Nasdaq: CBIO CATALYST BIOSCIENCES Corporate Overview 17 November 2020 CatalystBiosciences.com Catalyst Biosciences Forward looking statements This presentation includes forward-looking statements that involve Various imp

November 2020 CatalystBiosciences.com Catalyst BiosciencesExhibit 99.1 Nasdaq: CBIO CATALYST BIOSCIENCES Corporate Overview 17 November 2020 CatalystBiosciences.com Catalyst Biosciences

Forward looking statements This presentation includes forward-looking

statements that involve Various important factors could cause actual results or events to differ substantial risks and uncertainties All statements included in this materially, including, but not limited to, the risk that trials and studies

presentation, other than statement of historical facts, are forward- may be delayed as a result of the novel coronavirus (COVID-19) looking statements. Forward-looking statements include statements outbreak and other factors, that trials may not

have satisfactory about the potential benefits of products based on Catalyst's outcomes, that additional human trials will not replicate the results engineered protease platform; potential markets for and advantages of from earlier trials,

that potential adverse effects may arise from the MarzAA and DalcA; plans in Q4 2020 to enroll a pivotal Phase 3 testing or use of DalcA or MarzAA, including the generation of registration study of MarzAA , initiate a Phase 1/2 trial in FVII

neutralizing antibodies, which has been observed in patients treated Deficiency, Glanzmann Thrombasthenia, and patients treated with with DalcA, the risk that costs required to develop or manufacture the Hemlibra; the potential for MarzAA and DalcA

to effectively and Company's products will be higher than anticipated, including as a therapeutically treat hemophilia subcutaneously; potential markets for result of delays in development and manufacturing resulting from our anticomplement

and gene therapy programs; potential payments COVID-19 and other factors, the risk that Biogen will terminate from Biogen; plans to declare a development candidates in our Catalyst's agreement, competition and other risks described in the

systemic complement program in Q4 2020; the superiority of CB "Risk Factors" section of the Company's quarterly report filed with the 2679d-GT over other gene therapy candidates; and the Company's Securities and Exchange

Commission on November 5, 2020, and in collaboration with Biogen for the development and commercialization other filings with the Securities and Exchange Commission. The of pegylated CB 2782 for the potential treatment of geographic Company does not

assume any obligation to update any forward- atrophy-associated dry age-related macular degeneration (AMD). looking statements, except as required by law. Actual results or events could differ materially from the plans, intentions, expectations and

projections disclosed in the forward- looking statements. Catalyst Biosciences 2Forward looking statements This presentation includes forward-looking statements that involve Various important factors could cause actual results or events to

differ substantial risks and uncertainties All statements included in this materially, including, but not limited to, the risk that trials and studies presentation, other than statement of historical facts, are forward- may be delayed as a result of

the novel coronavirus (COVID-19) looking statements. Forward-looking statements include statements outbreak and other factors, that trials may not have satisfactory about the potential benefits of products based on Catalyst's outcomes, that

additional human trials will not replicate the results engineered protease platform; potential markets for and advantages of from earlier trials, that potential adverse effects may arise from the MarzAA and DalcA; plans in Q4 2020 to enroll a

pivotal Phase 3 testing or use of DalcA or MarzAA, including the generation of registration study of MarzAA , initiate a Phase 1/2 trial in FVII neutralizing antibodies, which has been observed in patients treated Deficiency, Glanzmann

