Science-Based Innovation-Focused ADC Company

Corporate Overview June 2018 Forward-Looking Statements

This presentation, in addition to historical information, contains certain forward- looking statements made pursuant to the Private Securities Litigation Reform Act of 1995. Such statements may involve significant risks and uncertainties, and actual results could differ materially from those expressed or implied herein. Factors that could cause such differences include, but are not limited to, new product development (including clinical trials outcome and regulatory requirements/actions); competitive risks to marketed products; forecasts of future operating results; availability of required financing and other sources of funds on acceptable terms, if at all; as well as those discussed in the Company's filings with the Securities and Exchange Commission.

2 Our Company Vision for Value Creation

Immunomedics is deeply committed to become the leading antibody-drug conjugate (ADC) company worldwide delivering breakthrough therapies to treat complex cancers and transform patient outcomes

3 First-in-class ADC Platform

Suite of Humanized Antibodies for Creating ADCs 1. hRS7, used in sacituzumab govitecan, targets Trop-2 for solid cancers 2. Labetuzumab, used in IMMU-130, targets CEACAM5 for colorectal cancer 3. IMMU-114, used in IMMU-140, targets HLA-DR for solid and liquid cancers Linker for SN-38

Linker for SN-38 SN-38 Payload 1. Hydrolysable linker for payload 1. SN-38 more potent than release parent compound, irinotecan 2. High drug-to-antibody ratio (7.5:1) 2. In xenograft models, ADC delivers up to 136-fold more SN-38 than irinotecan

4 Sacituzumab Govitecan, an Antibody-Drug Conjugate for Targeted Drug Delivery to Solid Cancers

• Target: Trop-2 Trop-2 expression in TNBC liver – Pan-epithelial cancer antigen with broad tumor biopsy expression in many different cancers – ≥80% of patients have moderate to strong expression by immunohistochemistry – Internalizes upon antibody binding - ideal target for drug delivery with antibody-drug conjugates

• Antibody: Humanized RS7-3G11 – Binds human breast, lung, colon, renal, prostate, urothelial, and many other solid cancers

5 Significant Progress with Sacituzumab Govitecan vs. Key Milestones

• Submission of BLA for metastatic triple-negative breast cancer (mTNBC) on May 18, 2018

• Oral ASCO presentation of Phase 1/2 study in estrogen receptor-positive metastatic breast cancer (ER+ mBC)

• Initiation of pivotal Phase 2 TROPHY U-01 study in metastatic urothelial cancer (mUC)

• Announcement of clinical partnership with Clovis to develop the combination of sacituzumab govitecan and rucaparib in mTNBC and mUC

• Implementation of protocol changes under revised SPA to further improve probability of success for ongoing Phase 3 ASCENT study in 3rd-line mTNBC

• Launch preparation underway, commercial manufacturing on track to meet demand

6 Building a Blockbuster Brand in Oncology

Line of Therapy Cancer Types 3rd Line+ 2nd Line 1st Line (Neo)Adjuvant

Mono/ Mono mTNBC Mono CPI combo PARPi combo CPI combo Cisplatin- eligible Mono +PARPi CPI combo mUC Cisplatin-ineligible Mono Mono +PARPi CPI combo

ER+ mBC Mono

NSCLC Mono/CPI combo

Ongoing Planned Evaluating

7 Sacituzumab Govitecan in Metastatic Triple-Negative Breast Cancer Low Response Rates in Pre-treated mTNBC*

Drug Phase N Population ORR (%) PFS (mos) OS (mos) 1st line treatment

Carboplatin1 3 188 1st line 31 3.1 12.4

Docetaxel1 3 188 1st line 36 4.5 12.3

Cisplatin/ 2 86 1st line (80.2%) 25.6 2.9 11.0 Carboplatin2 >1st line treatment Resistant to anthracycline, 2 (pooled Ixabepilone3 60 cyclophosphamide & taxane or 6 - 17 1.6 - 2.7 -- analysis) taxane only 3 (pooled Prior or resistant to anthracycline Capecitabine3 208 15 1.7 -- analysis) & taxane

