A randomized phase III trial of oral S-1 plus cisplatin versus docetaxel plus cisplatin in Japanese patients with advanced non-small-cell lung cancer: TCOG0701 CATS trial.

BACKGROUND: Platinum-based two-drug combination chemotherapy has been standard of care for patients with advanced nonsmall-cell lung cancer (NSCLC). The primary aim was to compare overall survival (OS) of patients with advanced NSCLC between the two chemotherapy regimens. Secondary end points included progression-free survival (PFS), response, safety, and quality of life (QoL). PATIENTS AND METHODS: Patients with previously untreated stage IIIB or IV NSCLC, an Eastern Cooperative Oncology Group performance status of 0-1 and adequate organ function were randomized to receive either oral S-1 80 mg/m(2)/day on days 1-21 plus cisplatin 60 mg/m(2) on day 8 every 4-5 weeks, or docetaxel 60 mg/m(2) on day 1 plus cisplatin 80 mg/m(2) on day 1 every 3-4 weeks, both up to six cycles. RESULTS: A total of 608 patients from 66 sites in Japan were randomized to S-1 plus cisplatin (n = 303) or docetaxel plus cisplatin (n = 305). OS for oral S-1 plus cisplatin was noninferior to docetaxel plus cisplatin [median survival, 16.1 versus 17.1 months, respectively; hazard ratio = 1.013; 96.4% confidence interval (CI) 0.837-1.227]. Significantly higher febrile neutropenia (7.4% versus 1.0%), grade 3/4 neutropenia (73.4% versus 22.9%), grade 3/4 infection (14.5% versus 5.3%), and grade 1/2 alopecia (59.3% versus 12.3%) were observed in the docetaxel plus cisplatin than in the S-1 plus cisplatin. There were no differences found in PFS or response between the two arms. QoL data investigated by EORTC QLQ-C30 and LC-13 favored the S-1 plus cisplatin. CONCLUSION: Oral S-1 plus cisplatin is not inferior to docetaxel plus cisplatin and is better tolerated in Japanese patients with advanced NSCLC. CLINICAL TRIAL NUMBER: UMIN000000608.

Feasibility trial for adjuvant chemotherapy with docetaxel plus cisplatin followed by single agent long-term administration of S-1 chemotherapy in patients with completely resected non-small cell lung cancer: Thoracic Oncology Research Group Study 0809.

BACKGROUND: We conducted a multicentre feasibility study for single agent long-term S-1 chemotherapy following docetaxel plus cisplatin in patients with curatively resected stage II-IIIA non-small cell lung cancer. METHODS: Patients received three cycles of docetaxel (60 mg m(-2)) plus cisplatin (80 mg m(-2)) and then received S-1 (40 mg m(-2) twice daily) for 14 consecutive days with a 1-week rest for >6 months (maximum, 1 year). The primary end point was feasibility, which was defined as the proportion of patients who completed eight or more cycles of S-1 chemotherapy. If the lower 95% confidence interval (CI) of this proportion was 50% or more, then the treatment was considered as feasible. The sample size was set at 125 patients. RESULTS: One hundred and thirty-one patients were enrolled, of whom 129 patients were eligible and assessable. In all, 109 patients (84.5%) completed 3 cycles of docetaxel plus cisplatin and 66 patients (51.2%, 95% CI: 42.5-59.8) completed 8 or more cycles of S-1 treatment. Grade 3/4 toxicities during the S-1 chemotherapy included anaemia (7.3%), neutropaenia (3.7%), and anorexia (3.7%). CONCLUSION: The toxicity level was acceptable, although the results did not meet our criterion for feasibility. Modification of the treatment schedule for S-1 chemotherapy might improve the treatment compliance.

A phase II trial of dose-dense chemotherapy, followed by surgical resection and/or thoracic radiotherapy, in locally advanced thymoma: report of a Japan Clinical Oncology Group trial (JCOG 9606).

