Nasdaq: CBIO CATALYST BIOSCIENCES Corporate Overview 7 September 2021 CatalystBiosciences.com Forward looking statements Certain information contained in this presentation and statements made orally during this presentat

September 2021 CatalystBiosciences.comExhibit 99.1 Nasdaq: CBIO CATALYST BIOSCIENCES Corporate Overview 7 September 2021 CatalystBiosciences.com

Forward looking statements Certain information contained in this

presentation and statements made orally during this presentation include forward-looking statements that involve substantial risks and uncertainties. All statements included in this presentation, other than statements of historical facts, are

forward- looking statements. Forward-looking statements include, without limitation, statements about the product candidates of Catalyst Biosciences, Inc. (the "Company") and the benefits of its protease engineering platform, potential

commercial opportunities for and advantages of MarzAA and DalcA, including their potential to treat hemophilia subcutaneously; plans to enroll the Crimson 1 Phase 3 registration study and report on actions of the DSMB and treatment of bleed data for

this study; plans to enroll the MAA Phase 1/2 study of MarzAA and report PK and treatment of bleed data for this study; the potential markets for and advantages of the Company's complement product candidates, including CB 2782-PEG as a

potential best-in-class C3 degrader for dry AMD, CB 4332 as a potential treatment for CFI deficiency, and complement degraders; plans for the Company's collaboration with Biogen; potential markets for the Company's CFI complement product

candidates, and plans to enroll the CB 4332 observational trial and to conduct human clinical trials for CB 4332. Actual results or events could differ materially from the plans, intentions, expectations and projections disclosed in the

forward-looking statements. Various important factors could cause actual results or events to differ materially, including, but not limited to, the risk that trials, studies or programs may be delayed or terminated as a result of COVID-19 and other

factors, that trials may not have satisfactory outcomes, that human trials will not replicate the results from earlier trials, that the Company will need to raise additional capital, which may not be available on favorable terms, if at all, the risk

that costs required to develop or manufacture the Company's products will be higher than anticipated, including as a result of delays in development and manufacturing resulting from COVID-19 and other factors, the risk that Biogen will

terminate its agreement with the Company, competition and other risks described in the "Risk Factors" section of the Company's Annual Report on Form 10-K filed with the Securities and Exchange Commission ( SEC ) on March 4, 2021,

on Form 10-Q filed with the SEC on August 5, 2021, and in other filings with the SEC. The forward-looking statements in this presentation represent the Company's view as of the date of this presentation and the Company does not assume any obligation

to update any forward-looking statements, except as required by law. Catalyst Biosciences 2Forward looking statements Certain information contained in this presentation and statements made orally during this presentation include

forward-looking statements that involve substantial risks and uncertainties. All statements included in this presentation, other than statements of historical facts, are forward- looking statements. Forward-looking statements include, without

limitation, statements about the product candidates of Catalyst Biosciences, Inc. (the "Company") and the benefits of its protease engineering platform, potential commercial opportunities for and advantages of MarzAA and DalcA, including

their potential to treat hemophilia subcutaneously; plans to enroll the Crimson 1 Phase 3 registration study and report on actions of the DSMB and treatment of bleed data for this study; plans to enroll the MAA Phase 1/2 study of MarzAA and report

PK and treatment of bleed data for this study; the potential markets for and advantages of the Company's complement product candidates, including CB 2782-PEG as a potential best-in-class C3 degrader for dry AMD, CB 4332 as a potential

treatment for CFI deficiency, and complement degraders; plans for the Company's collaboration with Biogen; potential markets for the Company's CFI complement product candidates, and plans to enroll the CB 4332 observational trial and to

conduct human clinical trials for CB 4332. Actual results or events could differ materially from the plans, intentions, expectations and projections disclosed in the forward-looking statements. Various important factors could cause actual

results or events to differ materially, including, but not limited to, the risk that trials, studies or programs may be delayed or terminated as a result of COVID-19 and other factors, that trials may not have satisfactory outcomes, that human

trials will not replicate the results from earlier trials, that the Company will need to raise additional capital, which may not be available on favorable terms, if at all, the risk that costs required to develop or manufacture the Company's

products will be higher than anticipated, including as a result of delays in development and manufacturing resulting from COVID-19 and other factors, the risk that Biogen will terminate its agreement with the Company, competition and other risks

described in the "Risk Factors" section of the Company's Annual Report on Form 10-K filed with the Securities and Exchange Commission ( SEC ) on March 4, 2021, on Form 10-Q filed with the SEC on August 5, 2021, and in other filings

with the SEC. The forward-looking statements in this presentation represent the Company's view as of the date of this presentation and the Company does not assume any obligation to update any forward-looking statements, except as required by law.

