Biomedical subjects

S Litwin

Publications and source records attributed to S Litwin.

At least 73 records · Page 4Linked to original sources

PubMed1994

Deletion and editing of B cells that express antibodies to DNA.

We previously demonstrated that in mice transgenic for genes coding for an anti-ssDNA autoantibody B cells were functionally inactivated but not physically deleted. We have now extended this model by introducing an arginine into the CDR2 of the heavy chain transgene. This change alters the specificity of the Ab from anti-ssDNA to anti-dsDNA and increases the affinity for ssDNA. Mice carrying this transgene displayed a significant reduction of peripheral B cells and anti-dsDNA B cells were not recovered from the spleens. The remaining B cells escape deletion by revising their Ag receptors in several ways: 1) elimination of the transgenic heavy chain gene via intrachromosomal recombination, followed by rearrangement and expression of endogenous VH genes; 2) ongoing rearrangement of endogenous kappa light chain genes to generate a non-dsDNA-binding Ab; and 3) expression of a rare V lambda gene, V lambda x, to generate a non-DNA-binding Ab.

Amino Acid Sequence↗

PubMed1994

Cytogenetic analysis of 63 non-small cell lung carcinomas: recurrent chromosome alterations amid frequent and widespread genomic upheaval.

A detailed cytogenetic analysis of 63 non-small cell lung carcinomas (NSCLCs) was carried out for identification of recurrent chromosomal alterations. Most specimens displayed very complex karyotypes with multiple numerical and structural changes (median number, 31). Losses of chromosomes 9 (65% of cases) and 13 (71%) were the most frequent numerical changes. Loss of the Y was often observed in tumors from males. Gain of chromosome 7 was also frequent (41%). Chromosome arms 1p, 1q, 3p, 3q, 6q, 7q, 8q, 9p, 11q, 17p, and 19q were particularly prone to rearrangement. The chromosome arm most often contributing to losses was 9p (79%). Other arms that were frequently lost included 3p, 6q, 8p, 9q, 13q, 17p, 18q, 19p, 21q, 22q, and the short arm of each acrocentric chromosome. The percentage of cases with loss of 3p was significantly higher in squamous cell carcinomas (94%) than in adenocarcinomas (60%). There was also a statistically significant increase in the proportion of cases with gains of 1q, 7p, and 11q in adenocarcinomas compared to squamous cell carcinomas. Several recurrent isochromosomes and unbalanced exchanges were found. Among these was i(5p), which was observed in nine tumors, eight of which displayed adenomatous features. An i(8q) was identified in six cases, including five adenocarcinomas. Double minutes and/or homogeneously staining regions were seen in seven specimens. These data indicate that numerous chromosome alterations contribute to the pathogenesis of NSCLC and that, amid this widespread genomic disarray, recurrent abnormalities exist that could have biological and clinical implications.

Adult↗

PubMed1994

Morbidity after intraperitoneal insertion of saline-filled tissue expanders for small bowel exclusion from radiotherapy treatment fields: a prospective four year experience with 34 patients.

UNLABELLED: When prolonged small bowel exclusion (SBE) from external radiotherapy (RT) fields or immediate exclusion of bowel from brachytherapy sources is required for a patient without adequate omentum, there are no simple proven methods available for accomplishing these goals. We report a prospective study of SBE by intraperitoneal, saline-filled tissue expanders (TE). Thirty-four patients had exclusion of small bowel from either external radiotherapy (RT) ports (20), afterloading catheter treatment fields (5), both (5), or from intracavitary implants (4). Twenty-seven TEs were placed in the pelvis and 7 in the iliolumbar fossa. TE volume ranged from 400-1500 cc (median 550 cc). Patients had rectal (n = 15), colon (6), endometrial (4), anal (3), and vaginal (1) cancers and sarcomas (5). Fifteen patients had recurrent neoplasms, 13 of which were in previously irradiated fields. Nine patients had colorectostomies directly behind the TE, and 12 had other bowel (6) or ureteral (3) anastomoses or bladder repairs (3) adjacent to the TE. RESULTS: TEs remained in the patients from 6 to 173 days (median 95). Morbidity included three early TE withdrawals before RT was begun, one for a prolonged ileus, one for a perineal wound dehiscence, and one for an unrelated small bowel obstruction. Two patients (5.9%) early in the series had post-withdrawal complications (non-lethal small bowel fistulas requiring reoperation), although in a recent cohort of patients no post-withdrawal complications occurred using a different placement technique (0/17 vs. 2/14, P = 0.2). The patient injury complication rate was 4/34 (11.8%). None of these limited or delayed RT, but RT was limited to less than that planned in one other by TE deflation (total complication rate 14.7%). There were no clinical infections involving the prostheses, even though one patient had an abdominal wound dehiscence, 3 had pelvic abscesses, and 2 had exposure of the TE through the vagina (1 planned, 1 at dehisced vaginal cuff) after TE placement. We noted no acute and one possible late RT complication in these patients (18 months median follow-up, range 3-43 months). Small bowel was displaced from > 95 per cent of the RT treatment volume in 70 per cent and from > 75 per cent of the treatment volume in 89 per cent of 27 evaluable patients treated with external RT. CONCLUSION: Intraperitoneal placement of a saline-filled tissue expander is a simple, safe and effective means of small bowel exclusion from RT portals.

