A single-arm, multicenter, phase II trial of osimertinib in patients with epidermal growth factor receptor exon 18 G719X, exon 20 S768I, or exon 21 L861Q mutations.

BACKGROUND: For patients with stage IV non-small-cell lung cancer with epidermal growth factor receptor (EGFR) exon 19 deletions and exon 21 L858R mutations, osimertinib is the standard of care. Investigating the activity and safety of osimertinib in patients with EGFR exon 18 G719X, exon 20 S768I, or exon 21 L861Q mutations is of clinical interest. PATIENTS AND METHODS: Patients with stage IV non-small-cell lung cancer with confirmed EGFR exon 18 G719X, exon 20 S768I, or exon 21 L861Q mutations were eligible. Patients were required to have measurable disease, an Eastern Cooperative Oncology Group performance status of 0 or 1, and adequate organ function. Patients were required to be EGFR tyrosine kinase inhibitor-naive. The primary objective was objective response rate, and secondary objectives were progression-free survival, safety, and overall survival. The study used a two-stage design with a plan to enroll 17 patients in the first stage, and the study was terminated after the first stage due to slow accrual. RESULTS: Between May 2018 and March 2020, 17 patients were enrolled and received study therapy. The median age of patients was 70 years (interquartile range 62-76), the majority were female (n = 11), had a performance status of 1 (n = 10), and five patients had brain metastases at baseline. The objective response rate was 47% [95% confidence interval (CI) 23% to 72%], and the radiographic responses observed were partial response (n = 8), stable disease (n = 8), and progressive disease (n = 1). The median progression-free survival was 10.5 months (95% CI 5.0-15.2 months), and the median OS was 13.8 months (95% CI 7.3-29.2 months). The median duration on treatment was 6.1 months (range 3.6-11.9 months), and the most common adverse events (regardless of attribution) were diarrhea, fatigue, anorexia, weight loss, and dyspnea. CONCLUSIONS: This trial suggests osimertinib has activity in patients with these uncommon EGFR mutations.

Clinical outcomes in elderly patients with advanced non-small cell lung cancer: results from ARIES, a bevacizumab observational cohort study.

AIMS: Retrospective analyses from first-line clinical studies in advanced non-small cell lung cancer (NSCLC) have reported conflicting results on progression-free survival (PFS) and overall survival benefits with the addition of bevacizumab to chemotherapy in elderly patients. Here we report effectiveness and safety outcomes by age subgroup for patients with NSCLC in the ARIES observational cohort study. MATERIALS AND METHODS: ARIES enrolled patients with advanced non-squamous NSCLC who received first-line bevacizumab-containing treatment per physician's choice. Kaplan-Meier estimates were used to calculate medians and 95% confidence intervals for PFS and overall survival for patients aged <65, ≥65, <75 and ≥75 years. RESULTS: In total, 1967 patients receiving first-line treatment with bevacizumab and chemotherapy were enrolled. The median PFS and overall survival values were 6.4 (95% confidence interval = 6.0-6.8) and 14.2 (95% confidence interval = 12.7-15.2) months for patients aged <65 years, respectively, and 6.8 (95% confidence interval = 6.3-7.0) and 12.1 (95% confidence interval = 11.4-13.1) months for patients ≥65 years, respectively. For patients <75 years, the median PFS and overall survival values were 6.6 (95% confidence interval = 6.3-6.9) and 13.5 (95% confidence interval = 12.6-14.5) months, respectively, and 6.6 (95% confidence interval = 5.9-7.1) and 11.6 (95% confidence interval = 10.0-12.5) months, respectively, for patients ≥75 years. Incidence proportions of bevacizumab-associated adverse events were generally similar across all age groups. CONCLUSIONS: Data from the ARIES study suggest that treatment with bevacizumab in combination with chemotherapy is a viable first-line treatment option for elderly bevacizumab-eligible patients with advanced non-squamous NSCLC.

Randomized phase II trial of pemetrexed/cisplatin with or without CBP501 in patients with advanced malignant pleural mesothelioma.

