This page aggregates SPRO's FDA catalysts from pdufa.bio's own calendar and decision archive. Each item links to its source page. Facts and dates only; verify against primary FDA / SEC / company filings.
SPRO run-up, measured
Computed from this stock's own daily closing prices, on the same T-120 basis as the run-up study: the baseline is the close 120 trading sessions before the eve of the decision. These are measurements of what already happened, not predictions.
SPRO's past FDA decisions (n=2)
Decision
Outcome
T-120 to eve
T-120 to peak
2026-06-17
APPROVAL
+16.9%
+25.7%
2022-06-27
CRL
-94.1%
+0.0%
With only 2 decisions on record, no median is shown: an average of 2 events would not be a meaningful statistic. The individual figures above are exact. For a statistical base see the run-up study, built on 1,839 decisions.
Common questions
When is the next FDA decision for Spero Therapeutics Inc. (SPRO)?
Spero Therapeutics Inc. has no dated FDA catalyst on our calendar right now. That means no scheduled decision or readout date has been published in a source we can point to, not that none exists. We would rather say that than estimate one.
Has Spero Therapeutics Inc. (SPRO) had an FDA decision before?
Yes, 1 in our archive: 1 approval(s) and 0 Complete Response Letter(s). The most recent was on June 17, 2026 and was an approval. Each one has its own page with the source document and the share-price reaction we measured.
How do stocks like SPRO move into an FDA decision?
We have no measured history for SPRO itself. Across the whole study of 1,839 FDA decisions, the median stock rose 17.7% at its best point in the 120 trading days before the decision, but was only 2.0% higher the day before it. Most of the move happened before the answer arrived and was largely given back.
Where does this SPRO data come from?
FDA publications, company filings with the SEC, company press releases and ClinicalTrials.gov, with share prices measured from daily closing data. Every date and outcome links the document it came from. Where an outcome was inferred from the price reaction rather than read from a filing, the page says so on its face.