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Biomedical subjects

D Raghavan

Publications and source records attributed to D Raghavan.

At least 37 records · Page 2Linked to original sources
PubMed1997

Metastatic bladder cancer: advances in treatment.

At present, a combination of cisplatin, methotrexate, vinblastine and doxorubicin is the most widely used chemotherapy for metastatic bladder cancer. However, long-term follow-up shows that this combination may have little effect on survival. In addition, this regimen is toxic. New agents are needed which combine efficacy with good safety profiles. Agents which have been investigated include gallium nitrate, interferon-alpha and paclitaxel both as single agents and in combination with established cytotoxic drugs. A number of studies have been conducted in bladder cancer with the novel nucleoside analogue, gemcitabine. Response rates of up to 33% have been recorded in two phase II studies. Gemcitabine was well tolerated in both studies with few of the side-effects normally associated with cytotoxic drugs. A third study is ongoing.

Adult↗
PubMed1997

Evolving strategies of cytotoxic chemotherapy for advanced prostate cancer.

Despite the use of cytotoxic chemotherapy for advanced prostate cancer for half a century, its clinical utility in this setting remains undefined. Based on traditional methods of assessment, the list of the most active cytotoxic agents includes cyclophosphamide, doxorubicin, mitoxantrone and cisplatin. With the introduction of more structured methods of assessment, including careful assessment of indices of quality of life and serial measurement of serum prostate-specific antigen (PSA), the role of cytotoxic agents is being re-assessed. In view of the cell cycle characteristics of prostate cancer, there appears to be an emerging role for combination inhibitors of mitosis, including estramustine in combination with the vinca alkaloids, etoposide or paclitaxel.

Antineoplastic Agents↗
PubMed1997

Unusual central nervous system toxicity in a phase I study of N1N11 diethylnorspermine in patients with advanced malignancy.

The objectives of this study were to determine the dose limiting toxicity (DLT) and other major toxicities, the maximum tolerated dose (MTD) and the human pharmacokinetics of N1N11 diethylnorspermine (DENSPM), a new polyamine analog which in experimental systems inhibits the biosynthesis of intracellular polyamines and promotes their degradation by inducing the enzyme spermine/spermidine N-acetyl transferase. These objectives were incompletely achieved because of the occurrence of an unusual syndrome of acute central nervous system toxicity which forms the basis of the present report. Fifteen patients with advanced solid tumors were entered into a phase I study of DENSPM given by a 1 h i.v. infusion every 12 h for 5 days (10 doses). The starting dose was 25 mg/m2/day (12.5 mg/m2/dose) with escalation by a modified Fibonacci search. Doses of 25 and 50 mg/m2/day were tolerated with only minor side effects of facial flushing, nausea, headache and dizziness (all grade I). At doses of 83 and 125 mg/m2/day, a symptom complex of headache, nausea and vomiting, unilateral weakness, dysphagia, dysarthria, numbness, paresthesias, and ataxia, was seen in 3 patients, one after 2 courses of 83 and 2 after 1 course of 125 mg/m2/day. This syndrome occurred after drug administration was complete and the patients had returned home. Lesser CNS toxicity was seen in 2 other patients at lower daily doses. Preliminary pharmacokinetics of DESPM measured in plasma by HPLC in 8 patients showed linearity with dose and a rapid plasma decay with a t1/2 of 0.12 h. We conclude that great caution is warranted in administering DENSPM on this schedule at doses of > or = 83 mg/m2/day.

Adenocarcinoma↗
PubMed1997

Phase II study of single-agent gemcitabine in previously untreated patients with metastatic urothelial cancer.

PURPOSE: To determine the activity of single-agent gemcitabine in previously untreated patients with metastatic transitional cell cancer. METHODS: Forty patients with measurable disease and a Karnofsky performance status > or = 60% were enrolled at five institutions between March 1994 and October 1995. Treatment consisted of gemcitabine (1,200 mg/m2) administered weekly times three on a 4-week cycle. One patient was ineligible for response evaluation because pathology review showed a metastatic melanoma. Responses were confirmed by all investigators and an independent radiologist and were maintained for at least 4 weeks. RESULTS: There were four complete and seven partial responses, for an overall response rate of 28%. Responses were seen at all sites, including liver. Median progression-free and overall survival times were 20 and 54 weeks, respectively. Toxicity was mild, with only two grade 4 toxicities. Twenty-five percent of patients experienced grade 3 neutropenia or thrombocytopenia that was rapidly reversible. CONCLUSION: Gemcitabine exhibits significant activity in metastatic transitional cell cancer with minimal toxicity, but survival remains short. Trials of gemcitabine in combination with other active agents are thus suggested.