Adult↗

PubMed1993

Neoadjuvant chemoradiation in pancreatic and duodenal carcinoma. A Phase II Study.

BACKGROUND: Low resectability rate and high locoregional recurrence are major factors contributing to the failure of surgical treatment for localized pancreatic adenocarcinoma. A Phase II study involving preoperative 5-fluorouracil (5-FU) and mitomycin C and radiation therapy was evaluated. METHODS: Thirty-one patients with biopsy-proven carcinoma (24, head of pancreas; 2, body; 5 duodenum) were treated with preoperative radiation therapy, 5040 cGy (180 cGy/fraction, 5 days/week), concurrent with 5-FU, 1000 mg/m2/day continuous infusion (days 2-5, 28-32) and mitomycin C 10 mg/m2 bolus (day 2). Ten patients had previous laparotomy or bypass surgery and were deemed unresectable; 21 had percutaneous, endoscopic retrograde choleangiopancreatic, or transhepatic stent biopsies. RESULTS: Toxicity included neutropenic fever (2 patients), biliary sepsis (2 patients), and nausea and vomiting requiring total parenteral nutrition. One patient died of biliary sepsis before completion of chemoradiation and 11 patients showed evidence of metastatic disease (clinical or occult). Resectability rate was 38% (10/26) for pancreatic carcinoma and 80% (4/5) for duodenal carcinoma. Pathology of the resected specimens revealed extensive necrosis and hyalinization with clear margins in all cases. Lymph node metastases were found in one case of pancreatic carcinoma. The four resected duodenal carcinomas contained no residual tumor in the specimens. At a median follow-up of 29 months, the median survival time for those with pancreatic carcinoma was not yet reached in the resection group and was 8 months in the nonresection group. The corresponding actuarial 5-year survival rates were 58% and 0%, respectively. CONCLUSIONS: Neoadjuvant chemoradiation therapy was given safely to patients with pancreatic and duodenal carcinoma. It facilitated complete resection in 38% of patients with pancreatic carcinoma and 80% of those with duodenal carcinoma. A significant downstaging of positive margins and regional lymph nodes occurs as a result of preoperative chemoradiation.

Adenocarcinoma↗

PubMed1993

Report of phase II trial of concurrent chemoradiotherapy with radical thoracic irradiation (60 Gy), infusional fluorouracil, bolus cisplatin and etoposide for clinical stage IIIB and bulky IIIA non-small cell lung cancer.

