Executive Summary

Q4 2023 revenue of $2.77M modestly beat consensus ($2.74M), but GAAP EPS of -$1.71 missed consensus (-$1.11) as operating and restructuring-related items outweighed higher collaboration revenue; cash and securities were $47.7M at quarter-end .
The strategic narrative pivoted in February 2024: Synlogic discontinued its pivotal PKU Phase 3 (Synpheny-3), initiated a ~90% workforce reduction (estimated ~$6M charges), and began exploring strategic alternatives, effectively ceasing operations aside from wind-down and review activities .
Trend into the quarter: collaboration revenue inflected upward (Q3: $0.39M; Q4: $2.77M) while OpEx declined YoY, narrowing the net loss YoY; however, the program discontinuation and strategic review overshadow near-term fundamentals .
No Q4 earnings call transcript was posted in our document set; communications were via 8-Ks and press releases, with management commentary centered on the program discontinuation and strategic options .

What Went Well and What Went Wrong

What Went Well
- Revenue beat vs consensus driven by collaboration revenue (Roche); Q4 revenue $2.77M vs $2.74M consensus; YoY growth vs $0.11M prior-year Q4 .
- Continued YoY cost discipline: R&D down to $10.2M (from $13.6M), G&A to $3.2M (from $3.8M), narrowing YoY net loss ($14.5M vs $16.7M) .
- Management acknowledged safety/tolerability for SYNB1934 despite discontinuation: “The decision was not based on concerns regarding safety or tolerability” .
What Went Wrong
- EPS missed consensus materially (actual -$1.71 vs -$1.11), reflecting negative operating leverage despite revenue uptick .
- The PKU Phase 3 (Synpheny-3) was discontinued after an internal review suggested the primary endpoint was unlikely to be met—removing the principal value driver .
- Massive restructuring (~90% workforce reduction; estimated ~$6M severance/termination benefits) and decision to cease operations pending strategic alternatives, increasing uncertainty on go-forward operations/value realization .

Financial Results

Metric	Q4 2022	Q3 2023	Q4 2023 Actual	Q4 2023 Consensus	Result vs Cons
Revenue ($USD Millions)	$0.11	$0.39	$2.77	$2.74	Beat +$0.03M (+1.2%)
GAAP EPS	-$3.54	-$2.57	-$1.71	-$1.11	Miss -$0.60

Profitability/Margins	Q4 2022	Q3 2023	Q4 2023
Net Loss ($M)	-$16.70	-$12.08	-$14.53
Net Income Margin %	-15,759%	-3,076%	-525%

Operating Expense Detail	Q4 2022	Q3 2023	Q4 2023
R&D Expense ($M)	$13.64	$9.62	$10.21
G&A Expense ($M)	$3.77	$3.40	$3.20
Total OpEx ($M)	$17.41	$13.02	$13.41

KPIs

Cash, cash equivalents, and marketable securities: $47.7M at 12/31/23; prior quarter 9/30/23 was $33.4M (excludes October financing and $2.5M milestone), and 6/30/23 was $46.3M .
Revenue composition: collaboration revenue associated with Roche in all cited periods .

Segment breakdown: Not applicable; Synlogic reports as a single operating segment with collaboration revenue .

Guidance Changes

Metric	Period	Previous Guidance	Current Guidance	Change
Cash runway	As communicated Nov 9, 2023	“Sufficient cash… into 1H 2025”	Ceasing operations; exploring strategic alternatives; focus on wind-down and review	Withdrawn/No longer applicable
Synpheny-3 (PKU Phase 3) milestones	2024-2025	Enrollment completion 2H 2024; top-line 1H 2025	Discontinued following internal review indicating unlikely to meet primary endpoint	Lowered/Terminated
Operating structure	2024	N/A	~90% workforce reduction; estimated ~$6M in severance/termination costs	Restructuring

Earnings Call Themes & Trends

Note: No Q4’23 earnings call transcript was posted in our document set; themes reflect management press releases across quarters .

Topic	Previous Mentions (Q2 2023, Q3 2023)	Current Period (Q4 2023)	Trend
PKU program (Synpheny-3)	Q2: Phase 3 initiated; FDA Fast Track; focus on execution . Q3: progress, safety board review planned 1H24; top-line 1H25 .	Discontinued after internal review suggested primary endpoint unlikely to be met .	Negative inflection (program terminated)
Collaboration revenue (Roche)	Modest revenue ($0.035M in Q2) tied to Roche collaboration .	Revenue ramp to $2.77M in Q4; still Roche-related .	Positive for revenue mix
Cash runway/financing	Q3: public offering + milestone extended runway into 1H 2025 .	Cash $47.7M at 12/31/23; subsequent operations ceased and strategic review launched .	Strategy pivot; runway guidance moot
Organizational structure	Normal operations in Q2/Q3 .	~90% workforce reduction; cease operations aside from wind-down .	Restructuring
Safety/tolerability	Q2/Q3: advancing GI-restricted synthetic biotics .	Discontinuation not due to safety/tolerability concerns .	Neutral on safety; efficacy issue

Management Commentary

On discontinuation of Synpheny-3 and impact: “It is with a heavy heart that we share this news, and our resulting decision to end Synpheny-3… The decision was not based on concerns regarding safety or tolerability.” — Aoife Brennan, President & CEO (Feb 8, 2024) .
Prior strategic tone (Q3): “Closing of a significant financing… extended our cash runway into the first half of 2025… we are pleased with our progress in Synpheny-3” — Aoife Brennan (Nov 9, 2023) .
Prior operational focus (Q2): “With our pivotal Phase 3 study, Synpheny-3, now underway, we are focused on trial execution…” — Aoife Brennan (Aug 10, 2023) .