Thrombasthenia, and patients treated with with DalcA, the risk that costs required to develop or manufacture the Hemlibra; the potential for MarzAA and DalcA to effectively and Company's products will be higher than anticipated, including as a

therapeutically treat hemophilia subcutaneously; potential markets for result of delays in development and manufacturing resulting from our anticomplement and gene therapy programs; potential payments COVID-19 and other factors, the risk that Biogen

will terminate from Biogen; plans to declare a development candidates in our Catalyst's agreement, competition and other risks described in the systemic complement program in Q4 2020; the superiority of CB "Risk Factors" section of

the Company's quarterly report filed with the 2679d-GT over other gene therapy candidates; and the Company's Securities and Exchange Commission on November 5, 2020, and in collaboration with Biogen for the development and

commercialization other filings with the Securities and Exchange Commission. The of pegylated CB 2782 for the potential treatment of geographic Company does not assume any obligation to update any forward- atrophy-associated dry age-related macular

degeneration (AMD). looking statements, except as required by law. Actual results or events could differ materially from the plans, intentions, expectations and projections disclosed in the forward- looking statements. Catalyst Biosciences

Catalyst Biosciences - Protease medicines Protease engineering

platform Late-stage asset Hemophilia Complement SQ MarzAA (FVIIa) IVT Anti-C3 Dry AMD SQ Marzeptacog alfa CB 2782-PEG (activated) SQ Dalcinonacog MarzAA (FVIIa) alfa - DalcA (FIX) Factor IX Gene Therapy SQ Systemic Phase 3 in 2020 Complement

Factor Xa Inhibitors Catalyst Biosciences 3Catalyst Biosciences - Protease medicines Protease engineering platform Late-stage asset Hemophilia Complement SQ MarzAA (FVIIa) IVT Anti-C3 Dry AMD SQ Marzeptacog alfa CB 2782-PEG (activated)

SQ Dalcinonacog MarzAA (FVIIa) alfa - DalcA (FIX) Factor IX Gene Therapy SQ Systemic Phase 3 in 2020 Complement Factor Xa Inhibitors Catalyst Biosciences 3

Harnessing the catalytic power of proteases One protease molecule

regulates 1000s of target molecules Therapeutic protease Target protein An adaptable protease platform Demonstrated efficacy of clinical stage assets Functionally enhanced natural proteases (FVIIa, FIX) Specific cleavage site Engineered novel

protein degraders (Anti-C3) Ideal for high concentration drug targets or controlling amplification cascades Potential to address novel targets Increased potency and extended half-life variants Catalyst Biosciences 4Harnessing the catalytic

power of proteases One protease molecule regulates 1000s of target molecules Therapeutic protease Target protein An adaptable protease platform Demonstrated efficacy of clinical stage assets Functionally enhanced natural proteases (FVIIa, FIX)

Specific cleavage site Engineered novel protein degraders (Anti-C3) Ideal for high concentration drug targets or controlling amplification cascades Potential to address novel targets Increased potency and extended half-life variants Catalyst

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

MarzAA" Hem A or B with inhibitors - ToB FVIID/Glanzmann/Hemlibra - ToB SQ Dalcinonacog alfa "DalcA" Hem B (rFIX) FIX-Gene Therapy Hem B (CB 2679d-GT) Complement IVT CB 2782-PEG Anti-C3 protease for Dry AMD SQ systemic

complement inhibitors - CB DC Catalyst Biosciences 5Pipeline R PC P1/2 P2 P3 Hemostasis SQ Marzeptacog alfa (activated) MarzAA" Hem A or B with inhibitors - ToB FVIID/Glanzmann/Hemlibra - ToB SQ Dalcinonacog alfa

"DalcA" Hem B (rFIX) FIX-Gene Therapy Hem B (CB 2679d-GT) Complement IVT CB 2782-PEG Anti-C3 protease for Dry AMD SQ systemic complement inhibitors - CB DC Catalyst Biosciences 5

Investment highlights Novel subcutaneous factors Anti-C3 Dry AMD with

Biogen with orphan drug designation; FVIIa SQ systemic complement MarzAA & DalcA - P2 efficacy FIX regulator research program in prophylaxis studies complete Multibillion-dollar market Experienced team opportunities 178 worldwide patents

