Jefferies 2017 Global Healthcare Conference

Stephen Doberstein, Ph.D.Senior Vice President & Chief Scientific Officer

June 7, 2017

This presentation includes forward-looking statements regarding Nektar’sproprietary drug candidates, the timing of the start and conclusion of ongoing or planned clinical trials, the timing and outcome of regulatory decisions, future availability of clinical trial data, and royalty and milestone revenue potential. Actual results could differ materially and these statements are subject to important risks detailed in Nektar's filings with the SEC including the Form 10-Q filed on May 10, 2017. Nektar undertakes no obligation to update forward-looking statements as a result of new information or otherwise.

ONZEALDMetastatic Breast Cancer& Brain Metastases

NKTR-255IL-15

Building a Biopharmaceutical Growth Company

3

Integrated R&D, Scale-Up and Manufacturing

Capabilities

R&D CenterSan Francisco, CA

Manufacturing & Scale-Up FacilityHuntsville, AL

Wholly-Owned Research & Development Pipeline

NKTR-181Abuse-deterrent Opioid NCE

NKTR-214CD122-biased agonistMultiple Tumor TypesCombination Trials

NKTR-358Autoimmune Disease

NKTR-262TLR Agonist

Revenue DriversPartnered Portfolio

$375-450MAnnual Revenue

By 2021Re

venu

e Po

tent

ial

2021

R&D Support FacilityHyderabad, India

Immuno-Oncology

Pain

Immunology

Cancer Chemotherapy

NKTR-181: A Novel Opioid Poised to Transform the Chronic Pain Market

NKTR-181 brings unique properties to the treatment of chronic pain:

Slow rate of entry into CNS designed to reduce euphoria and resulting abuse liability

Designed to cause less sedation, dizziness and reduce risk of respiratory depression

Targeting C-III or better scheduling

Properties are inherent to molecule

Received Fast Track Status from FDA

4

$20 Billion+Global Chronic Pain

Therapy Market

Opioids$12.6B

Antiepileptics$3.6B

Antidepressants$1.5B

NSAIDs/COX-2s$5.9B

Chronic pain market includes:Chronic back pain

OsteoarthritisFibromyalgia

Neuropathic pain

Source: 2013 IMS and Decision Resources

NKTR-181: Phase 3 Efficacy Trial Conclusions

NKTR-181 significantly reduced pain in opioid naïve patients with moderate-to-severe chronic low back pain.

• Primary efficacy analysis: p=0.0019

• Completer efficacy analysis: p<0.0001

Responder analyses (≥30% and ≥50% reductions in pain scores) both met statistical significance (p=0.0003 and p=0.001, respectively).

NKTR-181 improved overall general status and quality of life (p<0.0001).

NKTR-181 improved quality of sleep and led to less sleep disturbance.

NKTR-181 had a favorable safety profile and was well-tolerated.

NKTR-181 dose range evaluated in SUMMIT-07 (100-400mg) previously demonstrated significantly lower abuse potential than oxycodone (40mg) and rated similar to placebo in a separate Human Abuse Liability (HAL) trial.

5

Key Secondary Endpoint:Responder Analysis Based on Pain Scores (NRS) Relative to Screening Baseline

6Responder is defined as a randomized subject who completes the Double-Blind Randomized Treatment Period (Week 12) and achieves ≥30% or ≥50% reduction in the Week 12 Weekly Pain Score from Screening Pain Score

51.1%

71.2%

37.9%

57.1%

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

100%

90%

80%

70%

60%

50%

40%

30%

20%

10%

0%

Pain Score Reduction from Screening Baseline

Patie

nts R

espo

ndin

g (c

umul

ativ

e)

p=0.0003 vs. placebo

NKTR-181

Placebo

p=0.001 vs. placebo

HAL: Primary Drug High ProfileNKTR-181 is Significantly Differentiated from Oxycodone at All Dose Levels (p<0.0001)

7Study completed May 2013Pain Med pnw344 (Webster, et al.) March 2017

Time (Hours Post Dose)

Dru

g H

igh

Oral Human Abuse Liability (HAL)Mean VAS For Drug High

On a scale of 0 to 100,how high do you feel right now?

