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King SA. Assisted death and physician-assisted suicide. N Engl J Med 1993; 328:965; author reply 965-6. [PMID: 7680429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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77
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78
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King SA, Strain JJ. Revising the category of somatoform pain disorder. HOSPITAL & COMMUNITY PSYCHIATRY 1992; 43:217-9. [PMID: 1555817 DOI: 10.1176/ps.43.3.217] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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79
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Grem JL, King SA, Chun HG, Grever MR. Cardiac complications observed in elderly patients following 2'-deoxycoformycin therapy. Am J Hematol 1991; 38:245-7. [PMID: 1951329 DOI: 10.1002/ajh.2830380320] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Deoxycoformycin (dCF) is an investigational nucleoside with significant activity in hairy cell leukemia, cutaneous T-cell lymphoma, and chronic lymphocytic leukemia. During a 4-year period, 11 patients have experienced cardiac events as a complication of dCF therapy under NCI sponsorship. The cases are presented and recommendations for the administration of dCF to patients with pre-existing heart disease are made.
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80
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Shang AB, King SA. Parkinson's disease, depression, and chronic pain. HOSPITAL & COMMUNITY PSYCHIATRY 1991; 42:1162-3. [PMID: 1743647 DOI: 10.1176/ps.42.11.1162] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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81
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Cunningham MJ, Dunton CJ, Corn B, Noumoff J, Morgan MA, King SA, Rubin SC, Mikuta JJ. Extended-field radiation therapy in early-stage cervical carcinoma: survival and complications. Gynecol Oncol 1991; 43:51-4. [PMID: 1959788 DOI: 10.1016/0090-8258(91)90008-s] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Four hundred fifteen patients with early-stage cervical carcinoma were explored via a transperitoneal approach for radical hysterectomy at the Hospital of the University of Pennsylvania between January 1, 1960, and December 31, 1985. Twenty-four of these patients were found to have histologic documentation of para-aortic lymph node metastases. Twenty-one patients (88%) were treated primarily with extended-field radiotherapy. Forty-eight percent of these patients have survived greater than 5 years from diagnosis. Six patients have been followed more than 10 years after initial treatment. All six are alive although one patient has recurrent disease that was diagnosed at 164 months. Patients with adenocarcinoma or adenosquamous carcinoma had a survival significantly lower than that of those with squamous cell cancers (p = 0.022). Complications included one treatment-related death from multiple fistulas and sepsis, one vesicovaginal fistula, two enteric fistulas, and two small bowel obstructions. The major morbidity rate was 19%. Extended-field radiation is effective therapy for para-aortic nodal metastasis associated with early-stage squamous cell carcinomas of the cervix but carries a considerable morbidity rate. Other modalities such as combined chemotherapy and radiation may be necessary for adenocarcinoma.
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82
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Grem JL, King SA, Sorensen JM, Christian MC. Clinical use of thymidine as a rescue agent from methotrexate toxicity. Invest New Drugs 1991; 9:281-90. [PMID: 1838364 DOI: 10.1007/bf00176985] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Thymidine has been available for clinical research as a rescue agent since 1978 under sponsorship of the Division of Cancer Treatment, National Cancer Institute. Renal insufficiency following administration of high dose methotrexate results in prolonged exposure to toxic concentrations of drug. Thymidine has been used in conjunction with leucovorin and alkaline hydration to protect patients with acute renal dysfunction from life-threatening methotrexate toxicity. The outcome of eight cases in which thymidine was released under the special exception mechanism to treat patients who developed acute renal failure following methotrexate are reported. The clinical trials using thymidine in combination with methotrexate in patients with normal renal function are also reviewed.
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83
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King SA. Psychological aspects of pain. THE MOUNT SINAI JOURNAL OF MEDICINE, NEW YORK 1991; 58:203-7. [PMID: 1875957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Psychological factors have a major role in the development and maintenance of pain. Further research to clarify the nature of the relationship between these factors and pain is required. When evaluating patients with acute or chronic pain, attention must be given to psychological factors.
