As per this, they would have 30 days after they started enrollment to update clinicaltrials.gov. It seems to me that it was a news item a short while ago that responsible parties were being very negligent at updating the site. They talked like they were going to start clamping down some on them but have no idea if they have.

Required Registration Updates

Responsible Parties should update their records within 30 days of a change to any of the following:

• Recruitment Status and Overall Recruitment Status data elements on ClinicalTrials.gov
• Completion Date (See Primary Completion Date data element on ClinicalTrials.gov)

Other changes or updates to the record, such as protocol amendments, must be made at least every 12 months. It is recommended that the Record Verification Date be updated at least every 6 months for studies that are not yet completed, even if there were no changes to the record.