Corporate Presentation

October 2018

Statements in this presentation that are not descriptions of historical facts are forward‐looking statements within the meaning of the “safe harbor” provisions of the Private Securities Litigation

Reform Act of 1995. We have attempted to identify forward‐looking statements by terminology including “anticipates,” “believes,” “can,” “continue,” “could,” “estimates,” “expects,” “intends,” “may,”

“plans,” “potential,” “predicts,” “should,” or “will” or the negative of these terms or other comparable terminology. Forward‐looking statements are based on management’s current expectations and

are subject to risks and uncertainties that could negatively affect our business, operating results, financial condition and stock price. Factors that could cause actual results to differ materially from

those currently anticipated are risks relating to: results of research and development activities; uncertainties relating to preclinical and clinical testing; our growth strategy; our ability to obtain,

perform under and maintain financing and strategic agreements and relationships; our dependence on third party suppliers; our ability to obtain, perform under and maintain financing and strategic

agreements and relationships; our ability to attract, integrate, and retain key personnel; the early stage of products under development; our need for substantial funds; government regulation; patent

and intellectual property matters; and competition. We expressly disclaim any obligation or undertaking to update or revise any statements contained herein to reflect any change in our expectations

or any changes in events, conditions or circumstances after the date of this presentation.

Although we believe that the expectations reflected in the forward-looking statements are reasonable, we cannot guarantee future results, levels of activity, performance, achievements or events and

circumstances reflected in the forward-looking statements will occur. We are under no duty to update any of these forward-looking statements after the date of this presentation to conform these

statements to actual results or revised expectations, except as required by law. You should, therefore, not rely on these forward-looking statements as representing our views as of any date

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familiarizing such investors with Caelum Biosciences, Inc. and determining whether such investors might have an interest in a securities offering contemplated by Caelum Biosciences, Inc. Any such

offering of securities will only be made by means of a registration statement (including a prospectus) filed with the SEC, after such registration statement becomes effective. No such registration

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state or jurisdiction.

Disclaimer

1

Lead candidate CAEL-101 is a first-in-class anti-amyloid antibody for treating AL Amyloidosis

AL Amyloidosis is a rare systemic disorder with a large orphan population (~30-45k combined patients in US/EU)

No FDA-approved therapies for the treatment of AL Amyloidosis

Pre-clinical data shows high selectivity and binding affinity to multiple AL light-chain subtypes

Phase 1a/1b data demonstrated rapid improvement in both functional (12 weeks) and biomarker measures (3 weeks)

Advanced preparations are underway to test CAEL-101 in a broad Phase 2 program; potential for accelerated approval in high mortality population

Caelum Biosciences is a biopharmaceutical company focused on treatments for rare hematologic diseases

2

CAEL-101 is a rationally designed antibody that has shown rapid improvement in both functional and biomarker endpoints in a Phase 1a/b clinical study

Key leadership

3

Michael SpectorPresident and Chief Executive Officer, Caelum

25 years experience in the pharmaceutical industry

Multiple prior roles at GlaxoSmithKline across commercial, GM and R&D

Previous roles at Johnson & Johnson, Laurel Pharmaceuticals and North Creek Pharmaceuticals

B.S. in biology from University of Pittsburgh and M.B.A. from Rider University

Dr. Suzanne LentzschChair of Scientific Advisory Board, Caelum

Professor of Medicine and Director of the Multiple Myeloma and Amyloidosis Program at the College of Physicians and Surgeons of Columbia University and at New York Presbyterian Hospital

Lead clinical investigator of CAEL1-101 P1a/1b trial through November 2017

Fellowship and Residency at Humboldt University (Germany)

Paul BrookeChairman, Caelum

40+ years experience in biotech and pharma

Previously Head of Global Healthcare Research and Strategy at Morgan Stanley, and Founder and former Managing Partner of VenBio

Serves on the board of directors of Incyte and several privately held companies

BA from Columbia College and MA from Columbia University

David Barrett CPADirector, Caelum

Strategic Advisor at Assembly Biosciences, previously served as COO, CFO, and CAO

