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The clinical benefit and increased application of opioid rotation has focused attention on efficacy differences between opioids and their respective equianalgesic dose ratios. Understanding the differences between the opioids is critical to understanding their equianalgesic dose ratios and for adjusting therapy following rotation to a new analgesic. The purpose of this article is to describe controversies regarding the relative potencies of these agents as presented in current equianalgesic charts and to provide pharmacologic information to assist the clinician with opioid rotation.

The Southwest Oncology Group (SWOG) studied the response rate and toxicity of merbarone (1,000 mg/m2 IV continuous infusion days 1-5, q 21 days) in patients with advanced metastatic renal cell carcinoma. Among 36 eligible patients, there was one partial response for a response rate of 3% (95% C.I. 0.1-15%). There were no mixed responses. There were no treatment related deaths or adverse drug reactions. Significant anemia, diarrhea, and hypercalcemia were observed. Mild to moderate degrees of malaise/fatigue/lethargy, dizziness/vertigo, hyperglycemia, creatinine increase, nausea, vomiting, weight loss, pedal edema, dyspnea, and granulocytopenia were noted. Merbarone does not have significant activity as a single agent in advanced renal cell carcinoma.

The effect of [D-Leu 6 ,des-Gly-NH 2 10 , Proethylamide 9 ]-GnRH, leuprolide, was determined for the human primary prostate tumor cell line ALVA-31 by in vitro mitogenic assays. Prostate tumor cell proliferation was inhibited up to 50% by leuprolide. Inhibition was not observed in parallel cultures treated with other low molecular weight bioactive peptides. The incorporation and metabolic reduction of testosterone was not affected by concentrations of leuprolide that were inhibitory in the mitogenic assay. Specific high-affinity binding of 125 I-labeled leuprolide was also demonstrated on intact tumor cells with an estimated effective median dose (ED 50 ) of

In a Southwest Oncology Group phase II clinical trial, 68 patients with hormone refractory carcinoma of the prostate were treated with a combination of doxorubicin, mitomycin C and 5-fluorouracil. Of the patients 11 were classified as good risk and 57 as poor risk. There were 1 complete and 10 partial remissions for a response rate of 16.2% (exact 95% confidence interval 8.4 to 27.1%). Median survival was 9 months (maximum 14) for good risk patients and 10 months (maximum 42) for poor risk patients. Toxicity was significant with leukopenia identified as dose limiting. Because of the low rate of response and significant toxicity, this regimen cannot be recommended as standard therapy for metastatic hormone refractory prostate cancer.

Multiple agent combination chemotherapy was used to treat 16 patients with Stage D adenocarcinoma of the prostate in relapse. Agents employed were cyclophosphamide (Cytoxan), methotrexate, 5 fluorouracil, vincristine, and prednisone. Results were encouraging. Six of 16 patients achieved an objective response (2 complete, 3 partial, 1 stabilization) for a 37.5 per cent response rate. Eleven of 16 patients achieved a subjective response for a 69 per cent response rate. Soft tissue metastases may be more responsive than bony lesions. Employment of vincristine made no obvious difference in response rate in those patients in whom it was used. Toxicity was only moderate. Further studies are warranted.

From November 1976 to November 1978, the Southwest Oncology Group treated 254 patients with extensive (metastatic) small cell carcinoma of the lung with combination chemotherapy and radiotherapy with and without BCG immunotherapy. Patients receiving BCG achieved a response rate of 50% versus those patients not receiving BCG of 46% (P = .704). Response duration was 20 weeks for the BCG arms and 23 weeks for the no-BCG arms; survival was 28 weeks for the BCG arms versus 29 weeks for the no-BCG arms. An adverse effect in patients surviving more than one year was detected; those continuing to receive BCG had significantly shorter survival, 60 weeks versus 85 weeks (P = .019). Toxicities of the programs were not affected by the addition of BCG immunotherapy. It appears that BCG immunotherapy has no beneficial effect on response rate or duration of response in programs using chemotherapy and radiotherapy for control of metastatic small cell carcinoma of the lung. In addition, because of the adverse effect on long-term survival, we do not recommend the addition of BCG immunotherapy as a treatment modality in this tumor type.

Excerpt To the editor: Interferons have been shown to cause regression in several malignancies (1-3). Although the proper role of interferons in the treatment of cancer has yet to be defined, they ...