Treatment EmaxLS Mean

Placebo 8.50

NKTR-181 100mg 14.26

NKTR-181 200mg 14.34

NKTR-181 400mg 22.95

Oxycodone HCl 40mg 80.83

Link to Manuscript in Pain Medicine

NKTR-181 Development Strategy

8

Pivotal Human AbuseLiability Study Initiated

Long-term (52-wk) safety studyenrollment complete; 6 & 12-month

exposure requirements met

Discuss early NDA filing basedupon efficacy and HAL

trial results2H 2017

Initiate additional trial(s) with Partner to support expansion of

label and/or approval

Efficacy Study Ongoing inOpioid-naïve Patients with

Chronic Low Back PainTopline Data Announced

March 2017

Q1 2017 Q2 2017 Q3 2017

Initiate Partnering Discussions

Q2 2017

Topline Data Mid-2017

The Immunity Cycle and Multiple Points of Intervention for I-O Therapies

9

4. Trafficking of T cells to tumor

5. Infiltration of T cells into

tumors

6. Recognition of cancer cells

by T cells

7. Killing of cancer cells1. Release of

cancer cell antigens

2. Cancer antigen presentation

3. Priming and

activation

Source:Oncology Meets Immunology: The Cancer-Immunity CycleChen and MellmanImmunity, Volume 39, Issue 1, 1 - 10

3. Priming and activation

(APCs & T cells)

6. Recognition of cancer cells

by t cells (CTLs, cancer

cells)

5. Infiltration of T cells into tumors (CTLs, endothelial

cells)

7. Killing of cancer cells (immune and cancer

cells)

1. Release of cancer cell antigens (cancer

cell death)

2. Cancer antigen

presentation (dendritic

cells/APCs)

Nektar’s Immuno-Oncology Strategy to Create Therapies that Cover the Immunity Cycle

10

4. Trafficking of T cells to tumor (CTLs)

Therapies need to be

accessible as medicines

Target as many steps as possible in the cycle with as few therapies

as possible

NKTR-214 (CD122 Agonist)

Prime, Proliferate, Activate & Increase Tumor-Infiltrating

Lymphocytes (TILs), Increase PD-1 expression

NKTR-262 (TLR Agonist)

Activate Dendritic Cell Response

NKTR-255 (IL-15)

Stimulate NK Cells, Sustain Immune

Response & Generate T Cell Memory

Small Molecules(TLR Agonist,other targets)

NKTR-214 Provides A Central Mechanism to Combine with Multiple Modalities in Immuno-Oncology

11

CheckpointInhibitors

Cell Therapies(TIL therapy, ECT)

VaccinesNKTR-214:

T Cell GrowthFactor

NKTR-214: Biasing Action to CD 122, or IL-2R Beta, to Stimulate T-Cell Production

Biases signaling to favor the CD122 Receptor (IL-2Rβγ complex)

Eliminates over-activation of IL-2 pathway that results in serious safety issues

Achieves antibody-like dosing schedule in outpatient setting

12

CTLs

CD8+ T-Cellsand NK Cells

βγ

NKTR-214

Stimulates ImmuneResponse to Kill

Tumor Cells

CD4+ Regulatory T-Cells

Tregs αβγ

Down-Regulates Proliferation of CD8+ T-cells

and Suppresses Immune Response

NKTR-214 Selectively Grows T Cells, NK Cells in Tumor Microenvironment in Cancer Patients