BACKGROUND: This study aimed to evaluate the safety and efficacy of dose-dense weekly chemotherapy, followed by resection and/or thoracic radiotherapy. METHODS: Patients with histologically documented thymoma with unresectable stage III disease received 9 weeks of chemotherapy: cisplatin 25 mg m(-2) on weeks 1-9; vincristine 1 mg m(-2) on weeks 1, 2, 4, 6 and 8; and doxorubicin 40 mg m(-2) and etoposide 80 mg m(-2) on days 1-3 of weeks 1, 3, 5, 7 and 9. Patients went on to surgery and post-operative radiotherapy of 48 Gy; those with unresectable disease received 60 Gy radiotherapy. RESULTS: total of 23 patients were entered. The main toxicities of the chemotherapy regimen were neutropenia and anaemia, and 57% of patients completed the planned 9 weeks of therapy. There were no toxic deaths. Of the 21 eligible patients, 13 (62%) achieved a partial response (95% confidence interval: 38-82%). Thirteen patients underwent a thoracotomy and nine (39%) underwent complete resection. Progression-free survival at 2 and 5 years was 80 and 43%, respectively. Overall survival at 5 and 8 years was 85 and 69%, respectively. Survival did not seem to be affected by resection. CONCLUSION: In thymoma patients, weekly dose-dense chemotherapy has activity similar to that of conventional regimens. Although some patients could achieve complete resection, the role of surgery remains unclear.

A phase-II trial of dose-dense chemotherapy in patients with disseminated thymoma: report of a Japan Clinical Oncology Group trial (JCOG 9605).

BACKGROUND: To evaluate the safety and efficacy of dose-dense weekly chemotherapy in the treatment of advanced thymoma. METHODS: Subjects comprised patients with histologically documented chemotherapy-naïve thymoma with stage-IVa or IVb disease. Thymic carcinoma, carcinoid or lymphoma cases were excluded. Patients received 9 weeks of chemotherapy: cisplatin (25 mg m(-2)) on weeks 1-9; vincristine (1 mg m(-2)) on weeks 1, 2, 4, 6 and 8; and doxorubicin (40 mg m(-2)) and etoposide (80 mg m(-2)) on days 1-3 of weeks 1, 3, 5, 7 and 9. Chemotherapy courses were supported by granulocyte colony-stimulating factor. Post-protocol local therapy was allowed. RESULTS: From July 1997 to March 2004, 30 patients were entered. Three were ineligible due to different histology. Chemotherapy-associated toxicity was mainly haematological and was well tolerated, with no deaths due to toxicity, and 87% of patients completed the planned 9-week regimen. Overall response rate was 59%, with 16 of the 27 eligible patients achieving partial response. Median progression-fee survival (PFS) was 0.79 years (95% confidence interval: 0.52-1.40 years), and PFS at 1 and 2 years was 37 and 15%, respectively. Overall survival rates at 2 and 5 years were 89 and 65%, respectively. CONCLUSION: In stage-IV thymoma patients, weekly dose-dense chemotherapy offers similar activity to conventional regimens.

Characteristics and outcomes of patients with advanced non-small-cell lung cancer who declined to participate in randomised clinical chemotherapy trials.

There are inadequate data on the outcomes of patients who declined to participate in randomised clinical trials as compared with those of participants. We retrospectively reviewed the patient characteristics and treatment outcomes of both participants and non-participants in the two randomised trials for chemotherapy-naive advanced non-small-cell lung cancer. Trial 1 compared four platinum-based combination regimens. Trial 2 compared two sequences of carboplatin plus paclitaxel and gefitinib therapies. Nineteen of 119 (16%) and 153 (37%) patients declined to participate in Trials 1 and 2, respectively. Among the background patient characteristics, the only variable associated with trial participation or declining was the patients' attending physicians (P<0.001). Important differences were not observed in the clinical outcomes between participants and non-participants, for whom the response rates were 30.6 vs 34.2% and the median survival times were 489 vs 461 days, respectively. The hazard ratio for overall survival, adjusted for other confounding variables, was 0.965 (95% confidence interval: 0.73-1.28). In conclusion, there was no evidence to suggest any difference in the characteristics and clinical outcomes between participants and non-participants. Trial designs and the doctor-patient relationship may have an impact on the patient accrual to randomised trials.

A randomised trial of intrapericardial bleomycin for malignant pericardial effusion with lung cancer (JCOG9811).

Safety and efficacy of intrapericardial (i.p.c.) instillation of bleomycin (BLM) following pericardial drainage in patients with malignant pericardial effusion (MPE) remain unclear. Patients with pathologically documented lung cancer, who had undergone pericardial drainage for MPE within 72 h of enrolment, were randomised to either arm A (observation alone after drainage) or arm B (i.p.c. BLM at 15 mg, followed by additional i.p.c. BLM 10 mg every 48 h). The drainage tube was removed when daily drainage was 20 ml or less. The primary end point was survival with MPE control (effusion failure-free survival, EFFS) at 2 months. Eighty patients were enrolled, and 79 were eligible. Effusion failure-free survival at 2 months was 29% in arm A and 46% in arm B (one-sided P=0.086 by Fisher's exact test). Arm B tended to favour EFFS, with a hazard ratio of 0.64 (95% confidence interval: 0.40-1.03, one-sided P=0.030 by log-rank test). No significant differences in the acute toxicities or complications were observed. The median survival was 79 days and 119 days in arm A and arm B, respectively. This medium-sized trial failed to show statistical significance in the primary end point. Although ipc BLM appeared safe and effective in the management of MPE, the therapeutic advantage seems modest.

