Approval of the study protocol will normally apply to investigator-led studies where the sponsor is either providing the intervention for free, or funding the study. In this case, the investigator will be obligated to submit not just the protocol but any amendments, as well as planned publication to the sponsor for approval. In addition, the sponsor may require an ongoing update at agreed intervals - usually annually to monitor trial progress.

In studies where the sponsor is funding and running the trial, they will usually have an internal approval process to ensure that the protocol is critiqued by an independent team of trial professionals including statisticians, medics, regulatory and the clinical operations team. The internal approval process will vary from company to company but the main aim will be to ensure that the protocol is robust and will achieve the objectives of the study and also to obtain cross functional agreement in terms of funding and resources required to conduct the study. For either processes, sponsor approval will need to be in place prior to any necessary submissions. 

A useful resource for this section is the Regulatory Database http://regulatory.ghtcoalition.org/

References

Clinical Research Governance Office, Imperial college London “what is a Sponsor”
http://www3.imperial.ac.uk/clinicalresearchgovernanceoffice/projectplanning/isasponsorneeded