BS in Accounting and Economics and MS in Accounting from Florida University

Dr. Lindsay RosenwaldChairman, President and CEO, Fortress Biotech

Chairman, President and CEO of Fortress Biotech

Founded Cougar Biotechnology, Chelsea Therapeutics, Cypress Bio, Keryx and Indevus, co-founded Ziopharm and TG Therapeutics, and former director of BioCryst

− 13 FDA approvals from companies founded B.S. in finance from Pennsylvania State University and M.D. from Temple University School of

Medicine

Three Main Types of Systemic Amyloidosis: CAEL-101 Is Targeted to Primary (AL) Subtype Systemic amyloidosis are a group of protein-misfolding diseases with different individual disease pathologies

Rationally designed drugs must be targeted toward the specific precursor protein

Source: Blancas-Mejia, Luis M., and Marina Ramirez-Alvarado. “Systemic Amyloidoses.” Annual Review of Biochemistry, vol. 82, no. 1, 2013, pp. 745–774.Note: GSK is developing an Anti-Sap antibody for the treatment of AA Amyloidosis; the program is early with limited cardiac data.

AL amyloidosis AA amyloidosis Hereditary amyloidosis (ATTR)

Prevalence ~30k - 45k(1)(2) ~10k – 15k(1)(3) ~50k(4)(5)

Precursor protein Immunoglobulin light chains Serum amyloid A protein Transthyretin

Point of misfolding Plasma cells (bone marrow) Liver cells Liver cells

Cause Acquired mutation and overproduction Overproduction secondary to chronic infections / inflammation (e.g. RA, IBD)

Hereditary mutation of TTR

Organs commonly affected Heart, kidney, liver Kidney, liver, spleen Nerves, heart, kidney

Developed to specifically bind to the AL light chain

Identified from an amino-terminal peptide fragment from human kappa light chain

CAEL-101 is a chimeric fibril reactive mAb that binds to both kappa and lambda light chains

NEOD001 was derived from Serum amyloid A protein and developed

to bind to C-terminal region

(1) Estimated patient populations in the US and Europe.(2) www.ncbi.nlm.nih.gov/pmc/articles/PMC4635176/

(3) Bellus Health Press Release, June 20, 2016.(4) Estimated worldwide patient population.

(5) Alnylam Corporate Presentation,February 2018.

4

ProthenaNEOD001

Repurposed and studied as a treatment for AL Amyloidosis

DiscontinuedPatisiran Inotersen

Tafamidis AG10

GLS and NT-proBNP(fixed time point and

response) are standard endpoints

Caelum has shown rapid improvement at fixed time points in both GLS and NT-

proBNP

Prothena failed to demonstrate best response in NT-proBNP in

phase 2b/3 trials

Rare systemic disease characterized by misfolding of pre-amyloid light chain proteins produced by plasma cells

Misfolded proteins are toxic and aggregate as fibrils

Fibrils deposit in and around tissues causing damage and affecting function

Symptoms of AL Amyloidosis frequently mimic other diseases (e.g. CHF, respiratory distress, proteinuria), often leading to misdiagnosis

AL Amyloidosis: many patients have severe organ damage at diagnosis…

5

~30k -45k

~4.5k

Plasma cells are produced in the bone

marrowBone

Plasma cells produce proteins. Abnormal plasma

cells produce misfoldedproteins called pre-amyloid

light chain proteins which are toxic to cardiomyocytes

Misfolded proteins collect

together

Collections of misfolded proteins

create amyloid fibrils

Amyloid fibrils deposit in tissues

Heart and kidney impacted in 60-75%

of patients

CAEL-101 may neutralize

CAEL-101 potentially dissolves and removes

Plasma cell production Mechanism of Amyloid formation in tissues

U.S. and EuropePopulation

Newly-diagnosed patients in the U.S. per year

Plasma cell therapies

Potentially understated given AL Amyloidosis often mis-diagnosed

Image of uptake of CAEL-101 in the

myocardium

…And die before getting benefit from current standard of care

6

No FDA-approved therapies for AL Amyloidosis

An effective treatment would:

a) reduce plasma light chain production; and,

b) eliminate existing light chains and amyloid fibrils infiltrating organs

Current standard-of-care inhibits plasma cells through either cytotoxic or anti-CD38 therapy