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84
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King SA. Liver transplantation for the alcoholic patient. PSYCHOSOMATICS 1991; 32:112-4. [PMID: 2003131 DOI: 10.1016/s0033-3182(91)72124-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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85
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Trout DL, King SA, Bernstein PA, Halberg F, Cornelissen G. Circadian variation in the gastric-emptying response to eating in rats previously fed once or twice daily. Chronobiol Int 1991; 8:14-24. [PMID: 1814598 DOI: 10.3109/07420529109063915] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Four experiments dealt with circadian variation in the gastric emptying (GE) response to eating, among rats accustomed to eating once (1x) or twice daily (2x). In measuring GE response, a test meal [10 g accustomed diet per (kg body weight)3/4] was fed close to a scheduled eating time or after a delay of up to 24 h. GE response was the fraction of the ingested test meal emptied per hr, up to a known degree of emptying, e.g., 50-58% of the test meal. Animals accustomed to the prescribed eating patterns ate promptly and at similarly rapid rates at all times of day. GE response, as plotted against time of response, fit a 24-h cosine model. Acrophase (time of maximum GE response of the fitted model) was similar, being 1.5 and 2.1 h, respectively, after the starting time of the accustomed dark-span meal for 1x and 2x rats, while amplitude (1/2 the maximum-to-minimum difference) was 41 and 24% of the MESOR (rhythm-adjusted mean). Characteristics of the GE rhythm appeared to be unchanged among 1x rats, severely versus minimally restricted in food intake during a final 9 days.
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86
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Abstract
Trimetrexate is a nonclassical antifol currently being tested for efficacy in cancer patients and as an antiparasitic agent against Pneumocystis carinii pneumonia in AIDS patients. We have now received the first reports of hypersensitivity reactions in Phase II cancer trials. Two types of reactions were noted. The most severe reaction, immediate hypotension with loss of consciousness, occurred in only one patient. Four other patients exhibited an immediate systemic effect with one or more of the following symptoms: facial flushing, fever, shaking, pruritus, bronchospasm, periorbital edema, and difficulty in swallowing. Immediate hypersensitivity should now be considered a known side effect of trimetrexate therapy, occurring in less than 2% of patients.
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87
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Grem JL, Rubinstein L, King SA, Cheson BD, Hawkins MJ, Shoemaker DD. Clinical toxicity associated with tiazofurin. Invest New Drugs 1990; 8:227-38. [PMID: 2200759 DOI: 10.1007/bf00177266] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Tiazofurin, an investigational antimetabolite, is undergoing clinical evaluation in leukemia. We analyzed the data base of 198 patients entered in Phase I trials to characterize the incidence and severity of toxicities associated with tiazofurin according to dose and schedule. Severe myelosuppression occurred infrequently, and was not dose-dependent. A five day bolus schedule had a higher incidence of severe or life-threatening neutropenia than other schedules. Tiazofurin produced lymphopenia which was not dose-dependent in the range of 23-36% decrease from baseline, and the effect on lymphocyte count was generally greater than the decline in neutrophil count. Non-hematologic toxicity of a moderate or worse severity (greater than or equal to grade 2) included nausea and vomiting (18% of all courses), serum transaminase elevations (SGOT, 16%; SGPT, 9%), rash (9%), stomatitis (3%), conjunctivitis (3%), headache (10%), other signs of central nervous system toxicity (8%), and cardiac toxicity, primarily pleuropericarditis (4%). Dose-related cutaneous toxicity, headache, and nausea and vomiting were evident in the five day bolus schedule, and myalgia was more frequently reported at higher doses on the single dose schedule. The five day continuous infusion (CI) schedule had a higher incidence of neurotoxicity, cardiac toxicity, SGPT elevations and ocular toxicity than the daily for five days bolus schedule, but none of these differences attained statistical significance. Although the peak plasma concentrations of tiazofurin achieved with the five day bolus schedule were 3-fold higher than the steady-state plasma levels seen with an equal dose given by CI, the area under the concentration-time curve (AUC) was approximately 1.6-fold higher with CI. These observations suggest that both high peak plasma concentrations (above 400 microM) and prolonged exposure to plasma levels exceeding 50 microM may result in a higher incidence of serious non-hematologic toxicity.
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88
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Abstract
Because of the difficulty in applying psychiatric diagnostic nomenclature to the problem of pain in the medical setting, medical and surgical inpatients referred for a psychiatric consultation with pain as a presenting complaint (N = 167) are compared with "nonpain" patients (N = 1,634). "Pain" patients were more often male (p less than 0.05), had additional presenting problems of coping with their illness (p less than 0.0001), drug misuse and abuse (p less than 0.0001), and terminal illness (p less than 0.0001); evidenced less severity of psychiatric impairment (p less than 0.05); received different treatment recommendations; and were more likely to be assigned less frequently employed DSM-III psychiatric diagnoses than those most commonly found in consultation populations. However, these diagnoses were nonspecific for the problem of pain and provided minimal information about the nature of the pain. Enhancements of the diagnostic classification systems that would better address the nature of the psychiatric disorders associated with pain are presented.
