amplification. No amplification of the three other family members (FGFR1, 3 and 4) was detected. A FISH analysis was performed on 7 cases among 11 FGFR2-amplified cases and showed that 6 of these 7 cases were highly amplified, while the remaining 1 had a relatively low grade of amplification. Although the difference was not significant, patients with FGFR2 amplification tended to exhibit a shorter overall survival period. CONCLUSION: FGFR2 amplification was observed in 4.1% of gastric cancers and our established PCR-based copy number assay could be a powerful tool for detecting FGFR2 amplification using FFPE samples. Our results strongly encourage the development of FGFR-targeted therapy for gastric cancers with FGFR2 amplification.

FcγR2A and 3A polymorphisms predict clinical outcome of trastuzumab in both neoadjuvant and metastatic settings in patients with HER2-positive breast cancer.

BACKGROUND: Antibody-dependent-mediated cytotoxicity (ADCC) is one of the modes of action for trastuzumab. Recent data have suggested that fragment C γ receptor (FcγR) polymorphisms have an effect on ADCC. This prospective phase II trial aimed to evaluate whether these polymorphisms are associated with clinical efficacies in patients who received trastuzumab. PATIENTS AND METHODS: Patients in a neoadjuvant (N) setting received Adriamycin and cyclophosphamide followed by weekly paclitaxel/trastuzumab. Patients in a metastatic (M) setting received single trastuzumab until progression. In total, 384 distinct single nucleotide polymorphisms of different FcγR, HER2, and fucosyltransferase loci were assessed. RESULTS: Fifteen operable and 35 metastatic HER2-positive breast cancer patients were enrolled in each of the N and M settings, respectively. The FcγR2A-131 H/H genotype was significantly correlated with the pathologically documented response (pathological response) (P = 0.015) and the objective response (P = 0.043). The FcγR3A-158 V/V genotype was not correlated with the pathological response, but exhibited a tendency to be correlated with the objective response. Patients with the FcγR2A-131 H/H genotype had significantly longer progression-free survival in the M setting (P = 0.034). CONCLUSION: The FcγR2A-131 H/H polymorphism predicted the pathological response to trastuzumab-based neoadjuvant chemotherapy in early-stage breast cancer, and the objective response to trastuzumab in metastatic breast cancer.

Evaluation of epidermal growth factor receptor mutation status in serum DNA as a predictor of response to gefitinib (IRESSA).

The aim of this study was to evaluate the usefulness of EGFR mutation status in serum DNA as a means of predicting a benefit from gefitinib (IRESSA) therapy in Japanese patients with non-small cell lung cancer (NSCLC). We obtained pairs of tumour and serum samples from 42 patients treated with gefitinib. EGFR mutation status was determined by a direct sequencing method and by Scorpion Amplification Refractory Mutation System (ARMS) technology. EGFR mutations were detected in the tumour samples of eight patients and in the serum samples of seven patients. EGFR mutation status in the tumours and serum samples was consistent in 39 (92.9%) of the 42 pairs. EGFR mutations were strong correlations between both EGFR mutation status in the tumour samples and serum samples and objective response to gefitinib (P<0.001). Median progression-free survival time was significantly longer in the patients with EGFR mutations than in the patients without EGFR mutations (194 vs 55 days, P=0.016, in tumour samples; 174 vs 58 days, P=0.044, in serum samples). The results suggest that it is feasible to use serum DNA to detect EGFR mutation, and that it's potential as a predictor of response to, and survival on gefitinib is worthy of further evaluation.

NK105, a paclitaxel-incorporating micellar nanoparticle, is a more potent radiosensitising agent compared to free paclitaxel.

NK105 is a micellar nanoparticle formulation designed to enhance the delivery of paclitaxel (PTX) to solid tumours. It has been reported to exert antitumour activity in vivo and to have reduced neurotoxicity as compared to that of free PTX. The purpose of this study was to investigate the radiosensitising effect of NK105 in comparison with that of PTX. Lewis lung carcinoma (LLC)-bearing mice were administered a single intravenous (i.v.) injection of PTX or NK105; 24 h after the drug administration, a proportion of the mice received radiation to the tumour site or lung fields. Then, the antitumour activity and lung toxicity were evaluated. In one subset of mice, the tumours were excised and specimens were prepared for analysis of the cell cycle distribution by flow cytometry. Combined NK105 treatment with radiation yielded significant superior antitumour activity as compared to combined PTX treatment with radiation (P=0.0277). On the other hand, a histopathological study of lung sections revealed no significant difference in histopathological changes between mice treated with PTX and radiation and those treated with NK105 and radiation. Flow-cytometric analysis showed that NK105-treated LLC tumour cells showed more severe arrest at the G2/M phase as compared to PTX-treated tumour cells. The superior radiosensitising activity of NK105 was thus considered to be attributable to the more severe cell cycle arrest at the G2/M phase induced by NK105 as compared to that induced by free PTX. The present study results suggest that further clinical trials are warranted to determine the efficacy and feasibility of combined NK105 therapy with radiation.

