Jefferies 2015 Global Healthcare Conference

Howard W. Robin

President & CEO

June 2, 2015

This presentation includes forward-looking statements regarding Nektar’s

technology platform, drug candidates, clinical and regulatory objectives,

market opportunity estimates, and royalty and milestone payment 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-K filed on February 26, 2015 and Form 10-Q filed on May 1, 2015. Nektar

undertakes no obligation to update forward-looking statements as a result of

new information or otherwise.

Two Key Products Approved or Filed Nine Clinical and Preclinical

Drug Candidates

Nektar Therapeutics: Building a Sustainable Biopharma Company

3

Partnered Portfolio Wholly-Owned Drug Candidates

NKTR-181Abuse-deterrent

Opioid NCE

NKTR-102Metastatic Breast Cancer

NKTR-214Cancer Immunotherapy

NKTR-171Neuropathic Pain

NKTR-195Kappa Agonist

Movantik™Approved &

launched

BAX 855Filed (US)

Amikacin Inhale Cipro DPI

Fovista® PEGPH20

NKTR-218IDO inhibitor

NKTR-255IL-15 Cancer

Immunotherapy

NKTR-223Peptide Antibiotic

NKTR-173Neuropathic Pain

Four Phase 3 Candidates

U.S. Launch of Movantik™ (naloxegol) by

AstraZeneca & Daiichi Sankyo

First once-daily oral PAMORA tablet to treat

opioid-induced constipation

• 12.5 mg and 25 mg tablets priced at $8.32/day

Significant sales efforts underway with positive

physician reception

• AstraZeneca and Daiichi Sankyo co-promoting in

U.S. with AZ recording all revenues

• 1000+ sales reps (primary care and specialty care)

Product sampling began with launch

Direct-to-consumer (DTC) campaigns designed to

reach high number of OIC patients

• First unbranded campaign began in May

• Partnering with Olympic Medalist Jackie Joyner-

Kersee as OIC spokesperson

• Branded DTC advertising to commence following

educational campaign

4

Source: 2013 IMS, Global Data – Reflects patients on opioid regimens for greater than 30 days

U.S. OIC Patient Population38M Chronic, Non-Cancer Pain Patients on Opioid Regimens

38M chronic, non-cancer

pain patients taking

opioids in the U.S.

• A common side effect is

constipation

• At least half do not benefit

from existing therapies

PCPs + Pain Specialists

write ~75% of chronic

opioid prescriptions

5

U.S. Opioid Prescribers

by Specialty

Primary Care

Physicians

(PCPs)includes

Physician Assistants /

Nurse Practitioners

Pain

Specialists

Other

Specialties

2011 Opioid Patients: Global Data reported October 2013

EU OIC Patient Population:12M Chronic Pain Patients on Opioid Regimens in EU-5

12M chronic pain patients

in the European Union

EU label includes both

non-cancer and cancer

pain patients

6

Chronic Pain Patients Receiving

Opioid Medications

UK2.1M

France1.9M

Germany3.8M

Italy1.3M

Spain2.8M

Significant Economics to Nektar on Global

Sales of Movantik

7

www.movantik.com

EU launch planned in Q3 2015

• Approval for treatment of adult patients with OIC who

have had an inadequate response to laxative(s)

AstraZeneca responsible for all development,

regulatory and commercial activities

Economics to Nektar

• $100 million milestone for U.S. launch (received Q1)

• $40 million milestone for first major EU country launch

• U.S. tiered escalating royalty on net sales starting at

20%

• EU and ROW tiered escalating royalty on net sales

starting at 18%

• Plus an additional $375 million in sales milestones at

various annual sales levels

Source: Evaluate Group: Factor VIII Top 10, 2014

BAX 855: Longer-Acting ADVATE®

for Hemophilia A

Baxter submitted US BLA in December 2014

• Approval and launch planned for Q4 2015

Designed to expand Baxter’s leadership

position as a longer-acting therapy based

upon ADVATE, the gold standard treatment

for hemophilia A

Positive topline Phase 3 data reported by

Baxter

• Primary endpoint achieved

• No treatment-related SAEs and no inhibitors

Nektar entitled to receive:

• Up to $84 million in development

and sales milestones

• Royalties in mid-single digits up to $1.2B

• Royalties in low teens > $1.2B0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

Sale

s ($

USD

Billio

ns)

8

Projected Growth in

Factor VIII MarketAll Factor VIII Products

Bayer

Pfizer

CSL Behring

Other/Biogen

$6.5B

$7.6B

Growth

drivers:

Primarily

long-acting

prophylaxis

Global

expansion

2014

Actual

2020

Estimate

Source: Nektar internal estimates

Nektar-Bayer Anti-Infective Programs:

Phase 3 Data Anticipated in 2016

Both products granted Qualified Infectious Disease Product (QIDP)

Designation from FDA

Eligible for fast-track, priority review & 5-year extension of market exclusivity

9

Amikacin Inhale Cipro DPI

Gram-Negative Pneumoniain Ventilated Patients

Non-Cystic Fibrosis Bronchiectasis

(NCFB)

Phase 3

Program

SPA in place for Phase 3 Program

Primary endpoint: clinical response at

test of cure visit (10-day treatment period)

Phase 3 RESPIRE program features

two 48-week multinational,

randomized, placebo-controlled

studies in NCFB

Nektar Royalties

on Net Sales

30% flat (U.S.)

