Biomedical subjects
Publications and source records attributed to N Thatcher.
There are no data in the literature about the efficacy of influenza vaccination in lung cancer patients. Paired sera were available from 59 patients who received Fluvirin (Evans Medical). Of 41 patients susceptible to one or more influenza strains, 78% responded fully to vaccination. This response rate is comparable to that obtained from healthy volunteers.
Anaemia commonly occurs in cancer patients receiving chemotherapy, often necessitating blood transfusion. This multicentre study was designed to evaluate the efficacy and safety of epoetin alpha in preventing the decline in haemoglobin (Hb) level, and to determine whether the transfusion requirement could be reduced, in patients receiving 4-6 cycles of primarily platinum-based combination cyclic chemotherapy for small cell lung cancer (SCLC). A total of 130 non-anaemic SCLC patients were randomized to receive no additional treatment (n = 44), epoetin alpha 150 IU kg(-1) subcutaneously (s.c.) three times a week (n = 42) or 300 IU kg(-1) s.c. three times a week (n = 44). Reductions in epoetin alpha dosage were made during the study if Hb level increased to >15 g dl(-1). The mean weekly dosage was 335 and 612 IU kg(-1), respectively, in the two active treatment groups. Significantly fewer (P < 0.05) epoetin alpha-treated patients experienced anaemia (Hb < 10 g dl(-1)) during the course of chemotherapy (300 IU kg(-1), 39%; 150 IU kg(-1), 48%; untreated, 66%). This was reflected in the significantly lower number of treated patients transfused [300 IU kg(-1), 20% (P< 0.001); 150 IU kg(-1), 45% (P< 0.05); untreated, 59%]. Epoetin alpha was well-tolerated, and there was no evidence of sustained, clinically significant, hypertension. In summary, epoetin alpha is effective and well-tolerated in maintaining Hb level and reducing transfusion requirement in patients undergoing cyclic chemotherapy for SCLC.
The effect of expression of an O6-benzylguanine (O6-beG)-resistant mutant (hATPA/GA) of human O6-alkylguanine-DNA alkyltransferase (ATase) on the in vivo toxicity and clastogenicity of the anti-tumour agent N,N'-bis(2-chloroethyl)-N-nitrosourea (BCNU) to murine bone marrow has been investigated. When compared with control animals, the bipotent granulocyte-macrophage colony-forming (GM-CFC) progenitor population of the hATPA/GA transduced mice were somewhat more resistant to BCNU (1.4-fold, P = 0.047) and this effect was more significant in the presence of the ATase inactivator O6-beG (3. 5-fold, P = 0.001). The polychromatic erythrocytes were also significantly protected against BCNU-induced clastogenicity both in the presence (P < 0.001) and absence of O6-beG (P < 0.05). The primitive, multipotent spleen colony-forming cells (CFU-S) in these animals also showed moderate (1.6-fold, P = 0.034) protection in the absence of O6-beG but in the presence of the inactivator they remained as sensitive to BCNU toxicity as those in the control animals (P = 0.133). This result contrasts with previous findings demonstrating significant hATPA/GA-mediated, O6-beG-resistant protection against the toxicity and clastogenicity of a number of O6-alkylating agents, including temozolomide, fotemustine and chlorozotocin. The possibility that our strategy for protective gene therapy may be highly agent and cell-type specific is unexpected and has possible implications for clinical trials of this approach using BCNU or related agents.
