How to Get FDA to Tell You Which Center Will Regulate Your Product: The Pre-RFD Playbook

Introduction: The High Stakes of Product Jurisdiction

In the modern life sciences landscape, the line separating medical devices, pharmaceuticals, and biological products has blurred. Developers are increasingly engineering sophisticated systems that combine multiple therapeutic modalities. Examples include drug-delivery systems (such as pre-filled syringes, auto-injectors, and transdermal patches), software algorithms that both diagnose a condition and guide pharmaceutical dosing, and physical matrices impregnated with active agents or cellular scaffolds.

These products are classified by the U.S. Food and Drug Administration (FDA) as combination products or borderline products. Determining which regulatory pathway applies to them is one of the most critical gating decisions in the product lifecycle.

If a sponsor makes an incorrect assumption about which FDA center has jurisdiction over their product, the consequences can be catastrophic. Preparing a Premarket Notification (510(k)) or a Premarket Approval (PMA) for a device only to have the agency declare that the product must be regulated as a drug under an Investigational New Drug (IND) application or a New Drug Application (NDA) can waste years of development time, render preclinical testing protocols invalid, and exhaust millions of dollars in venture capital.

To address this uncertainty early in the development lifecycle, sponsors can leverage the FDA's Office of Combination Products (OCP) through the Pre-Request for Designation (Pre-RFD) process. The Pre-RFD pathway provides a structured, cost-free mechanism to obtain informal, preliminary feedback regarding which center—the Center for Devices and Radiological Health (CDRH), the Center for Drug Evaluation and Research (CDER), or the Center for Biologics Evaluation and Research (CBER)—will lead the review of a borderline or combination product.

This guide provides a comprehensive playbook for utilizing the Pre-RFD process. It details the procedural mechanics, compares the Pre-RFD against alternative FDA pathways, integrates OCP's own performance statistics, and outlines the strategic considerations necessary to navigate the designation process successfully under the FDA's recently revised guidelines.

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First-Screen Answer: How to Get FDA's Jurisdictional Determination

If your product combines a drug, device, or biologic, or if its classification sits on the borderline between these categories, you can obtain a preliminary jurisdictional determination by submitting a Pre-Request for Designation (Pre-RFD).

To submit a Pre-RFD:

1. Prepare a submission dossier (typically under 15 pages) that details the product’s physical description, active ingredients, materials, exact mechanisms of action, and intended use.
2. Submit the dossier via email directly to the Office of Combination Products (OCP) at combination@fda.gov, placing "Pre-RFD" in the subject line.
3. Wait 60 to 90 days for OCP’s written response.

A Pre-RFD does not require a user fee. While OCP's feedback is formally non-binding, the agency and its centers treat the preliminary designation as a de facto decision in almost all subsequent interactions, provided the product's design, formulation, and intended use do not change.

If you require a legally binding determination, you must escalate to a formal Request for Designation (RFD) under 21 CFR Part 3. Because a formal RFD triggers a strict, public-record 60-day clock (with a sponsor-default rule) and a rigid 15-page limit, it is usually worth using the Pre-RFD process first to preview the agency's logic, address technical concerns, and refine your arguments before lock-in — though the FDA itself notes that a Pre-RFD is not necessary for every product, since most products have clearly established classification and center assignment.

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Pre-RFD vs. RFD vs. 513(g) vs. Pre-Sub: Which Pathway to Use?

Sponsors seeking clarity from the FDA often confuse the Pre-RFD with other early-feedback mechanisms. Understanding the operational differences between these pathways is vital for choosing the right tool at the right time.

The table below outlines the differences between the four primary pathways:

