Characteristics of the anticoccidial activity of 6-azauracil

The characteristics of anticoccidial activities of 6-azauracil (AzU) were investigated in the battery trials utilizing the White Leghorn cockerels, which were infected with Eimeria tenella, E. necatrix, E. acervulina, E. maxima and/or E. brunetti. AzU was mixed into the basal starter feed and fed ad libitum to the birds from 1 day before the inoculation of oocysts to the time of necropsy. AzU showed remarkable anticoccidial activity against E. tenella and E. necatrix infections at doses of 1,000 ppm in feed or more, and fairly good effect against E. acervulina infection at the dose of 4,000 ppm in feed. Inadequate effect against E. maxima infection and null in effect against E. brunetti at the dose of 4,000 ppm were resulted for this drug. The effect of 6-azauridine, ribonucleoside of AzU against E. tenella and E. necatrix infections at 1,000 ppm was tested and revealed negative results. In the test with AzU-resistant line of E. tenella, cross resistance was confirmed between AzU and emimycin riboside, a uridine analogue. Activity of AzU was studied in vitro against E. tenella in chick kidney cells. AzU inhibited the development of the first- and second-generation schizonts at 100-200 ppm in the medium. Degenerated parasites were observed.

Rationally designed combination chemotherapy for the treatment of patients with recalcitrant psoriasis

In an effort to improve clinical response and reduce systemic toxicity, nine patients with recalcitrant psoriasis were treated with rational combinations of chemotherapeutic agents. Five patients received methotrexate by injection, 7.5 or 10 mg, followed 1 hour later by intravenous 5-fluorouracil, 170 to 562 mg/m2, on a weekly schedule. Four patients received oral triacetyl-azauridine, 2 to 4 gm daily, in combination with intravenous 5-fluorouracil, 225 to 600 mg/m2, administered every week. Three patients experienced greater than 75% clearing of disease, five patients experienced greater than 50% clearing, and only one patient failed to respond. Response rates did not differ between the two treatment groups. Adverse effects of these therapies were mild and infrequent. We conclude that 5-fluorouracil in combination with either methotrexate or triacetyl-azauridine is a relatively safe and effective alternative for the therapy of patients with severe psoriasis.

First clinical experiences with a selective chemotherapy of hepatocellular carcinoma with 5-fluorouridine in combination with other antipyrimidines

Sixteen unselected patients with non-resectable hepatocellular carcinoma were treated in a phase I study with 261 cycles of D-galactosamine and 6-azauridine prior to 5-fluorouridine. Thirty % of the patients survived for more than one year without signs of tumor progression and with an unchanged performance status. The compatibility of this chemotherapeutical method was quite satisfactory. The only extrahepatic side effect was a leucopenia and/or thrombocytopenia which was reversible upon reduction of the 5-fluorouridine dose. The heterogeneity of the 16 patients treated to date does not allow a definite statistical evaluation of the reported clinical observations and results. A final decision about the clinical applicability of this concept of a selective chemotherapy of hepatocellular carcinoma requires further experience.

Anemia of azaribine in the treatment of psoriasis

Azaribine is an effective agent in the treatment of psoriasis. In this investigation the extent of clinical dermatologic remission appeared to correlate with the degree of metabolic block induced by 6-azauridylic acid, as quantitated by the urinary excretion of orotic acid and orotidine, and the development of anemia. Following azaribine therapy there was a coordinate rise of the specific activities of erythrocyte orotate phosphoribosyltransferase and orotidine-5'-monophosphate decarboxylase. There was no correlation between the pretreatment activity of these enzymes and the clinical response to azaribine. The anemia of azaribine therapy was mile and of a megaloblastic type. Uridine effectively corrected the azaribine-induced anemia, but led to exacerbation of the patients' psoriasis. Following uridine therapy there was a reduction in the urinary excretion of orotic acid and orotidine, presumable reflecting end-product inhibition or repression of the first steps of a repeated pyrimidine biosynthesis.

Reproductive performance of women successfully treated for gestational trophoblastic tumors

The reproductive performance of 36 women who had been successfully treated for gestational trophoblastic tumors with multiple courses of cytotoxic agents including methotrexate, 6-mercaptopurine, actinomycin D, and 6-azauridine, between 1962 and 1972, has been studied in comparison with 36 patients who had spontaneously aborted a hydatidiform mole but received no treatment and a control group consisting of 36 women attending an antenatal clinic. The majority of patients who wanted further pregnancies following chemotherapy had one or more successful conceptions. The incidence of abnormal pregnancies in the treated group was higher than that of the control group. Similarly, there was a higher number of abnormal pregnancies in the untreated mole patients when compared with the control group. This suggests that patients who develop trophoblastic tumors tend to have a poor obstetric history and that this is not significantly worsened by chemotherapy.

Systemic chemotherapy for psoriasis: a national survey

A questionnaire that was mailed to 510 randomly selected dermatologists in the United States surveyed their use of three systemic chemotherapeutic agents for the treatment of psoriasis during the two-year period of 1973 to 1974. Methotrexate was used by 52% of the surveyed dermatologists, while hydroxyurea and azaribine were used by 10% and 2%, respectively. Seventy-five percent of the dermatologists who used methotrexate treated ten or fewer psoriatic patients with this drug. Multiple dose therapy with methotrexate divided over a period of 36 hours each week was the preferred schedule of 66% of the dermatologists. Liver biopsy specimens and creatinine clearance tests were obtained for only 17% and 35% of patients, respectively, prior to initiating methotrexate therapy. The estimated number of dermatologist-treated psoriatics nationwide receiving methotrexate is 25,000.