22% average (ex-U.S.)10% average

Global Market ~ $700 million* ~ $750 million*

Source: IMS MIDAS; Decision Resources

NKTR-181: New Opioid Molecule

for Chronic Pain in Phase 3

NKTR-181 designed to target

chronic pain market

with a novel opioid:

Slow rate of entry into CNS

designed to reduce abuse liability

Plasma PK profile supports BID

dosing

Properties inherent to molecule

Received Fast Track Status from FDA

10

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

Osteoarthritis

Fibromyalgia

Neuropathic pain

Slow brain entry inherent to molecular structure,

and not a result of a formulation approachSource: 1) Kharash et. al, Clinical Pharmacology and Therapeutics, 2006 (Table IV - t1/2 eO, effect site equilibration half-life);

2) Nektar Therapeutics, Data from Phase 1 Multiple Ascending Dose Study of NKTR-181 (t1/2 eO, effect site equilibration half-life)

Human Studies Demonstrate that NKTR-181

Enters the Brain Slowly

11

OxycodonePlasma to CNS Equilibration1

NKTR-181Plasma to CNS Equilibration2

2.9 Hours

Pla

sma C

on

cen

trati

on

Pla

sma C

on

cen

trati

onP

up

il Co

nstrictio

n

Pu

pil C

on

striction

Plasma Drug

Concentration

Pupil Constriction

11 Minutes

NKTR-181 Achieves Maximum Pupil Diameter

Reduction Comparable to Oxycodone

12* Benzinger et al, J Pain Symptom Management, (1997) 13;75

** Webster et al, Substance Abuse and Rehabilitation, (2012) 3;101

Maximum CNS

opioid responses

are comparable to

those reported for

oxycodone

Indicates that

NKTR-181 can

elicit substantial

CNS opioid effect

NK

TR

-18

1

NKTR-181: Phase 3 Registrational Program

Underway

First efficacy study underway in opioid-naïve patients with

chronic low back pain (SUMMIT-07)

Second efficacy study planned in opioid-experienced

patients with chronic low back pain (SUMMIT-12)

Long-term (52-week) safety study (SUMMIT-LTS) initiated

Human abuse liability studies planned to support

scheduling and labeling

13

SUMMIT-07: First Phase 3 EERW Study in

Patients with Chronic Lower Back Pain

14

21 days2 – 7 weeks

Including 1 week at stable dose12 weeks

Opioid Naïve

Patients w/

Chronic Low

Back Pain NKTR-181 BID (mg) Base

lin

e

Primary Endpoint:

• Change in Weekly

Pain Score

(0-10 NRS)

Secondary Endpoints:

• 30% responder

analysis

• Patient Impression of

Change

100 200 300 400PLACEBO (n=208)

NKTR-181 (n=208)

1:1 Randomization

Single interim analysis for sample size

reassessment to occur Q3/Q4 2016

Must Achieve Substantial and

Sustained Pain ResponseNo Background Analgesics

NKTR-102: Highlights from ASCO 2015

NKTR-102 prolonged median OS by 2.1 months (p=0.08) in late-stage

metastatic breast cancer patients

Significant prolongation of median OS in pre-specified subgroups

• Patients with brain metastases prolongation by 5.2 months (p<0.01)

• Patients with baseline liver metastases prolongation by 2.6 months

(p<0.002)

NKTR-102 has fewer grade 3 or higher toxicities (48% vs

63%; p<0.001) with convenient “every 3 week” schedule

Quality of life is improved with NKTR-102 compared with treatment

of physician’s choice

15

Using BEACON data, we are pursuing potential paths forward for

NKTR-102 in metastatic breast cancer with both US and EU

regulatory authorities

Source: Adapted from Mellman, Ira, George Coukos and Glenn Dranoff. "Cancer Immunotherapy Comes of Age." Nature 480.7378 (2011): 480-89