Feature / Parameter	Pre-Request for Designation (Pre-RFD)	Request for Designation (RFD)	Section 513(g) Request	Pre-Submission (Q-Sub)
Legal Binding Status	Non-binding (informal feedback from OCP)	Legally binding on the FDA (barring changes or misrepresentation)	Non-binding (informal feedback on device class/product code)	Non-binding (advisory feedback on science/testing)
Responsible Office	Office of Combination Products (OCP)	Office of Combination Products (OCP)	Lead Center (e.g., CDRH)	Lead Center (e.g., CDRH, CDER, or CBER)
MDUFA User Fee	$0 (No user fee)	$0 (No user fee)	$7,820 (FY2026 standard rate)	$0 (No user fee)
Submission Deadline	60 days (statutory goal, though often slips to 90 days)	60 days (strict statutory clock); defaults to sponsor if missed	60 days (statutory goal)	70 to 75 days (review goal before meeting)
Submission Page Limit	None (the guidance suggests roughly 15–20 pages)	15-page limit including attachments (only courtesy copies of published literature are excluded)	None	None
Primary Scope	Jurisdictional identity (drug vs. device vs. biologic) and Lead Center assignment	Jurisdictional identity (drug vs. device vs. biologic) and Lead Center assignment	Device classification and product code identification	Clinical study design, testing protocols, and regulatory pathways within a center
Best Used For	Gaining early, informal feedback on borderline or combination products to de-risk development.	Securing legal certainty before a major submission (IND, BLA, PMA, NDA) when the pathway is contested.	Determining the classification or product code of a standalone device when no clear predicate exists.	Aligning on specific clinical trials, testing standards, or software validation plans after center assignment.

The Strategic Hierarchy of Engagement

A logical progression of regulatory engagement ensures that a sponsor does not waste resources or lock in unfavorable paths prematurely. The decision tree flows as follows:

• Step 1: Check Standalone Status
  • If the product is a standalone medical device with no drug or biological component:
    • Determine if a clear predicate exists. If the classification or product code is completely unknown, submit a 513(g) Request to CDRH.
    • If the product code and risk class are known but you need feedback on testing protocols or clinical study design, submit a Pre-Submission (Q-Sub).
  • If the product is a borderline or combination product:
    • Proceed to Step 2.
• Step 2: File a Pre-RFD
  • Draft a comprehensive jurisdictional dossier.
  • Submit it informally via email to the OCP (combination@fda.gov).
  • If the OCP assigns the lead to your preferred center (e.g., CDRH for a device-led system), lock in the decision and transition to that center's Pre-Submission program for technical development alignment.
  • If the OCP assigns the lead to a non-preferred center (e.g., CDER as a drug):
    • Analyze the OCP's written rationale.
    • If you have strong scientific counter-arguments, refine your data, address the gaps highlighted by OCP, and file a formal, binding Request for Designation (RFD).
    • If the OCP's rationale is scientifically unassailable, accept the center assignment and align your testing with the assigned center's requirements.

By utilizing the Pre-RFD first, you can engage OCP in a dialog without triggering a public, binding classification. This is especially important because a formal RFD must be filed before a sponsor submits their primary marketing or investigational application; if you file an RFD and receive an unfavorable, binding decision, reversing it is exceptionally difficult and usually requires formal administrative appeals.

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What Must a Pre-RFD Include After the November 2025 Revision?

To navigate this complexity, sponsors should refer to what the November 2025 Pre-RFD guidance clarifies about regulatory identity and center assignment to align their documentation with the FDA's current expectations. The revised guidance, titled "How to Prepare a Pre-Request for Designation (Pre-RFD)" (Docket FDA-2017-D-0040), replaces the previous February 2018 version.

While a Pre-RFD is less formal than a 21 CFR Part 3 RFD, the November 2025 revision significantly raises the bar for the level of scientific detail and precision that sponsors must include in their dossiers. OCP screens each submission for adequacy — generally within about 10 business days of receipt — and if the information is insufficient it issues an "additional information request" describing what is needed. Importantly, the roughly 60-day feedback goal does not start until OCP sends an acknowledgment that it has accepted the submission for review, so an inadequate initial package effectively delays (rather than "resets") the clock before it has begun.

Under Section IV of the revised guidance, a Pre-RFD dossier must contain the following structural elements:

1. Sponsor Identification and Contact Information: The name, address, and contact details of the manufacturer.
2. Product Description: A detailed description of the product, including its physical state, constituent parts (if a combination product), and all materials, ingredients, or components.
   • Crucial Update: Sponsors must quantify all ingredients and materials precisely. The revised guidance instructs sponsors not to use ranges (e.g., "1% to 5% hyaluronic acid") but to specify the exact concentrations and compositions.
3. Proposed Indication for Use and Intended Use: The medical conditions the product is designed to treat, prevent, or diagnose, and the patient populations it target.
4. Detailed Mechanism of Action (MOA): How the product achieves its intended therapeutic or diagnostic effect.
   • For combination products, the sponsor must describe the mechanism of action of each constituent part (e.g., the device component and the drug component) and how they interact.
   • Sponsors must explain how the chemical, pharmacological, or physical actions of the components contribute to the overall clinical effect, backed by scientific data or literature.
5. Primary Mode of Action (PMOA) Analysis: The sponsor's reasoning for which mode of action provides the "most important therapeutic effect." This is the core argument that determines center assignment.
6. Sponsor's Recommended Assignment: A clear statement of whether the product should be regulated as a drug, device, biologic, or combination product, and which center (CDER, CBER, or CDRH) should hold the lead.
7. Supporting Data, Literature, and Predicate Analysis: Citations to scientific studies, clinical trials, or published literature supporting the mechanism of action. Sponsors should also list similar products already cleared or approved by the FDA, detailing their center assignments.

