"A set of proteins involved in the body's natural defenses produces a large number of mutations in human DNA, according to a study led by researchers at the National Institutes of Health. The findings suggest that these naturally produced mutat"...
Generally, the actinomycins exert an inhibitory effect on gram-positive and gram-negative bacteria and on some fungi. However, the toxic properties of the actinomycins (including dactinomycin) in relation to antibacterial activity are such as to preclude their use as antibiotics in the treatment of infectious diseases.
Because the actinomycins are cytotoxic, they have an antineoplastic effect which has been demonstrated in experimental animals with various types of tumor implants. This cytotoxic action is the basis for their use in the treatment of certain types of cancer. Dactinomycin is believed to produce its cytotoxic effects by binding DNA and inhibiting RNA synthesis.
Pharmacokinetics and Metabolism
Results of a study in patients with malignant melanoma indicate that dactinomycin (3H actinomycin D) is minimally metabolized, is concentrated in nucleated cells, and does not penetrate the blood-brain barrier. Approximately 30% of the dose was recovered in urine and feces in one week. The terminal plasma half-life for radioactivity was approximately 36 hours.
A wide variety of single agent and combination chemotherapy regimens with COSMEGEN have been studied. Because chemotherapeutic regimens are constantly changing, the decision to employ COSMEGEN should be directly supervised by physicians familiar with current oncologic practices and new advances in therapy.
The neoplasm responding most frequently to COSMEGEN is Wilms' tumor. Data from the National Wilms' Tumor Studies (NWTS-1, NWTS-2, NWTS-3 and NWTS-4) support the use of COSMEGEN in Wilms' tumor. The NWTS-3 evaluated results in 1,439 patients randomized to various regimens incorporating COSMEGEN (see table below).
The Third National Wilms' Tumor Study
|Stage||Regimen||4-Year Relapse Free Survival (%)||4-Year Overall Survival (%)|
|I (favorable histology)||L||89||95.6|
|II (favorable histology)||DD||87.9||93.6|
|III (favorable histology)||DD1||82||90.9|
|IV (favorable histology)||DD-RT J||71.9||78.4|
|I-III (unfavorable histology)||DD-RT J||67.1||68.3|
|IV (unfavorable histology)||DD-RT J||58.3||58.3|
L = COSMEGEN and vincristine (10 weeks)
It should be noted that the complete results from NWTS-4 have not yet been published. Changes in NWTS-4 and NWTS-5 have consisted of alterations in duration as well as dose intensity of COSMEGEN. As a consequence, appropriate consultation with physicians experienced in the management of Wilms' tumor should be sought.
The Third Intergroup Rhabdomyosarcoma Study (IRS-III) studied 1,062 previously untreated pediatric patients and young adults (≤21 years of age) and compared outcomes amongst a number of treatment regimens.
COSMEGEN was included in all arms as a standard component of the treatment regimen; thus, comparative data are not available from this study. Nevertheless, it does provide information on treatment outcomes in a large group of closely studied patients. For treatment purposes, patients were stratified according to clinical group, histologic subtype, and site of disease. Patients in most strata were randomized, but clinical group I patients with favorable histology were not randomized and treated according to a single regimen.
The Third Intergroup Rhabdomyosarcoma Study
|Group||Number of Arms||Chemotherapy Regimen||5-Year Progression Free Survival (%) (mean ± SEM)||5-Year Overall Survival (%) (mean ± SEM)|
|I (favorable histology)||1 (non-randomized)||cyclic sequential VA (1 year)||83 ± 3||93 ± 2|
|II (favorable histology, excluding orbit, head and paratesticular sites)||2 (randomized)||VA, doxorubicin and RT (1 year)||77 ± 6||89 ± 5|
|VA and RT (1 year)||56 ± 10||54 ± 13|
|III (excluding special pelvic, orbit, scalp, parotid, oral cavity, larynx, oropharynx and cheek)||3 (randomized)||pulsed VAC and RT (2 years)||70 ± 6||70 ± 6|
|pulsed VADRC-VAC, CDDP and RT (2 years)||62 ± 5||63 ± 5|
|pulsed VADRC-VAC, CDDP, VP-16 and RT (2 years)||56 ± 4||64 ± 5|
|IV (all)||3 (randomized)||pulsed VAC and RT (2 years)||27 ± 8||27 ± 6|
|pulsed VADRC-VAC, CDDP and RT (2 years)||27 ± 8||31 ± 6|
|pulsed VADRC-VAC, CDDP, VP-16 and RT (2 years)||30 ± 6||29 ± 7|
|VA = vincristine/COSMEGEN
VADRC = vincristine/doxorubicin/cyclophosphamide
VAC = vincristine/COSMEGEN/cyclophosphamide
CDDP = Cisplatin
VP-16 = Etoposide
RT = radiation therapy
Metastatic Nonseminomatous Testicular Cancer
Combinations of vinblastine, cyclophosphamide, COSMEGEN, bleomycin and cisplatin (VAB-6 regimen) have been employed in the treatment of metastatic nonseminomatous testicular cancer. In a retrospective analysis of 142 evaluable patients with primary advanced stage II or clinical stage III testicular cancer 112 (79%) achieved a complete response (CR) after treatment with VAB-6 alone or in combination with surgery. Relapses were uncommon (12%) and 117 of 166 patients (71%) were categorized as alive without evidence of disease during the four years covered by the study.
COSMEGEN in conjunction with vincristine, doxorubicin, cyclophosphamide and radiotherapy has been used in the management of both metastatic and non-metastatic Ewing's sarcoma. Of 120 previously untreated patients with non-metastatic disease treated with COSMEGEN as part of maintenance therapy in the United Kingdom Children's Cancer Study Group Ewing's Tumor Study (ET-1), 49 (41%) were free of disease at 5 years and 53 (44%) were alive at 5 years. Outcomes in regional and metastatic disease for previously untreated patients administered COSMEGEN resulted in 31 of 44 patients (70%) achieving a CR after a median time on study of 83 weeks. Eight of 44 (18%) patients achieved a partial response (PR) and the remaining 5 (11%) demonstrated no response to the regimen.
Gestational Trophoblastic Neoplasia
Single agent COSMEGEN has been used in the management of nonmetastatic gestational trophoblastic neoplasia. In a series of 31 patients with nonmetastatic disease, complete and sustained remissions were achieved with COSMEGEN alone in 94% of treated patients. Alternating combination regimens incorporating COSMEGEN in conjunction with etoposide, methotrexate, vincristine and cyclophosphamide (EMA-CO regimen) have also been used in the treatment of poor prognosis gestational trophoblastic neoplasia. Administration of EMA-CO to 148 women with poor prognosis gestational trophoblastic neoplasia resulted in 110 (80%) complete and 25 (18%) partial responses after a mean follow-up of 50.4 months. Overall survival during the study period was 85% and relapses were uncommon (5.4%). Meticulous monitoring of beta-hCG (human chorionic gonadotropin) must be incorporated into the treatment regimen.
Regional Perfusion in Locally Recurrent and Locoregional Solid Malignancies
COSMEGEN, as a component of regional perfusion, has been administered as palliative treatment and as an adjunct to tumor resection in the management of locally recurrent and locoregional sarcomas, carcinomas and adenocarcinomas.
Last reviewed on RxList: 9/18/2013
This monograph has been modified to include the generic and brand name in many instances.
Additional Cosmegen Information
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