Cautionary Note Regarding Forward-Looking Statements This presentation contains "forward-looking statements" within the meaning of the federal securities laws, which statements are subject to substantial risks and uncert

Nasdaq: ETNB Powerful Science

Meaningful Medicines Changing Lives October 2020 Exhibit 99.1

Cautionary Note Regarding

Forward-Looking Statements This presentation contains "forward-looking statements" within the meaning of the federal securities laws, which statements are subject to substantial risks and uncertainties and are based on estimates and

assumptions. Other than statements of historical facts, all statements included in this presentation are forward-looking statements, including statements concerning our plans, objectives, goals, strategies, future events, future revenues or

performance, financing needs, plans or intentions relating to product candidates, estimates of market size, business trends, the anticipated timing, costs, design and conduct of our planned clinical trials for BIO89-100, our only product candidate,

the association of preclinical data with potential clinical benefit, the timing of anticipated milestones, the effect of the COVID-19 pandemic on our clinical trials and business operations, the timing and likelihood of regulatory filings and

approvals for BIO89-100, our ability to commercialize BIO89-100, if approved, the pricing and reimbursement of BIO89-100, if approved, the potential to develop future product candidates, our ability to scale up manufacturing, the potential benefits

of strategic collaborations and our intent to enter into any strategic arrangements, the timing and likelihood of success, plans and objectives of management for future operations and future results of anticipated product development efforts and our

liquidity and capital resources. In some cases, you can identify forward-looking statements by terms such as "may," "might," "will," "objective," "intend," "should,"

"could," "can," "would," "expect," "believe," "design," "estimate," "predict," "potential," "plan" or the negative of these

terms, and similar expressions intended to identify forward-looking statements. These statements involve known and unknown risks, uncertainties and other factors that could cause our actual results to differ materially from the forward-looking

statements expressed or implied in this presentation including those described more fully our most recent Form 10-K and Form 10-Q under the caption "Risk Factors" and elsewhere in such report and in other subsequent disclosure documents

filed with the SEC. We cannot assure you that we will realize the results, benefits or developments that we expect or anticipate or, even if substantially realized, that they will result in the consequences or affect us or our business in the way

expected. Forward-looking statements are not historical facts, and reflect our current views with respect to future events. Given the significant uncertainties, you should evaluate all forward-looking statements made in this presentation in the

context of these risks and uncertainties and not place undue reliance on these forward-looking statements as predictions of future events. All forward-looking statements in this presentation apply only as of the date made and are expressly qualified

in their entirety by the cautionary statements included in this presentation. We disclaim any intent to publicly update or revise any forward-looking statements to reflect subsequent events or circumstances, except as required by law. We obtained

the industry, market and competitive position data used throughout this presentation from our own internal estimates and research, as well as from industry and general publications, and research, surveys and studies conducted by third parties.

Internal estimates are derived from publicly available information released by industry analysts and third-party sources, our internal research and our industry experience, and are based on assumptions made by us based on such data and our knowledge

of the industry and market, which we believe to be reasonable. In addition, while we believe the industry, market and competitive position data included in this presentation is reliable and based on reasonable assumptions, we have not independently

verified any third-party information, and all such data involve risks and uncertainties and are subject to change based on various factors. Disclaimer

89bio - Investment Highlights Validated

in NASH demonstrating strong efficacy results, favorable safety/tolerability profile, and potential best-in-class dosing BIO89-100 has potential to be a leading DRUG FOR LIVER AND CARDIO-METABOLIC DISORDERS BIO89-100 DELIVERS ON THE PROMISE OF FGF21

FGF21 is a highly differentiated approach and potential backbone of treatment in NASH PURSUING Two Promising Large Indications NASH: Compelling benefit-risk profile in a differentiated class SHTG: Potential for quicker path to market with

competitive differentiation (first FGF21 to market based on registrational trials planned in 2022) MAJOR ANTICIPATED MILESTONES NASH: Initiation of a Phase 2b trial as part of a potential Phase 2b/3 trial in 1H21 SHTG: Topline data from Phase 2

trial in 2H21 ESTABLISHED MANUFACTURING EXPERTISE AND IP PROTECTION INTO 2038 AND BEYOND

ROBUST EFFIACCY RESULTS Statistically

significant reductions in liver fat and in key liver markers (ALT) Majority of patients achieved a 30% (up to 88%) or a 50% (up to 71%) reduction in liver fat KEY UPCOMING MILESTONES Initiation of a Phase 2b trial as part of a

potential Phase 2b/3 trial: 1H21 FAVORABLE SAFETY/TOLERABILITY PROFILE Very low frequency of GI adverse events and overall profile comparable to placebo Expected to drive physician adoption and patient compliance in this chronic, generally

asymptomatic patient population BIO89-100: A Compelling Drug Candidate for NASH POTENTIAL best in class dosing REGIMEN First FGF21 analog to show benefit in NASH with two-week dosing