Procedural Changes: No Meeting Minutes

One of the most notable procedural points clarified by the November 2025 guidance is that OCP does not provide formal meeting minutes for Pre-RFD discussions. This highlights the importance of keeping detailed, contemporaneous notes during any teleconference or meeting with OCP staff, since the agency will not produce an official written record of the discussion.

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Detailed Scientific Requirements for Chemical Characterization

The November 2025 guidance update places a significant burden on the physical and chemical characterization of the product. Sponsors must avoid vague descriptions of materials or polymers. To survive OCP's initial triage, the following characterization parameters must be documented:

• For Chemical Entities / Drugs: The IUPAC name, chemical structure, molecular weight, purity profile, and exact concentration. If the drug is a well-known active pharmaceutical ingredient (API), the sponsor must cite the USP/NF monograph when available.
• For Biologics: The cellular source, species of origin, purification process, amino acid sequence (for proteins/peptides), glycosylation pattern, and specific biological activity (potency).
• For Polymers and Structural Materials: The chemical name, molecular weight distribution (polydispersity index), degradation profile (both in vitro and in vivo), mechanical properties (tensile strength, elasticity, viscosity), and surface characteristics. If a hydrogel or scaffold is used, the cross-linking density and cross-linking agent (e.g., BDDE) must be quantified.
• Auxiliary vs. Primary Classification: If a drug component is added to a physical device matrix, the sponsor must provide in vitro release kinetics data. If the drug is released systematically or is intended to have a therapeutic effect on the body, the FDA will classify the drug action as primary or co-primary. If the drug remains localized and is intended only to perform an auxiliary function (such as preventing a localized inflammatory reaction to the device material), this must be backed by pharmacokinetic (PK) and pharmacodynamic (PD) modeling showing negligible systemic exposure.

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How OCP Picks the Lead Center: The PMOA Rule and Algorithm

The assignment of a combination product to a lead center is governed by Section 503(g) of the Federal Food, Drug, and Cosmetic (FD&C) Act and codified in 21 CFR Part 3. The guiding principle is the Primary Mode of Action (PMOA).

Defining the Mode of Action

A product's "mode of action" is the means by which it achieves its therapeutic, diagnostic, or preventive effect:

• Drug Mode of Action: Achieved through chemical, pharmacological, metabolic, or immunological action within or on the human body.
• Biological Product Mode of Action: Involves virus, therapeutic serum, toxin, antitoxin, vaccine, blood, blood component or derivative, or analogous product applicable to the prevention, treatment, or cure of diseases or injuries of man.
• Device Mode of Action: Achieved physically, mechanically, structurally, or chemically without being metabolized or chemically active within or on the human body.

The PMOA Rule

Under 21 CFR § 3.4, the FDA must assign the lead center based on the Primary Mode of Action—defined as the single mode of action that provides the most important therapeutic effect.

• Example: A drug-eluting cardiovascular stent has two modes of action: a physical mode of action (opening the artery) and a pharmacological mode of action (preventing restenosis via the drug coating). If the primary therapeutic effect is opening the artery, the PMOA is mechanical, and the lead center is CDRH. The drug is considered a secondary constituent part.

The 21 CFR § 3.4 Assignment Algorithm

In cases where OCP cannot determine the PMOA with reasonable certainty (for example, if the relative therapeutic contributions of the device and drug components are equal, or if the product has a novel mechanism where the relative contributions are unknown), OCP must apply a two-step assignment algorithm:

1. Step 1: Historical Consistency. OCP looks at whether there are other combination products of the same type that have already been assigned to a center. If historical precedents exist, OCP will assign the new product to that same center to maintain regulatory consistency.
2. Step 2: Safety and Effectiveness Questions. If no historical precedents exist, OCP assigns the product to the center that has the most expertise related to the most significant safety and effectiveness questions raised by the product.
   • Example: If a combination product consists of a novel device delivering a well-known drug, the primary safety and effectiveness questions will likely focus on the device's delivery mechanism, accuracy, and physical integrity. In this case, Step 2 would direct the product to CDRH. If the delivery mechanism is simple but the drug is a highly toxic, novel chemical entity, the safety questions focus on pharmacology, directing the product to CDER.