NKTR-214: A CD122-Biased Cytokine to

Stimulate the Immune System

16

CD28

OX40

GITR

CD122

CD27

CD360

HVEM

CD137

CTLA-4

PD-1

TIM-3

BTLA

VISTA

LAG-3

Immune-Stimulating

ReceptorsInhibitory Receptors

CTLs

CD8+ Memory T-Cells

b

1. Wang et al., Science Vol 310 18 Nov. 2005

IL-2 Receptor is an Attractive Cancer Target

but Has Pleiotropic Opposing Effects

17

Structure of the human IL-2/Rb

quaternary signaling complex.1

CD4+ Regulatory T-Cells

Tregs b

IL-2

IL-2R

IL-2

Stimulates Immune

Response to Kill

Tumor Cells

Down-Regulates

Proliferation of CD8+ T-cells

and Suppresses Immune

Response

NKTR-214: Biasing Action to CD 122, or IL-2R Beta,

to Stimulate T-Cell Production

18

NKTR-214

CTLs

CD8+ Memory T-Cells

b

CD4+ Regulatory T-Cells

Tregs b

NKTR-214

IL-2R

Stimulates Immune

Response to Kill

Tumor Cells

Down-Regulates

Proliferation of CD8+ T-cells

and Suppresses Immune

Response

19

IL-2 Treated Tumor NKTR-214 Treated Tumor

CD8+ Memory T-cells

B16F10 mouse melanoma model; Representative images five days after a single dose of NKTR-214 or after 5 doses of aldesleukin; cells stained with anti-CD8 antibody

NKTR-214 Results in Proliferation of CD8+ Memory

T-Cells Within the Tumor Microenvironment

6 to 8 Fold Increase in CD8+ Memory T-cellsTumor Cells

Synergistic Response with NKTR-214 &

Anti-PD-1 Combination in Mouse Colon Cancer Model

20

CT-26 (Colon)

Source: Nektar Therapeutics. CT-26 Colon Model, End Points: Tumor Volume Growth to 400% Deep Tumor Lesion, N=12; Dosing: NKTR-214: 0.8 mg/kg Q9Dx3;

Anti CTLA-4: 100 µg; Anti PD1: 200 µg; NKTR-214, 0.8 mg/kg (Day 4) + Anti PD1 200 µg (Day 0); Anti CTLA-4, 100 µg (Day 0) + Anti PD1, 200 µg (Day 0)

NKTR-214 in Combination with Anti-CTLA-4:Long-term Immunity in Mouse Model Following Multiple Tumor Rechallenges

21*Anti-CTLA-4, 100 μg x 5 q2w (Day 0) + NKTR-214, 0.8 mg/kg Q 9Dx3 (Day 4)

TREATMENT

PERIOD

Treated44% Complete

Responses (CR)

Established EMT6

breast tumors

2nd Tumor Implant

into CR Mice

Rechallenged70% Remained

Tumor Free

3rd Tumor Implant

into Tumor Free Mice

Rechallenged100% Remained

Tumor Free

NO ADDITIONAL TREATMENT

Control

Anti-CTLA-4 +

NKTR-214*

Phase 1 / 2 Clinical Study of NKTR-214:

New Collaboration with MD Anderson

Collaboration led by Dr. Patrick Hwu, Division Head of Cancer

Medicine at MD Anderson

Phase 1/2 single-agent clinical study of NKTR-214 to start 2H 2015

• Dose escalation cohorts enrolling advanced cancer solid tumor

patients in groups of 3 (Bayesian Model)

• Dose expansion cohort with NKTR-214 as single-agent in renal cell

carcinoma and melanoma

• Additional combination cohorts to include checkpoint inhibitors

and/or other inhibiting agents

MD Anderson and Nektar to collaborate on translational preclinical

research to identify predictive biomarkers

22

Nektar R&D Pipeline

23

Program Preclinical Phase 1 Phase 2 Phase 3 Filed Approved

Late

-Sta

ge /

Filed

MOVANTIK™(naloxegol) (OIC)

BAX 855 (Hemophilia A)

NKTR-102 (Breast Cancer)

Amikacin Inhale (Ventilator Pneumonia)

Ciprofloxacin DPI (Bronchiectasis)

FOVISTA® (Neovascular AMD)

NKTR-181 (Chronic Pain)

Earl

y/M

id-S

tag

e NKTR-102 (IST-High Grade Glioma)

NKTR-102 (IST-Small Cell Lung Cancer)

NKTR-102 (IST-Non-small Cell Lung Cancer)

PEGPH20 (Pancreatic Cancer)

NKTR-171 (Neuropathic Pain)

NKTR-119 (Naloxegol + Opioid)

Pre

clin

ical

NKTR-214 (Cancer Immunotherapy)

NKTR-255 (IL-15 Cancer Immunotherapy)

NKTR-218 (IDO Inhibitor)

NKTR-195 (Kappa Agonist)

NKTR-173 (Neuropathic Pain)

NKTR-223 (Peptide Antibiotic)

FDA/EU Approved

BLA Filed December 2014

Jefferies 2015 Global Healthcare Conference

Howard W. Robin

President & CEO

June 2, 2015