Patients exhibit variable hematological responses, ~10-11 month median time to organ response, and high morbidity and mortality

• Anti-CD38s

• Traditional chemotherapy agents

• Proteasome inhibitors and immunomodulators

• Stem cell therapy and organ transplants (primarily for earlier stage patients)

Current treatments

(1) NT-proBNP > 8,500 ng/L.(2) Stage 4 patients based on the Mayo Clinic’s staging system.

Median time to response for CAEL-101 vs. current standard-of-care…

One-year mortality rate of approximately 50% in patients with cardiac disease;5 months mean overall survival for most severe patients(2)

Standard of care CAEL-101

NT-proBNP 10.4 months 3 weeks

GLS No change seen over 12 months Improvement seen after 12 weeks

CAEL-101 is first-in-class anti-AL amyloid mAb

7

CAEL-101

Amyloid type Specific for AL misfolded light chain protein

In-vitro binding Strong in-vitro binding with high specificity to a neo epitope that forms on kappa and lambda misfolded proteins, but is not present on the native light chains

Animal imaging Clear co-location of CAEL-101 with human amyloid (both kappa and lambda sub-types) in murine models

Human amyloid dissolution in mice

7 different human amyloid samples; all were fully cleared rapidly

Human imaging In vivo binding in human imaging studies, including the heart

Cardiac response(1)

(Biomarker and functional data)

Phase 1a/1b (n=27)

Biomarker:67% response with single dose or 4 weekly doses3 week median time to response

Functional:90% of cardiac patients responded (statistically significant improvement)

Clinical efficacy in kappa and lambda subtypes

(1) Biomarker response measured by >30% and >300 pg/ml decrease in baseline NT-proBNP, functional response measured by change in left ventricular function in an echocardiogram analysis.

CAEL-101 is a rationally designed antibody that has shown rapid improvement in both functional and biomarker endpoints in a Phase 1a/b clinical study

Phase 1a/b, open-label dose escalation study completed in 2017

8

Patient criteria

Op

en

la

be

l d

ose

esc

ala

tio

n

Single IV infusion @

week 1

Weekly IV infusion for4 weeks @weeks 1 - 4

Primary endpoint

Secondary endpoints

Select exploratory

endpoints

Phase 1an=8

Phase 1bn=19

Patients with relapsed or refractory AL Amyloidosis

− Refractory AL Amyloidosis patients had no prior organ response; or

− Relapsed AL Amyloidosis patients had a prior organ response from chemotherapy

Establish maximum tolerated dose (up to 500mg/m2) of CAEL-101

Cardiac response (NT-proBNP)

Renal response (24-hour Proteinuria)

Pharmacokinetic profile (single dose vs. multiple weekly doses)

GLS

Phase 1a and 1b data presented at ASH in 2016 and 2017

Encouraging Early Functional Data9 out of 10 cardiac patients improved against baseline

9

Left ventricular data: All Phase 1b Cardiac Patients (N=10)

Mean

Improvement

Mean absolute improvement of 1.69 points in GLS scores (range of -10 to -20 points) in Phase 1b cardiac patients after 12 weeks

• Increasingly recognized as a more effective technique than conventional ejection fraction in detecting subtle changes in left ventricular (LV) function(1)

• Considered to be a sensitive measure of pre-treatment cardiac functional impairment in AL (cardiac) amyloidosis and a predictor of survival over and above cardiac biomarkers(2)

• Evidence suggests cardiac AL amyloidosis patients treated with chemotherapy showed no change in GLS from baseline to 1 year(3)