BACKGROUND: CBP501, a synthetic duodecapeptide, increases cisplatin influx into tumor cells through an interaction with calmodulin enhancing cisplatin cytotoxicity, and effects cell cycle progression by abrogating DNA repair at the G2 checkpoint. In phase I clinical trials of CBP501 alone or in combination with cisplatin, the most common toxicity was infusion-related urticaria. Activity of CBP501 plus cisplatin was observed in patients with ovarian cancer and mesothelioma, including some patients previously treated with cisplatin. METHODS: Chemotherapy naïve patients with unresectable MPM were stratified by histology and performance status, and randomized 2:1 to pemetrexed/cisplatin plus CBP501 25mg/m(2) IV (Arm A) or pemetrexed/cisplatin alone (Arm B). The primary endpoint was progression free survival (PFS) at 4 months. RESULTS: 65 patients were randomized, and 63 were treated. Patient characteristics in the two arms were balanced. Based on independent radiology review of the treated population, 25/40 patients (63%) in Arm A and 9/23 (39%) in Arm B had PFS≥4mo; the median PFS was 5.1mo (95% CI, 3.9, 6.5) vs 3.4mo (2.5, 6.7). Median OS was 13.3mo (9.2, 16.3) in Arm A and 12.8 (6.5, 16.1) in Arm B. Adverse events were not different than expected from standard chemotherapy, and comparable in the two arms, aside from infusion reactions which occurred in 70% of patients treated with CBP501. CONCLUSIONS: While this randomized phase II trial met its primary endpoint of PFS at 4 months, other parameters such as response rate and overall survival suggest that the addition of CBP501 does not improve the efficacy of standard chemotherapy for MPM.

Randomized phase III trial of paclitaxel plus carboplatin versus vinorelbine plus cisplatin in the treatment of patients with advanced non--small-cell lung cancer: a Southwest Oncology Group trial.

PURPOSE: This randomized trial was designed to determine whether paclitaxel plus carboplatin (PC) offered a survival advantage over vinorelbine plus cisplatin (VC) for patients with advanced non--small-cell lung cancer. Secondary objectives were to compare toxicity, tolerability, quality of life (QOL), and resource utilization. PATIENTS AND METHODS: Two hundred two patients received VC (vinorelbine 25 mg/m(2)/wk and cisplatin 100 mg/m(2)/d, day 1 every 28 days) and 206 patients received PC (paclitaxel 225 mg/m(2) over 3 hours with carboplatin area under the curve of 6, day 1 every 21 days). Patients completed QOL questionnaires at baseline, 13 weeks, and 25 weeks. Resource utilization forms were completed at five time points through 24 months. RESULTS: Patient characteristics were similar between the groups. The objective response rate was 28% in the VC arm and 25% in the PC arm. Median survival was 8 months in both arms, with 1-year survival rates of 36% and 38%, respectively. Grade 3 and 4 leukopenia (P =.002) and neutropenia (P =.008) occurred more frequently on the VC arm. Grade 3 nausea and vomiting were higher on the VC arm (P =.001, P =.007), and grade 3 peripheral neuropathy was higher on the PC arm (P <.001). More patients on the VC arm discontinued therapy because of toxicity (P =.001). No difference in QOL was observed. Overall costs on the PC arm were higher than on the VC arm because of drug costs. CONCLUSION: PC is equally efficacious as VC for the treatment of advanced non--small-cell lung cancer. PC is less toxic and better tolerated but more expensive than VC. New treatment strategies should be pursued.

A phase II study of weekly alternating chemotherapy in extensive-stage small cell lung cancer.

Despite the recent development of new chemotherapeutic agents with activity in small cell lung cancer (SCLC), the long-term prognosis of patients with extensive-stage disease remains poor and has not improved in the past 20 years. The present study was designed to evaluate the activity and toxicity of weekly, alternating-regimen chemotherapy in patients with extensive-stage SCLC. Patients with previously untreated extensive-stage SCLC and performance status 0-2 were treated with cyclophosphamide 250 mg/m2, etoposide 100 mg/m2, and cisplatin 50 mg/m2 on day 1; vincristine 1 mg/m2 on day 8; and ifosfamide 1.2 gm/m2 on days 8 and 9 with the entire treatment repeated every 14 days. Eighteen patients received chemotherapy for a median of 14 weeks (range, 1-35 weeks). Seventeen patients (94%) required dose delays and 16 patients (89%) required at least one dose reduction due to toxicity. Twelve patients (67%) exhibited an objective response (1 complete response, 11 partial response) with a median duration of response of 18 weeks (range, 8-32 weeks). Median survival was 33 weeks (range, 1-57 weeks) with a 1-year survival rate of 22%. Toxicity was primarily hematologic, including grade 3-4 leukopenia (82% of patients) and anemia (53% of patients). Only 2 patients developed grade 3 peripheral neuropathy and none exhibited grade 3-4 renal insufficiency. This regimen of weekly alternating combination chemotherapy resulted in tolerable toxicity as well as response and survival rates comparable to those achieved with standard chemotherapy in patients with extensive-stage SCLC. However, weekly chemotherapy regimens for the treatment of SCLC remain investigational.