NASH is a Serious Liver Condition With

Significant Co-Morbidities 16.5 million cases projected to grow to 27 million cases by 2030 Expected to become the leading cause of liver transplant Co-morbidity Prevalence in NASH population Hypertriglyceridemia 83% Obesity 82% Hyperlipidemia /

Dyslipidemia 72% Metabolic syndrome 71% Type 2 diabetes 44% Healthy liver NAFLD (Non-Alcoholic Fatty Liver Disease) NASH Cirrhosis Lipogenesis Inflammation Fibrosis Metabolic Dysregulation Excess Liver Fat Accumulation Progressive

Disease INSULIN RESISTANCE HEPATOCYTE INJURY FIBROSIS LIPID HANDLING

FGF21 Has Potential To Be Mainstay of

Therapy In NASH Endogenous metabolic hormone that regulates energy expenditure and glucose and lipid metabolism Reduces liver fat by action within liver and from periphery Impacts liver fibrosis via metabolic pathway and upregulation of adiponectin

Native FGF21 has a short half-life of < 2 hours FGF21 Glucose uptake Lipolysis Energy expenditure Adipogenesis M2 M polarization M2 M proliferation Adipose Muscle Lipid clearance

Insulin sensitivity Ceramide accumulation Liver Blood vessel HPA axis FGF21 adiponectin FGF21

FGF21 FGF19 FXR PPAR* THR- GLP-1

Liver fat reduction Fibrosis improvement ? Triglyceride reduction LDL-C improvement Worsens LDL Worsens LDL HDL-C

improvement Glycemic control Limited Side Effects GI effect** LDL Pruritis LDL Weight Gain Edema Drug-drug interaction GI effect Route of administration/ Dosing frequency

Injectable QD/QW/Q2W Injectable QD Oral QD Oral QD Oral QD Injectable QD Ability to address underlying co-morbidities Efficacy with respect to liver pathologies Well tolerated at effective dose FGF21 - Validated and Highly Differentiated

Mechanism for NASH * Based on pan-PPAR ** for some FGF21 analogs Note: Table representative of data published and/or presented on the mid/late stage clinical programs targeting these mechanisms. Conclusions on this slide are not based on head to

head results. Third party company data taken from publications/publicly available presentations. Effective Indeterminate Modest Effect ? Unknown or Unchanged

RELATIVE Change in liver fat from

PLACEBO (% reduction) FGF21 - Highly Promising Mechanism for NASH * Not placebo controlled; **No worsening of NAS (NAFLD Activity Score) Note: All data regarding third-party studies on this slide are based on third-party trials, some of which

are in different stages of development. Conclusions on this slide are not based in head-to-head results. Efficacy shown here may change in future clinical trials; Graphs are representative of data published and/or presented on the mid/late stage

clinical programs targeting these mechanisms 20mg QW 10 mg QD -32% -20% Pegbelfermin 16 week (n=23) (n=22) 27mg QW 36mg Q2W (n=10) (n=9) -60% BIO89-100 -70% 12 week (n=20) (n=19) 28mg QW 50mg QW Efruxifermin -71% -63% 12 week Liraglutide FGF21 1mg

QD Aldafermin (n=53) -26% 24 weeK FGF19 Resmetirom 80-100mg QD -26% 12 week (n=78) THRB 25mg QD OCA -17% 72 week (n=40) FXR 24 week (n=68) 1.2mg QD -31%* GLP-1 Reductions in liver fat as demonstrated through decreases in MRI-PDFF have been shown to

correlate with histology benefits especially in the case of proportion of patients achieving a 30% reduction in liver fat from baseline

BIO89-100 Is An FGF21 Optimally

Engineered To Balance Potential for Efficacy and Long Dosing Interval glycoPEG(20kD) C-terminus X Strong and flexible linker (glycoPEGylation technology) Mutations in positions 173 and 176 (glycoPEG attached at position 173) X N-terminus Position

182 FGF21 FGF21 is an endogenous metabolic hormone that regulates energy expenditure and glucose and lipid metabolism Proprietary glycoPEGylation technology with site-specific mutations Long half-life of 55-100 hours vs. native FGF21 half-life of

< 2 hours based on single ascending dose study Low nanomolar potency against FGF receptors 1c, 2c, 3c, similar to native FGF21; no activity against receptor 4 that can lead to increased LDL levels C-terminus N-terminus FGFR FGFR C-terminus