Adult↗
PubMed1997

Long-term follow-up of a phase III intergroup study of cisplatin alone or in combination with methotrexate, vinblastine, and doxorubicin in patients with metastatic urothelial carcinoma: a cooperative group study.

PURPOSE: A previously reported randomized intergroup trial demonstrated that combination chemotherapy with methotrexate, vinblastine, doxorubicin, and cisplatin (M-VAC) was superior to single-agent cisplatin in patients with advanced urothelial carcinoma. We conducted a long-term analysis of patients included in the intergroup trial to examine factors associated with long-term survival. PATIENTS AND METHODS: Two-hundred fifty-five assessable patients with urothelial carcinoma were randomized to receive either single-agent cisplatin (70 mg/m2 on day 1) or combination chemotherapy with methotrexate (30 mg/m2 on days 1, 15, and 22), vinblastine (3 mg/m2 on days 2, 15, and 22), doxorubicin (30 mg/m2 on day 2), and cisplatin (70 mg/m2 on day 2). Courses were repeated every 28 days. The association between patient characteristics and survival was assessed using Cox proportional hazards models. RESULTS: With long-term follow-up evaluation, survival in the M-VAC arm continues to be superior to cisplatin (P = .00015, log-rank test). Predictors of survival include performance status, histology, and the presence of liver or bone metastasis. Only 3.7% of the patients randomized to M-VAC are alive and continuously disease-free at 6 years. CONCLUSION: Long-term follow-up evaluation of the intergroup trial confirms that M-VAC is superior to single-agent cisplatin in patients with advanced urothelial carcinoma; however, durable progression-free survival is rare. Patients with non-transitional-cell histology, poor performance status, and/or bone or visceral involvement fare poorly and are unlikely to benefit significantly from M-VAC chemotherapy.

Aged↗
PubMed1997

Paclitaxel and carboplatin in early phase studies: Roswell Park Cancer Institute experience in the subset of patients with lung cancer.

The combination of paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) given by 3-hour infusion followed by carboplatin infused over 30 minutes has been evaluated in a series of phase I studies and is currently being explored in a phase II study in patients with limited- and extensive-stage small cell lung cancer. Pharmacokinetic measurements were performed at all dose levels in the phase I studies, in which the use of granulocyte colony-stimulating factor in previously treated patients enabled more than twice the dose of paclitaxel to be given with low to moderate doses of carboplatin (dosed to a target area under the concentration-time curve of 4.0 mg x min x mL[-1]). Treatment-naive patients tolerated high paclitaxel doses (270 mg/m2) with carboplatin (dosed to a target area under the curve of 4.5 mg x min x mL[-1]) without granulocyte colony-stimulating factor support. Twenty-three patients (including previously treated and untreated) with non-small cell lung cancer were entered at a variety of paclitaxel doses in the phase I studies. At 100 to 205 mg/m2 paclitaxel, none of nine treated patients responded; at 230 to 290 mg/m2, four (29%) of 14 responded. In the phase II study of paclitaxel 250 mg/m2 in previously untreated patients with small cell lung cancer, two of five evaluable patients with extensive-stage disease have shown a partial response. In a preliminary analysis of the pharmacodynamics of paclitaxel in relation to neurotoxicity (dose limiting in two of three phase I studies), neurotoxicity correlated with the total dose of paclitaxel, the area under the curve, and the peak paclitaxel concentration, but not with the length of time plasma paclitaxel levels remained above 0.05 micromol/L. These correlations were not strong, however, and analysis of these data is ongoing.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1997

Translational studies of glutathione in bladder cancer cell lines and human specimens.