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89
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Perkins RE, King SA, Hollyman JA. Resettlement of old long-stay psychiatric patients: the use of the private sector. Br J Psychiatry 1989; 155:233-8. [PMID: 2597921 DOI: 10.1192/bjp.155.2.233] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A follow-up study of 17 old long-stay psychiatric patients resettled in private facilities for the elderly is reported. Resident satisfaction with the placement and functioning (using the CAPE Behaviour Rating Scale) was assessed, together with the quality of the physical and social environment, and the regime characteristics in the establishments. All residents were satisfied with life and their functioning had improved significantly. The private facilities were more resident-orientated, and had a generally superior social environment to their local authority 'old people's home' counterparts. The physical amenities, safety features, and architectural choice available were of a similar standard to those in local authority old people's homes, but there were fewer prosthetic and orientational aids and on-site recreational amenities.
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90
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Dlugolecka MJ, King SA. A simple tool for heart disease risk appraisal in general practice. JOURNAL OF THE ROYAL SOCIETY OF HEALTH 1989; 109:98-9. [PMID: 2501495 DOI: 10.1177/146642408910900309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Health promotion is becoming an increasingly prominent part of the workload of the primary health care team. Widening a consultation out to encompass general health matters can be difficult and time consuming. In this paper a simple tool to assist general practitioners and primary health care workers to discuss coronary heart disease risk factors is outlined and the experience gained in West Dorset is described.
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91
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Grem JL, King SA, Cheson BD, Leyland-Jones B, Wittes RE. Pentostatin in hairy cell leukemia: treatment by the special exception mechanism. J Natl Cancer Inst 1989; 81:448-53. [PMID: 2783980 DOI: 10.1093/jnci/81.6.448] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
An analysis of the clinical outcomes in 66 patients with hairy cell leukemia treated with pentostatin under the Special Exception mechanism of the Division of Cancer Treatment, National Cancer Institute, between 1983 and 1987 has revealed a favorable balance of risk and benefit. Hematologic parameters and performance status were improved in most patients treated outside the clinical trials mechanism. The treating physicians considered 37 patients (56%) to be complete responders and 15 patients (23%) to be partial responders. Four patients (6%) died while receiving pentostatin. Life-threatening leukopenia (wbc count, less than 1,000/mm3) was reported in 24% of patients, and severe or life-threatening infection occurred in 11%. The experience gained with these patients supplements the information presently being collected from the controlled clinical trials and supports the development of a group C treatment protocol.
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92
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O'Dwyer PJ, King SA, Eisenhauer E, Grem JL, Hoth DF. Hypersensitivity reactions to deoxycoformycin. Cancer Chemother Pharmacol 1989; 23:173-5. [PMID: 2784360 DOI: 10.1007/bf00267950] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Deoxycoformycin (dCF) is a promising new antineoplastic agent in the treatment of lymphoid malignancies, particularly hairy cell leukemia (HCL). Skin toxicity in the form of a maculopapular eruption has previously been reported but has not clearly been associated with idiosyncratic reactions. We present five cases of dCF-related hypersensitivity reactions in which additional systemic manifestations indicated an allergic etiology. The value of dCF in treating lymphoid neoplasms suggests that further study of the treatment of these reactions is indicated.
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93
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O'Dwyer PJ, King SA, Plowman J, Grieshaber CK, Hoth DF, Leyland-Jones B. Pyrazole: preclinical reassessment. Invest New Drugs 1988; 6:305-10. [PMID: 3068185 DOI: 10.1007/bf00173649] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Pyrazole (NSC-45410) is a low molecular weight, heterocyclic compound which has been considered for reevaluation in the clinic as a potential cytotoxic agent (Fig. 1). Discovered in 1893, pyrazole is best known as an inhibitor of liver alcohol dehydrogenase (ki = 0.2 uM), and as a result, has been used extensively in studies of alcohol metabolism. In 1960, pyrazole was identified as being active in preclinical antitumor models, which led to preliminary clinical testing. The early Phase I studies were not followed by disease specific Phase II trials, and the clinical activity of the drug has never been evaluated. This omission was noted by the National Cancer Institute's Project for the Review of Old Drugs (PROD), at which time it was also noted that pyrazole is selectively toxic to thyroid tissue in an animal model. Hence, interest in pyrazole was revived for two reasons: (a) failure to screen it for clinical activity in the 1960's, and (b) current interest in discovering drugs with selective toxicity to specific tissues for evaluation of their activity in malignancies arising in the target tissue. In this review, we summarize the evidence which has accumulated concerning pyrazole's potential role as an anticancer agent.