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Real-World Timeliness and OCP Performance Statistics

While the FDA's statutory guidelines set a 60-day review target for formal RFDs and a general 60-day target for Pre-RFDs, sponsors must build their timelines around real-world performance rather than legal ideals.

An analysis of OCP's published performance reports reveals two critical trends that sponsors must account for in their project schedules:

1. Lead Center Concentration: CDER remains the dominant recipient of combination product assignments. In OCP's annual reports, CDER was designated as the lead center in 74% of combination product assessments (for example, leading 23 of 31 reviewed combination products in a representative reporting period). This means OCP has a strong structural tendency to assign products to CDER if there is any plausible pharmacological or drug-delivery mode of action.
2. Timeliness Slips: While formal RFD timelines are strictly maintained due to the sponsor-default rule (if the FDA fails to respond to an RFD within 60 days, the sponsor's recommended assignment becomes legally binding), Pre-RFD reviews frequently run longer than their 60-day goal. In the same reporting period, only 15% of non-combination CDER assignments under OCP review were finalized within the 60-day window. OCP does not separately publish Pre-RFD-specific cycle times — these figures are aggregated OCP designation data (mixing RFD and Pre-RFD outcomes, benchmarked against the 60-day RFD clock) — so treat a typical Pre-RFD as closer to about 90 days rather than 60, as a planning rule of thumb, not a measured average.

The Sponsor-Default Rule in Formal RFDs

Under Section 563 of the FD&C Act, if a sponsor submits a formal, binding RFD under 21 CFR Part 3, the FDA must write back within 60 calendar days with its determination. If the FDA fails to issue a written decision within that 60-day limit, the sponsor's proposed center assignment and regulatory classification become binding by default.

While this rule provides a powerful legal lever for sponsors, it also raises the stakes of a formal RFD. Note that the sponsor-default mechanism applies only to formal RFDs under 21 CFR Part 3 — it does not apply to Pre-RFDs, which carry no statutory default penalty. Some practitioners reason that, facing a binding 60-day RFD clock, OCP has an incentive to issue a well-supported designation on time rather than let the sponsor's recommendation take effect; treating a Pre-RFD as an alignment step before filing an RFD is a sensible way to avoid an unfavorable binding outcome, but OCP's exact behavior on any given filing is product-specific rather than predictable.

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Step-by-Step Pre-RFD Submission Workflow

Sponsors should execute the Pre-RFD process using a structured, five-stage workflow designed to maximize the likelihood of receiving their preferred center assignment.

Stage 1: Pre-Submission Analysis

Before writing a single line of the dossier, the regulatory affairs team must conduct an exhaustive audit of similar cleared or approved products.

• Search the FDA Product Classification Database, the 510(k) database, and the PMA database for similar technologies.
• Search the OCP’s Jurisdictional Decisions database (which lists redacted summaries of past RFD decisions) to see how OCP has ruled on similar chemical, physical, or biological combinations.
• Identify the constituent parts and draft a preliminary PMOA rationale.

Stage 2: Drafting the Dossier

Draft the Pre-RFD package following the requirements of the November 2025 guidance.

• Formatting: Maintain a highly structured, academic tone. Avoid marketing or commercial language.
• Composition: Disclose all materials and chemical entities. Do not use ranges; use exact concentrations (e.g., "Sodium Hyaluronate 20 mg/mL, Lidocaine Hydrochloride 3 mg/mL").
• Drafting the PMOA argument: Frame the physical or mechanical actions as the primary driver of therapeutic success. If claiming a device mode of action, emphasize that the chemical or pharmacological components are secondary, local, and auxiliary (e.g., a drug coating that merely prevents a device-induced tissue reaction rather than curing a systemic disease).

Stage 3: Submission

Submit the package by emailing a PDF copy to combination@fda.gov.

• The subject line must read "Pre-RFD Submission - [Product Name]".
• No user fees are required, and no electronic common technical document (eCTD) portal is needed.

Stage 4: OCP Review and Consultation

OCP will triage the submission and assign a project manager, typically sending an acknowledgment of receipt within 5 business days.

