Omadacycline in Acute Skin and Skin Structure Infections Study (OASIS) A Phase 3 Randomized, Double-Blind, Multi-Center Study to Compare the Safety and Efficacy of Oral and IV Omadacycline to Linezolid for Treating Adult Subjects with ABSSSI 16 June 2016 ABSI-1108 Study Design: Top-Line Data Results 1

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Omadacycline SPA-Approved Phase 3 Trial Design for ABSI (OASIS) [1] 655 Randomized Subjects, 10 subjects were randomized, but never treated [2] Early Clinical Response = primary end point for FDA. [3] PTE end point = Co-primary end points confirmed through EMA scientific advice. d2-3 FDA - Early Clinical Response [2] d7 to d14 End of Treatment d1 Omadacycline IV Omadacycline IV or Oral Linezolid IV Linezolid IV or Oral ABSSSI 645 treated subjects [1] 7-14d after last treatment day EMA - Post-Treatment Evaluation [3] 3

Key Populations: –Safety population  Subjects who received test article –Modified Intent-to-treat (mITT) population  Randomized subjects without a sole Gram-negative causative pathogen –Clinically evaluable (CE) population  mITT subjects who had a qualifying ABSSSI, PTE assessment, and met other key evaluability criteria (e.g., had no potentially confounding antibacterial therapy or surgical procedures) Key Populations 4

Demographics and Baseline Characteristics 5

Key Populations ITT: all subjects who were randomized Safety: subjects who received test article mITT: randomized subjects without a sole Gram-negative causative pathogen at Screening CE-PTE:mITT subjects who received test article, had a qualifying ABSSSI, an assessment of outcome at PTE, and met other key evaluability criteria (e.g., had no potentially confounding antibacterial therapy or surgical procedures) 6

Safety Population Demographics 7

Primary ABSSSI Infection Type at Baseline (mITT Population) 8

Clinical Efficacy Results 9

Primary Endpoints Achieved for Both FDA and EMA EMA Co-Primary Endpoints Delta (95% CI) -0.7 (-6.9, 4.9) Delta (95% CI) +2.5 (-3.2, 8.2) Delta (95% CI) +2.8 (-1.0, 6.9) 10 FDA Primary Endpoint

Safety Results 11

Premature Discontinuation – Safety Population 12

Overview of Adverse Events – Safety Population 1 TEAE is defined as an AE occurring after first dose of active test article. 13

Most Frequent TEAEs (> 3%) – Safety Population 1 Nausea: Omadacycline = 87.5% mild,12.5% moderate; Linezolid = 78.1% mild, 21.9% moderate 2 Events were reported as IV site infiltration, typically due to difficulty in finding reliable venous access sites. All events were mild. All but 3 subjects (2 omadacycline and 1 linezolid) had a history of drug abuse. Among these subjects, 79% in each treatment group had ABSSSI considered related to intravenous drug use. 14

Infusion Site Reactions – Safety Population 1 Events were reported as IV site infiltration, typically due to difficulty in finding reliable venous access sites. All events were mild. All but 3 subjects (2 omadacycline and 1 linezolid) had a history of drug abuse. Among these subjects, 79% in each treatment group had ABSSSI considered related to intravenous drug use. 2 MedDRA preferred terms = infusion site pain, infusion site erythema, infusion site irritation, infusion site discomfort, infusion site inflammation, and infusion site swelling. 15

Liver Chemistry – Safety Population No subjects met laboratory criteria for Hy’s Law 16