Anticoagulation therapy for radiation-induced myelopathy.

OBJECTIVE: To report the use of heparin and enoxaparin for radiation-induced myelopathy. CASE SUMMARY: A 48-year-old White woman with presumed metastatic lung cancer presented with worsening numbness and weakness of both legs. The neuro-oncology service was consulted and determined that the symptoms were consistent with radiation-induced myelopathy. The patient briefly responded to steroid treatment. A trial of intravenous heparin therapy was initiated by the primary team and managed by the clinical pharmacy services. Her symptoms improved when heparin was begun. She was able to walk and was subsequently discharged home on enoxaparin. DISCUSSION: Spinal cord injury is one of the known adverse effects of radiation. The onset of symptoms can be acute or delayed. The clinical signs and symptoms of delayed neurologic injury are related to the narrowing and occlusion of the vessel lumen, ischemia, edema, and cell death in the surrounding nervous tissue. Treatment often consists of corticosteroids and/or hyperbaric oxygen; however, the outcomes are often disappointing. In addition to the inhibition of serum protein-mediated coagulation, heparin inactivates or prevents the release of mediators of vascular injury inflammation, permeability, and edema. Therefore, patients with radiation-induced spinal cord injury may benefit from anticoagulant therapy. CONCLUSIONS: Heparin and/or enoxaparin may be considered as potential treatments for patients with radiation-induced myelopathy.

A phase II study of mitomycin C, etoposide, and cisplatin in advanced non-small cell lung cancer.

Standard chemotherapeutic regimens, such as cisplatin and etoposide, may improve quality of life and prolong survival in patients with incurable non-small cell lung cancer (NSCLC). This trial was designed to evaluate the activity and toxicity of a regimen combining three of the most active agents against advanced-stage NSCLC: mitomycin C, etoposide, and cisplatin (MEP). Sixty-eight patients with stage IIIB (pleural effusion) or IV NSCLC received cisplatin 80 mg/m2 i.v. on day 1 and etoposide 80 mg/m2 i.v. on days 1, 2, and 3 every 3 weeks along with mitomycin C 10 mg/m2 i.v. on day 1 of the first and third cycles for a median of four cycles (range, 1-11). Median age was 59 years, and nine patients were enrolled after relapse from previously treated early-stage NSCLC. Eighty-eight percent of patients had stage IV disease, and 14 (21%) had brain metastases at diagnosis. Palliative radiotherapy was given to 10 patients (15%) before MEP and to 17 (25%) concurrent with MEP. The major toxicity of MEP was myelosuppression, with grade 3-4 neutropenia in 74% of patients. Sixteen patients (24%) had documented infections, and there were eight (12%) treatment-related deaths. Partial response was observed in 24 patients (35%) with a median duration of 4.4 months, (range 1.4-13 months). Median survival was 8.1 months (range, 1-34 months), and 1-year survival was 32%. The addition of mitomycin C to cisplatin and etoposide resulted in response and survival rates comparable with those achieved with standard regimens in patients with advanced NSCLC but was associated with substantial hematologic toxicity and unacceptable treatment-related mortality.

Single-agent vinorelbine in the treatment of non-small cell lung cancer.

Vinorelbine, a vinca alkaloid, was the first drug in over 20 years to be approved by the Food and Drug Administration for treatment of advanced non-small cell lung cancer (NSCLC). The drug's nonhematologic toxicities are usually mild; its dose-limiting toxicity is neutropenia. Vinorelbine has been studied in many phase II trials. As a single agent it has produced objective response rates of 8% to 37% and median survivals ranging from 33 to 40.1+ weeks. Several phase III trials have included single-agent vinorelbine as one of the study arms. In a trial that compared vinorelbine with 5-fluorouracil and leucovorin, the vinorelbine recipients had better responses, median and 1-year survival rates, and improvement in cancer-related symptoms. In a large multicenter European trial single-agent vinorelbine was compared with vinorelbine/cisplatin and vindesine/cisplatin. Although the vinorelbine/cisplatin combination was superior to the other treatment arms with regard to response rate and median survival, single-agent vinorelbine was equivalent to the European standard of cisplatin and vindesine and was much less toxic. Vinorelbine is a reasonable alternative for patients not suited for cisplatin-containing regimens. Because of its favorable toxicity profile, vinorelbine has been investigated as a treatment for elderly patients with advanced NSCLC. In a multicenter randomized trial vinorelbine was compared with best supportive care in this particular patient group. Treated patients had a better survival and a trend toward improved quality of life. Single-agent vinorelbine has been used as second-line treatment for NSCLC but has not been particularly effective. Future directions for vinorelbine in the treatment of NSCLC include novel combinations with other agents as well as with radiation therapy in the treatment of locally advanced disease.