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94
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Grem JL, Ellenberg SS, King SA, Shoemaker DD. Correlates of severe or life-threatening toxic effects from trimetrexate. J Natl Cancer Inst 1988; 80:1313-8. [PMID: 2971817 DOI: 10.1093/jnci/80.16.1313] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Trimetrexate, an investigational antifol, has been associated with marked variability in drug tolerance among patients. The agent is extensively protein bound, and hepatic biotransformation plays a major role in its elimination. In early phase II testing, nine of 15 patients who experienced life-threatening or fatal toxic effects from trimetrexate had albumin levels less than or equal to 3.5 g/dL prior to treatment. This prompted a review of the data base on 272 patients entered in phase I clinical trails. The incidence of severe or life-threatening anemia, leukopenia, neutropenia, thrombocytopenia, mucositis, and hepatic toxic effects during the first course of trimetrexate was analyzed according to dose, schedule, prior treatment, and baseline protein and albumin levels. The schedules using doses given by short infusions of 30-60 minutes daily for 5 days or weekly for 3 weeks were generally associated with higher incidence of toxic effects than the schedules using doses given every other week by short infusions or those using continuous infusion. The occurrence of leukopenia and mucositis was dose related. Patients with baseline albumin levels less than or equal to 3.5 g/dL had higher incidence of all types of severe or life-threatening toxic effects than those with albumin levels greater than or equal to 3.6 g/dL, and the differences were significant for the development of anemia, thrombocytopenia, and mucositis. Similar correlations were noted for pretreatment protein levels less than or equal to 6.0 g/dL. The small cohort of patients with leukemia experienced substantial toxic effects and tended to have low protein and albumin levels. Performance status and prior therapy did not emerge as strong predictors of severe toxic effects in the univariate analysis. Multivariate analysis confirmed that the type of cancer (leukemia vs. solid tumor), dose, schedule, and baseline albumin level were significant and independent predictors of severe and life-threatening toxic effects in the phase I patient population. Multivariate analysis including only patients with solid tumors indicated that albumin level, dose, and schedule remained significant predictors of toxic effects. Since normal liver function as reflected by bilirubin and transaminase values were a requirement for eligibility, the results suggest that albumin and protein levels may provide a more sensitive index of hepatic function. Patients with hypoalbuminemia and hypoproteinemia are at increased risk of experiencing severe or life-threatening toxic effects from trimetrexate and should be treated cautiously.
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95
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Grem JL, Cheson BD, King SA, Leyland-Jones B, Suffness M. Cephalotaxine esters: antileukemic advance or therapeutic failure? J Natl Cancer Inst 1988; 80:1095-103. [PMID: 3045335 DOI: 10.1093/jnci/80.14.1095] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Clinical trials conducted in the People's Republic of China and the United States of the antileukemic efficacy of the cephalotaxine esters are reviewed. Harrington has been incorporated into combination regimens for the treatment of newly diagnosed acute nonlymphocytic leukemia (ANLL) in China, and activity with cephalotaxine esters has also been noted in chronic myelogenous leukemia. While the investigational agent homoharringtonine has shown some activity in the United States in ANLL, investigator interest in the United States has waned because of toxicity and inconvenient schedules. The Chinese trials have used different schedules than have U.S. studies and have been associated with less toxicity. These trials provide new information that may lead to further investigations of the cephalotaxine esters in the United States.
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96
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Grem JL, King SA, O'Dwyer PJ, Leyland-Jones B. Biochemistry and clinical activity of N-(phosphonacetyl)-L-aspartate: a review. Cancer Res 1988; 48:4441-54. [PMID: 3293772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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97
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Grem JL, King SA, Wittes RE, Leyland-Jones B. The role of methotrexate in osteosarcoma. J Natl Cancer Inst 1988; 80:626-55. [PMID: 3286880 DOI: 10.1093/jnci/80.9.626] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
High-dose methotrexate (MTX) is one of the agents currently used in intensive adjuvant chemotherapy regimens for nonmetastatic osteosarcoma. To elucidate the role of high-dose MTX in this disease, we present the history of trials conducted with MTX from the first single-agent studies through progressively complex combination regimens. With this background, some of the basic issues concerning MTX therapy in osteosarcoma are discussed.