3 (pooled Eribulin4 199 > 1 prior chemo 11 2.8 12.4 analysis)

* Includes breast cancer drugs with data from Phase 2/3’s with minimum mTNBC sample size > 60; ORR and PFS data Source of data: 1) Tutt A, SABCS 2014; 2) Isakoff SJ, J Clin Oncol 2015; 3) Perez EA, Breast Can Res Treat 2010; 4) Pivot X, Ann Oncol 2016

9 Adverse Events (Regardless of Causality)

Body system Adverse event All grades Grade 3 or 4 Neutropenia 63% 41% Febrile neutropenia 8% 7% Hematologic Anemia 52% 10% Leukopenia 24% 14% Nausea 63% 5% Diarrhea 56% 8% Gastrointestinal Vomiting 46% 5% Constipation 32% 1% Fatigue 50% 7% Alopecia 36% NA Decreased appetite 30% 0% Other Hyperglycemia 23% 4% Hypomagnesemia 21% 1% Hypophosphatemia 15% 8% Includes all events >20% (all grades) or >5% (grade 3 or 4); NA = not applicable • Adverse events were managed with supportive medication or dose modifications – 25% of patients had dose modifications predominantly to 7.5 mg/kg • Two patients (1.8%) discontinued due to adverse events (grade 3 transient infusion reaction/grade 2 fatigue) • There were no treatment-related deaths

10 Sacituzumab Govitecan in Late-Line mTNBC

108 patients in BLA Percent Reduction in Baseline Target Lesions* • Patients received ≥3rd prior line for metastatic disease: 100% • ORR: 33% (local), 32% (BICR) • Median DoR: 8.3 months (local), 6.7 months (BICR) • Median PFS: 5.5 months (local) * Two patients did not meet the criteria of two prior therapies for metastatic disease and were not included in the BLA package

11 Amended ASCENT Phase 3 Study (under SPA): Overview

mTNBC Sacituzumab govitecan (ASCO/CAP) 10 mg/kg IV d1 & 8, every 3 wks R/R after ≥2 prior SOC chemo N = 488 for advanced disease Continue treatment OR until progression Stratification Treatment of physician choice 1 therapy for advanced Factors • Capecitabine disease who also progressed • Eribulin • # prior therapies within 12 months of • Gemcitabine o o • Geography 1 Endpoint 2 Endpoints (neo)adjuvant therapy • Vinorelbine • +/- known BM • PFS ( BM-) • OS (BM-) (15% cap) • PFS (ITT) • OS (ITT) • First patient dosed in November 2017 in U.S. • SPA protocol accepted by EU regulatory authority • Clinical trial accruing globally

National Institutes of Health. https://clinicaltrials.gov/ct2/show/NCT02574455. Accessed March 14, 2018.

12 Triple-Negative Breast Cancer

Stage 1, 2 and 3 (resectable)

Neoadjuvant

Potential for CPI or other combo Adjuvant

Stage 3 locally advanced (unresectable), Stage 4 metastatic

st Phase 1/2 CPI combo 1 Line (10-11k Pts) Phase 2 single arm

Phase 2 single arm 2nd Line (9-10k Pts) Phase 1/2 PARPi combo

3rd Line+ BLA submitted (8-9k Pts) Phase 3 confirmatory “ASCENT”

Evaluating Planned Ongoing 13 Sacituzumab Govitecan in Advanced Urothelial Cancer Low Response Rates in Relapsed / “Refractory” mUC

Treatment Phase ORR PFS (months) OS (months) Source

Historical ~10% 3 4-9

Bellmunt Vinflunine 3 8.6% 3.0 6.9 J Clin Oncol 2009

Petrylak D Docetaxel 2 8.9% 2.8 9.2 J Clin Oncol 2016

Docetaxel + Petrylak D 2 24% 5.4 10.4 Ramucirumab J Clin Oncol 2016 Petrylak D Docetaxel 3 14% 2.8 Not Reported Lancet 2017