Catalyst Biosciences 2

The Protease Medicines Company Harnessing the catalytic power of

proteases Novel differentiated medicines Robust complement portfolio Clinical-stage assets Unique expertise in protease engineering Catalyst Biosciences 3The Protease Medicines Company Harnessing the catalytic power of proteases Novel

differentiated medicines Robust complement portfolio Clinical-stage assets Unique expertise in protease engineering Catalyst Biosciences 3

Catalyst protease platform Unique expertise enables design of optimized

& differentiated protease candidates Discovery Platform Our Proteases + Functionally enhanced Protease Protease natural proteases in Scaffold Candidate the complement & coagulation cascades + Engineered novel protein degraders in the

complement cascade + Modulate or target biological activation Structure Guided Design Engineered Regulation or inactivation Molecular Evolution Pharmacokinetic Improvement Catalyst Biosciences 4Catalyst protease platform Unique expertise

enables design of optimized & differentiated protease candidates Discovery Platform Our Proteases + Functionally enhanced Protease Protease natural proteases in Scaffold Candidate the complement & coagulation cascades + Engineered novel

protein degraders in the complement cascade + Modulate or target biological activation Structure Guided Design Engineered Regulation or inactivation Molecular Evolution Pharmacokinetic Improvement Catalyst Biosciences 4

Proteases are ideal for high abundancy targets & cascades A better

way to regulate biological processes compared with antibodies & small molecules Therapeutic target neutralization Protease Efficient regulation at low concentrations of therapeutic protease Antibodies Requires high concentrations in excess of

the target Small molecules / peptides Requires high concentrations & frequent dosing Catalyst Biosciences 5

Pipeline Hemostasis R PC P1/2 P2 P3 SQ Marzeptacog alfa (FVIIa)

MarzAA" Hemophilia A or B with inhibitors - ToB FVIID/Glanzmann/Hemlibra - ToB Complement IVT CB 2782-PEG C3 degrader for Dry AMD Observational SQ CB 4332 Enhanced CFI (ConFIrm) Study C4b Degrader Additional programs Hemostasis SQ

Dalcinonacog alfa (FIX) "DalcA" Hemophilia B CB 2679d-GT Hemophilia B FIX Gene Therapy Catalyst Biosciences 6Pipeline Hemostasis R PC P1/2 P2 P3 SQ Marzeptacog alfa (FVIIa) MarzAA" Hemophilia A or B with inhibitors -

ToB FVIID/Glanzmann/Hemlibra - ToB Complement IVT CB 2782-PEG C3 degrader for Dry AMD Observational SQ CB 4332 Enhanced CFI (ConFIrm) Study C4b Degrader Additional programs Hemostasis SQ Dalcinonacog alfa (FIX) "DalcA" Hemophilia B

CB 2679d-GT Hemophilia B FIX Gene Therapy Catalyst Biosciences 6

Catalyst protease platform Validated across three programs Marzeptacog

alfa CB 2782-PEG Dalcinonacog alfa (activated) 90% reduction in Best-in-class profile for dry AMD Achieved sustained & high annualized bleed rate Extended pharmacodynamics target levels of FIX Normal clotting levels 50% Mild Hemophilia 5%

Moderate Hemophilia 1% Severe Hemophilia Before treatment On treatment Engineered rFIX protease Engineered rFVIIa protease Novel C3 degrader Catalyst Biosciences 7Catalyst protease platform Validated across three programs Marzeptacog alfa CB

2782-PEG Dalcinonacog alfa (activated) 90% reduction in Best-in-class profile for dry AMD Achieved sustained & high annualized bleed rate Extended pharmacodynamics target levels of FIX Normal clotting levels 50% Mild Hemophilia 5% Moderate

