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Biomedical subjects

David H Johnson

Publications and source records attributed to David H Johnson.

At least 19 recordsLinked to original sources
PubMed2006

Paclitaxel-carboplatin alone or with bevacizumab for non-small-cell lung cancer.

BACKGROUND: Bevacizumab, a monoclonal antibody against vascular endothelial growth factor, has been shown to benefit patients with a variety of cancers. METHODS: Between July 2001 and April 2004, the Eastern Cooperative Oncology Group (ECOG) conducted a randomized study in which 878 patients with recurrent or advanced non-small-cell lung cancer (stage IIIB or IV) were assigned to chemotherapy with paclitaxel and carboplatin alone (444) or paclitaxel and carboplatin plus bevacizumab (434). Chemotherapy was administered every 3 weeks for six cycles, and bevacizumab was administered every 3 weeks until disease progression was evident or toxic effects were intolerable. Patients with squamous-cell tumors, brain metastases, clinically significant hemoptysis, or inadequate organ function or performance status (ECOG performance status, >1) were excluded. The primary end point was overall survival. RESULTS: The median survival was 12.3 months in the group assigned to chemotherapy plus bevacizumab, as compared with 10.3 months in the chemotherapy-alone group (hazard ratio for death, 0.79; P=0.003). The median progression-free survival in the two groups was 6.2 and 4.5 months, respectively (hazard ratio for disease progression, 0.66; P<0.001), with corresponding response rates of 35% and 15% (P<0.001). Rates of clinically significant bleeding were 4.4% and 0.7%, respectively (P<0.001). There were 15 treatment-related deaths in the chemotherapy-plus-bevacizumab group, including 5 from pulmonary hemorrhage. CONCLUSIONS: The addition of bevacizumab to paclitaxel plus carboplatin in the treatment of selected patients with non-small-cell lung cancer has a significant survival benefit with the risk of increased treatment-related deaths. (ClinicalTrials.gov number, NCT00021060.)

Aged↗
PubMed2006

Vascular endothelial growth factor tyrosine kinase inhibitor AZD2171 and fractionated radiotherapy in mouse models of lung cancer.

The vascular endothelial growth factor receptor (VEGFR) tyrosine kinases are being explored as targets for antiangiogenic cancer therapy. Radiotherapy also inhibits tumor growth and affects vasculature. We investigated the combination of the potent VEGFR tyrosine kinase inhibitor AZD2171 and ionizing radiation in cell culture and mouse models of lung cancer. We show that ionizing radiation induces expression of phosphorylated VEGFR-2 (Flk-1) in endothelial cells and that this phosphorylation is inhibited by AZD2171. Human umbilical vascular endothelial cells become more sensitive to radiation after treatment with AZD2171 as determined by clonogenic assay. Matrigel assay showed a decrease in in vitro endothelial tubule formation with AZD2171/radiation combination treatment. When similar combination was applied to the H460 lung cancer xenograft model in nude mice, loss of radiation-induced phosphorylated Flk-1 was observed in the combination treatment group, which also showed a large decrease in tumor vascular density by staining of the von Willebrand factor. H460 tumor growth delay was enhanced in the combination treatment group compared with the groups treated with AZD2171 or radiation alone. Additionally, after therapy, Ki67 index showed >4-fold reduction of tumor proliferation in the combination therapy group, which also showed increased intratumoral apoptotic index by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling staining. In conclusion, AZD2171 sensitizes lung tumor xenografts to radiation and inhibits angiogenesis both in vitro and in vivo. When used as a radiation enhancer, AZD2171 has the potential to improve tumor growth delay by inhibiting tumor proliferation and promoting apoptosis. Clinical trials are needed to determine the potential of this combination therapy in patients with locally advanced lung cancer.

Animals↗
PubMed2006

Host and direct antitumor effects and profound reduction in tumor metastasis with selective EP4 receptor antagonism.

Prostaglandin E(2) (PGE(2)), one of the major metabolites of cyclooxygenase-2, has been implicated in tumorigenesis and tumor progression in several human cancers, including colorectal and lung. Here, we show that one of the PGE(2) receptors, the EP4 receptor, plays an important role in metastasis in both of these tumor types. Using i.v. injected Lewis lung carcinoma (3LL), we found that tumor metastasis to lung was significantly reduced when mice were treated with a specific EP4 antagonist ONO-AE3-208 or when EP4 receptor expression was knocked down in the tumor cells using RNA interference technology. Host EP4 receptors also contributed to tumor metastasis and tumor growth with decreased metastasis and tumor growth observed in EP4 receptor knockout animals. In vitro tumor cell adhesion, motility, invasion, colony formation, and Akt phosphorylation were all significantly inhibited when 3LL cells were treated with the EP4 receptor-specific antagonist. When the cells were treated with an EP4-specific agonist (AE1-734), we observed a worsening of these same features in vitro. Treatment with ONO-AE3-208 also profoundly decreased liver metastases after intrasplenic injection of MC26 colon cancer cells. Our data show that selective antagonism of EP4 receptor signaling results in a profound reduction in lung and colon cancer metastasis. Selective antagonism of the EP4 receptor may thus represent a novel therapeutic approach for the treatment of cancer and especially its propensity to metastasize.