Docetaxel + Petrylak D 3 24.5% 4.1 Not Reported Ramucirumab Lancet 2017

15 Sacituzumab Govitecan in ≥2nd Line mUC

41 patients enrolled Percent Reduction in Baseline Target Lesions

• Median number of prior e n

i 6 0 C o m p le te re s p o n s e l

e P a rtia l re s p o n s e

lines: 3 (range, 1‐6) s S ta b le d is e a s e

a 4 0 b • ORR: 34% (14/41) P r o g r e s s io n

m 

2 0  P rio r c h e c k p o in t in h ib ito r T x e

o 

r

s

f

D D – Prior CPI: 29% (4/14)

n 

S

P L

o 0

T 

p

• Median duration of    s

n 

i e

-2 0

e R

response: 12.6 months  g

t  n

s -4 0 a

e 

(95% CI: 7.5, 12.9) h 

B c

-6 0 %

• Clinical benefit rate t  s -8 0 (CR+PR+SD≥6 months): e 72% (26/36) of patients with at least one CT response B assessment had reduction of target lesions (sum of diameters) 49% -1 0 0

Tagawa et al, Annals of Oncology (2017) 28 (suppl_5): v295-v329. 10.1093/annonc/mdx371

16 mUC Phase 2 Pivotal TROPHY U-01 Study Overview

mUC Cohort 1: 3rd line post platinum- Cohort 1: N = 100 Sacituzumab govitecan and PD-1/PD-L1 based therapies Continue treatment until 10 mg/kg IV progression OR Cohort 2: N = 40 d1 & 8, every 3 wks Cohort 2: 2nd line for cisplatin- ineligible patients 1o Endpoint 2o Endpoints • ORR • DoR (BICR) • PFS • OS

• Patients will be enrolled across 60 sites in North America and Europe

17 Metastatic Urothelial Cancer

Cisplatin eligible Cisplatin ineligible

st st 1 Line 1 Line Potential for CPI combo (8-10k Pts) (10-12k Pts)

2nd Line 2nd Line Phase 1/2 PARPi combo TROPHY U-01 Study Potential for CPI combo (6-7k Pts) (7-8k Pts)

3rd Line+ 3rd Line+ Phase 1/2 PARPi combo (3-4k Pts) TROPHY U-01 Study (3-4k Pts) TROPHY U-01 Study

Ongoing Evaluating Planned 18 Sacituzumab Govitecan in ER+/HER2– Metastatic Breast Cancer Estrogen-Receptor Positive/HER2-Negative mBC

• Most common form of mBC in the U.S. U.S. Stage 4 Breast Cancer Prevalent Population Distribution by Subtype (SEER) • Treatments involve: – Initially endocrine-based therapies, including CDK 4/6 inhibitors 13% – Subsequently chemotherapy, but response ER+/HER2neg 9% ER+/HER2+ rates to later-line therapies are low ERneg/HER2+ TNBC 61% • Poor prognosis for patients with visceral 17% metastases • New therapeutic options needed for treatment-refractory ER+/HER2– mBC

20 Low Response Rates to Chemotherapy in Pre-Treated mBC

PFS OS Drug N* Population HR+ % ORR % Source (months) (months)

Prior A, T and Ixabepilone 126 52 18.3 3.1 8.6 Perez EA capecitabine JCO 2007 Prior A, T Kaufman PA Capecitabine 548 ≤ 3 prior chemo (incl. 47 19.9 4.2 14.5 JCO 2015 adjuvant) Capecitabine Twelves C, Breast 219 Idem 100 NA 5.3 16.8 Cancer Research, ER+ subgroup 2016 Eribulin Twelves C, Breast 198 Idem 100 NA 4.3 18.2 Cancer Research, ER+ subgroup 2016 Prior A and T Eribulin 508 64 13 3.7 13.1 Cortes J ≥2 prior chemo Lancet 2010