PURPOSE: To assess the response rate, median and long-term survival of patients (pts) with locally advanced, initially inoperable non-small cell lung cancer (NSCLC) treated on a phase II study of radical thoracic radiotherapy (TRT) and concurrent radiosensitizing chemotherapy. METHODS AND MATERIALS: From 3/87 to 7/90, 41 previously untreated patients at Fox Chase Cancer Center with locally advanced non-small cell lung cancer, 24 with bulky clinical Stage IIIA, and 17 with IIIB disease, received concurrent thoracic radiotherapy (60 Gy/2.0 Gy/d in 6 weeks) and 2 cycles of infusional 5FU (640-800 mg/m2/24 hrs x 5 d); cisplatin (20 mg/m2 qd x 5); and etoposide (50 mg/m2 d 1, 2, 5) administered days 1 and 28 of TRT. RESULTS: Forty of 41 were evaluable. Response rate was 90%, with radiographic CR in 20%. Thirteen pts (33%) underwent thoracotomy and complete resection with clinical downstaging in 10, including three pathologic CR's. Overall median survival was 14 months and 2-year survival was 38% with no difference between CS IIIA and IIIB pts (p = 0.2224). At median potential follow-up of 42 months, 8/40 pts. (20%) are alive and progression-free, including 4 of 13 resected pts. The chief toxicity was esophagitis, occurring in 32 pts. (80%), Grade 3-4 in 21 (52%), with 13 (33%) requiring hospitalization and 7 (18%) needing TPN. Grade 3-4 granulocytopenia was noted in 20 pts. (50%) with ten episodes of fever mandating intravenous antibiotics. Cardiac ischemia was documented in 2 (5%). Of 13 thoracotomy pts, six underwent lobectomy without perioperative mortality; 3 of 7 pneumonectomy pts died post-operatively, two from broncopleural fistula, and one from ARDS. CONCLUSION: This aggressive regimen produced a 2-year survival (38%) comparable to the best arm of cancer and leukemia groups B study 8433, which administered radical thoracic radiotherapy after protoadjuvant vinblastine and cisplatin in similar and earlier stage non-small cell lung cancer patients. Toxicity, particularly esophagitis, was severe, but of short duration. An unacceptably high complication rate was seen following pneumonectomy, but not lobectomy.

Adult↗

PubMed1993

B lymphocytes may escape tolerance by revising their antigen receptors.

To explore mechanisms that prevent autoreactivity in nonautoimmune mice, endogenous immunoglobulin (Ig) light (L) chains that associate with a transgenic anti-DNA heavy chain were analyzed. The antibodies from splenic B cell hybridomas of such mice did not bind double-stranded DNA (dsDNA) and their L chain sequences showed a biased use of V kappa and J kappa gene segments. The 44 L chains in this survey were coded for by just 18 germline genes. Six of the genes, each belonging to a different V kappa group, were used more than once and accounted for three fourths of all sequences. Based on the distribution of V kappa genes, the L chain repertoire in this line of transgenic mice was estimated at 37 V kappa genes. The most frequently observed gene, a member of the V kappa 12/13 group, was identified in 16 hybrids. In addition, the majority of V kappa genes used J kappa 5. We interpret the skewed representation of V kappa and J kappa gene segments to result from negative selection. Based on the data, we suggest that V kappa rearrangements giving rise to anti-dsDNA reactivity are removed from the repertoire by a corrective mechanism capable of editing self-reactive Ig.

Animals↗

PubMed1993

Statistical strategy for stereospecific hydrogen NMR assignments: validation procedures for the floating prochirality method.

We examine the statistical and other considerations which determine the validity and reproducibility of stereospecific hydrogen NMR assignments obtained by the floating prochirality method. In this method, the assignment of a prochiral configuration of hydrogens at selected centers is allowed to 'float' during the structure refinement, and the distribution of prochiral orientations in highly refined structures is subjected to statistical analysis. The underlying statistical basis for this approach is examined and potential limitations of current approaches are identified. As an example, approximately 1300 distance constraints obtained from NOESY spectra of oxidized horse cytochrome c have been used to examine several computational strategies. Repeated calculations were done by several different methods on both the whole molecule (104 residues plus heme) and on a 23-residue fragment containing two helices, a turn, and flanking residues. The results show that, even with NOE constraints alone, one third of the centers may be reproducibly assigned, provided appropriate precautions are taken. These precautions include adjustments for multiple statistical comparisons and characterization of statistical interactions between prochiral centers. The analysis demonstrates that inadequately constrained systems, such as fragments from a larger molecule, may produce misleading results, raising concerns about methods which rely solely on intraresidue and sequential interresidue constraints. A mathematical model describing interactions among prochiral centers is described and validated, and protocols for assignment and statistical validation are presented.

Animals↗

PubMed1993

Preservation of immune effector cell function following administration of a dose-intense 5-fluorouracil-chemotherapy regimen.