Reference profiling of the genomic response induced by an antimicrotubule agent, TZT-1027 (Soblidotin), in vitro.

TZT-1027 is an antimicrotubule agent targeting beta-tubulin that is undergoing clinical development. The genomic response of cancer cells to TZT-1027 was profiled to evaluate its biochemical activity. A lung cancer cell line, PC-14, was exposed to antimicrotubule agents including dolastatins, Vinca alkaloids and taxanes at an equivalent toxicity level. Alterations in the TZT-1027-induced gene expression of approximately 600 genes were then examined using microarray technology and the resulting gene profiles were compared with those for cells exposed to the other antimicrotubule agents. A principle component analysis using the whole gene set demonstrated that TZT-1027 produced similar gene profiles to those produced by dolastatin 10, but that these gene profiles differed from those produced by other agents. The agents were classified according to their induced genomic response in a molecular structure-dependent manner. Genes whose expression profiles differed according to drug class included intermediate filaments, extracellular matrix protein and Rho regulatory genes that may be involved in cytoskeletal and angiogenesis processes that are regulated by microtubule dynamics. TZT-1027 produces a unique genomic response profile distinct from that of Vinca alkaloids and taxanes, suggesting that this agent has a different mechanism of action. The selected genes may act as pharmacodynamic biomarkers allowing the unique mode of action of TZT-1027 to be discriminated from those of other antimicrotubule agents.

Cisplatin-incorporating polymeric micelles (NC-6004) can reduce nephrotoxicity and neurotoxicity of cisplatin in rats.

In spite of the clinical usefulness of cisplatin (CDDP), there are many occasions in which it is difficult to continue the administration of CDDP due to its nephrotoxicity and neurotoxicity. We examined the incorporation of CDDP into polymeric micelles to see if this allowed the resolution of these disadvantages. Cisplatin was incorporated into polymeric micelles through the polymer-metal complex formation between polyethylene glycol poly(glutamic acid) block copolymers and CDDP (NC-6004). The pharmacokinetics, pharmacodynamics, and toxicity studies of CDDP and NC-6004 were conducted in rats or mice. The particle size of NC-6004 was approximately 30 nm, with a narrow size distribution. In rats, the area under the curve and total body clearance values for NC-6004 were 65-fold and one-nineteenth the values for CDDP (P<0.001 and 0.01, respectively). In MKN-45-implanted mice, NC-6004 tended to show antitumour activity, which was comparable to or greater than that of CDDP. Histopathological and biochemical studies revealed that NC-6004 significantly inhibited the nephrotoxicity of CDDP. On the other hand, blood biochemistry revealed transient hepatotoxicity on day 7 after the administration of NC-6004. Furthermore, rats given CDDP showed a significant delay (P<0.05) in sensory nerve conduction velocity in their hind paws as compared with rats given NC-6004. Electron microscopy in rats given CDDP indicated the degeneration of the sciatic nerve, but these findings were not seen in rats given NC-6004. These results were presumably attributable to the significantly reduced accumulation of platinum in nerve tissue when NC-6004 was administered (P<0.05). NC-6004 preserved the antitumour activity of CDDP and reduced its nephrotoxicity and neurotoxicity, which would therefore seem to suggest that NC-6004 could allow the long-term administration of CDDP where caution against hepatic dysfunction must be exercised.

Bismuth glass holey fibers with high nonlinearity.

We report on the progress of bismuth oxide glass holey fibers for nonlinear device applications. The use of micron-scale core diameters has resulted in a very high nonlinearity of 1100 W-1 km-1 at 1550 nm. The nonlinear performance of the fibers is evaluated in terms of a newly introduced figure-of-merit for nonlinear device applications. Anomalous dispersion at 1550 nm has been predicted and experimentally confirmed by soliton self-frequency shifting. In addition, we demonstrate the fusion-splicing of a bismuth holey fiber to silica fibers, which has resulted in reduced coupling loss and robust single mode guiding at 1550 nm.

Reversal of cisplatin resistance by the 1,4-benzothiazepine derivative, JTV-519.