Hemophilia 1% Severe Hemophilia Before treatment On treatment Engineered rFIX protease Engineered rFVIIa protease Novel C3 degrader Catalyst Biosciences 7

Marzeptacog alfa (activated) - MarzAA: SQ rFVIIa Designed to

address a clear unmet need in hemophilia & other bleeding disorders 9-fold higher activity vs NovoSeven RT P129A T128N + Potency allows for SQ dosing that prolongs half-life + NovoSeven RT is administered IV Preclinical efficacy of SQ episodic

ToB M298Q + HA mouse after tail cut; HA dog; HA rat P2 proof of concept & preliminary safety in HA or HB Q286R with inhibitors - prophylactic ToB + 46 patients treated including: single dose IV, up to 3 SQ doses/day, & daily SQ up to

97 days - no ADA Increased FDA Fast Track designations procoagulant activity + HA/HB with inhibitors, episodic ToB + FVIID, episodic ToB Catalyst Biosciences 8Marzeptacog alfa (activated) - MarzAA: SQ rFVIIa Designed to address a

clear unmet need in hemophilia & other bleeding disorders 9-fold higher activity vs NovoSeven RT P129A T128N + Potency allows for SQ dosing that prolongs half-life + NovoSeven RT is administered IV Preclinical efficacy of SQ episodic ToB M298Q +

HA mouse after tail cut; HA dog; HA rat P2 proof of concept & preliminary safety in HA or HB Q286R with inhibitors - prophylactic ToB + 46 patients treated including: single dose IV, up to 3 SQ doses/day, & daily SQ up to 97 days

- no ADA Increased FDA Fast Track designations procoagulant activity + HA/HB with inhibitors, episodic ToB + FVIID, episodic ToB Catalyst Biosciences 8

SQ MarzAA is a large commercial opportunity Global NovoSeven sales

breakdown SQ MarzAA profile by indication (2020) + SQ is patient-preferred & eliminates IV barrier to fast & effective treatment $126M + Ideal for pediatrics & patients with venous $53M access issues $545M $74M + Long half-life without

high Cmax for optimal $1.08B control of bleeds $71M + In vitro data support combination with Hemlibra without increased thrombogenicity $213M + Prophylaxis opportunity demonstrated in P2 Hem A Inh (50.3%) Hem B Inh (11.7%) Other (19.7%) FVII

Def (4.9%) Glanzmann (6.9%) AHA (6.5%) Catalyst Biosciences Source: Adivo Associates market research; Catalyst Biosciences market research. Data on file. 9SQ MarzAA is a large commercial opportunity Global NovoSeven sales breakdown SQ MarzAA

profile by indication (2020) + SQ is patient-preferred & eliminates IV barrier to fast & effective treatment $126M + Ideal for pediatrics & patients with venous $53M access issues $545M $74M + Long half-life without high Cmax for optimal

$1.08B control of bleeds $71M + In vitro data support combination with Hemlibra without increased thrombogenicity $213M + Prophylaxis opportunity demonstrated in P2 Hem A Inh (50.3%) Hem B Inh (11.7%) Other (19.7%) FVII Def (4.9%) Glanzmann

(6.9%) AHA (6.5%) Catalyst Biosciences Source: Adivo Associates market research; Catalyst Biosciences market research. Data on file. 9

MarzAA could provide SQ prophylaxis for Glanzmann & FVIID Growing

number of Glanzmann Thrombasthenia and FVIID patients treated with NovoSeven $144M $131M $121M 9% total 2017 2018 2019 increase in patients Global NovoSeven on demand sales Unmet need in over 3 years Glanzmann Thrombasthenia, FVIID prophylaxis

Source: Catalyst Biosciences, Adivo Associates Market Research, Data on file. *Note: 2019 estimates Treated patients may be counted multiple times as Catalyst Biosciences patients may have multiple bleeding events per year needing factor

treatment 10MarzAA could provide SQ prophylaxis for Glanzmann & FVIID Growing number of Glanzmann Thrombasthenia and FVIID patients treated with NovoSeven $144M $131M $121M 9% total 2017 2018 2019 increase in patients Global NovoSeven on demand

sales Unmet need in over 3 years Glanzmann Thrombasthenia, FVIID prophylaxis Source: Catalyst Biosciences, Adivo Associates Market Research, Data on file. *Note: 2019 estimates Treated patients may be counted multiple times as Catalyst