Glutathione (GSH) levels were measured in 13 human tumor cell lines derived from carcinomas of the bladder, ovary, and colon and from melanoma and glioblastoma. High levels were found in four of five bladder cell lines. The average GSH concentration in the bladder cell lines was approximately 6-fold higher than in the non-bladder cell lines. Because this difference suggested the possibility of elevation of GSH in urothelial neoplasia, we measured GSH in bladder tumor tissue from patients with transitional cell carcinoma (TCC) of the bladder (Group I, n = 17). GSH was also measured in two types of control tissues: (a) nontumor bladder tissue from patients with TCC or a history of TCC of the bladder (Group II, n = 23); and (b) bladder tissue from patients without bladder cancer (Group III, n = 14). Thirteen sets of paired specimens of tumor and nontumor bladder tissue from the same patient were evaluated. The tissues were flash-frozen, and GSH was measured after histological assessment of the same samples. Free and total GSH (free + mixed disulfides) were measured by a high-performance liquid chromatography assay with fluorescence detection and expressed as nanomoles/mg protein. The mean free GSH (+/- SD) for groups I, II, and III was 32.0 +/-18.7, 17.3 +/- 11.4, and 9.3 +/- 4.0, respectively, and the mean total GSH was 45.9 +/- 32.5, 23.7 +/- 17.1, and 12.2 +/- 6.7. The respective differences between groups (I and II, I and III, and II and III) were statistically significant for both free and total GSH (Ps ranging from <0.0001 to </=0.05). Free and total GSH were higher in tumor than in nontumor tissue in 11 of 13 paired specimens (free, 29.5 +/- 20.4 versus 18.7 +/- 11.7, P = 0.017; total, 41.7 +/- 33.8 versus 24.9 +/- 18.4, P = 0.005). No correlation was found between GSH levels and the proportion of tumor cells in the tissue. Influence of smoking on GSH expression could not be assessed because 81% of the patients with TCC had a smoking history. Similarly, because only 11% had prior cytotoxic chemotherapy, the influence of prior cytotoxic exposure on GSH could not be assessed. The results indicate: (a) significantly higher levels of GSH in TCC compared to tumor-free bladder tissue; and (b) higher GSH levels in nontumor bladder tissue from patients with bladder cancer than from patients without TCC. The clinical implications of this work include the possibility that GSH may play a role in the resistance of bladder cancer to chemotherapy and may be associated with bladder carcinogenesis.

Brain Neoplasms↗
PubMed1997

Antitumor efficacy of N1,N11-diethylnorspermine on a human bladder tumor xenograft in nude athymic mice.

The spermine analogue N1,N11-diethylnorspermine (DENSPM) has been shown to induce the polyamine-acetylating enzyme spermidine/spermine N1-acetyltransferase, disrupt polyamine pool homeostasis, and inhibit tumor growth. DENSPM is currently being developed as an anti-neoplastic agent and is about to enter Phase II clinical trials. In this report, the antitumor efficacy of DENSPM was evaluated against a human transitional cell bladder BL13 carcinoma xenograft implanted orthotopically and s.c. in nude athymic mice. DENSPM was administered via continuous s.c. infusion at 93 mg/kg/day for 5 days. Treatment with DENSPM was well tolerated and produced tumor regressions in all mice with a significant proportion (up to 50%) of apparent cures. On the basis of low toxicity and good therapeutic efficacy, there is a strong rationale for evaluation of the therapeutic efficacy of DENSPM against bladder carcinomas in Phase II clinical trials.

Animals↗
PubMed1997

Magnetic resonance imaging of response to chemotherapy in orthotopic xenografts of human bladder cancer.

Although orthotopic xenografts offer the potential for improved modeling of tumor development and response to therapy, noninvasive methods are not readily available to serially monitor tumors growing at internal sites in small rodents. In this study, magnetic resonance (MR) imaging techniques were developed using a clinical 1. 5 T whole body scanner to routinely monitor tumor growth kinetics of orthotopic UCRU-BL13 human bladder cancer xenografts after systemic chemotherapy. As a vehicle to test the system, comparisons were made between a standard agent, doxorubicin (DOX), and a novel formulation of liposome-encapsulated doxorubicin (DOXIL) to determine whether liposome encapsulation would alter chemosensitivity of BL13 in an orthotopic model. High resolution MR images acquired using direct three-dimensional data acquisitions yielded accurate volumetric measurements and detected tumors calculated to be </=10 mm3. MR volume measurements were comparable with tumor volumes calculated from direct caliper measurements. Both DOX and DOXIL demonstrated statistically significant therapeutic effect against orthotopic tumors; DOXIL reduced tumor volumes by approximately 33% (P < 0.005), whereas treatment with free DOX resulted in 70% reduction in tumor volume at termination (P < 0.002). We show that noninvasive MR assessments can be performed longitudinally to construct classical tumor growth curves, which can be used to evaluate therapeutic response in animal models. Translation of the MR techniques used in this study into clinical diagnostic evaluation would allow optimization of individual treatment schedules and facilitate assessment of therapeutic response.