Strong balance sheet, CBIO retains full ownership $104M cash - Q3 of all compounds Catalyst Biosciences 6 6Investment highlights Novel subcutaneous factors Anti-C3 Dry AMD with Biogen with orphan drug designation; FVIIa SQ systemic

complement MarzAA & DalcA - P2 efficacy FIX regulator research program in prophylaxis studies complete Multibillion-dollar market Experienced team opportunities 178 worldwide patents Strong balance sheet, CBIO retains full ownership $104M

cash - Q3 of all compounds Catalyst Biosciences 6 6

Marzeptacog alfa (activated): MarzAA rFVIIa Addresses a clear unmet need

in hemophilia & other bleeding disorders P129A T128N 9-fold higher activity vs NovoSeven RT + Potency allows for SQ dosing that prolongs half-life + Simple, small volume SQ administration M298Q Preclinical efficacy of SQ on-demand treatment

Q286R + HA mouse after tail cut; HA dog; HA rat P2/3 prophylaxis efficacy & safety in HA or HB with inhibitors Increased procoagulant + 46 patients treated including: single dose IV, up to 3 SQ activity doses/day, & daily SQ up to 97 days

Catalyst Biosciences 7Marzeptacog alfa (activated): MarzAA rFVIIa Addresses a clear unmet need in hemophilia & other bleeding disorders P129A T128N 9-fold higher activity vs NovoSeven RT + Potency allows for SQ dosing that prolongs

half-life + Simple, small volume SQ administration M298Q Preclinical efficacy of SQ on-demand treatment Q286R + HA mouse after tail cut; HA dog; HA rat P2/3 prophylaxis efficacy & safety in HA or HB with inhibitors Increased procoagulant + 46

patients treated including: single dose IV, up to 3 SQ activity doses/day, & daily SQ up to 97 days Catalyst Biosciences 7

SQ MarzAA is a large commercial opportunity Global NovoSeven sales

breakdown SQ MarzAA has a superior profile by indication (2019) Faster & easier to administer vs N7 dosed every 2 hours IV until hemostasis $139M MarzAA SQ half-life ~8x longer than N7 $63M 9-fold higher activity vs N7 $93M $578M Potential to

reduce rebleeding $1.2B $81M Stops bleeding in multiple preclinical models Can be combined with Hemlibra in vitro without increased thrombogenicity $263M Ideal for pediatrics and patients with venous access issues Hem A Inh (47%) Hem B Inh (11%)

Prophylaxis efficacy demonstrated in P2 Other (22%) FVII Def (5%) Glanzmann (7%) AHA (8%) Source: Adivo Associates market research; Catalyst Biosciences market research. Data on file Catalyst Biosciences 8SQ MarzAA is a large commercial

opportunity Global NovoSeven sales breakdown SQ MarzAA has a superior profile by indication (2019) Faster & easier to administer vs N7 dosed every 2 hours IV until hemostasis $139M MarzAA SQ half-life ~8x longer than N7 $63M 9-fold higher

activity vs N7 $93M $578M Potential to reduce rebleeding $1.2B $81M Stops bleeding in multiple preclinical models Can be combined with Hemlibra in vitro without increased thrombogenicity $263M Ideal for pediatrics and patients with venous access

issues Hem A Inh (47%) Hem B Inh (11%) Prophylaxis efficacy demonstrated in P2 Other (22%) FVII Def (5%) Glanzmann (7%) AHA (8%) Source: Adivo Associates market research; Catalyst Biosciences market research. Data on file Catalyst Biosciences

MarzAA could be the first prophylaxis for Glanzmann & FVIID Growing

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

Associates Market Research, Data on file. *Note: Treated patients may be counted multiple times as patients may have multiple bleeding events per year needing factor treatment Catalyst Biosciences 9MarzAA could be the first prophylaxis for