The CDKN2 locus expresses two different mRNA transcripts, designated alpha and beta. The protein product of the alpha transcript is the cell cycle inhibitor and tumour suppressor p16INK4a. The beta transcript is translated in an alternate reading frame (ARF) and in humans encodes a 15 kDa protein (p19ARF). Immunohistochemical and Western analysis of p16INK4a has shown that the protein is downregulated in a significant number of tumours, but less is known on the expression of the p19ARF. We have examined the expression of p16INK4a and p19ARF in resectable non-small cell lung cancer (NSCLC) by immunostaining (n=49) and multiplex RT-PCR (n=28). In order to investigate the mechanism responsible for p16INK4a downregulation, exon 1alpha methylation was analysed in a PCR-based assay. Of 49 tumours examined by immunostaining, 24 and 20 tumours expressed p16INK4a and p19ARF at nil to low levels, respectively. p19ARF was localized primarily to the nuclei of tumour cells, but was also seen to varying degrees in nuclei of lymphocytes, chondrocytes, fibroblasts, and epithelial cells. No tumour with normal p16INK4a had decreased p19ARF expression. Among 16 tumours with nil to low p16INK4a expression, 11 tumours exhibited full methylation of at least one site within exon 1alpha and these tumours showed normal p19ARF expression. In contrast, no methylation of exon 1alpha was observed in five tumours which also lacked p19ARF. In normal lung, p16INK4a and p19ARF were not expressed at detectable levels, the multiplex RT-PCR results were balanced, and sites within exon 1alpha were strongly methylated. In tumours, imbalanced multiplex RT-PCR data (p16INK4a<p19ARF) predicted methylation of exon 1alpha (P=0.0006) as well as downregulation of p16INK4a. p19ARF downregulation was inversely correlated with p53 overexpression (P=0.025), whilst negative immunostaining for p16INK4a was inversely correlated with pRb down-regulation (P=0.003) and directly correlated with p53 overexpression as assessed by immunostaining (P=0.015). Our results show that: (1) p16INK4a and p19ARF expression are altered in almost half of resectable NSCLC; (2) methylation within exon 1alpha is a frequent, but not the only mechanism of p16INK4a downregulation; and that (3) the inverse association of p19ARF and p53 alteration is consistent with a linked pathway.
A randomized phase II trial was performed to compare the efficacy and toxicity of interleukin 2 (IL-2) with an IL-2 and interferon alpha (IFN-alpha) regimen for the treatment of metastatic renal carcinoma. Sixty patients with recurrent renal cell carcinoma (RCC) who had previously undergone a nephrectomy were randomized to receive three cycles of IL-2 or IL-2 with IFN-alpha2b. Eighteen MU of IL-2 were administered subcutaneously on Mondays-Fridays for 3 weeks out of 4. Those patients randomized to receive the combination received the same regimen of IL-2 with 9 MU of IFN-alpha2b subcutaneously on Mondays, Wednesdays and Fridays for 3 weeks out of 4. Thirty patients were randomized to receive each arm. Twenty-nine were evaluable in each arm. Twenty-two patients received three cycles of IL-2 but only 14 patients received three cycles of IL-2/IFN-alpha because of the greater toxicity of the combination. The principal toxicities included nausea, fatigue and fever. There were no complete responses in either arm and only two patients who were treated with IL-2 attained a partial response. Twelve patients in each arm had stable disease and 15 patients in the IL-2 arm and 16 patients in the IL-2/IFN-alpha arm progressed through treatment. There were no significant differences in survival. Ten patients who received IL-2 are alive with a median follow-up of 266 days, whereas six patients who received IL-2/IFN-alpha are alive after a median of 278 days. The median survival from the time of identification of metastatic disease is 444 days in the IL-2 arm and 381 days in the IL-2/IFN-alpha arm. The IL-2/IFN-alpha combination is more toxic than IL-2 alone and this resulted in a reduced number of cycles of treatment. However, the median survival of the two groups was the same, suggesting that further evaluation of the IL-2/IFN-alpha combination should be confined to large prospective randomized clinical trials.