NKTR-214 drives immune activation in the tumor • Increase in total T cells, NK

and CD8 T cells • No increase in Tregs• Increase in PD-1 positive CD8

T cells• Increase in newly proliferating

CD8 T cells• Activation and expression of

anti-tumor genes• Change in T cell clonality in

the tumor

13

Fold change expressed as Week 3 / predoseShown are results from N=10 patients

N=10; Q3w dose schedule; SITC 2016; JP Morgan 2016

Analysis of T cell Populations in Tumor

0

1 0

2 0

3 0

4 0

C D 8 T r e g s

0

10

20

30

40

CD8 Tregs

1.6

29.8

PIVOT Program: NKTR-214 plus Opdivo® withEight Expansion Cohorts Planned

14

Renal Cell Carcinoma1st line, 2nd line I-O naïve, N=26

NSCLC1st, 2nd line I-O naïve

Triple Negative BC2nd line I-O naïve, N=36

Melanoma1st line

Renal Cell Carcinoma1st, 2nd line I-O naïve

Phase 1 Dose Escalation (on label indications)

N= 20-30

Phase 2 Expansion Cohorts3Q 2017

Melanoma2nd line I-O relapsed, N=26

Urothelial Carcinoma (Bladder)1st line, cisplatin ineligible, N=40

Renal Cell Carcinoma2nd line I-O relapsed, N=26

Melanoma1st line, N=28

NSCLC2nd line I-O relapsed, N=26

NSCLC1st, 2nd line I-O naïve, N=36

Initial Dose Combination Arm:Group 1: 0.006 mg/kg q3w NKTR-214 + 240 mg q2w nivoq2w and q3w Parallel Dose Combination Arms:Group 2: 0.003 mg/kg q2w NKTR-214 + 240 mg q2w nivoGroup 3: 0.006 mg/kg q2w NKTR-214 + 240 mg q2w nivoGroup 4: 0.006 mg/kg q3w NKTR-214 + 360 mg q3w nivoGroup 5: 0.009 mg/kg q3w NKTR-214 + 360 mg q3w nivo

PIVOT PIVOT Expansion

Opdivo is a registered trademark of Bristol-Myers Squibb

NKTR-214: Additional Clinical Development Programs in 2H 2017/1H 2018

15

Phase 1 trial of NKTR-214 and TECENTRIQ (Q317)

Phase 1/2 trial of NKTR-214 in combination with Endogenous T Cell regimen in NSCLC patients (with MDA)

Triplet combination of NKTR-214 with anti-PD-1 and anti-CTLA-4 agents

Preclinical studies underway with NKTR-214 and vaccines with potential for clinical advancement in 2018

CheckpointInhibitors

Vaccines

Cell Therapies

Opdivo is a registered trademark of Bristol-Myers Squibb

IST in Sarcoma with NKTR-214 and Opdivo® at Memorial Sloan Kettering and MD Anderson (Q317)

Phase 1 trial of NKTR-214 and NKTR-262 (TLR Agonist 7/8)TLR

Agonist

Takeda and Nektar Research Collaboration

16

Takeda and Nektar collaborating oncombining NKTR-214 with five Takedaoncology compounds

Collaboration will explore five targeted mechanismsin Takeda’s oncology portfolio including:• SYK-inhibitor• Proteasome inhibitor

Combinations will be tested in preclinical models of lymphoma, melanoma and colorectal cancer

Takeda and Nektar will share costs and each will maintain global commercial rights to respective drugs/candidates

3. Priming and activation

(APCs & T cells)

6. Recognition of cancer cells

by t cells (CTLs, cancer

cells)

5. Infiltration of T cells into tumors (CTLs, endothelial

cells)

7. Killing of cancer cells (immune and cancer

cells)

1. Release of cancer cell antigens (cancer

cell death)

2. Cancer antigen

presentation (dendritic

cells/APCs)

Nektar’s Immuno-Oncology Strategy to Create Therapies that Cover the Immunity Cycle

17

4. Trafficking of T cells to tumor (CTLs)

Therapies need to be

accessible as medicines

Target as many steps as possible in the cycle with as few therapies

as possible

NKTR-214 (CD122 Agonist)