Phase I trial of concurrent thoracic radiation and continuous infusion cisplatin and etoposide in stage III non-small cell lung cancer.

OBJECTIVE: Although combined modality therapy appears to be superior to radiotherapy alone for the treatment of locally advanced non-small cell lung cancer (NSCLC), the optimal treatment regimen has not been determined. We designed this trial to determine the maximal tolerated doses (MTD) of continuous intravenous infusion (CI) cisplatin and etoposide that could be administered concurrently with thoracic irradiation. METHODS: 19 patients with stage IIIA or IIIB NSCLC were treated at three different dose levels of CI cisplatin and etoposide with concurrent single daily fraction thoracic radiotherapy to 4500 cGy. This chemoradiotherapy phase of treatment was followed by a 1500-2000 cGy radiotherapy boost and three cycles of standard intermittent bolus cisplatin 80 mg/m2 i.v. on day 1 and etoposide 80 mg/m2 i.v. on days 1, 2 and 3. RESULTS: The MTD of CI chemotherapy was determined to be cisplatin 5 mg/m2/day plus etoposide 18 mg/m2/day for 5 days per week over 5 weeks along with thoracic irradiation. Overall, 37% of patients required breaks in the chemoradiotherapy course and 32% required attenuation of the planned duration of CI chemotherapy. Only 42% of patients received all three planned cycles of bolus chemotherapy and 16% received < 6000 cGy of thoracic irradiation. The major toxicities during concurrent chemoradiotherapy were grade 3-4 esophagitis (42%) and myelosuppression (47%). Subsequent chemotherapy was complicated by grade 3-4 myelosuppression in 38% of patients. An objective response was documented in 58% of patients (CR 11%, PR 47%). Median survival was 18 months with 2- and 5-year survival rates of 42 and 11%, respectively. CONCLUSIONS: These results demonstrate that CI cisplatin and etoposide can be administered safely to patients with locally advanced NSCLC, and that such potentially radiosensitizing strategies deserve further evaluation in this setting.

Lung cancer in patients < 50 years of age: the experience of an academic multidisciplinary program.

OBJECTIVE: To determine if the clinicopathologic features and survival of lung cancer patients < 50 years of age differ from those of older patients. DESIGN: Retrospective review of patients with primary bronchogenic carcinoma diagnosed at a single, multidisciplinary cancer center. SETTING: A National Cancer Institute-designated comprehensive cancer center in urban Detroit, MI. PATIENTS: All patients with primary bronchogenic carcinoma evaluated in the Multidisciplinary Lung Cancer Clinic at the Barbara Ann Karmanos Cancer Institute between 1990 and 1993. RESULTS: Of 1,012 patients with lung cancer, 126 (12.5%) were < 50 years old at diagnosis, with a median age of 44 years. The median age of the 886 patients > or = 50 years of age was 65 years. The gender (p = 0.08) and racial (p = 0.12) characteristics of the younger and older patient groups were not significantly different. More than 90% of patients in both groups were smokers. The incidence of adenocarcinoma was significantly higher in younger patients (48.4% vs 36.0%, p < 0.001), and early-stage disease was less frequently diagnosed in younger patients (4.8% vs 19.7%, p < 0.001). Younger patients were more likely than older patients to undergo treatment, including surgery and combined-modality therapy (p < 0.001). Median survival was 13 months in younger and 9 months in older patients, while overall survival was similar in younger and older patients (p = 0.13). CONCLUSIONS: Although younger patients with lung cancer present with more advanced-stage disease, their overall survival is similar to that of older patients, suggesting that lung cancer is not an inherently more aggressive disease in patients < 50 years of age.

