In this paper, we focus on the study of six multi-center genomic trials, promoted by four different French cancer centers. Following recent work that investigated the organizational dimensions of biomedical innovations, we explore the “mutually constitutive relation between epistemic and organizational innovation” (Cambrosio, Keating & Nelson, 2014, p.13) in the domain of “precision medicine”. As a matter of fact, one may observe a great diversity of genomic trials regarding their scientific as well as their organizational design. We show that, in our case, the relations between organization/ing and experimentation/ing are manifold and, in fact, may be framed as cascading experimentations. First, the genomic clinical trials under investigation may be conceptualized as instances of experimenting (temporary) organization, since the organizational design that accompanies their deployment has changed over time in order to adapt to emerging problems. Second, these trials (are meant to) challenge and change the functioning of the healthcare organizations within which they are deployed. Reciprocally, the functioning of healthcare organizations enables and constrains the trials’ design as well as their successful completion. Fundamentally, these trials must be analyzed as epistemic as well as organizational innovation.