The 1,4-benzothiazepine derivative JTV-519 is a new type of calcium ion channel modulator. We examined the modulatory effect of JTV-519 on the antitumor activity of several platinum compounds (cisplatin, carboplatin, and nedaplatin) in a human cancer cell line resistant to cisplatin (PC-14 / CDDP) in vitro. PC-14 / CDDP cells showed 8-fold resistance to cisplatin compared with the parental PC-14 cells as determined by dye formation [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, MTT] assay. In PC-14 / CDDP, but not PC-14 cells, augmentation of cytotoxicity was observed when a nontoxic concentration (10 mM) of JTV-519 was combined with the platinum compounds. Increased intracellular cisplatin accumulation was observed in PC-14 / CDDP cells in the presence of JTV-519 as measured by atomic absorption assay. Therefore, increased cisplatin accumulation was considered to be a possible mechanism underlying the reversing effect of JTV-519 on cisplatin resistance. These results suggest that JTV-519 is a potent agent reversing cisplatin resistance.

In vitro synergistic interactions between the cisplatin analogue nedaplatin and the DNA topoisomerase I inhibitor irinotecan and the mechanism of this interaction.

Among the numerous clinical regimens used in combination chemotherapy, synergy is particularly marked in combinations containing cisplatin (CDDP). However, the clinical use of CDDP is sometimes limited due to its nephrotoxicity. Nedaplatin (NDP) is a second-generation platinum complex with reduced nephrotoxicity that may substitute for CDDP or even surpass it for use in combination with other drugs. We investigated the effects of combinations of NDP and other anticancer drugs on the growth of human small cell lung cancer cells (SBC-3) and non-small cell lung cancer cells (PC-14) using a three-dimensional analysis model. Among the combinations tested, the combination of NDP and irinotecan (CPT-11) showed the most marked synergistic interaction, and the synergism has also been observed against PC-14 cells. With regard to treatment schedule, a remarkable synergistic interaction was produced by concurrent exposure to NDP and CPT-11. On the other hand, sequential exposure to the two drugs led only to additivity. To analyze the interaction between the drugs, the effect of NDP on the 7-ethyl-1-hydroxy-CPT (the active form of CPT-11)-induced inhibitory effect on DNA topoisomerase I was examined. The topoisomerase I-inhibitory effect of 7-ethyl-1-hydroxy-CPT was enhanced 10-fold in the presence of NDP at microgram/milliliter concentrations. These biochemical interactions might be responsible for the synergistic interaction between NDP and CPT-11. These results suggest that the combination of NDP with CPT-11 may be clinically useful for the chemotherapy of lung cancer.

DNA/RNA-dependent ATPase activity is associated with ATBF1, a multiple homeodomain-zinc finger protein.

The AT motif-binding factor 1 (ATBF1)-A is a large transcription factor containing four homeodomains and 23 zinc finger motifs. It has a number of motifs involved in transcriptional regulation, and in addition, several motifs found in enzymes, such as ATPases and helicases. In this study, we examined whether ATPase activity is associated with the ATBF1-A molecule. A 263-amino acid segment of the ATBF1-A molecule, termed AHZ, which contains the ATPase A-motif, homeodomain IV and zinc finger 21, was expressed in Escherichia coli in the form of glutathione S-transferase fusion protein and analyzed for ATPase activity. We found that AHZ was able to hydrolyze ATP with K(m) 10.6 microM and K(cat) 0.055 min(-1) at 5 mM Mg(2+) and pH 7.75. AHZ retained bacterial DNA and removal of the DNA resulted in 70% decrease in ATPase activity. The addition of double- or single-stranded DNAs restored 70-75% ATPase activity and that of RNA restored 50-55% activity. Site-directed mutagenesis of the A-motif resulted in 34% reduction of ATPase activity with no significant loss of bound DNA. In contrast, mutation of homeodomain IV and zinc finger 21 resulted in 90 and 80% reduction of ATPase, respectively, with the loss of the ability to bind to DNA and RNA. These results show that ATBF1 has at least one enzyme activity in addition to regulation of DNA transcription. The ATPase activity associated with ATBF1-A is DNA/RNA-dependent and unique in that it requires both homeodomain and zinc finger motifs.

Animal model of diabetic nephropathy.

Injection of subtotally nephrectomized rats with streptozotocin produced metabolic abnormalities resembling diabetic nephropathy in humans. These abnormalities were hyperglycemia, hypoinsulinemia, azotemia, hypertriglyceridemia and hypercholesterolemia, accompanied with an increase in glycosylated protein. Extraordinary changes in the urinary excretion of glucose and protein were also observed in rats that received streptozotocin treatment after subtotal nephrectomy. In addition, the level of creatinine clearance was significantly decreased. The pathological findings in the kidney of these rats revealed lesions of the glomerular capillary loops, mesangial area and Bowman's capsule. Coagulation was also found in the glomerular capillaries. Our results suggest that this rat model would be useful for studies of diabetic nephropathy.

