Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0854467 (myelosuppression)
 5,932 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Chemotherapeutic alkylnitrosoureas (BCNU, CCNU, streptozotocin) and alkyltriazenes (DTIC, temozolomide) produce a cytotoxic lesion at the O(6)-position of guanine. The DNA repair protein, O(6)-alkylguanine-DNA alkyltransferase removes damage from the O(6)-position in a single-step mechanism without co-factors. There is extensive evidence that this protein is one of the most important factors contributing to alkylnitrosourea and alkyltriazene treatment failure. There is an inverse correlation between the level of this protein and the sensitivity of cells to the cytotoxic effects of O(6)-alkylating agents. Attempts have been made to modulate AGT activity using anti-sense technology, methylating agents, O(6)-alkylguanines, and O(6)-benzylguanine analogs. O(6)-Benzylguanine and its analogs are clearly the most potent direct inactivators of the AGT protein. The mechanism involves O(6)-benzylguanine acting as a low-molecular weight substrate with transfer of the benzyl group to the cysteine residue within the active site of the repair protein. Pretreatment of cells with non-toxic doses of O(6)-benzylguanine results in an increase in the sensitivity to O(6)-alkylating agents. Animal studies revealed that the therapeutic index of BCNU increased when administered in combination with O(6)-benzylguanine. This drug is currently in phase I clinical trials. Evidence from animal studies indicates that myelosuppression may be the dose-limiting toxicity, thus, efforts are aimed at improving the therapeutic index by the stable expression of O(6)-benzylguanine-resistant AGT proteins into targeted normal tissue such as bone marrow. The successful modulation of alkyltransferases brings on an exciting new era for alkylnitrosoureas and alkyltriazenes.
 ...
PMID:Inhibition of DNA repair as a means of increasing the antitumor activity of DNA reactive agents. 1083 37

A Phase II trial was conducted in patients with advanced malignant melanoma with intravenous Paclitaxel and Dacarbazine (DTIC). The initial starting dose for Paclitaxel was 135 mg/m2 followed by DTIC 800 mg/m2. Due to the lack of myelosuppression and other toxicities, the starting dose for Paclitaxel was escalated to 250 mg/m2 and the dose for DTIC escalated to 1000 mg/m2. Twenty-five patients were enrolled in this study. Among the 25 patients assessable for response, three patients had a partial response with a response rate of 12% (CI 3-31%) and one patient had stable disease. Three additional patients showed evidence of anti-tumor activity with minor responses. For patients who had no prior chemotherapy or biochemotherapy, the response rate was 20%. Toxicity was generally tolerable and included mainly neurotoxicity from Paclitaxel. At the doses and schedule used, the combination of Paclitaxel and DTIC did not appear to increase the response rate compared to each agent used singly.
 ...
PMID:Phase II trial of Paclitaxel and Dacarbazine with filgrastim administration in advanced malignant melanoma. 1202 31

High-dose chemotherapy with autologous marrow or stem cell rescue (HDC/ASCT) is an effective strategy in patients with relapsed Hodgkin lymphoma. Various chemotherapy regimens have been used for cytoreduction prior to HDC/ASCT. In this study, our objective was to determine the response rate to PEND in a group of patients with relapsed Hodgkin lymphoma. Nineteen patients with relapsed or primary refractory Hodgkin lymphoma underwent treatment with the PEND regimen and received a median of 2 cycles (1 - 6 cycles). The PEND regimen builds on our prior results with ABDIC and consists of prednisone 40 mg/m2 orally (PO) daily x 5 days; etoposide 50 mg/m2 PO daily x 14 days; mitoxantrone 5 mg/m2/d IV, days 1 and 3; and DTIC 200 mg/m2/d intravenous continuous infusion (CIV) over 24 h, days 1 to 5, via central venous catheter. The treatment was given every 28 days. There were 3 complete responses (16%) and 10 partial responses (53%) yielding a total response rate of 69% (95% C.I. 43%, 87%). Myelosuppression was the predominant toxicity; no deaths were due to toxicity. After achieving maximum response to PEND, 10 eligible patients received a consolidative treatment with HDC/ASCT. All 6 patients who did not respond to PEND died from disease progression whereas 5 of 13 responders were alive after 10 years of follow-up (3 without disease). There were 11 deaths due to disease progression; three from other causes. The initial response to PEND before subsequent ASCT consolidation treatment appears to be associated with survival. All patients who failed to achieve a response have died. We conclude that PEND is an effective treatment strategy in Hodgkin lymphoma patients previously treated with both ABVD and MOPP.
 ...
PMID:Phase II study of PEND chemotherapy in patients with refractory/relapsed Hodgkin lymphoma. 1537 Feb 53