(1) Krishnasamy et. Al. 2015, “Left Ventricular Global Longitudinal Strain (GLS) Is a Superior Predictor of All-Cause and Cardiovascular Mortality When Compared to Ejection Fraction in Advanced Chronic Kidney Disease.”(2) Salinaro et. Al. 2016, “Longitudinal systolic strain, cardiac function improvement, and survival following treatment of light-chain (AL) cardiac amyloidosis.”(3) Salinaro et. Al. 2016, “Longitudinal systolic strain, cardiac function improvement, and survival following treatment of light-chain (AL) cardiac amyloidosis.”

No change in GLS was seen from baseline to 1 year both in patients that were recorded as achieving a hematologic complete response and those that did not achieve a complete response.(4) Buss et Al. 2012, “Longitudinal Left Ventricular Function for Prediction of Survival in Systemic Light-Chain Amyloidosis: Incremental Value Compared With Clinical and Biochemical Markers.”

Reduced LV longitudinal function was shown to serve as an independent predictor of survival in AL amyloidosis(4)

Importance of GLS

Positive Initial Biomarker Data

10

Biomarker data: Evaluable Phase 1b Cardiac Patients (N=8)

(1,000)

(800)

(600)

(400)

(200)

0

Mean of 8 patients

Treatment period Post treatment period

0.02010.0978

0.0525

0.3647

0.0031

0.2732

Mean 35.6% improvement in NTproBNP levels in 8 evaluable cardiac

patients after 4 weeks

LS

Me

an

(SE

) ch

an

ge

s fr

om

ba

seli

ne

in

NT

pro

BN

P

Data shows positive improvement during the treatment period followed by reversal post treatment period

Functional (global longitudinal strain) Biomarker (NT-proBNP)(1)

Absolute change in GLS score from baseline to 12 weeks after baseline Change from baseline to last dose (week 4) (pg/mL)

11

(1.23)

(1.94)

(3.07)

(2.05)

(2.21)

(3.81)

(0.43)

(1.23)

1.12

(1.99)

(1.69)

(5.00) (4.00) (3.00) (2.00) (1.00) 0.00 1.00 2.00

1

2

3

4

5

6

7

8

9

10

Mean

(1,182)

(348)

(171)

(1,148)

(316)

(415)

(445)

(1,105)

(641)

(1350) (850) (350) 150

Patient 10

Patient 9

Patient 8

Patient 7

Patient 6

Patient 5

Patient 4

Patient 3

Patient 2

Patient 10

Mean

NA(2)

Mean

Patient 1

Patient 2

Patient 3

Patient 4

Patient 5

Patient 6

Patient 8

Patient 9

Patient 10

Patient 7

(1) Mean baseline NTpro-BNP was 1,797.(2) Patient 9 and 10 were not evaluable for biomarker response as baseline NT-proBNP was less than 650 pg/mL.

Data measures taken at pre-determined time points which is considered more robust than best response data

Phase 1b cardiac patients: GLS and NT-proBNP data measured at fixed time points with consistent directional trend

NA(2)

(35.6%)

(29.0%)

(49.8%)

(30.1%)

(28.2%)

(18.5%)

(45.0%)

(41.3%)

(42.7%)

∆ from baseline

Dose(mg / m2)

100

5

10

500

250

250

500

500

500

250

Case Study 1: Organ response occurs independent of depth of response to chemotherapy

12

Patient with cardiac lambda AL Amyloidosis

Six prior treatments with no organ response

Best prior hematologic response was PR – partial response

Following the initial dose of CAEL-101, the patient’s NT-proBNP level decreased for three consecutive periods

A clinically meaningful organ response was observed after only three weeks but the patient continued to have an insufficient hematologic response

Source: 2017 ASH Presentation from Dr. Suzanne Lentzsch.