Animals↗
PubMed2006

Targeted therapies in combination with chemotherapy in non-small cell lung cancer.

With rare exceptions, attempts to combine so-called targeted agents with standard cytotoxic chemotherapy in advanced non-small cell lung cancer have yielded disappointing results. The reasons underlying these spectacular failures are not always fully understood, but certainly the lack of careful patient selection is a major contributing factor. In addition, recent preclinical and clinical studies indicate that antagonism may exist between the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors and chemotherapy primarily in tumor cells with wild-type EGFR. By contrast, tumor cells harboring somatic mutations in EGFR experience massive apoptosis when exposed to the EGFR tyrosine kinase inhibitors. Therefore, in theory, mutant tumor cells should exhibit enhanced cell kill when treated with concomitant chemotherapy and EGFR tyrosine kinase inhibitors akin to what is observed with chemotherapy and trastuzumab in breast cancer. Clinical data from the recently completed TRIBUTE trial support the latter possibility. Ideally, future studies of EGFR tyrosine kinase inhibitors and other targeted drugs will use careful patient selection criteria based on well-characterized and validated predictive markers. However, in the absence of such biomarkers, clinical judgment, common sense, and innovative clinical trial design are necessary to avoid undue delay in drug development.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2006

Changes in the natural history of nonsmall cell lung cancer (NSCLC)--comparison of outcomes and characteristics in patients with advanced NSCLC entered in Eastern Cooperative Oncology Group trials before and after 1990.

BACKGROUND: Demographic factors and treatment regimens were evaluated in relation to differences in outcome between patients with advanced nonsmall cell lung cancer (NSCLC) who were diagnosed and treated on Eastern Cooperative Oncology Group Phase II and III trials from 1981 to 1990 and from 1991 to 2000. METHODS: In this retrospective analysis, 6 advanced NSCLC trials were identified between 1981 and 1990, and 3 trials were identified after 1990. Patient characteristics (n = 3398 patients) and other clinical outcomes were analyzed, including progression-free survival (PFS) and overall survival (OS). RESULTS: Patients who entered on trials after 1990 more likely were women, received a cisplatin-containing regimen, had a performance status of 0 or 1, had Stage IIIB (vs. Stage IV) disease, had tumors with adenocarcinoma histology, had weight loss < or = 10%, and had pulmonary-only metastases (although more total metastases and brain metastases) compared with patients who were diagnosed before 1990. OS was longer post-1990 than pre-1990 (8.2 months vs. 5.8 months pre-1990), and PFS was longer post-1990 (3.5 months vs. 2.6 months pre-1990; P<.001 for both). In addition, the median interval from the date of disease progression to death increased by nearly 62% in the later decade. CONCLUSIONS: Improved survival in more recent NSCLC trials was explained in part by the enrollment of patients with more favorable prognostic factors. A change in the natural history of the disease was reflected by some of these changes, including increased numbers of women with the disease and changes in the patterns of metastases. Changes in eligibility criteria also accounted for some improvements in prognostic factors and improved second line therapies in the later decade. Thus, the survival improvements are likely to be multifactorial, with improved therapies also playing a major role.

Aged↗
PubMed2006

Neoadjuvant concurrent paclitaxel and radiation in stage II/III breast cancer.