Prime, Proliferate, Activate & Increase Tumor-Infiltrating

Lymphocytes (TILs), Increase PD-1 expression

NKTR-262 (TLR Agonist)

Activate Dendritic Cell Response

NKTR-255 (IL-15)

Stimulate NK Cells, Sustain Immune

Response & Generate T Cell Memory

NKTR-262: Adding a Unique Intratumoral TLR Agonist to Nektar’s Immuno-Oncology Portfolio

TLR agonists activate innate immunity, myeloid cell response and increase tumor antigen presentation

• Creates tumor-suppressing micro-environment by mimicking local infection

Nektar technology optimizes specific abscopal effect in tumors without systemic exposure of TLR agonist

NKTR-262 designed to be highly synergistic with NKTR-214

NKTR-262 with NKTR-214 represent a novel, wholly-owned combination regimen in immuno-oncology

18

NKTR-214 proliferates &

expands T Cells

NKTR-262 activates

innate immunity

DendriticCell

M1Macrophage

CD8+T Cell

Present antigens to prime T Cell

NKTR-262 0.8 mg in 40 L volume given in a single IT dose, NKTR-214 0.8 mg/kg q9dx3 IV; N=10 per groupμ

Complete Regression and Abscopal Effect with Combination of NKTR-262 and NKTR-214

19

NKTR-214

D 0 D 9 D 18

NKTR-262

Primary (injected) CT-26 Colon Tumor

0 1 0 2 0 3 0 4 0 5 0

0

5 0 0

1 0 0 0

Tu

mo

r V

olu

me

(m

m3

±

SE

M)

D a y s a f t e r f i r s t d o s e

0 1 0 2 0 3 0 4 0 5 0

0

5 0 0

1 0 0 0

Tu

mo

r V

olu

me

(m

m3

±

SE

M)

D a y s a f t e r f i r s t d o s e

Vehicle

NKTR-214

NKTR-262 NKTR-262 + NKTR-214

Vehicle

NKTR-214

NKTR-262

NKTR-262 + NKTR-214

NKTR-262 + NKTR-214

NKTR-214

NKTR-262

Vehicle

Secondary (non-injected) CT-26 Colon Tumor

Survival CT-26 Colon Tumor

Primary (injected) Tumor

Secondary (non-injected) Tumor

Dosing

TLR Agonist + NKTR-214: Synergistic Immune Effects on Distal Tumor

20

V e h icle

N K T R -21 4

T L R

C o mb o

0

1 0

2 0

3 0

4 0

5 0

% N e u tr o p h ils

% N

eu

tro

ph

ils

V e h icle

N K T R -21 4

T L R

C o mb o

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

% C D 1 1 c + C D 8 + D e n d r it ic C e lls

% C

D1

1c

+ C

D8

+ D

Cs

V e h icle

N K T R -21 4

T L R

C o mb o

0

1 0

2 0

3 0

4 0

5 0

% C D 8 T C e lls

% C

D8

T C

ell

s

V e h icle

N K T R -21 4

T L R

C o mb o

0

2

4

6

8

1 0

% M o n o c y te s

% M

on

oc

yte

s

V e h icle

N K T R -21 4

T L R

C o mb o

0

1

2

3

4

% T r e g s

% T

reg

s

V e h icle

N K T R -21 4

T L R

C o mb o

0

2 0

4 0

6 0

8 0

% M a c ro p h a g e s

% M

ac

rop

ha

ge

s

Combination of TLR Agonist + NKTR-214

Prom

otes

Imm

une

Activ

atio

nO

verc

omes

Imm

une

Supp

ress

ion

Auto-Immune Disease is Characterized by Imbalance of T-Reg Cells to T-Effector Cells

21

Pathologicaloverpopulation ofantigen-specific(self-reactive)effector T cells

Insufficient T-reg cell

population to control the

pathological effector T cells

Beneficial effector T cell

population

• Current auto-immune disease therapies work by suppressing overall immune system function– Treat symptoms of the

over-active immune system

– Do not address underlying pathology

– Block both pathological and beneficial effector T cells resulting in infection, bleeding, cancer risks, etc.