In a phase II clinical trial of 5-fluorouracil (5FU) plus N-(phosphonacetyl)-L-aspartate (PALA) therapy administration, a number of slowly developing clinical responses were observed. Because of this, a variety of immune parameters were sequentially studied in 21 patients on this trial. Of the 21 patients studied, 20 provided sufficient samples to compare baseline with subsequent values, 10 of the 20 patients responded to treatment. Responders and non-responders did not differ in any studied parameter at baseline. After 2 months of therapy, non-specific monocyte cytotoxicity (NSMC), antibody-dependent monocyte cytotoxicity (ADMC) and natural killer (NK) activity were higher in the entire study population, but these increases were not statistically significant. When responders and non-responders were evaluated separately, it was apparent that the trend was due solely to the changes observed in the responding patient population. When mean lysis values for each patient group were determined for each studied time point, it was possible to generate a mean area under the cytotoxicity/time curve (AUC) for each studied parameter. NSMC and ADMC did not differ in responders and non-responders. However, NK activity was significantly greater by mean AUC analysis (P = 0.006) in the responding group; NK activity was maintained in the responders, but decreased in non-responders. When lymphocyte and monocyte expression of the surface markers beta 2-microglobulin, HLA-DR, CD56, HNK-1, CD16 and interleukin-2 receptor were evaluated, there were no differences among responders and non-responders at baseline by mean AUC analysis or when comparing baseline with non-baseline values. It is concluded that although baseline immunological characteristics do not identify patients who are likely to respond to weekly 5FU and PALA, treatment is not associated with deleterious effects on the immune effector function parameters evaluated in this study, there being no effects on expression of a variety of associated cell-surface molecules.

Adenocarcinoma↗

PubMed1993

Phase I/pharmacokinetic/biochemical study of the nitroimadazole hypoxic cell sensitiser SR2508 (etanidazole) in combination with cyclophosphamide.

SR2508 sensitises certain hypoxic tumor cells in vitro and in vivo to the cytotoxic action of radiation and alkylating agents. The mechanism of sensitisation may derive in part from depletion of glutathione (GSH) and possibly inhibition of GSH-dependent enzymes in target cells. We treated 46 evaluable patients with cyclophosphamide 750-1000 mg m-2 followed by SR2508 at eight dose levels ranging from 2.5 to 15.0 g m-2. Each patient received SR2508 as a single agent initially, followed a week later by the combination of cyclophosphamide and SR2508. Initially, myelosuppression was the major toxicity; potentiation of cyclophosphamide-induced leukopenia by SR2508 required a dose reduction of cyclophosphamide to 750 mg m-2 at SR2508 doses above 7.2 g m-2. At doses above 9.4 g m-2 an acute syndrome of muscle pains and painful paresthesias of the extremities lasting 12-24 h was observed to occur with increasing severity. This side-effect was intolerable in two of three patients treated at 15.0 g m-2. The only other reproducible side-effect was nausea and vomiting which was controllable with antiemetics. Plasma and urine SR2508 concentrations were measured by HPLC in 45 patients. Plasma elimination curves fit a 2-compartment model. The mean terminal half-life at each dose level ranged from 5.1-5.8 h. The mean area under the plasma concentration-time curve was linearly related to dose, and mean total body clearance ranged from 46.6-94.0 ml-1 min-1 m-2; renal clearance accounted for 65.7-79.3%. Pretreatment with cyclophosphamide did not influence the kinetics of SR2508 in individual patients. Examination of the glutathione content of peripheral mononuclear cells and tumour samples showed that depletion to below 50% of control occurred in the majority of patients. GSH transferase inhibition occurred with a similar time-course, but to a lesser extent. These data suggest that the further evaluation of this regimen should be conducted with SR2508 administration preceding that of cyclophosphamide and that its evaluation in cyclophosphamide-sensitive tumours is warranted.

Adult↗

PubMed1993

A single institutional experience with preoperative chemoradiotherapy for stage I-III pancreatic adenocarcinoma.