PURPOSE: The aim of this study was to determine the safety and pathologic response rates following neoadjuvant paclitaxel and radiation in patients with stage II/III breast cancer and to evaluate the use of sequential biopsies to allow an in vivo assessment of biological markers as potential predictive markers of response to this regimen. PATIENTS AND METHODS: Patients with high-risk, operable breast cancer were treated with three cycles of paclitaxel 175 mg/m2 every 3 weeks, followed by twice-weekly paclitaxel 30 mg/m2 and concurrent radiation. Core biopsies were obtained at baseline and 24 to 72 hours after the first cycle of paclitaxel. After completing neoadjuvant treatment, patients underwent definitive surgery. The primary end point was pathologic complete response, which is defined as the absence of any invasive cancer at surgery. Potential markers of therapeutic response were evaluated including markers of proliferation, apoptosis, p21, HER2, estrogen receptor, and progesterone receptor status. RESULTS: Of the 38 patients enrolled, 13 (34%) had a pathologic complete response. There was no significant difference in baseline Ki-67 between responders (35%) and nonresponders (28%; P = 0.45). There was also no significant change in Ki-67 following paclitaxel administration. Despite this lack of immunohistologic change in proliferative activity, baseline mitotic index was higher for patients with pathologic complete response over nonresponders (27 versus 10, P = 0.003). Moreover, the increase in mitotic index following paclitaxel administration was associated with pathologic complete response. CONCLUSIONS: Neoadjuvant paclitaxel/radiation is effective and well tolerated. Tumor proliferation at baseline and response to chemotherapy as measured by mitotic activity may serve as an important indicator of pathologic response to neoadjuvant paclitaxel/radiation.

Adult↗
PubMed2006

SGCEdb: a flexible database and web interface integrating experimental results and analysis for structural genomics focusing on Caenorhabditis elegans.

The SGCEdb (http://sgce.cbse.uab.edu) database/interface serves the primary purpose of reporting progress of the Structural Genomics of Caenorhabditis elegans project at the University of Alabama at Birmingham. It stores and analyzes results of experiments ranging from solubility screening arrays to individual protein purification and structure solution. External databases and algorithms are referenced and evaluated for target selection in the human, C.elegans and Pneumocystis carinii genomes. The flexible and reusable design permits tracking of standard and custom experiment types in a scientist-defined sequence. The database coordinates efforts between collaborators and is adaptable to a wide range of biological applications.

Animals↗
PubMed2006

Thioredoxin-1 modulates transcription of cyclooxygenase-2 via hypoxia-inducible factor-1alpha in non-small cell lung cancer.

Hypoxic induction of gene expression occurs mainly via the hypoxia-inducible factor-1 (HIF-1) transcription factor and is a critical step in tumor growth. Cyclooxygenase-2 (COX-2) is commonly overexpressed in non-small cell lung cancer (NSCLC). In this study, we sought to determine the role of HIF-1 in the induction of COX-2 expression during hypoxia. Through sequence comparison of hypoxia-responsive genes, COX-2 promoter deletion analysis, and site-directed mutagenesis, we identified a hypoxia-responsive element within the COX-2 promoter that interacts with HIF-1alpha and underlies the mechanism of hypoxic activation of COX-2 in lung cancer cells. Proteomic analysis of NSCLC identified thioredoxin-1 as a redox protein overexpressed in NSCLC correlated with poor prognosis. We also show that thioredoxin-1 stabilizes HIF-1alpha to induce hypoxia-responsive genes under normoxic conditions. Our results identify two new mechanisms for regulation of COX-2 expression in NSCLC.

Carcinoma, Non-Small-Cell Lung↗
PubMed2005

Response to combined modality therapy correlates with survival in locally advanced non-small-cell lung cancer.

PURPOSE: Although concurrent chemoradiotherapy can now achieve demonstrated long-term survival in patients with locally advanced non-small-cell lung cancer (LANSCLC), it is difficult to predict which patients will benefit most from this therapeutic approach. Studies have suggested that local control, and the response to therapy, may be linked to improved survival; however, detailed analysis of the impact of tumor response to chemoradiotherapy on survival has not been thoroughly reported. Therefore, we sought to determine the impact of the response rate on survival for patients who were treated with combined modality therapy for LANSCLC. METHODS AND MATERIALS: We reviewed the data from 116 patients enrolled between 1994 and 1997 in three trials investigating paclitaxel-based concurrent chemoradiotherapy for LANSCLC. Tumor size measurements were assessed immediately before and 2 months after completion of combined modality therapy to determine the response and to calculate the percentage of decrease in tumor size. RESULTS: Patients with a response (complete or partial) had an improved 4-year overall survival rate compared with patients with no response (stable or progressive disease; 21.1% vs. 3.3%, p <0.0001) in the 109 assessable patients. Progression-free survival also improved significantly with response. An analysis of the percentage of decrease in tumor size vs. survival was performed (n = 74) using Cox proportion model analysis. After combined modality therapy, a 20%, 40%, 60%, 80%, and 100% decrease in tumor size conferred a 39%, 63%, 78%, 86%, and 92% reduction in risk of death compared with a 0% decrease in tumor size (p <0.0001). CONCLUSION: The response by conventional response criteria correlated strongly with improved overall survival and progression-free survival and an increasing percentage of decrease in tumor size resulted in a reduction in the risk of death. Additional investigation of the degree of response as a factor predictive of improved therapeutic efficacy, translating into improved survival, is warranted.

