Objectives: Given the limited resources available to conduct clinical trials, it is important to understand how trial sponsorship differs among different therapeutic modalities and cancer types and to consider the ramifications of these differences.

Methods: We searched clinicaltrials.gov for a cross-sectional register of active, phase III, randomized controlled trials (RCTs) studying treatment-related endpoints such as survival and recurrence for the 24 most prevalent malignancies. We classified the RCTs into 7 categories of therapeutic modality: (1) chemotherapy/other cancer-directed drugs, (2) targeted therapy, (3) surgery, (4) radiation therapy (RT), (5) RT with other modalities, (6) multimodality therapy without RT, and (7) other. RCTs were categorized as being funded by one or more of the following groups: (1) government, (2) hospital/university, (3) industry, and (4) other. χ² analysis was performed to detect differences in funding source distribution between modalities and cancer types.

Results: The percentage of multimodality trials (5%) and radiation RCTs (4%) funded by industry was less than that for chemotherapy (32%, P<0.01) or targeted therapy (48%, P<0.01). Trials studying targeted therapy were less likely to have hospital/university funding than any of the other modalities (P<0.01 in each comparison). Trials of chemotherapy were more likely to be funded by industry if they also studied targeted therapy (P<0.01).

Conclusion: RCTs studying targeted therapies are more likely to be funded by industry than trials studying multimodality therapy or radiation. The impact of industry funding versus institutional or governmental sources of funding for cancer research is unclear and requires further study.