In order to determine whether preresectional chemoradiotherapy (CTRT) would influence resectability, local control, and survival of patients with localized pancreatic adenocarcinoma, a 5 1/2-year prospective study of 39 patients treated with preoperative radiation therapy, 5-Fluorouracil (5-FU), and Mitomycin C has been performed. Thirty patients had celiotomy after CTRT (1/39 died while receiving CTRT, one refused surgery, and seven had extrapancreatic disease progression). Seventeen (57%) had resections (seven total, two distal subtotal, and eight Whipple pancreaticoduodenectomies). All had clear margins of excision, and only one had any positive lymph nodes in the resected specimen. Eleven patients with resection had Stage I cancers (5 T1b, 6 T2), five had Stage II, and one had a Stage III lesion. Previous bypass surgery, age, clinical response to CTRT, and tumor size had no influence on resectability. Two patients died postoperatively (12%) early in the series. Three others suffered major morbidity (chylous ascites requiring peritoneovenous shunt, ARDS, and prolonged afferent loop obstruction leading to a fatal liver abscess 5 months after surgery). Two patients with resection are alive without recurrence at 48 months after tissue diagnosis, and six others are also alive without recurrence, after from 6 to 23 months. In summary, resectability is probably enhanced and nodal metastases and resection margins are downstaged by preoperative CTRT. Demonstration of an improved survival benefit awaits further observation and phase III trials.

Adenocarcinoma↗

PubMed1993

Isolated locally recurrent rectal cancer: a review of incidence, presentation, and management.

Locoregional recurrence after treatment for rectal cancer may be largely prevented by wide pelvic surgical margins, adjuvant radiotherapy, and chemotherapy. Approximately half of these recurrences will present with recurrence only at the surgical site; one third to one half will be resectable with conventional surgical procedures, but the rest will require extended resections, including sacrum and hypogastric vessels, to achieve clean margins. Only a small fraction of those treated will be cured. There is no proof that radiotherapy or chemotherapy added to surgical excision afford better results, since no trials have been or are likely to occur, given the rarity of the situation. However, best results seem to follow multimodality therapy using complete surgical resection and radiotherapy (IORT or brachytherapy with or without teletherapy) with chemopotentiation. Yet, there is no multimodality series with a sufficient number of patients and follow-up period to be able to distinguish the actual value of the treatment and which patients are most likely to benefit. It is important to note that there will be some patients with second LRR who can be further aided by aggressive locoregional therapy.

Brachytherapy↗

PubMed1992

Phase II study of estramustine and vinblastine, two microtubule inhibitors, in hormone-refractory prostate cancer.

PURPOSE: Estramustine phosphate (EMP) and vinblastine are two microtubule inhibitors with distinct molecular targets and at least additive antimicrotubule effects in vitro. Their modest single-agent activities in hormone-refractory prostate cancer, nonoverlapping toxicities, and lack of cross-resistance prompted a phase II trial in hormone-refractory prostate cancer. PATIENTS AND METHODS: Thirty-six assessable patients at the Fox Chase Cancer Center and seven Fox Chase Cancer Center Network institutions were treated with oral EMP 600 mg/m2 on days 1 to 42 and vinblastine 4 mg/m2 intravenously (IV) once a week for 6 weeks. Courses were repeated every 8 weeks. Response assessment was based on a change in serum prostate-specific antigen (PSA) levels and was correlated with change in pain scores. RESULTS: PSA decreased from baseline by at least 50% in 22 patients (61.1%) and by > or = 75% in eight patients (22.2%). A 50% or more decrease in PSA on three successive 2-week measurements together with an improved or stable pain score, performance status, and measurable soft tissue disease (if present) was required for a partial response (PR), which occurred in 11 patients for an overall response rate of 30.5% (95% confidence interval, 15.6% to 45.6%). In seven patients with measurable nonosseous disease, there was one PR (14%) and one minor response (MR). In 28 patients with assessable pain, major pain responses occurred in 12 (42.9%). PSA response (> or = 50% decrease times three measurements) was predictive of major pain response with a 93.7% specificity, a 50% sensitivity, and a positive predictive value of 85.7%. CONCLUSION: We conclude that EMP and vinblastine is an active combination in hormone-refractory prostate cancer.

Aged↗

PubMed1992

Effects of formaldehyde on xenotransplanted human respiratory epithelium.