Biosciences patients may have multiple bleeding events per year needing factor treatment 10

Unmet need for a long-acting SQ episodic treatment of bleeds NovoSeven

MarzAA + Patients reported needing an + MAA-102: PK MarzAA levels average of 6 hours and 3 support SQ ToB infusions of NovoSeven to + Target therapeutic levels are resolve bleeds rapidly achieved + Some bleeds take longer than + Target levels can be

maintained for 1,2,3 72 hours to resolve 18 hours with a single SQ dose of 60 g/kg Current bypass agents require multiple Clinical MarzAA levels support SQ ToB infusions over the course of hours 1 2 3 Catalyst Biosciences Source:

NovoSeven PI Rev 7/2020; Adivo Associates market research; Catalyst Biosciences' market research; Data on file; Neuman et al. ISTH 2020 11Unmet need for a long-acting SQ episodic treatment of bleeds NovoSeven MarzAA + Patients reported needing

an + MAA-102: PK MarzAA levels average of 6 hours and 3 support SQ ToB infusions of NovoSeven to + Target therapeutic levels are resolve bleeds rapidly achieved + Some bleeds take longer than + Target levels can be maintained for 1,2,3 72 hours to

resolve 18 hours with a single SQ dose of 60 g/kg Current bypass agents require multiple Clinical MarzAA levels support SQ ToB infusions over the course of hours 1 2 3 Catalyst Biosciences Source: NovoSeven PI Rev 7/2020; Adivo

Associates market research; Catalyst Biosciences' market research; Data on file; Neuman et al. ISTH 2020 11

Crimson 1 Phase 3 study: Treatment of episodic bleeding Hemophilia A or

B with inhibitors, ABR 8 Primary endpoint N = 30 N = 30 + Non-inferior hemostatic efficacy: MarzAA SQ SoC IV standard 4-point scale at 24 h 60 g/kg 1-3 doses 5 bleeds 5 bleeds 1-3 doses per patient per patient Secondary

endpoints + Time to bleed resolution; number of doses; rescue meds 130 bleeds 130 bleeds per sequence per sequence Safety + Adverse events, anti-drug antibodies (ADA); thrombosis MarzAA SQ SOC IV 60 g/kg 1-3 doses 5 bleeds Statistics

5 bleeds 1-3 doses per patient per patient + SoC estimate 85% Excellent/good treatment of bleeds + Non-inferiority margin of 12% 114 bleeds per 114 bleeds sequence per sequence + 2.5% significance, one-sided + 90% power Catalyst

Biosciences 12Crimson 1 Phase 3 study: Treatment of episodic bleeding Hemophilia A or B with inhibitors, ABR 8 Primary endpoint N = 30 N = 30 + Non-inferior hemostatic efficacy: MarzAA SQ SoC IV standard 4-point scale at 24 h 60 g/kg

1-3 doses 5 bleeds 5 bleeds 1-3 doses per patient per patient Secondary endpoints + Time to bleed resolution; number of doses; rescue meds 130 bleeds 130 bleeds per sequence per sequence Safety + Adverse events, anti-drug antibodies

(ADA); thrombosis MarzAA SQ SOC IV 60 g/kg 1-3 doses 5 bleeds Statistics 5 bleeds 1-3 doses per patient per patient + SoC estimate 85% Excellent/good treatment of bleeds + Non-inferiority margin of 12% 114 bleeds per 114 bleeds

sequence per sequence + 2.5% significance, one-sided + 90% power Catalyst Biosciences 12

MAA-202 Phase 1/2 study design FVII deficiency, Glanzmann

Thrombasthenia and HA on Hemlibra: N = 8 each Phase 2 ToB Phase 1 PK Phase 1 + Primary endpoint: MarzAA IV MarzAA SQ Pharmacokinetics each cohort 1-3 doses + Secondary endpoint: Pharmacodynamics FVIID 30 bleeds Single dose Phase 2 ToB +