Analysis of Variance↗
PubMed2005

Epidermal growth factor receptor mutations and gene amplification in non-small-cell lung cancer: molecular analysis of the IDEAL/INTACT gefitinib trials.

PURPOSE: Most cases of non-small-cell lung cancer (NSCLC) with dramatic responses to gefitinib have specific activating mutations in the epidermal growth factor receptor (EGFR), but the predictive value of these mutations has not been defined in large clinical trials. The goal of this study was to determine the contribution of molecular alterations in EGFR to response and survival within the phase II (IDEAL) and phase III (INTACT) trials of gefitinib. PATIENTS AND METHODS: We analyzed the frequency of EGFR mutations in lung cancer specimens from both the IDEAL and INTACT trials and compared it with EGFR gene amplification, another genetic abnormality in NSCLC. RESULTS: EGFR mutations correlated with previously identified clinical features of gefitinib response, including adenocarcinoma histology, absence of smoking history, female sex, and Asian ethnicity. No such association was seen in patients whose tumors had EGFR amplification, suggesting that these molecular markers identify different biologic subsets of NSCLC. In the IDEAL trials, responses to gefitinib were seen in six of 13 tumors (46%) with an EGFR mutation, two of seven tumors (29%) with amplification, and five of 56 tumors (9%) with neither mutation nor amplification (P = .001 for either EGFR mutation or amplification v neither abnormality). Analysis of the INTACT trials did not show a statistically significant difference in response to gefitinib plus chemotherapy according to EGFR genotype. CONCLUSION: EGFR mutations and, to a lesser extent, amplification appear to identify distinct subsets of NSCLC with an increased response to gefitinib. The combination of gefitinib with chemotherapy does not improve survival in patients with these molecular markers.

Adult↗
PubMed2005

Targeting cyclooxygenase-2 in recurrent non-small cell lung cancer: a phase II trial of celecoxib and docetaxel.

Cyclooxygenase-2 (COX-2) catalyzes the rate-limiting step in prostaglandin (PG) synthesis and is overexpressed in 70% to 90% of non-small cell lung cancers (NSCLC). Preclinical studies suggest inhibition of COX-2 can enhance the cytotoxic effect of docetaxel. To test this concept clinically, we administered celecoxib (400 mg p.o. twice daily) plus docetaxel (75 mg/m(2) every 3 weeks) to a cohort of patients with recurrent, previously treated NSCLC. Patients first received single agent celecoxib for 5 to 10 days to ascertain the effectiveness of COX-2 inhibition, which was determined by measuring pre- and post-celecoxib levels of urinary 11alpha-hydroxy-9,15-dioxo-2,3,4,5-tetranor-prostane-1,20-dioic acid (PGE-M), the major metabolite of prostaglandin E(2) (PGE(2)). We enrolled 56 patients (35 men, 21 women; median age, 61 years). All patients had received at least one prior chemotherapy regimen. The overall response rate was 11% and median survival was 6 months, similar to that observed with docetaxel alone. Pre-celecoxib urinary PGE-M decreased from a mean level of 27.2 to 12.2 ng/mg Cr after 5 to 10 days of celecoxib (P = 0.001). When grouped by quartile, patients with the greatest proportional decline in urinary PGE-M levels experienced a longer survival compared to those with no change or an increase in PGE-M (14.8 versus 6.3 versus 5.0 months). Our data suggest that combining celecoxib with docetaxel using the doses and schedule employed does not improve survival in unselected patients with recurrent, previously treated NSCLC. However, in light of the apparent survival prolongation in the subset with a marked decline in urinary PGE-M levels, further investigation of strategies designed to decrease PGE(2) synthesis in NSCLC seems warranted.

Adult↗
PubMed2005

Long term follow up and analysis of long term survivors in patients treated with paclitaxel-based concurrent chemo/radiation therapy for locally advanced non-small cell lung cancer.