Vinorelbine 115 Prior A, ≤ 2 lines 51 13 3** 7.5 Jones JCO 1995 A: Anthracycline; T: Taxane. *N represents mBC population which includes HER2+ and/or TNBC; ORRs are based on local review. ** TTF 21 Single-Arm, Open-Label Study Design

Sacituzumab govitecan Continue treatment ER+/HER2– mBC 10 mg/kg IV until progression/ at last biopsy d1 & 8, every 3 wks unacceptable toxicity

Key Eligibility Criteria Evaluations • Adults, ≥18 years of age • Response by local assessment • ECOG: 0-1 (RECIST v1.1) • ≥1 prior metastatic therapies • Other: safety • Measurable disease

22 Demographics and Patient Characteristics (N=54)

Female/male, n 54/0 Taxane – any setting 93% Median age, years (range) 54 (33-79) Anthracycline – any setting 69% ECOG performance status 0 35% CDK 4/6 inhibitors 69% 1 56% mTOR inhibitors 54% Missing 9%

Median time from metastatic disease to Prior chemotherapy for metastatic disease 3.50 study entry, years Fluoropyrimidine agents 80% Taxane 57% ≥ 1 prior chemotherapy line for metastatic disease 98% Eribulin 33% Platinum agents 24% Median number of metastatic chemotherapy lines 2 (0-9)* Median number of metastatic hormonal therapy lines 3 (1-6)* Sites of metastatic disease at study entry** Median number of prior metastatic treatment lines 5 (2-17)* Bone 80% Liver 82% Hormonal therapy for metastatic disease 100%* Chest 37% ≥ 3 lines of hormonal therapy for metastatic disease 67%* Lung 31%

*Includes lines of therapy given in the (neo)adjuvant setting if patient became metastatic within 12 months (N=4) **Metastatic sites in >20% patients; 89% (48/54) of patients had liver or lung metastases 23 Adverse Events (Regardless of Causality) All events >20% or Grade 3+ >5%

Body system Adverse event (AE) All grades* Grade 3 or 4* • AEs managed with supportive Neutropenia 64% 42% medication or dose modifications Febrile neutropenia 2% 2% Hematologic – 28% received growth factor support Anemia 36% 6% Leukopenia 16% 8% • 22% of patients had dose reduced to Nausea 58% 2% 7.5 mg/kg; 9% occurring in 1st cycle Diarrhea 40% 4% Gastrointestinal Vomiting 38% 4% • Two patients (3.7%) discontinued due to Constipation 30% 0% AEs (grade 3 neutropenia not recovered within 3 weeks; grade 3 diarrhea/ Fatigue 46% 2% dehydration) Alopecia 36% NA Decreased appetite 28% 0% Other • No treatment-related deaths Cough 22% 0% Alk Phos increase 20% 6% Hypophosphatemia 16% 8% ** AE frequency based on the available reporting of 50/54 pts. AE data for the remaining 4/54 patients are being collected

24 Tumor Response to Sacituzumab Govitecan

4 0 Local Response Evaluation by RECIST1.1

) e

n Objective response rate 31% (17/54)

i l

e CR 0

s 2 0 a

b PR 17

m

e

o s

r Clinical benefit rate f

0 48% (26/54) n

n (CR+PR+SD ≥6 months)

o

o

i

p s

s +

e

l

e

t -2 0 • 63% (34/54) of patients with at least e

R +

g t

r one CT response assessment had

+

a s

t +

e reduction of target lesions (sum of n

i -4 0 B + + e P a rtia l re s p o n s e diameters)

g +

n S ta b le d is e a s e + + a • Median number of metastatic chemo h -6 0 c P r o g r e s s io n + lines: 2

% + ( 6 p ts w ith o u t C T a s s e s s m e n t a re n o t s h o w n -8 0 + C o n tin u in g tre a tm e n t • Median number of prior metastatic lines: 5