A laboratory animal model that permits the exposure of xenotransplanted human respiratory epithelium to formaldehyde was used to study the effects of formaldehyde alone or in combination with the ultimate carcinogenic metabolite of benzo[a]pyrene, benzo[a]pyrene diol epoxide. Epithelial cells obtained from autopsies of full-term human fetuses or infants less than one year old were isolated, amplified in primary cultures, and then inoculated into rat tracheas from which the epithelial layer had been removed. These tracheas then were sealed and transplanted subcutaneously into irradiated athymic nude mice. Four weeks after transplantation, the tracheal lumen was completely covered by epithelium, most of which was of the mucociliary respiratory type. At this stage, tracheal transplants containing tracheobronchial epithelium from 20 different human infant donors were exposed to silastic devices containing 0, 0.5, 1, or 2 mg of formaldehyde. The tracheal transplants were examined histologically 2, 4, 8, or 16 weeks after transplantation. Before being killed, all animals were injected with a single pulse of tritiated thymidine. Important epithelial alterations were seen in the transplants treated with formaldehyde, with a maximum effect visible two weeks after exposure. In most cases, the highest dose of 2 mg produced numerous areas of epithelial erosion and inflammation; however, this effect was not as evident with the lower doses. All doses produced areas of hyperplastic epithelium alternating with areas of atrophic epithelium. Although the differences in predominance of different types of epithelium were not clearly dependent on dose, the labeling index showed dose dependence between two and four weeks after the initiation of exposure. The maximum mean labeling index was three to four times higher than normal, although in some focal hyperplastic-metaplastic lesions the labeling index increased up to 20 times. These studies show that formaldehyde, although toxic at higher doses, is able to elicit at lower doses a proliferative response of the human infant tracheobronchial epithelium that is not preceded by a massive toxic effect. Similar studies were performed using xenotransplanted human adult nasal respiratory epithelium (Study 2). The response pattern was very similar to that of the xenotransplanted human tracheobronchial epithelium from human infants (Study 1). In Study 3, using cells obtained from 11 human infant tracheobronchial epithelia, the formaldehyde applied simultaneously or sequentially with benzo[a]pyrene diol epoxide did not induce epithelial alterations different from those observed with formaldehyde treatments alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

Phase I study of thiotepa in combination with the glutathione transferase inhibitor ethacrynic acid.

The glutathione transferases comprise a family of isoenzymes, one or more of which are involved in the conjugation of alkylating agents to glutathione (GSH). Increased GSH transferase activity has been shown to underlie acquired resistance to several alkylating agents. Ethacrynic acid inhibits the isoenzymes of GSH transferase with 50% inhibitory concentration values ranging from 0.3 to 6.0 microM and has been shown to restore sensitivity to alkylating agents in drug-resistant animal tumor models. We entered 27 previously treated patients with advanced cancer on a study of ethacrynic acid (25 to 75 mg/m2 p.o. every 6 h for 3 doses) and thiotepa (30 to 55 mg/m2 i.v. 1 h after the second dose of ethacrynic acid). The major toxicity of ethacrynic acid was diuresis, which was observed at every dose level; in addition, severe metabolic abnormalities occurred at 75 mg/m2. At 50 mg/m2, the diuretic effects were manageable. Myelosuppression was the most important effect of the combination. Two of seven courses of ethacrynic acid, 50 mg/m2, and thiotepa, 55 mg/m2, were associated with grade 3 or 4 neutropenia and/or thrombocytopenia. Nausea/vomiting greater than or equal to grade 2 was observed in 16% of courses. GSH transferase activity was assayed spectrophotometrically in the peripheral mononuclear cells of all patients. At each dose level, activity decreased following ethacrynic acid administration, with recovery by 6 h. Administration of ethacrynic acid, 50 mg/m2, resulted in a mean nadir of transferase activity of 37% of control. The pharmacokinetics of thiotepa and its principal metabolite TEPA were studied in 23 patients. The plasma disappearance of thiotepa fit a two-compartment open model with a terminal half-life of approximately 2 h. Plasma TEPA levels peaked at a mean of 2.16 h following thiotepa administration. The harmonic mean terminal half-life of TEPA was 10.4 h, and the TEPA area under the curve (AUC) did not increase with increasing thiotepa dose. The AUC of thiotepa was approximately twice, and the clearance about one-half, of the values obtained in a previous study of single agent thiotepa. The AUC of TEPA was lower than that previously observed. The data suggest that ethacrynic acid inhibits enzymes involved in the metabolic disposition of thiotepa, including its oxidative desulfuration to TEPA. The severity of the platelet toxicity was correlated with the AUC of thiotepa, but not with that of TEPA. This combination of thiotepa and ethacrynic acid will be tested further in Phase II trials.