Modulation of collagen synthesis by tumor necrosis factor alpha in cultured vascular smooth muscle cells.

Collagen synthesis in vascular smooth muscle cells (SMCs) after exposure to tumor necrosis factor alpha (TNF-alpha) was investigated using a culture system. The synthesis of collagenase-digestible proteins (CDP) and noncollagenous proteins (NCP) was evaluated by the [3H]proline incorporation. It was shown that TNF-alpha markedly suppresses the incorporation of [3H]proline into both CDP and NCP in confluent cultures of SMCs but not in sparse cultures of the cells. Such a marked suppression by TNF-alpha was not observed in confluent bovine aortic endothelial cells and human fibroblastic IMR-90 cells. In confluent SMCs, the synthesis of CDP was more strongly inhibited by TNF-alpha than that of NCP. When the CDP synthesis was stimulated by transforming growth factor beta, TNF-alpha suppressed the stimulation in both confluent and sparse SMCs. Human SMCs synthesized types I, III, IV and V collagens; TNF-alpha markedly decreased the relative proportion of types IV and V. It was therefore suggested that TNF-alpha modulates the collagen synthesis by SMCs depending on their cell density and modifies the formation of atherosclerotic lesions.

Molecular determinants of UCN-01-induced growth inhibition in human lung cancer cells.

UCN-01 (7-hydroxystaurosporine) inhibits the growth of various malignant cell lines in vitro and in vivo. In this study, a human small cell lung carcinoma subline resistant to UCN-01, SBC-3/UCN, was established and characterized. SBC-3/UCN cells showed 8-fold greater resistance to the UCN-01-induced growth-inhibitory effect than the parent cells, SBC-3. No UCN-01-induced G1 accumulation in SBC-3 cells was observed in SBC-3/UCN cells and decreased expression of phosphorylated RB protein was found in SBC-3 cells. Neither basal expression nor induction of p21(Cip1) by UCN-01 treatment was detected in the SBC-3/UCN cell line. An inhibitory effect of UCN-01 on CDK2 activity, which is mediated by p21(Cip1)/CDK2 complex formation upon UCN-01 treatment, was observed in SBC-3 but not in SBC-3/UCN cells. SBC-3/UCN showed higher CDK6 activity than SBC-3 cells. UCN-01 did not inhibit the CDK4 and CDK6 activities in both cells. We screened the cell cycle regulatory molecules associated with G(1)/S progression and found a remarked decrease in interferon regulatory factor 1 (IRF-1), which is known to cooperate with p53 in p21(Cip1) induction. Our results suggest that p21(Cip1) regulation via the IRF-1-associated pathway may represent a major determinant of UCN-01-induced growth inhibition in human lung cancer cells.

Smoking accelerates absorption of inhaled neutrophil elastase inhibitor FK706.

PURPOSE: We compared the pharmacokinetics of the inhaled novel neutrophil elastase inhibitor FK706 between healthy nonsmokers and smokers. METHODS: Six healthy nonsmokers and six smokers inhaled 50 to 400 mg FK706 in two different doses. Series of plasma concentrations of the SSS form of FK706 (pharmacologically active epimer) were analyzed model dependently and independently. Pharmacokinetic parameters obtained from each group were compared after standardization by doses. RESULTS: The plasma concentration-time curve of inhaled FK706 was apparently different between smokers and nonsmokers. The maximum plasma concentrations (Cmax) were significantly higher in the smokers than in the nonsmokers (smokers, 1.47 +/- 0.62 ng/mL/mg; nonsmokers, 0.49 +/- 0.14 ng/mL/mg [mean +/- SD; P < .01]). The time to reach Cmax (tmax) and elimination half-life (t1/2) were statistically smaller in the smokers compared with the tmax and elimination t1/2 in the nonsmokers (tmax in smokers, 0.44 +/- 0.27 hours; tmax in nonsmokers, 1.17 +/- 0.39 hours [P < .01]; t1/2 in smokers, 1.23 +/- 0.40 hours; t1/2 in nonsmokers, 2.73 +/- 0.57 hours [P < .01]). The area under the plasma concentration-time curve and plasma clearance were not significantly different between the two groups. Model-dependent pharmacokinetic analysis, assuming a flip-flop model, revealed that the absorption rate constant (ka) was about 10 times greater in smokers than the ka in nonsmokers. CONCLUSION: Significant increases of Cmax and ka and reductions of tmax and elimination t1/2 of the inhaled FK706 were observed in the healthy smokers, suggesting that the smoking habit accelerates the drug absorption after inhalation. These results suggest that we should pay attention to the drug-related adverse events caused by smoking, especially when the drug has a narrow therapeutic range.