Cancer Trials: Raising Accrual Rates

• Published in: Applied clinical trials Vol. 20; no. 3; p. 52
• Main Authors: Joubert, Richard, Raeth, Ulrich, Moehler, Thomas
• Format: Journal Article
• Language: English
• Published: Monmouth Junction MultiMedia Healthcare Inc 01.03.2011
• Subjects: Business conditions; Cancer; Cancer therapies; Chemotherapy; Clinical trials; Colleges & universities; Colorectal cancer; Enrollments; Metastasis; Oncology; Patients; Radiation therapy; Recruitment; United States > US
• ISSN: 1064-8542; 2150-623X

As displayed in Table 1, the highest enrollment rate was observed for Phase II trials with a mean of 1.35 Pts/M/S (range, 0.23 to 6.50). The study with the highest enrollment rate in our analysis was in Phase II setting of metastatic colorectal cancer with a recruitment rate of 6.5 Pts/M/S. Mean enrollment rate of Phase II trial was followed by the enrollment rate of Phase I and I /I I trials with a mean of 0.67 Pts/M/S (range, 0.15 to 1.81). The mean enrollment rate observed for Phase III trials was 0.32 Pts/M/S (range, 0.10 to 0.75). There was a significant difference in the mean enrollment rates among the phases of the trials (P = 0.004). Phase II trial enrollment rate versus Phase III trial enrollment rate was significant by pairwise comparison (P = 0.001, Fig 1). The publications reviewed reported results from studies evaluating five categories of treatment including radiotherapy and adjuvant treatments. For each of them, a mean enrollment rate was estimated (Table 1). The highest mean enrollment rate was observed for trials for targeted therapy-based treatments with a mean of 2.05 Pts/M/S (range, 0.10 to 6.50). The study with highest recruitment in our series belonged to this category. Trials evaluating treatments based on combined chemotherapy with targeted therapy were able to recruit at a mean rate of 0.87 Pts/M/S (range, 0.21 to 2.67). Trials evaluating treatments based on a combined chemoradiotherapy or a cytotoxic chemotherapy were able to recruit subjects with a similar mean rate of 0.55 Pts/M/S (range, 0.15 to 1.34) and 0.50 Pts/M/S (range, 0.14 to 1.81) respectively. Trials evaluating treatments based on radiochemotherapy combined with targeted therapy were able to recruit subjects with a mean rate of 0.32 Pts/M/S. A small percentage of studies evaluated radiotherapy (11%, four studies) and adjuvant treatment (19%, seven studies). A statistical analysis was not able to demonstrate a significant difference in the mean rate among the type of treatment investigated (P = 0.642). Among the 37 trials reviewed, 21 (57%, Table 1) evaluated first-line treatment. Overall, these trials were able to enroll participants at a mean of 0.65 Pts/M/S (range, 0.15 to 2.67). Ten trials (27%) evaluated second-line treatment and the mean enrollment rate was 0.41 Pts/M/S (range, 0.14 to 1.34). Three trials (10%) evaluated third-line treatment with a mean enrollment rate of 2.94 Pts/M/S (range, 0.10 to 6.50). Three studies had broader inclusion criteria and were not restricted on a single specific line of treatment. One trial recruited subjects with up to one previous treatment. We decided to consider this drug as a first- or second-line treatment. The mean enrollment rate in this study was 0.77 Pts/M/S. Another trial recruited subjects as a second- or third-line treatment with a mean enrollment rate of 0.67 Pts/M/S. A third trial recruited in third- or fourth-line treatment with a mean enrollment rate of 0.24 Pts/M/S. The Kruskal-Wallis test, however, did not reveal any statistically significant correlation between the recruitment rates and the line of treatment (P = 0.379). The number of sites participating and the corresponding mean enrollment rates are presented in Table 3. The mean rates for single- site studies, for single- and multiple sitestudies, and for multiple site- studies only are presented in Table 4. Four publications reported results from trials involving a single site. These trials were able to enroll subjects with a mean rate of 3.30 Pts/M/S (range, 1.81 to 6.50). Thirty- three publications reported results from trials involving two to 237 sites with mean rates ranging from 0.14 Pts/M/S (118 participating sites) to 1.38 Pts/M/S (two participating sites). For the multiple- site studies, a mean enrollment rate of 0.46 Pts/M/S (range, 0.10 to 1.38) was estimated (Table 4). Based on all studies reviewed (single and multiple sites), a global mean enrollment rate of 0.77 Pts/M/S (range, 0.10 to 6.50) was estimated. The statistical analysis showed that the differences observed were not significant (P = 0.076).