There is no FDA “approval letter” for an Investigational New Drug application. Under 21 CFR 312.40(b)(1), your IND goes into effect 30 days after the FDA receives it — unless the Agency places it on clinical hold. Silence on Day 30 is the green light. First-time sponsors who sit idle waiting for an approval that never arrives lose weeks they did not have to lose.
It is one of the most common misunderstandings among first-time and foreign sponsors, and it costs real time: the belief that somewhere in the process the FDA sends a letter saying your IND is “approved.” It does not.
What the regulation actually says
The mechanism is proceed-on-silence. You submit the IND; a 30-day clock starts when the FDA receives it; and if the Agency has not placed the application on clinical hold by the end of that period, the IND is in effect and you may begin your clinical investigation. The FDA can also notify you earlier in writing that you may proceed, but the default is the clock.
That is the opposite of an approval regime. There is no affirmative sign-off to wait for. The absence of a hold on Day 30 is the authorization.
The two ways sponsors get this wrong
The first failure mode is waiting. A team finishes the 30 days, hears nothing, and assumes something is missing — so they sit, email the division, and let the calendar run. The trial could have started; instead it stalls on a misunderstanding.
The second failure mode is more dangerous: reading the silence as endorsement. The absence of a clinical hold is not the FDA blessing your protocol, your endpoints, or your safety plan. It means the Agency did not find a reason to stop you within the window. The responsibility for the science, the monitoring, and the safety reporting remains entirely yours.
Why India makes this worth understanding
If you run a program across the U.S. and India, the two systems run on opposite defaults, and your start dates depend on knowing which applies where.
In the U.S., no news by Day 30 is the news — you proceed. In India, under the NDCT Rules, you generally wait for affirmative permission before beginning; deemed approval is the exception, not the rule. A sponsor who applies U.S. instincts to an India trial may start too early; one who applies India instincts to a U.S. IND may sit idle past Day 30 for nothing.
Mapping the permission logic of each market before you build the timeline is not a detail. It is the difference between a clean, parallel start and a program that drifts because someone was waiting for the wrong signal.
What to do with Day 30
Plan your activation around it. Have your sites, your supply, and your monitoring ready so that when the clock runs out without a hold, you move. Treat a written “may proceed” as a bonus, not a prerequisite. And document your own diligence — because the regulatory silence transfers none of the responsibility to the Agency.
Frequently asked questions
Q: Does the FDA approve an IND? A: No. An IND goes into effect 30 days after the FDA receives it unless the Agency issues a clinical hold. There is no approval letter; proceed-on-silence is the default under 21 CFR 312.40.
Q: What is a clinical hold? A: A clinical hold is the FDA’s order to delay or suspend a clinical investigation. If no hold is issued within the 30-day window, the IND is in effect.
Q: Is India’s IND process the same? A: No. India generally requires affirmative permission before a trial begins, the opposite of the U.S. proceed-on-silence default. Programs spanning both markets should plan start dates around each system’s rule.
Building a U.S.–India regulatory strategy? Our in-house team has filed in these markets. → eteraflexconnects.com