PURPOSE: For patients with locally advanced non-small cell lung cancer (LANSCLC), concurrent chemotherapy/radiation therapy (RT) has become the standard of care. Three multi-institutional phase II studies with paclitaxel-based chemotherapeutic regimen given concurrently with RT for patients with LANSCLC were performed from March of 1994 to May of 1997. We sought to determine mature data from this database of patients, as well as to perform analysis of a cohort of patients who have achieved long term survival (LTS) when treated with this regimen. PATIENTS AND METHODS: Database of these patients was analyzed retrospectively upon longer follow up, with median follow up for the three studies being 498 days (range 11-2905 days, average 780 days). Weight loss limitation for the three studies was liberal: weight loss <10% and <15% 3 months preceding diagnosis (LUN-27 and LUN-63, respectively), and no weight loss limitation for LUN-56. RESULTS: The 4-year overall survival (OS) for the three trials was 16.3%, and 2-year progression free survival (PFS) was 25.7%. Statistical analysis of the long term survivors (OS > 4 years) was performed, and performance status (PS) was found to be a significant factor predictive of LTS. PS of 0 compared to 1 yielded a 2.5-fold increased likelihood of LTS (p = .04). There was also a trend (p = .067) for responders (complete or partial response) to yield a five-fold likelihood of LTS compared to non-responders (stable or progressive disease). CONCLUSION: Our results support the efficacy of combined modality therapy (CMT) for patients with LANSCLC even despite our more liberal weight loss eligibility criteria. Furthermore, our analysis indicates that LTS is more likely to be achievable in patients with PS = 0 compared to 1 when treated with CMT for LANSCLC.

Adult↗
PubMed2005

TRIBUTE: a phase III trial of erlotinib hydrochloride (OSI-774) combined with carboplatin and paclitaxel chemotherapy in advanced non-small-cell lung cancer.

PURPOSE: Erlotinib is a potent reversible HER1/epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor with single-agent activity in patients with non-small-cell lung cancer (NSCLC). Erlotinib was combined with chemotherapy to determine if it could improve the outcome of patients with NSCLC. PATIENTS AND METHODS: TRIBUTE randomly assigned patients with good performance status and previously untreated advanced (stage IIIB/IV) NSCLC to erlotinib 150 mg/d or placebo combined with up to six cycles of carboplatin and paclitaxel, followed by maintenance monotherapy with erlotinib. Random assignment was stratified by stage, weight loss in the previous 6 months, measurable disease, and treatment center. The primary end point was overall survival (OS). Secondary end points included time to progression (TTP), objective response (OR), and duration of response. RESULTS: There were 1,059 assessable patients (526 erlotinib; 533 placebo). Median survival for patients treated with erlotinib was 10.6 v 10.5 months for placebo (hazard ratio, 0.99; 95% CI, 0.86 to 1.16; P = .95). There was no difference in OR or median TTP. Patients who reported never smoking (72 erlotinib; 44 placebo) experienced improved OS in the erlotinib arm (22.5 v 10.1 months for placebo), though no other prespecified factors showed an advantage in OS with erlotinib. Erlotinib and placebo arms were equivalent in adverse events (except rash and diarrhea). CONCLUSION: Erlotinib with concurrent carboplatin and paclitaxel did not confer a survival advantage over carboplatin and paclitaxel alone in patients with previously untreated advanced NSCLC. Never smokers treated with erlotinib and chemotherapy seemed to experience an improvement in survival and will undergo further investigation in future randomized trials.

Administration, Oral↗
PubMed2005

Mutations in the epidermal growth factor receptor and in KRAS are predictive and prognostic indicators in patients with non-small-cell lung cancer treated with chemotherapy alone and in combination with erlotinib.

PURPOSE: Epidermal growth factor receptor (EGFR) mutations have been associated with tumor response to treatment with single-agent EGFR inhibitors in patients with relapsed non-small-cell lung cancer (NSCLC). The implications of EGFR mutations in patients treated with EGFR inhibitors plus first-line chemotherapy are unknown. KRAS is frequently activated in NSCLC. The relationship of KRAS mutations to outcome after EGFR inhibitor treatment has not been described. PATIENTS AND METHODS: Previously untreated patients with advanced NSCLC in the phase III TRIBUTE study who were randomly assigned to carboplatin and paclitaxel with erlotinib or placebo were assessed for survival, response, and time to progression (TTP). EGFR exons 18 through 21 and KRAS exon 2 were sequenced in tumors from 274 patients. Outcomes were correlated with EGFR and KRAS mutations in retrospective subset analyses. RESULTS: EGFR mutations were detected in 13% of tumors and were associated with longer survival, irrespective of treatment (P < .001). Among erlotinib-treated patients, EGFR mutations were associated with improved response rate (P < .05) and there was a trend toward an erlotinib benefit on TTP (P = .092), but not improved survival (P = .96). KRAS mutations (21% of tumors) were associated with significantly decreased TTP and survival in erlotinib plus chemotherapy-treated patients. CONCLUSION: EGFR mutations may be a positive prognostic factor for survival in advanced NSCLC patients treated with chemotherapy with or without erlotinib, and may predict greater likelihood of response. Patients with KRAS-mutant NSCLC showed poorer clinical outcomes when treated with erlotinib and chemotherapy. Further studies are needed to confirm the findings of this retrospective subset analysis.

Adult↗