Questions between the records

Why deep research starts where the FDA's Complete Response Letters meet the SEC filings that report them, and the five kinds of question found there.

When the FDA declines to approve a drug, two documents describe the same decision. The FDA's Complete Response Letter tells the company what is wrong and what it would take to fix. Within days, the company files an 8-K telling investors what happened. The same event, in two voices, for two audiences, under two different obligations.

Since the FDA began publishing its Complete Response Letters, both voices can be read side by side. That pairing is where EphemerisX's deep research begins.

Why start here#

The stakes are concentrated. A Complete Response Letter can decide a company's future. For a small company with one product, the letter and the 8-K are among the most consequential documents it will ever be part of.
Both records are public and primary. The letter is the FDA's own text; the 8-K is the company's own statement, filed under securities law. No commentary or secondary reporting is needed to answer the questions.
The two records are written to different ends. The FDA writes to explain a decision to the sponsor. The company writes to inform, and reassure, its investors. Where they agree, the record is solid. Where they differ, there is a question worth asking.
The story continues. After the letter come meetings, resubmissions, second letters, committees, approvals, disputes and lawsuits, across both records. A single pair of documents opens into a history.

The SEC Ephemeris already pairs FDA letters with each company's 8-K and 10-K filings, across hundreds of companies. Deep research asks what those pairs mean.

Five kinds of question#

The questions that live between the records fall into a few recurring shapes. Each one has examples on the published question webs.

1. Comparison: the letter and the filing#

How did the company describe the FDA's letter? Read the two side by side. The headline of Verrica's July 2020 announcement, filed with an 8-K, ended “No Clinical Safety or Efficacy Issues Identified”. The FDA's letter, in its human factors section, said it remained concerned that the product “is not safe for use by HCPs”. Both statements are quoted, both are sourced, and the reader can weigh them. Read the answer →

2. Omission: what the filing does not say#

What did the letter raise that the 8-K left out? The FDA's second letter to Replimune called the early Phase 3 analysis submitted with the resubmission insufficient. Replimune's 8-K responds to each of the letter's three deficiencies, and does not mention the early analysis: a whole-document search for its name and descriptions finds nothing. Read the answer →

3. Carryover: from one letter to the next#

Did the FDA ask for the same thing twice? The request for “at least one additional adequate and well controlled study” appears in Aldeyra's 2023 letter, as Aldeyra quotes it, and in the same words in the FDA's 2025 letter. A concern that survives a resubmission is one the company's answer did not resolve. Read the answer →

4. Drift: one account, changing over time#

How did the company's own description change? Outlook described its NORSE EIGHT trial first as agreed with the FDA as a second adequate and well-controlled trial, then as missing its week-8 endpoint, and then as confirmatory evidence supporting its NORSE TWO trial. Each description is in a filing; together they trace a strategy. Read the answer →

5. Counter-account: two versions of one event#

Was the FDA's advice consistent? The FDA's second letter to Replimune says it was, citing communications back to 2021. Replimune's filings say it was not, citing the mid- and late-cycle reviews and a September 2025 meeting. Deep research does not decide between them; it puts both accounts, and their sources, in one place. Read the answer →

Why the gap is informative#

A difference between the letter and the filing is not, by itself, a sign that anything is wrong. Companies summarise; letters are long; some details are commercially sensitive or still under discussion. But the difference is information, and it is the kind that is hardest to see without reading both documents in full:

An investor reading only the 8-K sees the company's framing. An investor reading only the letter misses the company's plan.
A sponsor facing a similar letter learns more from how another company's account held up over the next year than from either document alone.
When securities class actions follow a letter, as they did after letters to Replimune, CorMedix and Verrica, the questions they turn on are often exactly these: what the company knew, and what it said.

From one company to many#

Each of these question shapes can be asked of every company. Asked once, they reconstruct one history. Asked across companies, they start to show patterns: which kinds of concern carry over, how companies tend to describe them, which paths lead from a letter to an approval. That is the next step: Connections across cases.