-Klotho -Klotho Signal transduction Functional response

Extensive Pre-clinical and Early

Clinical Data With BIO89-100 Reduced Hepatocyte Injury Reduced Liver Steatosis, Inflammation & Fibrosis Improved Lipid Handling* Improved Insulin Sensitivity Body Weight Reduction PRECLINICAL STUDIES DIN mouse model (10 weeks)

DIN mouse model (19 weeks) Diabetic obese cynomolgus monkey study (8 weeks; weekly dosing) Not evaluated Diabetic

obese cynomolgus monkey study (4 weeks; weekly & 2-week dosing) Not evaluated HUMAN Single Ascending Dose Study in healthy volunteers BIO89-100 was safe, well tolerated, showed significant improvements in

key lipid parameters, and had a half-life of 55-100 hours with dose proportional PK Statistically significant benefit observed * Improved TG and cholesterol

Note: Obeticholic acid, 25 mg/kg

tested as active control - did not separate from control in this study Scoring system: Steatosis (0-3), Inflammation (0-3), Fibrosis (0-4), NAS (0-13) - all were assessed at week 19; mean scores *** *** Reduction In Steatosis, Inflammation,

Fibrosis and NAFLD Activity Score With BIO89-100 In DIN Model * Vehicle BIO89-100, 0.02 mg/kg BIO89-100, 0.1 mg/kg BIO89-100, 0.5 mg/kg *p<0.05 **p<0.01 ***p<0.001

Phase 1b/2a Results: Promising

Benefit-Risk Profile with Convenient Dosing Significant benefits across key liver parameters observed across all dose groups and patient populations Up to 60% reduction in liver fat versus baseline and up to 70% versus placebo Up to 44% reduction in

ALT (35 U/L decrease in high ALT group) Up to 27% reduction in Pro-C3 Significant responder rates- Up to 88% and 71% of subjects showed fat reduction 30% and 50% Significant improvements in lipids-triglycerides, non-HDL and

LDL ROBUST EFFICACY RESULTS FAVORABLE SAFETY RESULTS & TOLERABILITY Well tolerated at all doses with low incidence of adverse events that occurred in 10% of subjects Very low frequency of gastrointestinal events and similar profile to

placebo No hypersensitivity or tremor observed; no adverse effects on heart rate or blood pressure POTENTIAL BEST-IN-CLASS DOSING REGIMEN Strong efficacy and favorable tolerability seen with weekly and two-week dosing

BIO89-100-002: Trial Design (n=2)

9mg Placebo (n=14) (n=4) (n=12) (n=3) (n=6) 3mg Placebo 18mg Placebo 18mg Placebo 27mg Placebo 36mg Placebo 12-week treatment duration + 4-week safety follow up Placebo (n=19) combined across cohorts for analysis (n=9) (n=3) (n=11) (n=4) (n=10)

(n=3) KEY TRIAL ENDPOINTS Safety, PK Relative changes in liver fat Serum lipids, liver and metabolic markers NASH* or phenotypic NASH (PNASH)# PDFF 10% *Subjects with biopsy-proven F1-3 #Central obesity plus T2DM or evidence of liver injury

KEY INCLUSION CRITERIA Randomization QW SC Q2W SC Randomized, pharmacodynamic (PD) and safety analysis set n=81; Study completers n=71 MRI analysis set n=75 (subjects with post-baseline MRI)

Baseline Characteristics Parameter

Mean or % Placebo (n=19) Pooled BIO89-100 (n=62) 3mg QW (n=6) 9mg QW (n=12) 18mg QW (n=11) 27mg QW (n=10) 18mg Q2W (n=14) 36mg Q2W (n=9) Age (years) 52.6 51.7 56.1 49.5 51.5 52.0 51.2 52.5 Male/Female 36.8% 38.7% 16.7% 50% 27.3% 20% 28.6% 88.9%

Weight (kg) 93.6 93.6 87.9 87.2 87.1 94.0 101.5 101.1 BMI (kg/m2) 33.8 34.8 34.3 32.7 32.8 36.8 37.0 34.8 Type 2 Diabetes 63.2% 40.3% 83.3% 33.3% 63.6% 40.0% 21.4% 22.2% ALT (U/L) 38.8 42.3 45.0 32.8 38.4 53.3 39.1 50.4 AST (U/L) 29.0 31.5 34.5 22.8

30.9 39.0 28.8 38.1 MRI-PDFF (%) 21.8 21.2 22.4 21.4 19.3 22.0 21.6 20.9 Baseline characteristics were similar between NASH (n=15) and PNASH (n=66) subjects