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98
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O'Dwyer PJ, Cheson BD, Leyland-Jones B, King SA, Hoth DF. Deoxycoformycin: an active new drug for indolent lymphomas and hairy cell leukemia. ONCOLOGY (WILLISTON PARK, N.Y.) 1988; 2:17-23, 26-7. [PMID: 3079330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Promising results in the treatment of indolent lymphomas have been reported with the use of 2'deoxycoformycin. This antimetabolite, an adenosine deaminase inhibitor, also shows particular efficacy in hairy cell leukemia. Of 65 patients treated to date, 44 have achieved complete and lasting remission after a limited course of deoxycoformycin. While results are not as striking as those in hairy cell leukemia, deoxycoformycin may also be a valuable adjunct to alkylating agents in the treatment of CLL. The drug also is being studied in the treatment of mycosis fungoides and other lymphoid neoplasms. Side effects in all neoplasms are dose- and schedule-dependent.
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99
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Grem JL, Hoth DF, Leyland-Jones B, King SA, Ungerleider RS, Wittes RE. Teniposide in the treatment of leukemia: a case study of conflicting priorities in the development of drugs for fatal diseases. J Clin Oncol 1988; 6:351-79. [PMID: 3276827 DOI: 10.1200/jco.1988.6.2.351] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Teniposide, a semisynthetic epipodophyllotoxin, was found to be highly active against murine leukemias, and the combination of teniposide with cytosine arabinoside (ara-C) was curative in murine leukemia models. The antitumor activity in preclinical models prompted introduction of teniposide into the clinic in 1971. Although teniposide as a single agent rarely produced a complete remission in heavily pretreated leukemia patients, teniposide plus ara-C produced complete remissions in some patients with refractory and relapsed acute lymphoblastic leukemia (ALL). Innovative front-line and salvage regimens using teniposide have been developed that incorporate a multi-drug strategy with early intensification, rotation of drug combinations in maintenance, and regional therapy in an effort to improve the cure rate in leukemia. However, as the complexity of these regimens increases, the contribution of an individual component such as teniposide becomes less clear. Although some of these regimens for newly diagnosed and relapsed ALL are now thought to represent the best available therapy, teniposide remains an investigational agent. In this review, we outline and discuss the conflicts arising from the need to answer drug-specific issues, and, at the same time, facilitate the implementation of innovative, curative regimens.
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100
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Grem JL, Shoemaker DD, Hoth DF, King SA, Plowman J, Zaharko D, Grieshaber CK, Harrison SD, Cradock JC, Leyland-Jones B. Arabinosyl-5-azacytosine: a novel nucleoside entering clinical trials. Invest New Drugs 1987; 5:315-28. [PMID: 2449402 DOI: 10.1007/bf00169970] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Arabinosyl-5-azacytosine is a new compound which has been selected by the Division of Cancer Treatment, National Cancer Institute for clinical development as an antineoplastic agent based on its high degree of activity against a broad range of tumor types in preclinical studies. Therapeutic activity has been observed against murine and human leukemias, transplantable murine solid tumors, and human tumor xenografts. Arabinosyl-5-azacytosine exhibited a broader spectrum of activity against human solid tumors than cytosine arabinoside. Arabinosyl-5-azacytosine is phosphorylated to the nucleotide level by deoxycytidine kinase. Upon further anabolism to the triphosphate level, it can be incorporated into DNA. The mechanism of cytotoxicity is thought to be related to inhibition of DNA synthesis. Leukemic and solid tumor cell lines that are resistant to cytosine arabinoside due to deletion of deoxycytidine kinase activity are cross-resistant to arabinosyl-5-azacytosine. Unlike cytosine arabinoside, arabinosyl-5-azacytosine does not readily undergo deamination. Schedule dependence has been demonstrated in mice bearing L1210 leukemia, with superior activity seen with multiple doses administered on each treatment day compared to administration of larger but less frequently administered doses. From preliminary data in solid tumor models, however, antitumor activity did not appear to be superior with continuous infusion compared to that observed on a bolus schedule. Preclinical toxicology studies indicated that the bone marrow and gastrointestinal tract were the main target organs. A single large dose of arabinosyl-5-azacytosine could be tolerated by both mice and dogs. When administered as a continuous infusion, the toxicity was related to both the dose and duration of exposure, suggesting that toxicity resulted from a critical time above a threshold concentration as opposed to the total area under the concentration-time curve. Phase I clinical trials have been initiated to determine the maximum tolerated dose on a low dose continuous infusion schedule for 72 hours and also on a high dose short infusion daily times five schedule.
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