Preclinical data suggest that one method of inducing autoimmunity to tumor is the administration and subsequent withdrawal of cyclosporine A following chemotherapy and that this effect may be enhanced with interferon and interleukin-2. Consequently, we performed a phase II trial in patients with advanced melanoma to explore this approach. Thirty-three patients were treated with BCNU (150 mg/m2 iv every 8 weeks), cisplatin (25 mg/m2 iv days 1-3) every 4 weeks, DTIC (220 mg/m2 iv days 1-3 every 4 weeks) along with tamoxifen (10 mg po BID days 1-4). Cyclosporine A at 3 mg/kg/day in two divided doses was given on days 4-21, alpha-interferon 1 million units/m2 subcutaneously every other day on days 4-21 and interleukin-2 1 million units/m2 BID subcutaneously days 21-28 were also given. Of the 33 patients, 3 patients (9%) had complete response and 8 patients (24%) had a partial response for a total response rate of 33% (95% confidence interval 18-52%). Median duration of response was 17 months (range 3+ to 24+ months). Six patients continue to show no signs of tumor progression for 3+, 5+, 10+, 24+, 60+, and 72+ months. Toxicity was generally well tolerated and included myelosuppression and fatigue. This regimen is feasible and generally tolerable and has produced an antitumor response rate comparable with inpatient biochemotherapy regimens.
 ...
PMID:Cyclosporine A, alpha-lnterferon and interleukin-2 following chemotherapy with BCNU, DTIC, cisplatin, and tamoxifen: a phase II study in advanced melanoma. 1577 61

Treatment of advanced soft tissue sarcoma usually includes dacarbazine (DTIC), an alkylating agent that methylates DNA and is active during all phases of the cell cycle. Common side effects of DTIC include nausea, vomiting, impaired liver and kidney function, myelosuppression, and pneumonia. There are no accounts, however, of histological and hematological changes caused by DTIC. We investigated acute hematological and morphological changes in different organs and in tumors that were caused by a single dose of DTIC. Adult Syrian golden hamsters were inoculated with a suspension of tumorigenic baby hamster kidney (BHK) cells by subcutaneous injection. On day 14 after inoculation, doses of 1.4, 1.6, 1.8 or 2.0 g/m(2) DTIC were injected intraperitoneally into the hamsters. Hamsters in the control group were injected with physiological saline in the same way. Seven days after drug or saline injection the animals were sacrificed and samples of blood, heart, kidney, liver, lungs, spleen, small intestine and tumor were excised, processed and analyzed. Mitoses were counted using an ocular extension with engraved frame. Anemia, thrombocytopenia and leukocytosis were found in the control group of hamsters with fibrosarcoma, whereas animals with fibrosarcoma treated with DTIC developed anemia, thrombocytopenia and leukopenia. Severe pneumonia and moderate hepatitis were detected in all DTIC treated groups. Effects of DTIC on tumor cells included rounding and enlargement of nuclei and rarefaction of chromatin. The number of mitoses was reduced with increasing doses of DTIC. Hepatitis, myelosuppression, pneumonia, and dose-related inhibition of tumor cell proliferation were observed after a single dose of DTIC.
 ...
PMID:Acute toxic effects of single dose dacarbazine: hematological and histological changes in an animal model. 2486 97


<< Previous 1 2 3 4