Up to 43% of subjects normalized

their liver fat (<5%) BIO89-100 significantly reduced liver volume up to 15% Changes in liver fat were similar between NASH and PNASH subjects BIO89-100 Significantly Reduces Liver Fat Across All Dose Groups MRI Analysis Set; MMRM LS Mean; *

p<0.05; ** p<0.01; *** p<0.001 versus placebo ** *** *** *** *** *** Absolute Change in Liver Fat (%) from Baseline at Week 13 Q2W QW

BIO89-100 Reduces Liver Fat in

Significant Percentage of Subjects MRI Analysis Set; MMRM LS Mean; * p<0.05; ** p<0.01; *** p<0.001 versus placebo *** *** *** *** *** *** Proportion of Subjects with 30% Relative Reduction in Liver Fat Placebo 0% QW 3mg 60%** 9mg

82%*** 18mg 60%** 27mg 86%*** Q2W 18mg 69%** 36mg 88%*** Relative Reduction in Liver Fat from Baseline at Week 13 Q2W QW 30% relative reduction in liver fat has been correlated with NASH resolution and fibrosis improvement

Majority of Subjects on BIO89-100

Achieved 50% Reduction in Liver Fat MRI Analysis Set; MMRM LS Mean; * p<0.05; ** p<0.01; *** p<0.001 versus placebo Proportion of Subjects with 50% Relative Reduction in Liver Fat Placebo 0% QW 3mg 20% 9mg 54%** 18mg 50%**

27mg 71%*** Q2W 18mg 39%** 36mg 50%** Relative Reduction in Liver Fat versus Placebo at Week 13 *** *** *** *** *** ***

BIO89-100 Showed Substantial

Reduction in Liver Fat and Liver Volume After 12 Weeks of Treatment (Subject at 27mg QW) Liver fat (%) Parameter Baseline Liver fat 41.1% Liver volume (L) 2.2 Week 13 % Change 5.1% -87.6% 1.4 -35.4%

BIO89-100 Significantly Reduces ALT

PD Analysis Set; Pre-planned sensitivity analysis; MMRM LS Mean; * p<0.05; ** p<0.01; *** p<0.001 versus placebo *** * * *** Percent Change from Baseline at Week 13 Percent Change Over Time -30 U/L -22 U/L * *** ** * *** * * * *** *** Q2W

BIO89-100 has Clinically Meaningful

Impact on Subjects with High ALT PD Analysis Set in baseline ALT > 45 U/L (placebo n=6, pooled BIO89-100 n=22); Pre-planned sensitivity analysis; MMRM LS Mean; * p<0.05; ** p<0.01; *** p<0.001 versus placebo n=5 n=17 Change in ALT of

17 U/L has been correlated with improvement in fibrosis * Placebo Pooled BIO89-100 * Absolute Change in ALT (U/L) (Baseline ALT > 45 U/L) Absolute Change in ALT at Week 13 (Baseline ALT > 45 U/L) -17 U/L

Decrease from baseline in BIO89-100

treated subgroup with baseline TG 200 mg/dL TG: 33%-49% Non-HDL: 8%-29% BIO89-100 Significantly Reduces Triglycerides with Greater Benefit Observed in Subjects with High Triglycerides PD Analysis Set; MMRM LS Mean; * p<0.05; ** p<0.01;

*** p<0.001 versus placebo; # TG <150 mg/dL * * * Percentage Change from Baseline at Week 13 (All Subjects) Q2W QW TG Normalization# Rate at week 13 (Subgroup with Baseline TG 200 mg/dL) 53%

Safety Overview Treatment Emergent

Adverse Event (TEAE) Placebo (n=18) 3mg QW (n=7) 9mg QW (n=12) 18mg QW (n=11) 27mg QW (n=10) 18mg Q2W (n=14) 36mg Q2W (n=9) TEAE Leading to Death 0 0 0 0 0 0 0 TEAE Leading to Discontinuation 0 0 0 0 1a 1b 0 Serious Adverse Event COVID 19 [Not Drug

Related] 0 0 0 0 0 1 1 Safety Analysis Set; one placebo subject received one dose of BIO89-100 3mg and is summarized in 3mg QW group a skin rash; b hyperglycemia [Not Drug Related]

Treatment-Related Emergent AEs in

10% of Pooled BIO89-100 Group Preferred Term n (%) Placebo (n=18) Pooled BIO89-100 (n=63) 3mg QW (n=7) 9mg QW (n=12) 18mg QW (n=11) 27mg QW (n=10) 18mg Q2W (n=14) 36mg Q2W (n=9) Increased Appetite 0.0% 15.9% 4 2 0 2 2 0 Safety Analysis Set;