Adult↗

PubMed1991

Phase I evaluation of combination therapy with interleukin 2 and gamma-interferon.

Recombinant interleukin 2 (IL-2) is a potent inducer of lymphokine-activated killer (LAK) activity directed against autologous and allogeneic tumors; these effects are mediated by CD3-negative, CD56-positive, and CD16-positive lymphocytes. Although IL-2 therapy has been associated with clinical responses, particularly in patients with renal cell carcinoma and melanoma, these responses have occurred with high, toxic doses of this cytokine. Since gamma-interferon (IFN-gamma) potentiates LAK activity in vitro and in animal models, we initiated a dose-escalating Phase I trial of IFN-gamma and IL-2 in patients with advanced cancer. Patients were treated three times weekly (Monday, Wednesday, and Friday) for 6 weeks with bolus injections of IL-2; each dose was preceded 2 h earlier by a s.c. injection of IFN-gamma. Patients were treated with IFN-gamma at 0.01, 0.05, 0.1, or 0.25 mg/m2/dose. At each IFN-gamma dose, cohorts of at least three patients were treated with IL-2 at 1, 2.5, 5.0, or 7.5 x 10(6) Cetus units/m2 dose. Patients with clinical responses continued therapy three times weekly, while those with stable disease at 6 weeks were then treated twice weekly. A total of 41 patients were treated, all with Eastern Cooperative Oncology Group performance status 0 or 1. All patients were evaluable for toxicity. Dose-limiting toxicities were cumulative fatigue and constitutional symptoms. One documented transmural myocardial infarct occurred. The maximally tolerated dose combination, based on analysis of IL-2 dose intensity, was 0.1 mg IFN-gamma/m2 and 7.5 x 10(6) Cetus units IL-2/m2 per dose. Two partial responses and two minor responses were observed. Treatment was not associated with dose-associated changes in peripheral blood lymphocyte phenotype, but there was a trend favoring IFN-gamma dose-associated rises in IL-2 induction of natural killer and LAK activity by treated patients' lymphocytes. Analysis of the cumulative effects of therapy on induction of natural killer and LAK activity by measurement of the median area under the curve of activation showed clear evidence of IFN-gamma and IL-2 dose-associated changes. The IL-2 dose effects on cell lysis were monotone, while the optimal IFN-gamma dose appeared to be 0.1 mg/m2/dose, with a bell-shaped dose-response curve described previously for other effects of this cytokine. Using this novel statistical method of evaluating the biological effects of treatment, the optimal biological dose was identical to the maximally tolerated dose.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗

PubMed1991

Phase I/pharmacokinetic reevaluation of thioTEPA.

Because the initial evaluation of N,N',N''-triethylenethiophosphoramide (thioTEPA) preceded the standardized approach to the Phase I trials, uncertainty surrounds the recommended dose. Since it has recently been demonstrated that an almost 100-fold increase in dose can be administered in bone marrow transplant regimens, we conducted a Phase I reevaluation of thioTEPA. ThioTEPA was administered i.v. in 50 ml 5% dextrose in water over 10 min. Twenty-seven patients were entered at doses ranging from 30 to 75 mg/m2. The major toxic effect was myelosuppression; thrombocytopenia greater than or equal to grade 3 occurred in four of seven patients, and leukopenia greater than or equal to grade 3 in two of seven patients at 75 mg/m2. Among eight patients at 65 mg/m2 only two had greater than or equal to grade 3 myelosuppression making this the recommended new phase II dose for the majority of patients. Moderate (grade 2) easily controlled nausea and vomiting was the only other major side effect. There was no alopecia or mucosal or neurological toxicity. Three partial remissions were observed among nine previously treated ovarian cancer patients. Plasma concentrations of thioTEPA and its major active metabolite triethylenephosphoramide (TEPA) were measured by gas chromatography. The half-life of thioTEPA ranged from 51.6 to 211.8 min, and its pharmacokinetics was dose dependent; total body thioTEPA clearance decreased with increasing dose. The half-life of TEPA was considerably longer than that of the parent compound (3.0 to 21.1 h); as a result, the area under the plasma concentration-time curve (AUC) of TEPA was severalfold greater than that of the parent compound. The ratio of TEPA AUC to thioTEPA AUC decreased with increasing dose, suggesting that formation of TEPA is a saturable step in elimination. The AUC and total body clearance of thioTEPA, but not of TEPA, were closely correlated with neutrophil but not platelet toxicity.