A randomised phase II trial of preoperative chemotherapy of cisplatin-docetaxel or docetaxel alone for clinical stage IB/II non-small-cell lung cancer results of a Japan Clinical Oncology Group trial (JCOG 0204).

Preoperative chemotherapy is a promising strategy in patients with early-stage resectable non-small-cell lung cancer (NSCLC); optimal chemotherapy remains unclear. Clinical (c-) stage IB/II NSCLC patients were randomised to receive either two cycles of docetaxel (D)-cisplatin (P) combination chemotherapy (D 60 mg m(-2) and P 80 mg m(-2) on day 1) every 3-4 weeks or three cycles of D monotherapy (70 mg m(-2)) every 3weeks. Thoracotomy was performed 4-5 weeks (DP) or 3-4 weeks (D) after chemotherapy. The primary end point was 1-year disease-free survival (DFS). From October 2002 to November 2003, 80 patients were randomised. Chemotherapy toxicities were mainly haematologic and well tolerated. There were two early postoperative deaths with DP (one intraoperative bleeding and one empyema). Pathologic complete response was observed in two DP patients. Docetaxel-cisplatin was superior to D in terms of response rate (45 vs 15%) and complete resection rate (95 vs 87%). Both DFS and overall survival were better in DP. Disease-free survival at 1, 2 and 4 years were 78, 65 and 57% with DP, and were 62, 44 and 36% with D, respectively. Preoperative DP was associated with encouraging resection rate and DFS data, and phase III trials for c-stage IB/II NSCLC are warranted.

Randomised phase III trial of carboplatin plus etoposide vs split doses of cisplatin plus etoposide in elderly or poor-risk patients with extensive disease small-cell lung cancer: JCOG 9702.

We compared the efficacy and the safety of a carboplatin plus etoposide regimen (CE) vs split doses of cisplatin plus etoposide (SPE) in elderly or poor-risk patients with extensive disease small-cell lung cancer (ED-SCLC). Eligibility criteria included: untreated ED-SCLC; age >/=70 and performance status 0-2, or age <70 and PS 3. The CE arm received carboplatin area under the curve of five intravenously (IV) on day 1 and etoposide 80 mg m(-2) IV on days 1-3. The SPE arm received cisplatin 25 mg m(-2) IV on days 1-3 and etoposide 80 mg m(-2) IV on days 1-3. Both regimens were given with granulocyte colony-stimulating factor support in a 21-28 day cycle for four courses. A total of 220 patients were randomised. Median age was 74 years and 74% had a PS of 0 or 1. Major grade 3-4 toxicities were (%CE/%SPE): leucopenia 54/51, neutropenia 95/90, thrombocytopenia 56/16, infection 7/6. There was no significant difference (CE/SPE) in the response rate (73/73%) and overall survival (median 10.6/9.9 mo; P=0.54). Palliation scores were very similar between the arms. Although the SPE regimen is still considered to be the standard treatment in elderly or poor-risk patients with ED-SCLC, the CE regimen can be an alternative for this population considering the risk-benefit balance.

How to evaluate the risk/benefit of trimodality therapy in locally advanced non-small-cell lung cancer.

The trimodality approach represented by concurrent chemoradiotherapy followed by surgical resection is a highly effective, but potentially toxic therapy for locally advanced non-small-cell lung cancer (NSCLC). In this review, we discuss the current status of this therapy in patients with mediastinal node-positive (N2) stage III NSCLC or superior sulcus tumor, and present an overview of the principles for optimisation of the risk/benefit. Numerous clinical questions remain, and enrolment of patients into well-designed clinical trials should be encouraged.

EGFR mutation status in tumour-derived DNA from pleural effusion fluid is a practical basis for predicting the response to gefitinib.