Q&A Highlights

No Q4 2023 earnings call transcript was found in our document set; investor communications were delivered through 8-Ks and press releases (financial results on Mar 19, 2024 and program discontinuation on Feb 8/12, 2024) .
Guidance clarifications came via press releases, not a live Q&A: runway communicated in Q3 (into 1H 2025) was effectively withdrawn by the decisions announced in Feb 2024 to cease operations and pursue strategic alternatives .

Estimates Context

Revenue: Q4 2023 actual $2.77M vs S&P Global-derived consensus $2.74M (via Moomoo aggregator); modest beat (+$0.03M, +1.2%) .
EPS: Q4 2023 GAAP EPS -$1.71 vs consensus -$1.11 (per Zacks/Yahoo Finance); miss of -$0.60 as operating and other items outweighed revenue upside .
Prior quarter context (Q3 2023): revenue $0.39M vs est $0.04M; EPS -$2.57 vs -$2.55 (small miss) .
Note: Direct S&P Global estimates via API were unavailable due to rate limits; consensus comparisons reference external aggregators (Moomoo cites S&P for estimates; Zacks/MarketBeat for EPS) .

Key Takeaways for Investors

The fundamental driver (Synpheny-3 PKU) is gone; investment case shifts to strategic alternative outcomes (e.g., merger/reverse merger/asset sale/dissolution), not operating execution .
Q4 showed a revenue beat on collaboration income, but EPS missed; this likely has limited relevance given the February strategic reset .
Cash of $47.7M at year-end provides a resource base for the review and potential transaction costs; workforce reduction (~90%) and lease/other actions reduce burn into 2024 .
For short-term trading, stock moves are likely headline-driven by strategic process updates rather than quarterly KPIs; watch for 8-Ks disclosing deal milestones .
Collaboration revenue (Roche) boosted Q4, but with operations ceasing, future recurring revenue is uncertain; no ongoing product revenue exists .
Safety/tolerability signals for SYNB1934 were not the issue; the efficacy read-through might limit out-licensing prospects for PKU-specific assets but could preserve value perceptions for platform elements in other indications .
Risk skew is binary toward transaction terms and residual cash value; diligence should focus on probable transaction structures and any contingent liabilities (e.g., restructuring/lease) .

Supporting detail tables

Revenue, EPS, and YoY/Sequential Context

Metric	Q4 2022	Q3 2023	Q4 2023
Revenue ($M)	$0.11	$0.39	$2.77
GAAP EPS	-$3.54	-$2.57	-$1.71
YoY Revenue Growth	—	—	+2,512% (calc from $0.11→$2.77)
Seq Revenue Growth	—	—	+604% (calc from $0.39→$2.77)

Operating Expenses and Cash

Metric	Q2 2023	Q3 2023	Q4 2023
R&D ($M)	$11.77	$9.62	$10.21
G&A ($M)	$3.86	$3.40	$3.20
Total OpEx ($M)	$15.64	$13.02	$13.41
Cash & Equivalents/Marketable Securities ($M)	$46.3 (6/30)	$33.4 (9/30, pre-Oct financing/milestone)	$47.7 (12/31)

Discontinuation and Restructuring Highlights

Item	Detail
Synpheny-3 status	Discontinued after internal review indicated primary endpoint unlikely to be met; not a safety/tolerability issue
Workforce	~90% reduction; estimated ~$6M severance/termination benefits; expected substantially completed by end of Q1 2024
Strategic alternatives	Exploring acquisition/merger/reverse merger/asset sales/dissolution; ceased operations aside from wind-down

Citations

Q4 2023 financial 8-K and press release exhibit with detailed P&L, balance sheet, and revenue/OpEx: .
Feb 8/12, 2024 8-K: Synpheny-3 discontinuation, strategic alternatives, workforce reduction details and estimated charges: .
Q3 2023 8-K with financials, cash runway guidance into 1H 2025, and PKU program milestones: .
Q2 2023 8-K with financials and initiation of Phase 3: .
Consensus/estimate references (external aggregators due to S&P API rate limit): Moomoo (S&P-attributed revenue cons/actuals), Yahoo/Zacks (EPS consensus), MarketBeat historical beats: .

SYNLOGIC, INC. (SYBX)·Q4 2023 Earnings Summary