Dose-Response Relationship, Drug↗

PubMed1991

Pharmacokinetic study of trimetrexate in combination with cisplatin.

The addition of the antifol methotrexate to cisplatin (DDP) produces supraadditive antitumor effects in preclinical studies, but in the clinic this combination of two nephrotoxic drugs is limited by excessive toxicity. Trimetrexate (TMTX) is a second generation antifol with predominantly nonrenal elimination and antitumor activity superior to that of methotrexate in preclinical models. In early clinical trials TMTX demonstrated promising activity in non-small cell lung cancer, and nephrotoxicity was rare. We performed a Phase I clinical and pharmacological study of TMTX (escalating doses) in combination with DDP (20 mg/m2), both administered i.v. for 5 consecutive days, every 4 wk. The pharmacokinetics of TMTX was determined in 15 patients after administration of the single agent (baseline study) and following the Day 1 and Day 5 doses in the TMTX-DDP combination. The recommended Phase II single-agent dose of TMTX on this schedule, 8 mg/m2, did not produce excessive toxicity when given concurrently with DDP. Significant drug-related nephrotoxicity was not observed, even in patients receiving multiple courses of TMTX-DDP. The mean renal clearance of TMTX increased 1.4-fold and 2.8-fold over baseline on Days 1 and 5, respectively, of TMTX-DDP. Urinary flow was similarly greater on days of TMTX-DDP treatment. The nonrenal clearance of TMTX was unaffected by concurrent DDP. The steady-state volume of distribution, Vdss, and terminal elimination half-life were significantly greater on Day 5 of TMTX-DDP compared to baseline. The plasma protein-binding of TMTX in vitro was not altered by DDP, and the disappearance of ultrafilterable DDP from normal plasma in vitro was unchanged by TMTX. Although a protein-binding interaction of TMTX and DDP was not detected in normal plasma in vitro, the changes in renal clearance, Vdss, and the terminal half-life were consistent with a greater fraction of unbound TMTX in plasma following Day 5 of TMTX-DDP. Effects of DDP on the binding of TMTX to extravascular tissue components, or on the renal handling of TMTX, cannot be excluded. The increase in TMTX renal clearance correlated with increased urinary flow, which may improve the therapeutic index of TMTX as both an antineoplastic and antiparasitic agent.

Antineoplastic Agents↗

PubMed1991

Somatic hypermutation of the JC intron is markedly reduced in unrearranged kappa and H alleles and is unevenly distributed in rearranged alleles.

Somatic hypermutation of the Ig genes occurs in rearranged V(D)J and its flanking sequences after Ag stimulation. Even though C regions and unrearranged V segments have been found to lack mutations, it is not known whether the mutational mechanism can be active in unrearranged J segments and their flanking regions. By polymerase chain reaction and direct sequencing of the 500 bp at the 5' end of the JC intron of hybridoma DNA derived from splenic B cells, we show that the frequency of mutations in unrearranged J regions of kappa and H chain genes is 0/7849 bp (upper 95% confidence interval, less than 0.00038) and 1/3209 bp (upper 95% confidence interval, less than 0.0015), respectively. The frequency (f) for the same region of rearranged kappa and H chain genes was 29/9380 bp (95% confidence, 0.0021 less than f less than 0.0044) and 16/2750 bp (95% confidence, 0.0033 less than f less than 0.0094), respectively. The significantly higher frequency of mutations in the rearranged alleles indicates that rearrangement is needed to effect full activation of the mutational mechanism. The data also show that mutations occur predominantly in the 5'-most 250 bp of the JC kappa intron. Statistical analysis of the distribution of mutations within the 5'-most 521 bp of the JC kappa intron reveals significant deviation (p = 0.000085) from a theoretically determined uniform distribution, indicating that mutations are not evenly distributed within this region.

Alleles↗