Epidermal growth factor receptor (EGFR) mutations are strong determinants of tumour response to EGFR tyrosine kinase inhibitors in non-small-cell lung cancer (NSCLC). Pleural effusion is a common complication of lung cancer. In this study, we assessed the feasibility of detection of EGFR mutations in samples of pleural effusion fluid. We obtained 43 samples, which was the cell-free supernatant of pleural fluid, from Japanese NSCLC patients, and examined them for EGFR mutations. The epidermal growth factor receptor mutation status was determined by a direct sequencing method (exons 18-21 in EGFR). EGFR mutations were detected in 11 cases (E746_A750del in seven cases, E746_T751del insA in one case, L747_T751del in one case, and L858R in two cases). The EGFR mutations were observed more frequently in women and non-smokers. A comparison between the EGFR mutant status and the response to gefitinib in the 27 patients who received gefitinib revealed that all seven patients with partial response and one of the seven patients with stable disease had an EGFR mutation. No EGFR mutations were detected in the patients with progressive disease. The results suggest that DNA in pleural effusion fluid can be used to detect EGFR mutations and that the EGFR mutation status may be useful as a predictor of the response to gefitinib.

Genetic variations and haplotype structures of the ABCB1 gene in a Japanese population: an expanded haplotype block covering the distal promoter region, and associated ethnic differences.

As functional ABCB1 haplotypes were recently reported in the promoter region of the gene, we resequenced the ABCB1 distal promoter region, along with other regions (the enhancer and proximal promoter regions, and all 28 exons), in a total of 533 Japanese subjects. Linkage disequilibrium (LD) analysis based on 92 genetic variations revealed 4 LD blocks with the same make up as previously described (Blocks -1, 1, 2 and 3), except that Block 1 was expanded to include the distal promoter region, and that a new linkage between polymorphisms -1,789G>A in the distal promoter region and IVS5 + 123A>G in intron 5 was identified. We re-assigned Block 1 haplotypes, and added novel haplotypes to the other 3 blocks. The reported promoter haplotypes were further classified into several types according to tagging variations within Block 1 coding or intronic regions. Our current data reconfirm the haplotype profiles of the other three blocks, add more detailed information on functionally-important haplotypes in Block 1 and 2 in the Japanese population, and identified differences in haplotype profiles between ethnic groups. Our updated analysis of ABCB1 haplotype blocks will assist pharmacogenetic and disease-association studies carried out using Asian subjects.

Haplotype structures of the UGT1A gene complex in a Japanese population.

Genetic polymorphisms of UDP-glucuronosyltransferases (UGTs) are involved in individual and ethnic differences in drug metabolism. To reveal co-occurrence of the UGT1A polymorphisms, we first analyzed haplotype structures of the entire UGT1A gene complex using the polymorphisms from 196 Japanese subjects. Based on strong linkage disequilibrium between UGT1A8 and 1A10, among 1A9, 1A7, and 1A6, and between 1A3 and 1A1, the complex was divided into five blocks, Block 8/10, Block 9/6, Block 4, Block 3/1, and Block C, and the haplotypes for each block were subsequently determined/inferred. Second, using pyrosequencing or direct sequencing, additional 105 subjects were genotyped for 41 functionally tagged polymorphisms. The data from 301 subjects confirmed the robustness of block partitioning, but several linkages among the haplotypes with functional changes were found across the blocks. Thus, important haplotypes and their linkages were identified among the UGT1A gene blocks (and segments), which should be considered in pharmacogenetic studies.

Lower incidence of Bronchiolitis obliterans in allogeneic hematopoietic stem cell transplantation with reduced-intensity conditioning compared with myeloablative conditioning.

Bronchiolitis obliterans (BO) is one of the most devastating complications after allogeneic stem cell transplantation (HSCT). However, its true pathogenesis is still to be elucidated. We conducted this study to find whether tissue damage due to high-dose chemo-radiotherapy is related to its pathogenesis. In all, 144 patients who received allogeneic HSCT between May 1999 and October 2001, and survived more than 80 days after transplant, were analyzed. Clinical course, pulmonary function tests, imaging studies including CT scan, and pathology results were reviewed. The overall incidence of BO was 9.7% (14/144). The cumulative incidence of BO at 2 years after transplant was 17% with myeloablative conditioning, and 2.3% with reduced intensity conditioning (P=0.024). Multivariate analysis showed that myeloablative conditioning was the only factor which affected the incidence of BO. Development of BO did not significantly affect the overall survival of patients. However, if they developed BO earlier than 200 days post transplant, the prognosis was significantly worse than if they developed it later than 200 days post transplant (P=0.003) or if they did not develop BO (P=0.002). Our results imply that tissue damage secondary to intensive chemo-radiotherapy may contribute to the pathogenesis of BO.