Case study shows the antibody effect of CAEL-101 on the heart as well as its potential to neutralize the toxic pre-amyloid light chain protein

Skin biopsy showed amyloid caused by lambda light chain

Case Study 2: Co-location of Amyloid, CAEL-101, Neutrophils, and Macrophages

13

Phase 1a patient (lambda light chain) showed symptoms of rash and pruritus after a single dose of CAEL-101

Onset 4 days after infusion, duration of 11 days Subcutaneous fat with positive immunohistochemical staining

for CAEL-101

Neutrophils and macrophages co-located at the site of amyloid and CAEL-101

Patient developed less pronounced rash and pruritis when re-dosed with 100 mg/m2

in Phase 1b

Supports the hypothesis of antibody binding and amyloid dissolution

The same patient also had a sustained cardiac response measured as a reduction in NT-proBNP

(1) Baseline measurements were taken prior to first dosing on Day 1 for Phase 1a and Phase 1b.

Case Study 3: Organ response and reduction in liver size occurred independent of free light chain (FLC) response

14

Patient with liver kappa AL Amyloidosis

Organ response 8 months before FLC response

Source: 2017 ASH Presentation from Dr. Suzanne Lentzsch.

Case study shows enlarged liver returned to normal size in patient that had a hematologic response 8 months post organ response

US-Liver Pre-treatment

6/2/16: “The liver is enlarged with normal echogenicity. The liver measures 19.4 cm in length. Liver surface is smooth.”

US-Liver Post-treatment

8/2/16: “The liver is normal in size and echogenicity. The surface is smooth. Right lobe measures 17.3 cm in length at the midclavicular.”

Development of CAEL-101

Robust and Unique Development of CAEL-101

16

3. In vivo data (cont’d) 4. Clinical data

1. Design

Specifically designed to bind to light chain fibrils

2. In vitro data

Shows high binding specificity to light chains (both kappa and lambda)

3. In vivo data

Showed in-vivo binding in animal imaging studies(both kappa and lambda)

CAEL-101 is a first-in-class anti-amyloid antibody

CAEL-101 showed in-vivo binding in human imaging studies

Murine models showed CAEL-101’s amyloid clearance ability in 7 different human amyloid samples

(2 kappa samples, 5 lambda samples)

Mean absolute improvement of 1.69 points in GLS scores (range of 9 – 20 points)

Mean 35.6% improvement in NT-proBNP levels after 4 weeks

Mean

22.0%

9.5%

Kappa Lambda

11-1F4 specificity

(mean % ID / g)

0.3

Kd

Kd tested against K4

(nM)

CAEL-101 expedites the clearance of amyloid deposits in a human patient derived xenograft mouse model

17

Results from an in vivo mouse model showed that CAEL-101 dissolved human amyloid deposits taken from seven different patients

CAEL-101 cleared both kappa and lambda deposits

Day 14

Amyloid fibril suspensions sourced from human postmortem samples were injected into mice to form amyloid deposits

Mice received either CAEL-101 or no

treatment

Untreated mouse

CAEL-101 treated mouse

Day 1

Day 14

Source: Hrncic et al, Am J Path 2000.

CAEL-101 mediates complete clearance of human kappa and lambda amyloid deposits in mouse model

18

Day 0 2 4 6

Clearance

Day 0 2 4 6

AmyloidDeposit

Clearance

28

24

17

9

8

4

4

28

25

24

21

14

15

14

0 5 10 15 20 25 30

λ-05

λ-04

λ-03

λ-02

λ-01

k-02

k-01

Untreated Treated

Single Dose Multiple Doses

AmyloidDeposit

7

6

9

9

28

25

26

24

0 5 10 15 20 25 30

λ-05

λ-04

λ-03

λ-02

λ-01

k-02

k-01

Untreated Treated

Not Tested

Not Tested

Not Tested

Am

ylo

id S

ub

-Typ

e

Time to Clearance (Days)

Am

ylo

id S

ub

-Typ

e

Time to Clearance (Days)

Dissolved kappa deposits 10 days fasterthan the mouse on its own

Dissolved lambda deposits ~3 weeks fasterthan the mouse on its own