Quantitative estimation of the thermal dose-modifying factor for cis-diamminedichloroplatinum (CDDP) in tumour-bearing dogs.

A statistical method for estimating clinical toxicity was used to determine a theoretical isoeffect dose-modifying factor for dogs with disseminated or refractory neoplasia treated with cis-diammine dichloroplatinum (II) plus whole-body hyperthermia or CDDP alone. CDDP was administered every 3 weeks with vigorous saline hydration to 54 dogs (CDDP alone n = 21, CDDP/WBH n = 33) that were eligible for entry into this non-randomized study. CDDP was administered during the plateau phase of WBH in dogs receiving combined therapy. Acute toxicity included myelosuppression (CDDP n = 7; CDDP/WBH n = 5), nephrotoxicity (CDDP n = 1, CDDP/WBH n = 1) and respiratory distress (CDDP/WBH n = 2). Eight dogs experienced chronic renal dysfunction as a result of CDDP (n = 2) or CDDP/WBH (n = 6). A theoretical thermal dose-modifying factor was determined for both acute and cumulative toxicity by comparing the maximum tolerated dose of each treatment group. The maximum tolerated dose (MTD) of CDDP +/- WBH was defined as that dose producing a 50% incidence of moderate acute toxicity or acute plus mild chronic toxicity as estimated from logistic regression analysis of the toxicity data. The MTD (+/- .standard error) of CDDP/WBH for acute toxicity only was 54.6 (4.3) mg/M2 and for CDDP alone the MTD was 73.6 (40) mg/M2. Thus, the isoeffect dose-modifying factor for acute toxicity was 1.35 (0.12). The MTD (SE) of CDDP/WBH for cumulative toxicity (acute plus chronic toxicity) was 46.4 (2.7) mg/M2 and for CDDP alone waas 70.0 (2.9) mg/M2. The isoeffect dose-modifying factor for total cumulative toxicity was 1.5 (0.1).(ABSTRACT TRUNCATED AT 250 WORDS)

Phase I evaluation of doxorubicin and whole-body hyperthermia in dogs with lymphoma.

Fifteen previously untreated dogs with histologically confirmed, high-grade multicentric lymphoma were entered into a phase I study to evaluate combined doxorubicin and whole-body hyperthermia (DOX/WBH). Groups of three, four, and eight dogs were treated with whole-body hyperthermia and concurrent doxorubicin at 12 mg/m2, 24 mg/m2 and 30 mg/m2, respectively, after one doxorubicin induction dose at 30 mg/m2. Plateau temperature (42 +/- 0.1 degree C) was maintained for 90 minutes using a radiant heating device. A total of five DOX/WBH treatments per dog were planned, and these were given every 21 days. Treatment-related toxicity was not seen in the 12-mg/m2 doxorubicin dose group. Tumor progression prohibited administration of more than three DOX/WBH treatments to any dog in the 12-mg/m2 group. Premature ventricular contractions developed after the fifth treatment in one of the four dogs treated with 24 mg/m2 of doxorubicin. Two dogs (25%) in the 30-mg/m2 dose group had treatment-related toxicity. One dog experienced acute serious myelosuppression 1 week after the third treatment. This dog received all planned DOX/WBH treatments. Asymptomatic cardiac toxicosis consisting of decreased ejection fraction and fractional shortening developed in the second dog. This dog received only two DOX/WBH treatments. The three dogs treated at 12 mg/m2 had partial responses of short duration (60-83 days). Four dogs treated at 24 mg/m2 had complete responses for 150, 164, 186, and 200 days. Eight dogs treated at 30 mg/m2 had complete responses with a mean and median duration of 241 and 190 days, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Phase III evaluation of doxorubicin and whole-body hyperthermia in dogs with lymphoma.

Sixty-one dogs with histologically confirmed, untreated, high-grade lymphoma were evaluated and treated with doxorubicin (DOX, 30 mg/m2) alone. Forty-seven dogs (77%) achieved a complete response. Forty-six of the 47 dogs were randomized to receive five additional treatments with doxorubicin +/- whole-body hyperthermia (WBH). Median disease-free survival for the group treated with DOX alone (n = 22) was 189 days and for the DOX plus WBH (n = 24) was 239 days (p = 0.17). After the analysis was adjusted for stratification variables (i.e. institution, weight, stage), the effect of heat on disease-free survival remained statistically insignificant (p = 0.10), but suggested a tendency towards increased disease-free survival in hyperthermic dogs. Intact male dogs had significantly shorter disease-free survival than neutered males and neutered females (178 days vs 266 days, respectively; p = 0.013). No intact females were treated. Body weight, when evaluated as a continuous variable, was found to be a negative prognostic factor (p = 0.036). Tumour volume, stage and institution were not significant. Clinical incidence of cardiac dysfunction was not increased in dogs receiving DOX and WBH; however, post-mortem histological analysis of cardiac tissue suggested that the combined therapy of DOX and WBH was associated with greater myocyte degeneration (p = 0.012) and a tendency for increased cardiac fibrosis (p = 0.08). We concluded that continued refinement of DOX-WBH protocols is warranted, and may ultimately result in significant therapeutic improvement.

Phase I study of melphalan alone and melphalan plus whole body hyperthermia in dogs with malignant melanoma.

The maximum tolerated dose of melphalan combined with whole body hyperthermia (WBH) in dogs with spontaneous malignant melanoma was lower than in dogs not receiving WBH by a factor of 1.9 +/- 0.71. Thirty-three dogs were treated monthly with escalating doses of melphalan and followed weekly for toxicity and, when possible, tumour response. Toxicity was manifested as myelosuppression with nadir neutrophil and platelet counts occurring at 7-10 days post-treatment. The TD50 (+/- S.E.), defined by logistic regression analysis, was 0.63 (+/- 0.07) mg/kg and 0.33 (+/- 0.10) mg/kg for melphalan alone and combined with WBH, respectively. Objective tumour response in this limited series occurred in three of fourteen evaluable dogs (three of eleven treated with melphalan alone and none of three treated with WBH plus melphalan). It is concluded that melphalan combined with WBH can be safely administered, although a reduction in dose is necessary. A randomized clinical trial is required to investigate the possibility of achieving therapeutic benefit from combined melphalan and WBH.