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

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

MarzAA is efficacious with daily prophylaxis Phase 2: Daily SQ dosing

for 44 - 97 days Annualized bleed rate Proportion of days n = 9 with bleeding n = 9 12.3% 19.8 + Greater than 90% reduction in all bleeding - Median ABR = 0 + 2 subjects had dose escalation from 30 to 60 g/kg + Safe & well

tolerated, ~1% ISR (6/517 doses) & no ADA 0.8%, p = 0.009 1.6, p = 0.009 6 m pre-treatment On treatment 6 m pre-treatment On treatment Mahlangu et al. EAHAD 2020 Catalyst Biosciences 10MarzAA is efficacious with daily prophylaxis Phase 2:

Daily SQ dosing for 44 - 97 days Annualized bleed rate Proportion of days n = 9 with bleeding n = 9 12.3% 19.8 + Greater than 90% reduction in all bleeding - Median ABR = 0 + 2 subjects had dose escalation from 30 to 60 g/kg + Safe

& well tolerated, ~1% ISR (6/517 doses) & no ADA 0.8%, p = 0.009 1.6, p = 0.009 6 m pre-treatment On treatment 6 m pre-treatment On treatment Mahlangu et al. EAHAD 2020 Catalyst Biosciences 10

Current bypass agents require multiple IVs over the course of hours

NovoSeven 6 hours + Patients reported needing an average of 6 hours and 3 injections of NovoSeven 72 to resolve bleeds + Some bleeds take longer Hours 1,2,3 than 72 hours to resolve 1 2 3 Source: NovoSeven PI Rev 7/2020; Adivo Associates market

research; Catalyst Biosciences market research. Data on file Catalyst Biosciences 11Current bypass agents require multiple IVs over the course of hours NovoSeven 6 hours + Patients reported needing an average of 6 hours and 3 injections of

NovoSeven 72 to resolve bleeds + Some bleeds take longer Hours 1,2,3 than 72 hours to resolve 1 2 3 Source: NovoSeven PI Rev 7/2020; Adivo Associates market research; Catalyst Biosciences market research. Data on file Catalyst Biosciences

MAA-102: PK MarzAA levels support SQ treatment of a bleed 8 subjects at

each dose level 100 60 g/kg SQ 3-hou 60 g/kg SQ 3-hourly x3 + Target of 24-120 ng/mL to treat a 60 g/kg SQ 3-hou 60 g/kg SQ 3-hourly x2 bleed is based on continuous 60 g/kg SQ 1x 60 g/kg SQ 1x 80 infusion levels

of NovoSeven for hemostasis during surgery 60 + Target levels are rapidly achieved 40 + Target levels can be maintained for MarzAA M 18 hours with a single SQ dose of target level 20 60 g/kg + No ADA 0 0 6 12 18 24 30 36 42 48 Hours Neuman et

al. ISTH 2020 Catalyst Biosciences 12 MarzAA (ng/mL) MAA-102: PK MarzAA levels support SQ treatment of a bleed 8 subjects at each dose level 100 60 g/kg SQ 3-hou 60 g/kg SQ 3-hourly x3 + Target of 24-120 ng/mL to treat a 60

g/kg SQ 3-hou 60 g/kg SQ 3-hourly x2 bleed is based on continuous 60 g/kg SQ 1x 60 g/kg SQ 1x 80 infusion levels of NovoSeven for hemostasis during surgery 60 + Target levels are rapidly achieved 40 + Target levels can be

maintained for MarzAA M 18 hours with a single SQ dose of target level 20 60 g/kg + No ADA 0 0 6 12 18 24 30 36 42 48 Hours Neuman et al. ISTH 2020 Catalyst Biosciences 12 MarzAA (ng/mL)

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

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

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

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

Catalyst Biosciences 13Crimson 1 Phase 3 study: Treatment of episodic bleeding Hemophilia A or B with inhibitors, ABR 8 N = 30 N = 30 Primary endpoint MarzAA SQ SOC IV Non-inferior hemostatic efficacy: 60 g/kg 1-3 doses

standard 4-point scale at 24 h 5 bleeds 5 bleeds 1-3 doses per patient per patient Secondary endpoints Time to bleed resolution; 130 bleeds number of doses; rescue meds 130 bleeds per sequence per sequence Safety