Multi-institutional phase II trial of irinotecan, cisplatin, and etoposide for sensitive relapsed small-cell lung cancer.

Irinotecan (CPT-11) has been shown to exhibit excellent antitumour activity against small-cell lung cancer (SCLC). A multi-institutional phase II study was therefore conducted to evaluate the efficacy and toxicity of CPT-11 combined with cisplatin (CDDP) and etoposide (ETOP) (PEI regimen) for the treatment of sensitive relapsed SCLC. Patients who responded to first-line chemotherapy but relapsed more than 8 weeks after the completion of first-line therapy (n=40) were treated using the PEI regimen, which consisted of CDDP (25 mg m(-2)) weekly for 9 weeks, ETOP (60 mg m(-2)) for 3 days on weeks 1, 3, 5, 7, and 9, and CPT-11 (90 mg m(-2)) on weeks 2, 4, 6, and 8 with granulocyte colony-stimulating factor support. Five complete responses and 26 partial responses were observed, and the overall response rate was 78% (95% confidence interval 61.5-89.2%). The median survival time was 11.8 months, and the estimated 1-year survival rate was 49%. Grade 3/4 leucocytopenia, neutropenia, and thrombocytopenia were observed in 55, 73, and 33% of the patients, respectively. Nonhaematological toxicities were mild and transient in all patients. In conclusion, the PEI regimen is considered to be highly active and well tolerated for the treatment of sensitive relapsed SCLC.

Phase I study of cisplatin analogue nedaplatin (254-S) and paclitaxel in patients with unresectable squamous cell carcinoma.

The recommended phase II dose of paclitaxel 180 mg m(-2) given as a 3-h infusion followed by nedaplatin 100 mg m(-2) in a 1-h infusion every 3-4 weeks was determined in 52 chemo-naive patients with unresectable squamous cell carcinoma (SCC), with a promising response rate for lung SCC of 55%.

A phase II study of cisplatin and docetaxel administered as three consecutive weekly infusions for advanced non-small-cell lung cancer in elderly patients.

BACKGROUND: To evaluate the efficacy and safety of treatments for advanced non-small-cell lung cancer in elderly patients aged 75 years or older, we conducted a phase II study of cisplatin and docetaxel administered in three consecutive weekly infusions. PATIENTS AND METHODS: The eligibility criteria for the study included the presence of chemotherapy-naive advanced non-small-cell lung cancer, age > or =75 years, Eastern Cooperative Oncology Group performance status of 0 or 1, a measurable lesion, adequate organ functions and signed informed consent. The chemotherapy regimen consisted of cisplatin (25 mg/m(2)) and docetaxel (20 mg/m(2)) on days 1, 8 and 15 every 4 weeks. RESULTS: Between February 2000 and March 2002, 34 elderly patients with non-small-cell lung cancer were enrolled in the study and 33 patients were treated. Two complete responses and 15 partial responses were obtained for an objective response rate of 52% in 33 treated patients. The median survival period was 15.8 months, and the 1-year survival rate was 64%. Toxicities were mild with no grade 4 toxicities. Only grade 3 leukopenia (6%), neutropenia (12%), anemia (3%), hyponatremia (3%) and nausea/vomiting (3%) were observed. CONCLUSION: Cisplatin and docetaxel administered in three consecutive weekly infusions was safe and effective for the treatment of elderly patients with chemotherapy-naive non-small-cell lung cancer.

Distant failure after treatment of postoperative locoregional recurrence of non-small cell lung cancer.

BACKGROUND: The standard treatment for patients with locoregional recurrence of non-small cell lung cancer (NSCLC) after complete resection has not been established. The aim of this study was to evaluate clinicopathologic characteristics, type of locoregional recurrence, pattern of subsequent failure, and survival after the recurrence. METHODS: Of 743 patients undergoing pulmonary resection for NSCLC in the National Cancer Center Hospital between 1990 and 1995, we retrospectively reviewed the medical charts of the 43 patients (5.8 %) found to have locoregional recurrence without distant metastasis or pleural or pericardial involvement. RESULTS: The median time to locoregional recurrence was 13.6 months (range: 1.6 - 85.8 months). The most frequent site of recurrence was the mediastinal nodes in 21 of 43 patients (49 %). 33 patients (77 %) received further treatment for the recurrence: thoracic irradiation in 26, surgery in two, systemic chemotherapy in two, and a combination of the above in 3 patients. Subsequent distant failure was detected in 26 (68 %) of the 38 patients assessable for the analysis of failure pattern: lung in 11, brain in 6, bone in 5, and others in 13. The median interval from the recurrence to distant failure was 8.4 months (range: 1.7-56.4 months). The median survival time after diagnosis of the locoregional recurrence was 10.5 months (range: 0-74.0 months). A multivariate analysis showed that local therapy for the locoregional recurrence had no significant impact on postrecurrent survival or distant failure-free survival. CONCLUSIONS: Many patients with postoperative locoregional recurrence developed distant metastases early after the first recurrence. Systemic chemotherapy in addition to local therapy may be of benefit in this population.