Resistance of tumour cells to methylating and monochloroethylating agents in vitro and in vivo has been linked to levels of the DNA repair protein O6-methylguanine-DNA methyltransferase (MGMT). In a clinical trial of temozolomide in advanced malignant melanoma, the relationship between pretreatment MGMT levels in biopsies of cutaneous tumours and involved lymph nodes and clinical response to the drug has been studied. Among 50 evaluable patients, there were three complete responses (CR), four partial responses (PR), six with stable disease (SD) and 37 with progressive disease (PD), with an overall response rate of 14%. In 33 patients in whom MGMT level and clinical response could be evaluated, the tumour MGMT levels (fmol mg(-1) protein) were: CR, 158 +/- 119; PR, 607 +/- 481; NC, 171 +/- 101; PD, 185 +/- 42.3. Thus, measurements of pretreatment levels of MGMT in melanoma did not predict for response to temozolomide.
Retroviral transduction was used to introduce cDNAs encoding two mutants of human O6-alkylguanine-DNA alkyltransferase (hAT), one of which (hATPA) is 16 times more resistant to O6-benzylguanine (O6-beG), and the other (hATPA/GA) which is almost totally refractory to inactivation relative to the wild-type protein, into K562 human erythroleukaemic cells. A colony-forming assay was used to demonstrate significant protection (P < 0.001) against mitozolomide or temozolomide toxicity in K562 clones expressing either hAT mutant, as determined from an in vitro assay of activity. However, protection against these agents was reduced in hATPA expressing cells in the presence of 1 microM O6-beG and was lost in the presence of 20 microM O6-beG while cells expressing hATPA/GA retained protection even in the presence of 20 microM O6-beG (P < 0.001). Using primary human cord blood-derived CD34+ haemopoietic cells in which PCR analysis indicated that up to 70% of progenitors were transduced with retroviral constructs harbouring hATPA/GA, we observed significant protection of the granulocyte-macrophage colony-forming cells against mitozolomide (P < 0.05) and temozolomide (P < 0.001) induced toxicity in the presence of O6-beG. These findings indicate that retrovirus-mediated expression of hATPA/GA in primitive primary human haemopoietic cells is possible and does provide O6-beG-resistant protection for these cells. Using this strategy in patients may simultaneously permit attenuated myelosuppression and increased sensitivity of tumour cells to the effects of O6-alkylating agent chemotherapy. These data, taken together with the study reported by Chinnasamy et al in the accompanying article in this issue showing reduced toxicity and clastogenicity in murine haemopoietic progenitors, make a compelling case to test this strategy clinically.
Murine bone marrow cells were transduced ex vivo with a retrovirus encoding an O6-benzylguanine (O6-beG) insensitive, double mutant form of the human DNA repair protein O6-alkylguanine-DNA alkyltransferase (hATPA/GA). In animals reconstituted with the transduced bone marrow, about 50% of cells in the multipotent spleen colony-forming cells (CFU-S) and lineage restricted granulocyte-macrophage (GM-CFC) haemopoietic progenitor populations were found to be carrying the transgene and this correlated with the frequency of bone marrow cells and spleen colonies which stained positive for hATPA/GA by immunocyto-chemistry. Expression of hATPA/GA was associated with significant in vivo protection of both CFU-S (P = 0.001) and GM-CFC (P < 0.024) against the toxicity of the antitumour methylating agent, temozolomide, given in combination with O6-beG. Expression of hATPA/GA also led to a reduction in the frequency of combined O6-beG/temozolomide-induced micronuclei seen in polychromatic erythrocytes (P < 0.003). This study is the first to demonstrate in vivo protection of multipotent haemopoietic progenitors against the toxic and clastogenic effects of an O6-alkylating agent in the presence of O6-beG. It also represents the first report of reduced clastogenesis as a consequence of expression of an O6-beG-resistant ATase. In the accompanying article we report hATPA/GA-mediated resistance of human CD34+ haemopoietic progenitors to combined O6-beG/O6-alkylating agent toxicity. Together these two reports suggest that a gene therapy strategy whereby protection of normal haemopoietic tissue may be combined with O6-beG-mediated tumour sensitisation may be efficacious in achieving an increase in therapeutic index.