NKTR-358: Growing the Body’s Own Population of T-Reg Cells to Treat Auto-Immune Disease

22

Restore balance and normalize

T-reg cell and T-effector cell

function

What if you could grow the body’s own population of T-reg cells and directly treat

the underlying disease pathology?

NKTR-358 is Selective for Enhancing of T-RegProliferation and Activation in Non-Human Primates

23

• Single dose NKTR-358 produced greater Treg expansion than repeat low-dose IL-2• In mice, NKTR-358 treatment promotes >30-fold increase in Treg suppressive activity

TeffTreg

Dosing

NKTR-358 could be a superior approach to treating multiple auto-immune diseases including lupus, transplant, rheumatoid arthritis, Crohn’s disease and psoriasis

1M + 1F cynomolgus monkey per treatment, both agents given at 0.025 mg/kg – single dose SC for NKTR-358 vs QDx5 SC for IL-2.

Dosing

Fold Change in Treg and Teff T-Reg Activation Markers

NKTR-358 Suppresses Disease Progression in a Mouse Model of Systemic Lupus Erythematosus

24

MRL/MpJ-Faslpr model (N=15/group), NKTR-358 given SC twice weekly at 0.3 mg/kg from Week 8 – 20, beginning on 30Nov2016.Mouse protein levels in urine measured by standard methods. In-life completed on 23Feb2017, additional measures ongoing.

Pro

tein

Le

ve

l (g

/L)

3 0 -No v -1

6

7 -De c -1

6

1 4 -De c -1

6

2 1 -De c -1

6

2 8 -De c -1

6

4 -Ja n -1

7

1 1 -Ja n -1

7

1 8 -Ja n -1

7

2 5 -Ja n -1

7

1 -Fe b -1

7

8 -Fe b -1

7

1 5 -Fe b -1

7

2 2 -Fe b -1

70

1

2

3

SLE + Vehicle

SLE + NKTR-358

Normal Mouse Control

Protein Levels in Urine

NKTR-358: Phase 1/2 Clinical Development

25

H1 2017 2H 2017

Initiate Phase 1b Multiple Ascending Dose Trial in

Lupus (SLE) Patients

Multiple SQ Doses of NKTR-358 (n ~50)

• 3:1 randomization vs. placebo• Evaluate changes in T-reg cells

and activation markers• Establish P2 doses

Phase 1 Single Ascending Dose Trial in

Healthy Subjects

Single SQ Dose of NKTR-358(n ~50)

• Evaluate changes in T-regcells (number) and activation markers (function)

• Evaluate PK/PD to determine dosing for multiple dose trial

Data expected in 2H 2017

Additional Phase 1/2 trials in other immune disorders are

being explored• Allergy• GVHD• Crohn’s disease• Ulcerative colitis

Data expected in Q3/Q4 2018

• Rheumatoid arthritis• Type-1 diabetes• Multiple sclerosis• Psoriasis

• Dose first patients in Phase 1 PROPEL dose-escalation trial of NKTR-214 in combination with Tecentriq in patients with NSCLC and bladder cancer

• Potential European approval and launch for ADYNOVATE™ in hemophilia A (Partner Shire)

• Continuing data from PIVOT clinical trial of NKTR-214 with Opdivo in patients with melanoma, non-small cell lung cancer, renal cell carcinoma, triple-negative breast cancer, bladder (Ongoing)

• CHMP opinion regarding conditional market authorization for ONZEALD in Europe (Partner Daiichi Sankyo)

• Topline data from Amikacin Inhale Phase 3 Program in gram-negative pneumonia (Partner Bayer)(Q3)

• Data from Phase 1a clinical trial of NKTR-358; initiate potential Phase 1b clinical trial of NKTR-358 in lupus

• File IND for immuno-oncology candidate NKTR-262

2017 Anticipated Milestones

26