Phase I/II trial of weekly cisplatin, etoposide, and irinotecan chemotherapy for metastatic lung cancer: JCOG 9507.

Combinations of cisplatin-irinotecan and cisplatin-etoposide are active and well tolerated in patients with both small-cell lung cancer (SCLC) and nonsmall-cell lung cancer (NSCLC). To define the recommended dose for phase II trials of irinotecan combined with cisplatin and etoposide in chemonaive patients with stage IV disease, 56 patients (11 having SCLC and 45 NSCLC) received cisplatin 25 mg m(-2) weekly for 9 weeks, etoposide 60 mg m(-2) for 3 days on weeks 1, 3, 5, 7 and 9, and irinotecan 20-100 mg m(-2) (levels 1-8) on weeks 2, 4, 6 and 8, together with a prophylactical granulocyte colony-stimulating factor support (50 microg m(-2) on days 4-7 on weeks 1, 3, 5, 7 and 9, and on days 2-7 on weeks 2, 4, 6 and 8). Grade 3-4 leukocytopenia, neutropenia and thrombocytopenia were noted in 20 (36%), 28 (50%) and nine (16%) patients, respectively. Grade 3 diarrhoea, grade 3 cardiac toxicity, and grade 4 transaminase elevation developed in one (1.8%) patient each. Totally, four of 56 patients were removed from the study because of toxicity and recovered, and two other patients died in situations where drug toxicity might contribute to their death. Dose-limiting toxicity was noted in less than one-third of patients at dose levels 1-7, but in all patients at dose level 8. Thus, the recommended dose was determined to be level 7 (irinotecan 90 mg m(-2)). The response rates for SCLC and NSCLC were 91% (10/11) and 38% (17/45), respectively. The median survival time and 1-year survival rate were 11.9 months and 46% for SCLC and 10.1 months and 40% for NSCLC, respectively. This regimen was considered to be feasible and promising for the treatment of stage IV SCLC and NSCLC.

Relationship between objective responses in phase I trials and potential efficacy of non-specific cytotoxic investigational new drugs.

BACKGROUND: Although the evaluation of new investigational drugs in phase I, II and III trials requires considerable time and patient resources, only a few of these drugs are ultimately established as anticancer drugs. MATERIALS AND METHODS: We collected papers of phase I trials by a Medline search using the key words 'Neoplasms/Drug Therapy in MeSH' and 'Phase I' for the period from 1976 to 1993. A drug was defined as 'effective' if a regimen including the drug produced positive results in at least one phase III trial. We analyzed the relationship between objective (complete and partial) responses in phase I trials and the effectiveness of agents in phase III trials. RESULTS: A total of 399 single-agent phase I trials of cytotoxic agents in adult patients with solid tumors were obtained. Further clinical investigation was not recommended in 36 trials (9%) because of severe toxicity. In the remaining 363 trials, 174 drugs were evaluated and the median number of trials for each drug was two (range one to nine). Objective responses were observed in 495 (4.1%) of 12 076 patients, 178 (49%) of 363 trials, and 115 (66%) of 174 drugs. Of the 174 drugs, 48 (28%) were considered to be effective. Percentages of effective drugs rose as the number of responders in phase I trials increased. Logistic regression analyses showed the number of responders to be significantly associated with drug effectiveness [odds ratio = 1.16 (1.06-1.27), P = 0.001 for 174 drugs; odds ratio = 1.16 (1.05-1.28), P = 0.0038 for 363 trials]. Although 10 active drugs failed to produce an objective response in phase I trials, seven of them produced a tumor regression of <50%, and three reportedly produced objective responses in phase I trials conducted before 1975. The numbers of responders among patients with lung, ovarian, breast or colorectal cancer, but not those among patients with lymphoma, melanoma, sarcoma or renal-cell carcinoma, were associated significantly with drug effectiveness against the respective tumors. CONCLUSIONS: Objective responses observed in phase I trials are important for determining the future development of an anticancer drug.