Randomized trial comparing cisplatin with cisplatin plus vinorelbine in the treatment of advanced non-small-cell lung cancer: a Southwest Oncology Group study.

PURPOSE: Cisplatin has played a major role in the treatment of non-small-cell lung cancer (NSCLC). This randomized trial was performed by the Southwest Oncology Group (SWOG) to determine whether the combination of vinorelbine and cisplatin has any advantage with regard to response rate, survival, and time to treatment failure over single-agent cisplatin in the treatment of patients with advanced NSCLC. METHODS: Between October 1993 and April 1995, 432 patients with advanced stage NSCLC were randomized to receive arm I (cisplatin 100 mg/m2 every 4 weeks) or arm II (cisplatin 100 mg/m2 every 4 weeks and vinorelbine 25 mg/m2 weekly). All patients were chemotherapy-naive, had performance status (PS) 0 or 1, and had adequate hematologic, renal, and hepatic function. RESULTS: Four hundred fifteen patients were eligible and assessable. On arm I (cisplatin), there was a 12% partial response rate. Arm II (cisplatin and vinorelbine) had a 26% response rate (2% complete responses and 24% partial responses, P = .0002). There was a statistically significant advantage with regard to progression-free survival (median, 2 v 4 months; P = .0001) and overall survival (median, 6 v 8 months; P = .0018) for the cisplatin and vinorelbine arm. One-year survival was 20% for cisplatin alone and 36% for the combination arm. There was more hematologic toxicity on arm II of the study (81% grades 3 and 4 granulocytopenia v 5% on arm I). Other toxicities, such as renal insufficiency, ototoxicity, and nausea and vomiting, and neuropathy were similar. CONCLUSION: The results of this study indicate that the combination of cisplatin and vinorelbine is a superior treatment when compared with single-agent cisplatin in the treatment of advanced NSCLC. Cisplatin and vinorelbine is the new standard for SWOG against which new therapies will be evaluated.

Comparative molecular field analysis of in vitro growth inhibition of L1210 and HCT-8 cells by some pyrazoloacridines.

In vitro screening of a number of 2-(aminoalkyl)-5-nitropyrazolo[3,4,5- kl]acridines has previously indicated (Sebolt, J.S.; et al. Cancer Res. 1987, 47, 4299-4304) that these compounds, in general, exhibit selective cytotoxicity against the human colon adenocarcinoma, HCT-8, cell line, relative to mouse leukemia L1210 cells. Comparative molecular field analysis (CoMFA) was applied to HCT-8 and L1210 growth inhibition assays (IC50s) of a series (44) of the pyrazoloacridine derivatives with the objective of predicting improved solid tumor selectivity. In the absence of crystallographic data, the 9-methoxy derivative (15), which is currently in clinical study, was selected as the template molecular model. Two different structural alignments were tested: an alignment of structures based on root mean square (RMS)-fitting of each structure to 15 was compared with an alternative strategy, steric and electrostatic alignment (SEAL). Somewhat better predictive cross-validation correlations (r2) were obtained with models based on RMS vis-à-vis SEAL alignment for both sets of assays. A large change in lattice spacing, e.g., 2 to 1 A, causes significant variations in the CoMFA results. A shift in the lattice of half of its spacing had a much smaller effect on the CoMFA data for a lattice of 1 A than one of 2 A. The relative contribution of steric and electrostatic fields to both models were about equal, underscoring the importance of both terms. Neither calculated log P nor HOMO and/or LUMO energies contribute to the model. Steric and electrostatic fields of the pyrazoloacridines are the sole relevant descriptors to the structure-activity (cross-validated and conventional) correlations obtained with the cytotoxic data for both the L1210 and HCT-8 cell lines. The cross-validated r2, derived from partial least-squares calculations, indicated considerable predictive capacity for growth inhibition of both the leukemia and solid-tumor data. Evidence for the predictive performance of the CoMFA-derived models is provided in the form of plots of actual vs predicted growth inhibition of L1210 and HCT-8 cells, respectively, by the pyrazoloacridines. The steric and electrostatic features of the QSAR are presented in the form of standard deviation coefficient contour maps of steric and electrostatic fields. The maps indicate that increases or decreases in steric bulk that would enhance growth inhibition of HCT-8 cells would likewise promote growth inhibition of L1210 cells. Contour maps generated to analyze the electrostatic field contributions of the pyrazoloacridines to growth inhibition provide an essentially similar set of results.(ABSTRACT TRUNCATED AT 400 WORDS)

Cyclophosphamide, methotrexate, and 5-fluorouracil in the treatment of metastatic prostate cancer. A Southwest Oncology Group study.