PURPOSE: To assess whether granulocyte-macrophage colony-stimulating factor (GM-CSF) reduces the toxicity of chemotherapy and alters delivered dose-intensity. To assess the feasibility of dose-intensification of chemotherapy in small-cell lung cancer (SCLC) and determine whether it has an impact on outcome. MATERIALS AND METHODS: Patients with good- or intermediate-prognosis SCLC entered a prospective multicenter study that involved a 2 x 2 factorial design with randomization to six cycles of chemotherapy with ifosfamide 5 g/m2, carboplatin 300 mg/m2, etoposide 120 mg/m2 intravenously (I.V.) on days 1 and 2 and 240 mg/m2 orally on day 3, and vincristine 0.5 mg/m2 I.V. on day 15 (V-ICE) every 3 weeks (intensified arm) or every 4 weeks (standard arm). A second double-blind randomization to subcutaneous GM-CSF (250 microg/m2/d) or placebo for 14 days between chemotherapy cycles was made. RESULTS: Three hundred patients were entered. Myelosuppression was the main toxicity, with no significant difference in the incidence or grade between treatment groups. The incidence of febrile neutropenia and bacteriologically confirmed sepsis was unaffected by chemotherapy schedule or use of GM-CSF. Twenty-six percent greater dose-intensity was delivered in the intensified arm, with a trend for greater dose-intensity for those who received GM-CSF. Eighty-three percent of patients achieved a response (51% complete response [CR] rate), with no significant difference in response rates between treatment groups. Survival was significantly increased in the intensified compared with the standard arm (P = .0014); median survival rates were 443 versus 351 days and 2-year survival rates were 33% versus 18%, respectively. CONCLUSION: GM-CSF does not reduce the incidence of complications from myelosuppression of aggressive chemotherapy. Dose intensification of V-ICE to a 3-week schedule in SCLC is not associated with increased toxicity, but appears to improve survival significantly. Future studies should aim to deliver chemotherapy in maximal-tolerated dose-intensities.
PURPOSE: In patients with stage IV melanoma, durable responses have been reported with treatment regimens that involve high-dose interleukin-2 (IL-2). We analyze long-term results of 631 melanoma patients from 12 institutions who had received IL-2 alone, in combination with interferon alfa 2a or 2b (IFNalpha), or with cytotoxic drugs. METHODS: Case records that contained pretreatment parameters, response data, and updated survival information were collected. After univariate analysis, the multivariate evaluation of the impact of pretreatment parameters on response and survival was performed by logistic regression and Cox's regression, respectively. RESULTS: Patients were divided into four groups according to treatment: IL-2 alone (n=117), IL-2 and chemotherapy (n=49), IL-2 and IFNalpha (n=153), and IL-2, chemotherapy, and IFNalpha (n=312). The median survival of all patients was 10.5 months and the 2- and 5-year survival rates were 19.9% and 10.4%, respectively. Independent prognostic factors for response and survival were entirely different, treatment group being the only significant factor for response, and serum lactate dehydrogenase (LDH), metastatic site, and performance predicting survival. The addition of IFNalpha to IL-2 was associated with prolonged survival, but the effect of additional chemotherapy was less obvious. CONCLUSION: Serum LDH, metastatic site, and performance status are useful stratification factors for randomized trials in metastatic melanoma. The improved long-term survival rates observed in melanoma patients treated with IL-2/IFNalpha-containing regimens are notable in contrast to the reported 5-year survival rates of 2% to 6% achieved with chemotherapy, but because selection bias cannot be ruled out, the impact of IL-2, as well as all other components of the treatment regimens, on survival needs to be confirmed in prospective randomized trials.
Evidence from preclinical models and from clinical trials describing the importance of dose intensity in securing a better treatment outcome is reviewed. Recent randomized trials have shown statistically significant survival benefits with higher-dose, accelerated chemotherapy regimens with and without granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor. The novel use of peripheral blood progenitor cells contained in whole blood autotransfusions, which allow a marked increase in dose intensity of an ifosfamide/carboplatin/etoposide regimen, could provide a much easier method of delivering dose-intensive chemotherapy than previously available.