• OCP will distribute the dossier to the relevant centers (CDRH, CDER, and CBER) for a joint jurisdictional review.
• If the centers or OCP identify gaps in your description (especially around the chemical mechanism or degradation profile), they will issue a request for information. Respond immediately; these requests typically pause the review clock.

Stage 5: Final Determination

OCP will issue a written preliminary designation outlining their decision on center assignment and product classification.

• Review the logic of the decision.
• If OCP agrees with your recommendation, you can proceed to the assigned center and request a pre-submission meeting (Q-Sub) to discuss the specific testing requirements.
• If OCP disagrees, evaluate their reasoning to determine whether to accept the assignment or escalate to a formal RFD using refined scientific arguments.

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Detailed Comparison of CDER, CBER, and CDRH Technical Reviews

Once OCP assigns the lead center, the product must conform to that center's technical review culture. The differences in their scientific approaches are profound and drive development costs:

• CDRH (Device-centric Review): Focuses heavily on mechanical integrity, engineering validation, usability (human factors testing), software verification (IEC 62304), and physical safety. CDRH is accustomed to rapid iteration cycles and accepts bench testing and animal models to support safety claims.
• CDER (Drug-centric Review): Demands extensive chemical manufacturing and controls (CMC) documentation, prospective stability testing under multiple environmental conditions, pharmacokinetic (PK) and pharmacodynamic (PD) profiles, and safety margins defined by preclinical toxicology studies. CDER's review is highly standardized, risk-averse, and focused on systemic exposure.
• CBER (Biologics-centric Review): Focuses on biological complexity, raw material origin (preventing viral/prion contamination), sterility assurance, immunogenicity, and cellular viability. CBER reviews often require specialized manufacturing inspections (facility audits) and have the highest validation barriers due to the natural variability of biological materials.

If a device-led combination product is assigned to CDER, the sponsor must immediately adopt CDER's rigid CMC and stability testing standards, which can add 12 to 18 months to the development timeline compared to a CDRH review.

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Failure Cases and Strategic Risks in Designation

Sponsors who fail to prepare their Pre-RFD dossiers with sufficient scientific rigor face severe operational bottlenecks. The following three failure cases illustrate these risks:

Failure Case 1: The "Dual-Action" Software Trap

A software developer designed an AI algorithm that analyzes patient electrocardiogram (ECG) data. The software does two things: it detects atrial fibrillation (a device function under FDA's SaMD guidelines) and automatically calculates the optimal dosage of a blood-thinning drug for the physician to prescribe (a clinical decision support function that borders on a drug-management claim).

The sponsor assumed the product was a standalone Class II device and filed a Pre-Submission request directly with CDRH. During the Pre-Sub review, CDRH consulted CDER, and the agencies collectively determined that the dosage-recommendation component constituted a drug-use management system. Because the drug-management function had a significant clinical impact, OCP stepped in and designated the software as a combination product, assigning the lead to CDER under an IND/NDA track.

• The Consequence: The sponsor’s plan for a rapid 510(k) clearance was destroyed. They were forced to design a prospective clinical trial matching drug-clearance standards, delaying commercialization by three years and increasing development costs by $5 million.
• The Lesson: If software has a dual function that directly guides or manages pharmaceutical dosing, sponsors must clear jurisdiction via a Pre-RFD before engaging CDRH in a Q-Sub.

Failure Case 2: The Auxiliary Drug Mischaracterization

A manufacturer developed a wound-dressing matrix designed to physically protect diabetic foot ulcers. To prevent bacterial colonization of the dressing, they added a low concentration of a well-known antibiotic. In their Pre-RFD, the sponsor described the antibiotic as an active constituent part and claimed that "the dressing cures local wound infections."

OCP read the claim that the product "cures infections" as a pharmacological therapeutic effect. Consequently, OCP determined that the product's PMOA was pharmacological, assigning the lead to CDER as a drug, requiring an NDA.

• The Consequence: The sponsor was forced to conduct extensive safety, PK, and systemic absorption studies for the antibiotic component, even though the product’s physical matrix was its primary clinical benefit.
• The Lesson: The language used to describe a product's therapeutic claims is critical. If a chemical component's role is auxiliary (e.g., maintaining device sterility or preventing local colonization), the labeling and Pre-RFD dossier must describe it as such. Over-claiming a drug-like effect will drive OCP to make a CDER assignment.