BACKGROUND: Hormone-refractory metastatic prostate cancer remains a therapeutic challenge. Cyclophosphamide, methotrexate, and 5-fluorouracil (CMF), a drug combination that is active in solid tumors, was evaluated using specific response criteria. METHODS: Fifty-two eligible patients with measurable (19), evaluable (29), or bone scan only (4) metastatic prostate cancer were treated with cyclophosphamide, 100 mg/m2 every day by mouth, methotrexate, 15 mg/m2 intravenously weekly, and 5-fluorouracil, 300 mg/m2 intravenously weekly. Treatment was given continuously unless interrupted by toxicity or disease progression. RESULTS: There were two partial responses (7%) among the evaluable patients. Six (32%) measurable patients and four (14%) evaluable patients had stable disease. Median time to progression was 3.2 months for measurable and 2.8 months for evaluable disease patients. Median survivals were 10.9 and 10.2 months, respectively. There was no difference between the two groups with regard to response rate or survival. Toxicity was acceptable and consisted primarily of myelosuppression. CONCLUSIONS: CMF is minimally active in hormone-refractory metastatic prostate cancer.

Neurotoxicity of antineoplastic agents.

PURPOSE: to review the neurotoxicity associated with antineoplastic agents. METHODS: four hundred articles, abstracts and book chapters were selected for review. One hundred and ninety (articles, book chapters and abstracts) were identified as representative of the important aspects of neurotoxicity to be presented in this review. RESULTS: in general the dose, schedule and route of administration significantly determine the incidence and outcome of antineoplastic agents neurotoxicity. An updated and detailed review of neurotoxicity is provided with special attention to vinca alkaloids, cisplatin and biologic response modifiers. The neurotoxic side effects of some of the new approaches in cancer therapy and some of the investigational agents are discussed. Guidelines for the prevention and management of this toxicity are presented. In addition, suggestions are made in regard to the preclinical and clinical screening of new agents for neurotoxicity. CONCLUSION: quality of life issues have become a focal point in many clinical trials. Neurotoxicity associated with antineoplastic therapy clearly has an impact on the short and long term quality of the life of cancer patients. A better understanding of this toxicity requires developing reliable and predictive models to screen new agents prior to their introduction into clinical trials; a more detailed and uniform grading system; and the prospective evaluation of neurotoxicity in clinical trials of new antineoplastic agents.

A randomized trial of cisplatin, vinblastine, and bleomycin versus vinblastine, cisplatin, and etoposide in the treatment of advanced germ cell tumors of the testis: a Southwest Oncology Group study.

This is a Southwest Oncology Group (SWOG) prospective randomized trial of cisplatin, vinblastine, and bleomycin (PVB) versus vinblastine, cisplatin, and etoposide (VP-16) (VPV) in the treatment of advanced germ cell tumors of the testis. The study objective was to determine what effect the replacement of bleomycin with VP-16 has on complete response (CR), survival, and drug toxicity. One hundred sixty-nine patients were registered and randomized. Of these patients, 160 were assessable for response. All had histologically confirmed disseminated germ cell neoplasms of testicular origin. Forty-six had minimal metastatic disease, and 114 had maximal disease. Seventy-seven were randomized to PVB and 83 to VPV chemotherapy. There was no significant difference in pretreatment characteristics between the two arms with regard to tumor burden, histologic type, and overall performance status. Patients received four courses of induction chemotherapy, either PVB (cisplatin 120 mg/m2 day 3, vinblastine 12 mg/m2 day 1, bleomycin 15 U/m2 twice per week) or VPV (vinblastine 8 mg/m2 day 1, cisplatin 120 mg/m2 day 3, VP-16 50 mg/m2 days 2 to 5). Chemotherapy was given every 3 weeks. Cytoreductive surgery was done postinduction if a chemotherapy CR was not achieved. There was no difference in the percentage of patients achieving a disease-free status between PVB (77%) and VPV (73%). The mean leukocyte nadir was similar for both treatments, but the mean platelet nadir was significantly lower (P = .003) in the VPV arm. All bleomycin-related toxicities (pulmonary, mucositis, skin) were avoided in the VPV arm. We conclude that bleomycin can be replaced in first-line therapy for advanced germ cell tumors without sacrificing efficacy and with the advantage of avoiding unnecessary drug toxicity.