Evaluation of 6-azauridine and 5-iododeoxyuridine in the treatment of experimental viral infections

The potential antiviral activity of 6-azauridine and 5-iododeoxyuridine was evaluated in a coordinated study at five institutions. Experimental models in five species, the mouse, rabbit, swine, cat, and ferret, were established with use of 10 viruses: Herpesvirus hominis types 1 and 2, murine cytomegalovirus, vaccinia virus, Shope fibroma virus, transmissible gastroenteritis virus, swine influenza virus, feline viral rhinotracheitis virus, feline panleukopenia virus, and ferret distemper virus. Criteria for selection were: (1) representation from a number of major groups of viruses, (2) reproduction of natural routes of infection, and (3) simulation of potentially treatable viral infections of man. Antiviral activity was observed for 5-iododeoxyuridine in H. hominis infections in hairless mice and influenza in swine, and a slight degree of efficacy was noted in rabbits infected with Shope fibroma virus. Toxicity was also observed in most of the experimental models. There was a suggestion of antiviral activity with 6-azauridine in swine infected with transmissible gastroenteritis virus; however, enhancement of disease and some toxicity were seen in most of the other models. Efficacy of these two compounds was not well substantiated by these studies.

Chemotherapy of psoriasis: ten years of experience

The hunt for an effective, easier to administer, more acceptable therapeutic modality for extensive chronic psoriasis continues. The chemotherapy of psoriasis is reviewed in 246 patients from 1964 to 1974 treated with methotrexate, 92 patients from 1971 to 1974 with hydroxyurea, and 36 patients from 1972 to 1974 with azaribine. Currently, the available chemotherapy agents are the least palatable and desirable form of treatment. Methotrexate continues to be the most predictable, effective and least expensive. The use of photochemotherapy may prove to be more effective, less toxic, and more practical until a more specific and effective etiologically directed form of therapy becomes available.

Treatment of psoriatic arthritis with azaribine

Thirty-two patients with psoriatic arthritis unresponsive to conventional therapy were treated wtih the antipyrimidine azaribine. For the group, improvement was highly significant (P less than 0.01) when average painful joint count, ring size, grip strength, pain, and morning gel were compared with baseline measurements. The spectrum of response of individual patients varied from total remission or arthritis in 5 patients to no improvement in 7. Dermatitis improved more than 50% in 26 patients. Reduction in hematocrit, gastrointestinal irritation, and occasional central nervous system toxicity were readily reversed by decreasing or discontinuing dosage. Azaribine appears to be a useful agent for trial in the treatment of refractory psoriatic arthritis.

Azaribine therapy for psoriasis. Evaluation of potential effects on the liver and other organ systems

An open study of azaribine was carried out on 38 psoriatic patients for two years. Thirty-five patients had previously taken methotrexate. Thirty-four patients had liver biopsies performed before azaribine therapy and 14 had liver biopsies performed after azaribine therapy. Of these 14, five had grade 1 liver biopsies before and after therapy; one had grade III before and after therapy; and three had grade IV before and after therapy. Liver biopsy findings were slightly worse in two patients, and three patients showed improvement in liver biopsy findings.

Double-blind controlled crossover high-dose study of Azaribine in psoriasis

Azaribine used in high doses of 200 mg/kg a day is an effective agent in inducing temporary remissions in patients with severe psoriasis but potentially serious neurotoxicity may occur. Therapy should be initiated at lower doses of 125 mg/kg a day and advanced carefully only if clinical response does not ensue at the lower level.

The treatment of psoriasis with azaribine

An open study was made of 25 patients with severe, recalcitrant psoriasis treated with azaribine (6-azauridine triacetate). Most patients received 125 mg/kg/day for a period of 8 weeks. A good to excellent response with 60-100% clearing of lesions was observed in 14 patients and a fair response with 40-60% improvement in another 6 patients. Thus 20 patients (80% of the series) exhibited a favorable clinical response. 16 of these 20 patients relapsed to approximately pretreatment status within 1 month after stopping therapy. The most frequently observed side-effects were mild reversible anemia, fatigue and mild transient gastrointestinal symptons. 8 patients (32% of the series) exhibited sufficient toxicity to necessitate the discontinuance of therapy. 1 patient experienced an unexplained femoral arterial thrombotic episode while on the drug. Azaribine may find a place in the therapy of severe psoriasis particularly in patients with hepatic disease. However, further studies of its potential for toxicity are indicated.

Psoriasis: a review. II

Notwithstanding the intense interest in systemic cytotoxic therapy in recent years, the great majority in psoriatics are likely to go on needing topical therapy with tar, dithranol or corticosteroids, and a welcome trend is the spreading of interest in day care centres such as those in Paris (GRUPPER), Stockholm (THYRESSON), Stanford (FARBER) and San Francisco (CRAM) evolving from the out-patient regimes advocated by INGRAM in Leeds a generation ago.

Herpes simplex virus skin infection in hairless mice: treatment with antiviral compounds

A hairless mouse-herpes simplex virus skin infection experimental model was used to evaluate the efficacy of the antiviral compounds 9-beta-d-arabinofuranosyladenine (ara-A), 5-iodo-2'-deoxyuridine (IUdR), and 6-azauridine (aza-U). Ara-A and IUdR, when administered intraperitoneally by several different dosage schedules, reduced the severity of cutaneous herpetic lesions and the incidence of paralysis and increased significantly the number of survivors. A more rapid healing of the lesions and an increase in the mean survival time also was observed. A delay of 24 to 48 h in the initiation of treatment after the infection was more effective than treatments started at the time of inoculation. Treatment with ara-A was somewhat superior to that with IUdR, but aza-U was totally ineffective. Enhancement of the evolution of the infection was noted after treatment with aza-U.