Patients with cancer have inappropriately low levels of endogenous erythropoietin for the degree of anemia and further suppression of erythropoiesis results from chemotherapy. Patients with lung cancer, in particular, require a high frequency of transfusions, as they are unable to tolerate the symptoms of anemia due to their underlying pulmonary disease and, often, their age. Data from phase I and II trials indicated that epoetin alfa could increase hemoglobin concentration and reduce transfusion requirements. The beneficial response was dose dependent. These findings were confirmed in a series of three double-blind, placebo-controlled, multicenter phase III trials. Clinical trial evidence indicates that 150 IU/kg epoetin alfa three times weekly effectively treats anemia and decreases transfusion requirements in most cancer patients after the first month of chemotherapy. Furthermore, epoetin alfa will reduce the degree of anemia and markedly reduce the need for transfusions, thereby preventing anemia in patients undergoing multiple cycles of platinum-based combination chemotherapy. Epoetin alfa is well tolerated and shows marked activity in preventing anemia and reducing blood transfusion requirements in patients undergoing cyclic chemotherapy.
Glutamate transporters play an essential role in terminating the excitatory glutamatergic signal at post-synaptic receptors and in protecting neurones from excitotoxic effects, as well as replenishing the neurotransmitter supply at glutamatergic synapses. The distribution and density of glutamate transporters may be important determinants of vulnerability to glutamate-mediated injury. There is emerging evidence that glutamate transporter dysfunction may be present in motor neurone disease (MND). In this study, a monoclonal antibody, suitable for immunohistochemistry (IHC) in human post-mortem tissue, was produced to the human astrocytic glutamate transporter EAAT2 (excitatory amino acid transporter 2). Western blotting of homogenates of human cortical tissue with the EAAT2 antibody produced a discrete band at 66 kDa. Detailed IHC analysis of the expression of the EAAT2 protein in the human CNS was undertaken. EAAT2 was exclusively localised to astrocytes, with preferential expression in the caudate nucleus, nucleus basalis of Meynert, spinal ventral horn, cerebral cortex and hippocampus, but with lower levels of expression throughout many other CNS regions. Motor neurone groups vulnerable to neurodegeneration in MND appeared distinctive in being surrounded by extensive, coarse, strongly immunoreactive perisomatic glial profiles. Motor neurone groups which tend to be spared in MND, such as those present in the oculomotor nucleus, showed a lower expression of EAAT2, with fewer perisomatic profiles. The EAAT2 antibody will provide a useful tool for increasing our understanding of the role of EAAT2 in excitatory neurotransmission in health and disease states.
Progression through the mammalian cell cycle is controlled by a series of cyclins, cyclin-dependent kinases (cdks) and cdk inhibitors. Cyclin D1, cdk4 and the tumour suppressors p16 and retinoblastoma protein (pRb) are thought to comprise a linked system governing cell passage through the G1 phase of the cell cycle. Extending an earlier study on cyclin D1 expression, a series of resectable non-small cell lung carcinomas (NSCLCs) was examined for defects in other elements of this control system. Forty-six of fifty-one NSCLC specimens exhibited at least one alteration of these cell-cycle regulators. Immunohistochemical analysis revealed that 33% and 47% of the tumours failed to express pRb and p16, respectively. Failure to detect pRb did not correlate with loss of heterozygosity at the RB1 locus. Eleven of 12 tumours showing positive (normal) pRb staining over-expressed nuclear localised cyclin D1, including 8 with amplification of the cyclin D1 gene (CCNDI). However, in a number of lesions (n = 5) where cyclin D1 was over-expressed but localised to the cytoplasm, pRb expression was undetectable. Sequencing of exons 1 and 2 of the p16 gene (CDKN2) revealed 3/51 tumours with somatic mutations (in addition to 1 case with a germ-line alteration). All of these lesions were positive for p16 protein. No clear homozygous deletions of CDKN2 were observed by multiplex PCR. As assessed by immunostaining using a p16 monoclonal antibody, there was an inverse correlation of pRb and p16 down-regulation. Whilst patients with tumours over-expressing cyclin D1 had a significantly lower incidence of local relapse, the group whose tumours failed to express pRb had a significantly greater risk of local relapse and tended to have shortened event-free survival. Our data show that alteration of at least one cell cycle-regulator gene occurs in the majority of resectable NSCLCs.