Animals↗
PubMed1996

Systemic Therapy for Invasive Bladder Cancer.

BACKGROUND: Bladder cancer is one of the most common malignancies in Western society. In the United States, approximately 10,000 of these patients present with invasive disease, and more progress from superficial bladder cancer. METHODS: The authors review the literature on systemic treatment for both localized and metastatic bladder cancer, and they include their experience in defining approaches to various stages of disease. RESULTS: Cisplatin-based combination chemotherapy is the most effective systemic approach for advanced bladder cancers, although few patients are cured. Neoadjuvant, perspective, and adjuvant trials, as well as concurrent chemoradiation studies, are in progress to attempt to demonstrate better outcomes. CONCLUSIONS: The combination of systemic chemotherapy and definitive local therapy may have a useful role in the management of locally advanced bladder cancers, but optimal schedules and true survival benefit have not been established.

Journal Article↗
PubMed1996

Management of hormone-resistant prostate cancer: an Australian trial.

The management of metastatic prostate cancer that has relapsed after initial hormonal manipulation remains a major problem, with the majority of patients dying within 12 months. Their clinical course is frequently characterized by progressive debilitation, pain, and other tumor-related symptoms. A phase II, non-randomized multicenter clinical trial was carried out in Australia in 1985-1986 to assess the efficacy and toxicity of mitoxantrone. Substantial anticancer activity was shown against hormone-refractory prostate cancer, indicated by reduction in tumor-related symptoms, improvement in quality of life indices, and a median survival of 10 months in patients with a heavy tumor burden. Although it is not possible to equate this nonrandomized series more fully with current experience since routine prostate-specific antigen measurement was not performed, the median survival of 10 months was equivalent to or better than the survival times reported from most other institutional reports of the time. Even more importantly, however, major improvements were noted in such subjective indices as reduction in pain, weight gain, and performance status. Toxicity was also acceptable, with the major side effect being asymptomatic myelosuppression.

Aged↗
PubMed1996

Early phase studies with paclitaxel/low-dose carboplatin in patients with solid tumors.

In preparation for the design of phase II studies in lung cancer, low-dose carboplatin, fixed at a target area under the concentration-time curve (AUC) of 4.0 or 4.5 mg x min/mL, has been combined with escalating doses of paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) in a series of studies to establish the maximum tolerated dose of the combination. In patients who had received prior chemotherapy, the maximum tolerated paclitaxel dose was 135 mg/m2 (carboplatin target AUC 4.0); the dose-limiting toxicity was febrile neutropenia. Without granulocyte colony-stimulating factor support in chemotherapy-naive patients (carboplatin target AUC 4.5), and with granulocyte colony-stimulating factor in chemotherapy-pretreated patients, the current paclitaxel dose is 290 mg/m2. The maximum tolerated dose has not been defined. In a study in which paclitaxel was given by 1-hour infusion with carboplatin (target AUC 4.5), a 205 mg/m2 dose was poorly tolerated. No evidence of pharmacokinetic interactions between paclitaxel and carboplatin was found. Twenty-one evaluable patients with lung cancer have been treated to date. There have been two partial responses, one minor response, and 10 patients with stable disease at paclitaxel doses of 100 to 270 mg/m2.

Antineoplastic Agents, Phytogenic↗
PubMed1996

Novel bifunctional anthracycline and nitrosourea chemotherapy for human bladder cancer: analysis in a preclinical survival model.

