GYRE

Strategic decision to stop clinical development of MarzAA and focus on complement programs and protease medicines platform. Enrollment in MarzAA clinical trial was slow due to pandemic logistical challenges and increasing competition for study subjects. Estimate MAA-304/Crimson-1 study could be completed by late 2023 but couldn't overcome financing hurdle without a partner. Balance sheet had $64.5M cash as of Sept 30, 2021; halting MarzAA development will reduce burn by ~40%. Complement portfolio led by CB 4332 and CB 2782-PEG; CB 4332 enrolled first 2 CFI-deficient patients in natural history study, plans to submit IND in 2022 and start first-in-human trial. CB 2782-PEG licensed to Biogen, in preclinical development for dry AMD, Catalyst supporting IND-enabling activities.

Estimate cash runway of approximately 1 year after 40% burn reduction. Plan to report data from MAA-304/Crimson-1 trial showing MarzAA successfully treated bleeds subcutaneously with no treatment-related adverse or thrombotic events. Explore opportunities to license or sell MarzAA and DalcA portfolio. Intend to move forward with CB 4332 as swiftly as possible and generate more candidates from platform.

Risks related to forward-looking statements, including regulatory and clinical actions, development, and projected operating expenses. Uncertainties in clinical trial enrollments and competition for study subjects affecting MarzAA development.

Q: On CB 4332, early observations on natural history study, enrollment goals, and next clinical data A: Explained ConFIdence study, enrollment process, and plans for first-in-human study with safety, PK/PD data expected by end of year Q: On 2782-PEG partnership and cash runway A: Biogen controlling news flow on 2782-PEG, cash runway estimated at ~1 year Q: Timing of strategic decision to halt MarzAA A: Primarily due to slow enrollment pace impacting long-term feasibility Q: On MarzAA Phase I/II, immunogenicity, and partner outreach A: MarzAA study was non-registrational, no comment on immunogenicity, and engaged in business development but no specific partner outreach details Q: On complement factor I program immunogenicity, CFI deficiency prevalence A: Engineered 4332 for extended half-life, conducted immunogenicity risk assessment, and has KOL network for enrollment Q: On 4332 SAD/MAD data, indication selection, and complement degrader programs A: Post-SAD/MAD, Phase 2 in fully deficient CFI patients, exploring other complement-mediated diseases; prioritizing nephrology and inflammation for next development candidate Q: On MarzAA efficacy safety data sharing, partner search for MarzAA A: Will share data in a few months after trial wind-down, will pursue partner expeditiously Q: On Biogen collaboration transfer of CBIO-supported activities A: Catalyst responsible for IND-enabling studies and CMC development, transfer when those are complete