SYNLOGIC, INC. Q3 FY2020 earnings call

• Enteric Hyperoxaluria candidate entered the clinic this week ahead of schedule and initiation of PKU SynPheny-1 Phase 2 study. • Welcomed Dr. Dave Hava as Chief Scientific Officer, an experienced drug hunter with synthetic biology expertise. • Rapid progress in Metabolic and Immunomodulation programs, with 4 INDs into clinic in short order, each more rapidly than previous. • Phase 2 study of SYNB1618 (SynPheny-1) in PKU underway, with robust patient interest; SYNB8802 in Enteric Hyperoxaluria initiated ahead of schedule with preclinical data showing potential. • SYNB1891 Phase 1 study in solid tumors continues enrollment, focusing on safety, tolerability, and target engagement.

Research and Development expenses were $10.5 million for the three months ended September 30, 2020, compared to $10.6 million for the corresponding period in 2019. General and Administration expenses were $3 million in the third quarter of 2020, compared to $3.9 million for the same period in 2019. The company reported a net consolidated loss of $13.2 million or $0.36 per share in Q3 2020, compared to a net loss of $13.3 million or $0.39 per share in Q3 2019. There were no revenues in Q3 2020 compared to $305,000 in Q3 2019. Synlogic ended the third quarter of 2020 with $102 million in cash, cash equivalents and other investments.

• Cash at end of Q3 2020 was $102 million, expected to take the company into 2022 and enable advancement of clinical programs through important data readouts. • By end of 2021, proof-of-concept opportunities in patient populations like PKU and Enteric Hyperoxaluria.

Forward-looking statements subject to numerous factors, assumptions, risks, and uncertainties, including those described in press releases or SEC filings.

Q: How many patients will be seen at the end of the year for SYNB1891 study and what are the objectives?

A: Aoife and Richard discussed that the Phase 1 study's primary endpoints are safety and tolerability, and they're interested in monotherapy target engagement at tolerated doses with a heterogeneous patient population.

Q: What's the degree of natural variability assumed in patient Phe levels over time for SynPheny?

A: Richard responded that there's about 15% variability in measuring Phe and at least equal variability in patient-to-patient and day-to-day, and they designed the study to detect at least a 20% decrease in Phe.

Q: Plans for returned IBD asset from AbbVie?

A: Aoife and Dave Hava mentioned they're regenerating data from the collaboration and evaluating assets for potential advancement, with IBD being a consistent area of interest leveraging the platform.

Q: Enrollment and dosing status for Part B of SYNB8802 Phase 1 study?

A: Richard explained Part B will involve patients with enteric hyperoxaluria secondary to Roux-en-Y gastric bypass, with a crossover design enrolling ~20 patients with urinary oxalates above 70 mg/day, contingent on safety data from healthy volunteers.

Q: Prioritization of assets for pivotal studies if positive readouts in 2021?

A: Aoife stated focus on rare metabolic diseases internally for internal pipeline, with immunomodulation programs for potential partnerships, and 1891 and IBD assets potentially partnered once de-risked.

Q: Optimization of SYNB1618 NexGen strain and transition to clinic?

A: Aoife and Richard discussed ongoing optimization with Ginkgo and enEvolv, and plan to use healthy volunteer studies to evaluate second-gen strain, with regulatory strategy leveraging reusable parts and previous data.