Antitumor efficacy of PD115934 (NSC 366140) against solid tumors of mice.

PD115934 (NSC 366140) is a soluble pyrazoloacridine derivative presently undergoing preclinical toxicology evaluation with the anticipation of Phase I human investigation. The agent displayed both human and murine solid tumor selectivity in vitro in a soft agar disk diffusion assay, relative to its activity against murine L1210 leukemia. In vivo it was highly active against solid tumors colon adenocarcinoma 38 and pancreas ductal carcinoma 03, which was consistent with the cellular cytotoxicity seen in the disk diffusion assay. A log cell kill of greater than 4.0 was demonstrated in vivo against both models. PD115934 was administered by both bolus and infusional therapy. After completion of these trials, it was determined that this compound was a schedule category III agent, i.e., a schedule-independent agent with peak plasma level toxicity. The main toxicity encountered with infusional therapy was myelosuppression. With bolus therapy, central nervous system toxicities were dose limiting. On the basis of our preclinical infusion studies, we recommend a 2-h infusion twice weekly in humans in order to obtain a total dose of 360 mg/m2 over 8 weeks.

Inhibition of etoposide-induced DNA damage and cytotoxicity in L1210 cells by dehydrogenase inhibitors and other agents.

The mechanism of action of 4'-demethylepipodophyllotoxin-9-(4,6-O-ethylidene-beta-D-glucopyra noside) (VP-16), an important antitumor agent, is unclear. There is evidence that DNA may be the target of action because VP-16 causes single-strand and double-strand breaks in DNA and produces cytotoxicity over a similar dose range. We have hypothesized that an enzyme system, such as dehydrogenase, catalyzes an oxidation-reduction reaction involving the pendant phenolic group which forms an active metabolite that causes the DNA damage and cytotoxicity. To test our hypothesis, we investigated the effect of disulfiram, an aldehyde dehydrogenase inhibitor, and its metabolite, diethyldithiocarbamate, on VP-16-induced DNA damage in L1210 cells. Using the alkaline elution technique to assay DNA damage, we found that disulfiram and diethyldithiocerbamate inhibited VP-16-induced single-strand breaks. Both compounds were also capable of significantly reducing VP-16-induced cytotoxicity. Oxalic acid, pyrophosphate, and malonic acid, competitive inhibitors of succinate dehydrogenase, and the naturally occurring dehydrogenase substrates, succinic acid, beta-glycerophosphate, and isocitric acid, also blocked the effects of VP-16. Free-radical scavengers were also studied. While sodium benzoate was particularly effective in preventing drug-induced DNA damage and cytotoxicity, a number of other scavengers were not. Our data are consistent with the hypothesis that VP-16 is activated by an enzyme such as a dehydrogenase which transforms it into an active intermediate resulting in DNA damage and, consequently, cell death.

DNA damage as a basis for 4'-demethylepipodophyllotoxin-9-(4,6-O-ethylidene-beta-D-glucopyranoside) (etoposide) cytotoxicity.

The precise mechanism of action of 4'-demethylepipodophyllotoxin-9-(4,6-O-ethylidene-beta-D-glucopyranoside) (VP-16), an important chemotherapeutic agent, has yet to be determined. VP-16 has been shown to cause single-strand breaks (SSBs) in DNA, but their relationship to cytotoxicity has not been determined. We have investigated the action of VP-16 using mouse leukemia L1210 cells in culture. By using the alkaline elution technique, we reaffirmed the occurrence of SSBs in DNA over the drug concentration range 1 to 60 microM. We were able to demonstrate additional types of DNA damage in the form of DNA double-strand breaks and DNA-protein cross-links within the same dose range. The number of double-strand breaks formed per SSB was consistent over this dose range and greater than that found after exposure of L1210 cells to gamma-irradiation. DNA SSBs and double-strand breaks were also shown to occur in isolated nuclei, indicating that cytoplasmic components are not required for this drug action. Colony formation by L1210 cells in soft agar decreased over a drug concentration range similar to that which produced DNA damage. The correlation between the effective dose range in the colony-forming assay and the DNA scission experiments supports the hypothesis that DNA breakage is responsible for drug cytotoxicity. The demonstration of strand scission in isolated nuclei may provide an experimental model for elucidating the exact mechanism of action of VP-16.