Adverse events, anti-drug antibodies (ADA); thrombosis MarzAA SQ Statistics SOC IV 60 g/kg 1-3 doses 5 bleeds + SOC estimate 85% 5 bleeds 1-3 doses per patient per patient Excellent/good treatment of bleeds + Non-inferiority

margin of 12% 114 bleeds per 114 bleeds + 2.5% significance, one-sided sequence per sequence + 90% power Catalyst Biosciences 13

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

thrombasthenia and HA on Hemlibra: N = 8 each Phase 1 PK Phase 2 ToB 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 MarzAA SQ Primary endpoint: Hemostatic efficacy at 24 hours GT 30 bleeds Secondary endpoints: Single dose escalation Effective hemostasis at successive timepoints; doses needed; rescue meds Safety: Multiple dose Q3H HA 15 bleeds

Adverse events and ADA Catalyst Biosciences 14MAA-202 Phase 1/2 study design FVII deficiency, Glanzmann thrombasthenia and HA on Hemlibra: N = 8 each Phase 1 PK Phase 2 ToB 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 MarzAA SQ Primary endpoint: Hemostatic efficacy at 24 hours GT 30 bleeds Secondary endpoints: Single dose

escalation Effective hemostasis at successive timepoints; doses needed; rescue meds Safety: Multiple dose Q3H HA 15 bleeds Adverse events and ADA Catalyst Biosciences 14

Dalcinonacog alfa: novel FIX replacement for SQ delivery Three amino

acid substitutions + 22-fold increased potency vs BeneFIX Differentiated from marketed IV FIXs + Small volume SQ administration R318Y + Enhanced pharmacokinetics with prolonged half-life + Excellent extravascular distribution + Potential to maintain

continuous protective levels Resistance to T343R R338E antithrombin Increased FVIIIa affinity & procoagulant activity Catalyst Biosciences 15Dalcinonacog alfa: novel FIX replacement for SQ delivery Three amino acid substitutions + 22-fold

increased potency vs BeneFIX Differentiated from marketed IV FIXs + Small volume SQ administration R318Y + Enhanced pharmacokinetics with prolonged half-life + Excellent extravascular distribution + Potential to maintain continuous protective levels

Resistance to T343R R338E antithrombin Increased FVIIIa affinity & procoagulant activity Catalyst Biosciences 15

DalcA P2b demonstrated efficacy & safety Target levels >12%

achieved with daily SQ 100 IU/kg dosing for 28 days + Dosed 6 severe HB subjects Subject 102 withdrew on Day 7 + Steady state FIX levels up to 27% achieved after 14 days + No breakthrough bleeds Target + No neutralizing ADA Level + Mild to

moderate ISR - transient & Wash-Out self-limiting + Terminal half-life is Days 2.5 - 5.1 days Catalyst Biosciences 16 Factor IX Activity (%)DalcA P2b demonstrated efficacy & safety Target levels >12% achieved with daily SQ

100 IU/kg dosing for 28 days + Dosed 6 severe HB subjects Subject 102 withdrew on Day 7 + Steady state FIX levels up to 27% achieved after 14 days + No breakthrough bleeds Target + No neutralizing ADA Level + Mild to moderate ISR -

transient & Wash-Out self-limiting + Terminal half-life is Days 2.5 - 5.1 days Catalyst Biosciences 16 Factor IX Activity (%)

Catalyst's CB 2679d gene therapy for hemophilia B CB 2679d-GT has

a superior profile vs Padua in preclinical studies + Stable high activity levels with 1/10th vector dose in mouse model Novel Engineered Lower AAV + 4 to 5-fold reduction in bleeding time when Transgene Capsid Dose compared to the Padua + Potential