Primary endpoint: MarzAA SQ Hemostatic efficacy at 24 hours + Secondary endpoints: GT 30 bleeds Single dose escalation Effective hemostasis at successive timepoints; doses needed; rescue meds + Safety: Multiple dose Q3H Adverse events and ADA

HA 15 bleeds Catalyst Biosciences 13MAA-202 Phase 1/2 study design FVII deficiency, Glanzmann Thrombasthenia and HA on Hemlibra: N = 8 each Phase 2 ToB Phase 1 PK Phase 1 + Primary endpoint: MarzAA IV MarzAA SQ Pharmacokinetics each

cohort 1-3 doses + Secondary endpoint: Pharmacodynamics FVIID 30 bleeds Single dose Phase 2 ToB + Primary endpoint: MarzAA SQ Hemostatic efficacy at 24 hours + Secondary endpoints: GT 30 bleeds Single dose escalation Effective

hemostasis at successive timepoints; doses needed; rescue meds + Safety: Multiple dose Q3H Adverse events and ADA HA 15 bleeds Catalyst Biosciences 13

Growing Complement Pathway Protease Platform Catalyst

BiosciencesGrowing Complement Pathway Protease Platform Catalyst Biosciences

Complement is a perfect fit to develop protease therapeutics The

complement pathway is driven by a protease cascade CP LP AP Damaged/altered/foreign cells and debris Exacerbation Exacerbation ? Neoepitopes/ autoepitopes FP DAMP MBL Fcn CL NAb AAb Immune Tick-over ? MASP1 MASP2 C1qR C1q modulation C1r C1s FI FH

C3* C3 C3b MASP3 C1-INH pFD FD FB C4 C2 FD FB FP C4a C3*Bb Circulation FH FI C4BP C4b2b FI % turnover Extrinsic C3 C3bBb FP protease FD FP Immune 80 C3aR C3a C3bBb modulation Amplification C3 convertase FB C3a-dR C3b CD55 CPN of the complement FH FI

Adhesion CR1 CR1 FP C4b2b3b FH FI C3bBb3b Immune C5a-dR C5 convertase CR46 cascade is regulated C3b modulation CD46 CPN Chemotaxis, Extrinsic C5 FH FI inflammatory proteases by proteases C5aR2 signaling and C5a CR1 C5aR1 cell Phagocytosis CR4

activation Trafficking C5b iC3b CR3 Signaling C6 C7 CR1 FI C9 n C8 Lysis, cell Adaptive MAC CD59 C3dg CR2 damage signaling Terminal Breakdown pathway pathway Catalyst Biosciences Source: Figure adapted from Mastellos et al., Clinical promise

of next-generation complement therapeutics. Nature Reviews. 2019 15Complement is a perfect fit to develop protease therapeutics The complement pathway is driven by a protease cascade CP LP AP Damaged/altered/foreign cells and debris Exacerbation

Exacerbation ? Neoepitopes/ autoepitopes FP DAMP MBL Fcn CL NAb AAb Immune Tick-over ? MASP1 MASP2 C1qR C1q modulation C1r C1s FI FH C3* C3 C3b MASP3 C1-INH pFD FD FB C4 C2 FD FB FP C4a C3*Bb Circulation FH FI C4BP C4b2b FI % turnover Extrinsic C3

C3bBb FP protease FD FP Immune 80 C3aR C3a C3bBb modulation Amplification C3 convertase FB C3a-dR C3b CD55 CPN of the complement FH FI Adhesion CR1 CR1 FP C4b2b3b FH FI C3bBb3b Immune C5a-dR C5 convertase CR46 cascade is regulated C3b modulation

CD46 CPN Chemotaxis, Extrinsic C5 FH FI inflammatory proteases by proteases C5aR2 signaling and C5a CR1 C5aR1 cell Phagocytosis CR4 activation Trafficking C5b iC3b CR3 Signaling C6 C7 CR1 FI C9 n C8 Lysis, cell Adaptive MAC CD59 C3dg CR2 damage

signaling Terminal Breakdown pathway pathway Catalyst Biosciences Source: Figure adapted from Mastellos et al., Clinical promise of next-generation complement therapeutics. Nature Reviews. 2019 15