A hybrid drug [N-2-chloroethylnitrosoureidodaunorubicin (AD312)] that combines structural and functional features of both anthracyclines and nitrosoureas was evaluated in a preclinical survival model of human bladder cancer. To measure the therapeutic activity of AD312, UCRU-BL13 transitional cell carcinoma cells were grown as xenografts in nude mice, and tumor growth rates were compared after i.v. administration of the drug at three dose levels. AD312 treatment at 45 and 60 mg/kg achieved 7-10-fold inhibition of tumor growth and increased host survival by 156 and 249%, respectively. Doses of 60 mg/kg showed optimal therapeutic efficacy, with sustained tumor growth inhibition, an over 2-fold increase in life span, and 40% of mice tumor free ("cured") at 120 days. Tumors were unresponsive to maximum tolerated doses of doxorubicin, a standard anthracycline used as a single agent and in combination therapies for bladder cancer. 1,3-Bis-[2-chloroethyl]-1-nitrosourea was used as a control for the apparently enhanced response of human tumors in murine hosts to nitrosoureas. 1, 3-Bis-[2-chloroethyl]-1-nitrosourea administered in three injections of 20 mg/kg did not cure mice but temporarily inhibited tumor growth by 70% and prolonged survival by 55%; its activity in this model suggests that it may be included in the repertoire of alkylating agents currently used for treatment of bladder cancers. AD312 showed increased antitumor activity with less toxicity than doxorubicin, and its bifunctional properties provide the opportunity for simultaneous treatment of individual cancer cells with two cytotoxic modalities as well as treatment of heterogeneous populations typical of bladder cancers. This novel cytotoxic drug cured doxorubicin-refractory disease and should be investigated for the clinical management of bladder cancer.

Animals↗
PubMed1995

Neoadjuvant chemotherapy of stage III-A and B lung carcinoma using the PACCO regimen.

Previously, we reported an effective chemotherapeutic combination regimen for non-small cell lung carcinoma (NSCLC): cisplatinum, doxorubicin, cyclophosphamide, CCNU, and vincristine (PACCO). Forty-one patients with a diagnosis of NSCLC Stages III-A and III-B were entered into the protocol of neoadjuvant PACCO chemotherapy. Following two courses of chemotherapy, the patients were evaluated for surgical therapy. The overall response rate to the chemotherapy was 60%. Subsequently, 65% of the patients underwent surgical resection. The overall estimated median survival was 18 months. The survival of patients in III-A was 36 months and that of III-B was 18 months (95% confidence lower bounds for III-A: 8 months and for III-B: 13 months). There was one chemotherapy-related mortality but no surgical mortality. Neoadjuvant chemotherapy with PACCO regiment offers an alternative to chemoradiation therapy, without increasing the surgical mortality, and should be validated in a randomized clinical trial. For successful neoadjuvant chemotherapy of Stage III NSCLC, chemotherapy combination which would give a high response rate without significant side effects must be chosen.

Adult↗
PubMed1995

Intracellular glutathione and cytotoxicity of platinum complexes.

Although there have been a number of reports correlating cellular GSH levels with cytotoxicity of platinum agents, none has examined the relationship between GSH concentrations and cytotoxicity. In this study, using a highly specific HPLC method for measuring GSH and expressing GSH as concentration and also per cell number, we evaluated the correlation between GSH levels and the cytotoxicity to five agents in ten human tumor cell lines. The five platinum agents included the platinum(II) complexes cisplatin, carboplatin and oxaliplatin and platinum(IV) complexes iproplatin and tetraplatin. The correlation between intracellular GSH concentration and cytotoxicity was highly significant only for iproplatin (P = 0.002) followed by tetraplatin, which demonstrated a trend toward statistical significance (P = 0.06). Cytotoxicity of the other platinum complexes showed no relation to GSH concentration, cisplatin itself showing a P-value of 0.09. In contrast, the GSH levels normalized to cell number showed a statistically significant correlation with the cytotoxicity of four of the five platinum agents, the exception being carboplatin; the strongest correlation observed was that for iproplatin and tetraplatin. Glutathione-S-transferase (GST) activity in these cell lines showed no correlation with cytotoxicity of any of the platinum complexes. Our results, from the analyses of both GSH concentration as well as GSH per cell number, suggest a significantly higher interaction between GSH and iproplatin compared with the other platinum agents. Moreover, our data suggest that relationships between cytotoxicity and GSH levels on a per-cell basis may not persist when differences in cell volume are taken into account.

Antineoplastic Agents↗