25 Response Onset and Durability (N=17)

// (2 6 .1 ) • Median duration of response: 7.4 months (95% CI: 4.4, 18.3)

• Median time to onset of response:

N o p rio r C D K 4 /6 2.3 months (range: 1.5-7.8) in h ib ito r

P rio r C D K 4 /6 in h ib ito r • 7 responders were still receiving

C o n tin u in g sacituzumab govitecan at last O n s e t o f re s p o n s e assessment

0 4 8 1 2 1 6 Best response under RECIST 1.1, as per local assessment M o n th s fro m s ta rt o f s a c itu z u m a b g o v ite c a n

26 Progression-Free Survival (PFS)

100 Based on Local Assessment using RECIST 1.1 80 Median PFS, months 6.8 60 (95% CI) (4.6, 8.9)

40 • 32 patients had objective progression (maturity = 59%) • 10 patients are continuing

Survival probability (%) probability Survival 20 • 12 other patients censored – 5 with no CT assessment were censored at baseline 0 – 1 withdrew at 0.7 months after leaving 0 4 8 12 16 20 24 28 study with AE Months – The remaining censored pts left study with Number at risk their last response assessment SD or better 49 29 13 3 2 1 1 0

27 Response to Sacituzumab Govitecan in Subgroups

ORR, % (n/N) ORR, % (n/N)

Overall 31% (17/54) Onset of metastatic disease from diagnosis < 1 year 15% (2/13) Age ≥ 1 year 37% (15/41) <65 29% (12/42) ≥65 42% (5/12) ≥ 2 prior chemo for metastatic disease* 29% (12/41) < 2 prior chemo for metastatic disease* 38% (5/13) Visceral involvement at study entry (Liver/Lung) ≥ 3 prior hormonal therapies for metastatic Yes 25% (9/36) 27% (13/48) disease* No 67% (4/6) < 3 prior hormonal therapies for metastatic 44% (8/18) disease* Liver involvement 27% (12/44)

Clinical Benefit Rate in patients with liver Prior CDK 4/6 inhibitors 24% (9/37) involvement (CR+PR+SD ≥6 months) 48% (21/44) No prior CDK 4/6 inhibitors 47% (8/17)

**Includes lines of therapy given in the (neo)adjuvant setting if patient became metastatic within 12 months (N=4)

28 ER+/HER2– Breast Cancer

Stage 3 locally advanced (unresectable), Stage 4 metastatic

Endocrine & CDK 4/6i Therapy

1st Line Chemo (30-33k Pts)

2nd Line Chemo Pivotal study (26-28k Pts)

3rd Line Chemo (24-26k Pts)

Evaluating Planned Ongoing 29 Additional Corporate Information Broad Pipeline of ADC Therapies

Research/Preclinical Phase 1 Phase 2 Phase 3 FDA Review Registration

First-in-Class Antibody-Drug Conjugate (ADC) Programs Sacituzumab govitecan/IMMU-132 (anti-Trop-2-SN-38 ADC) Metastatic triple-negative breast cancer (FDA granted BTD) BLA Metastatic urothelial cancer Pivotal Metastatic ER+/HER2- breast cancer Solid tumors IITs

Labetuzumab govitecan/IMMU-130 (anti-CEACAM5-SN-38 ADC) Metastatic colorectal cancer

IMMU-140 (anti-HLA-DR-SN-38 ADC) Solid and liquid cancers

Other Product Candidates include Epratuzumab, Veltuzumab, Milatuzumab and IMMU-114 for Oncology and Autoimmune Disease Indications

31 Sufficient Cash Runway to Pursue Strategic Priorities

Cash balance as of 3/31/2018 $359 Million

Net proceed from equity offering (6/2018) $260 Million

Pro forma cash balance as of 3/31/2018 $619 Million

Debt (convertible senior notes) $20 Million

Pro forma basic shares outstanding (fully diluted) 179 (202) Million

32