Alongside objective response rate, quality of life of patients is important in the treatment of cancer, particularly in the palliative setting. Quality of life is difficult to define precisely and is correspondingly difficult to assess. However, a number of methods have been devised and self-report questionnaires are now widely used. Patients with metastatic non-small cell lung cancer (NSCLC) have a poor prognosis with few patients surviving longer than 8 or 9 months. Curative treatment is often not possible and few patients receive active treatment. Although some patients will accept toxic treatments in return for increased survival, it is generally hoped that any treatment, curative or palliative, will not adversely affect patients' quality of life. In three studies in which gemcitabine was used as a single agent in metastatic NSCLC, objective response rates of 20% were obtained. Gemcitabine was well tolerated. Symptoms improved in the studies where disease-related symptoms were assessed. The degree of improvement compared well with historical data on the relief offered by standard radiotherapy and combination chemotherapy. These findings have led to the initiation of a randomised trial to compare the relief offered by gemcitabine plus best supportive care with best supportive care, using quality of life assessments as a primary endpoint.
Tumours develop through the accumulation of genetic alterations associated with a progressive increase of the malignant phenotype. In lung cancer, chronic exposure of bronchial epithelium to carcinogens in cigarette smoke may lead to multiple dysplastic and hyperplastic lesions scattered throughout the tracheobronchial tree. Little is known about the genetic alterations in such lesions. This study was carried out to examine cyclin D1 (CCND1) and retinoblastoma (RB1) gene expression in the bronchial epithelium of patients with lung cancer. Lung tumours and their corresponding tumour-free resection margins from 33 patients who underwent resection of non-small-cell lung cancer (NSCLC) were examined by immunostaining with monoclonal antibodies against cyclin D1 (DCS-6; Novocastra) and pRb (NCL Rb-1; Novocastra). Examination of the resection margins revealed four carcinomas in situ, 19 hyperplasias and ten sections showing apparently normal bronchial epithelium. A control group of patients, without lung tumours and who had never smoked, revealed no or weak cyclin D1 and positive pRb staining within bronchial epithelia. Increased cyclin D1 and diminished pRb expression were found in 76% (n = 25) and 27% (n = 9) of the resection margins respectively, and in 12% (n = 4) both cyclin D1 and pRb expression were altered. In the corresponding tumours, 48% (n = 16) were normal, while altered expression was found for cyclin D1 in 33% (n = 11), pRb in 27% (n = 9) and both in 9% (n = 3) of cases. It appears that altered expression of cyclin D1 and pRb is an early event in NSCLC development in almost half of cases analysed. Further investigations are needed to determine the significance of immunostaining of bronchial specimens in individuals at risk of lung cancer, with the possibility that the observations are of importance in the early diagnosis of NSCLC.
Raltitrexed, a thymidylate synthase inhibitor, was given to 21 patients with advanced small-cell lung cancer, at a dose of 3 mg m(-2) as a 15-min intravenous infusion at 21-day intervals. All of the patients had extensive disease and 17 had received prior therapy. Patients with disease refractory to primary chemotherapy were excluded. Forty-one treatment cycles were given (median two, range one to four). The drug was well tolerated. No objective tumour response was documented. The patients had chemoresistant disease, as shown by a response in only one of ten patients who went on to receive alternative cytotoxic regimens. We conclude that raltitrexed given in this schedule is inactive as second line therapy for small-cell lung cancer.