Failure Case 3: The Cross-Center Biocompatibility Gap

A biotechnology firm developed an implantable orthopedic scaffold coated with a novel cell-growth factor designed to accelerate bone healing. In their Pre-RFD, the sponsor argued that the primary mode of action was mechanical (scaffolding), recommending CDRH lead. OCP rejected this, identifying the cell-growth factor's biological activity as the PMOA, and assigned the lead to CBER.

During CBER review, the agency demanded that the synthetic polymer scaffold meet CBER's biological safety criteria, rejecting the mechanical testing standards that CDRH would have accepted. Simultaneously, CBER consulted CDRH, who demanded additional mechanical stress tests that conflicted with CBER's sample preparation protocols.

• The Consequence: The sponsor was caught in a cross-center conflict, with CBER refusing to accept the biocompatibility data because it was generated under CDRH protocols, and CDRH refusing to sign off on the mechanical integrity because CBER's sterilization requirements altered the polymer's material structure. The project was delayed by 24 months due to protocol reconciliation.
• The Lesson: When OCP assigns a combination product, one center leads, but the secondary center remains an active consultant. Sponsors must address the technical requirements of both centers in their Pre-Sub meetings, using the joint consultation mechanism to resolve conflicting data requirements before commencing testing.

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Frequently Asked Questions (FAQs)

Is a Pre-RFD required before I submit a 510(k), IND, or BLA?

No. The Pre-RFD is entirely voluntary. If a sponsor is confident that their product is a standalone medical device, drug, or biologic, they can submit their 510(k), PMA, IND, or BLA directly to the appropriate center without OCP involvement. However, if the product has constituent parts that cross categories, or if its classification sits on a borderline, submitting a Pre-RFD is highly recommended to prevent the receiving center from rejecting the filing later due to lack of jurisdiction.

Can I rely on a Pre-RFD answer to choose between a device and a drug pathway?

Yes, in practice, but with caveats. A Pre-RFD determination is formally non-binding. However, OCP and the individual centers maintain a policy of consistency. As long as the product’s design, formulation, intended use, and scientific understanding do not change between the Pre-RFD response and the formal submission, the FDA will honor the preliminary assignment. If you need absolute legal certainty that the agency cannot retract, you must submit a formal Request for Designation (RFD) under 21 CFR Part 3.

What happens if FDA does not respond to a formal RFD within 60 days?

Under Section 563 of the FD&C Act, if the FDA fails to issue a written decision on a formal, binding RFD within 60 calendar days of filing, the sponsor’s recommended center assignment and product classification become legally binding on the agency by default. Note that this sponsor-default rule applies only to formal RFDs submitted under 21 CFR Part 3. It does not apply to Pre-RFDs, which have no statutory default penalty.

Does the Pre-RFD process cost a user fee?

No. Under the Medical Device User Fee Amendments (MDUFA V), neither the Pre-RFD nor the formal RFD requires a user fee. This makes the Pre-RFD an exceptionally cost-effective tool for early-stage startups and academic developers to de-risk their regulatory strategy before investing in high-fee submissions (such as a 510(k) or PMA, which carry significant user fees).

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Conclusion: Actionable Next Steps for Sponsors

Navigating the boundary between medical devices, drugs, and biologics requires a combination of scientific precision and regulatory strategy. For sponsors of borderline or combination products, the Pre-RFD process represents an invaluable opportunity to engage the FDA’s Office of Combination Products without fees or binding legal risks.

To maximize the success of your Pre-RFD engagement:

1. Do not use ingredient ranges. Specify exact concentrations to comply with the November 2025 revised guidelines.
2. Frame therapeutic claims carefully. If your product is primarily physical or mechanical, ensure that the drug or chemical component is positioned as auxiliary.
3. Use the Pre-RFD as a preview before a formal RFD. In most cases, it is prudent to run the informal process first to test your arguments and surface any scientific objections the OCP or centers might raise before triggering a binding 60-day RFD clock — reserving a direct formal RFD for the narrow situations where you already need a legally binding determination and informal alignment is not feasible.
4. Incorporate OCP timeliness. Budget roughly 90 days for the Pre-RFD review (the formal goal is 60 days), and prepare to document all OCP discussions, as the agency will not issue formal meeting minutes.

By executing this playbook, you can de-risk your regulatory pathway, secure your lead center assignment, and protect your development timelines from costly center-reassignment delays.