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•	Top-line Phase 2a Data from Etokimab (ANB020) in Eosinophilic Asthma Expected in Third Quarter of 2018

•	Etokimab Clinical Development Program Expanded to Include Chronic Rhinosinusitis with Nasal Polyps

•	Commercial Considerations Led to Deprioritization of Further AnaptysBio-Sponsored Clinical Development of Etokimab in Peanut Allergy

•	Five Top-line Clinical Efficacy Readouts from Wholly-Owned Pipeline Anticipated by End of 2019

•	In July 2018, etokimab (pronounced ee-toh-key-mab) was adopted as the nonproprietary name by the United States Adopted Names (USAN) Council, in consultation with the World Health Organization (WHO) International Nonproprietary Names Expert Committee, for AnaptysBio’s anti-IL-33 antibody drug candidate previously referred to as ANB020.

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In May 2018, updated data from the company’s Phase 2a trial of etokimab, AnaptysBio’s wholly-owned anti-IL-33 antibody program, in adult patients with moderate-to-severe atopic dermatitis were presented at the European Academy of Allergy and Clinical Immunology (EAACI) Congress 2018 in Munich by the principal investigator of the trial, Dr. Graham Ogg, professor of dermatology at Oxford University in Oxford, England. Key observations presented by Dr. Ogg during the aforementioned presentation included:

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Biomarker data demonstrated that reduction of circulating blood eosinophil was consistent with clinical efficacy measures in this Phase 2a trial, with a maximum reduction of 40 percent at day 29 after a single dose of etokimab relative to baseline, which is aligned with genotypic studies that associate lower eosinophil counts with human IL-33 loss-of-function mutations. In addition, clinical efficacy data in this Phase 2a trial were consistent with an ex vivo pharmacodynamic assay measuring IL-33 mediated interferon-gamma release, where 98 percent inhibition was observed within 72 hours following etokimab administration and 86 percent inhibition was sustained at day 57 post-ANB020 administration, which is consistent with the pharmacodynamic activity observed using the same assay in a prior Phase 1 trial of etokimab in healthy volunteers.

•	A single dose of etokimab resulted in achievement of EASI-50 by all 12 patients enrolled in this trial on or before day 57 post-etokimab administration. Rapid clinical response was observed by day 15 post-etokimab administration and day 29 results exceeded the primary efficacy objective of the trial

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Etokimab was generally well-tolerated by all patients and no drug-related safety signals were observed. The most frequent adverse events reported were dizziness in 17 percent of patients post-placebo and headache in 25 percent of patients post-etokimab administration. A single serious adverse event of depression was reported on day 140 post-etokimab administration, which was consistent with the patient’s pre-trial history of depression and was deemed not drug-related.

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The company is enrolling a Phase 2b randomized, double-blinded, placebo-controlled, multi-dose study in 300 adult patients with moderate-to-severe atopic dermatitis, also referred to as the ATLAS clinical trial, to assess different dose levels and dosing frequencies of subcutaneously-administered etokimab for a 16-week treatment period followed by an eight-week follow-up period, with data expected in the second half of 2019. Sixty patients are being randomized into each of the five arms in the ATLAS trial where dosing will occur as follows: (i) initial 600mg loading dose followed by 300mg monthly doses of etokimab, (ii) initial 300mg loading dose followed by 150mg monthly doses of etokimab, (iii) initial 300mg loading dose followed by 150mg doses of etokimab every eight weeks, (iv) monthly 20mg doses of etokimab and (v) monthly doses of placebo.

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AnaptysBio expects to report top-line efficacy and safety data, including improvement in Forced Expiratory Volume in One Second (FEV1), from its ongoing double-blinded, placebo-controlled severe eosinophilic asthma trial Phase 2a trial, where approximately 24 adult severe eosinophilic asthma patients are treated with a 300mg intravenous single dose of etokimab versus placebo, each in combination with inhaled corticosteroids and long-acting beta agonists as background therapy, in the third quarter of 2018.

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The Company has expanded development of etokimab into adult chronic rhinosinusitis with nasal polyps (CRSwNP), which is a debilitating atopic disorder associated with elevated IL-33 pathway signaling, affecting approximately 1.3 million adults in the U.S., and AnaptysBio estimates approximately 400,000 of these patients are inadequately controlled with standard-of-care. The Company plans to initiate a randomized, placebo-controlled Phase 2 trial, also referred to as the ECLIPSE trial, in approximately 100 adult CRSwNP patients treated with two different multi-dosing frequencies of subcutaneously-administered etokimab or placebo, each in combination with mometasone furoate nasal spray as background therapy, for a treatment period of 16 weeks followed by an eight-week follow-up period. The Company plans to initiate the ECLIPSE trial by the end of 2018, and anticipates top-line data will be available in the second half of 2019.

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As a result of market assessment regarding the adoption of the peanut oral food challenge in future commercial usage of etokimab in peanut allergy patients, AnaptysBio has decided to deprioritize further company-sponsored clinical development of etokimab in moderate-to-severe baseline adult peanut allergy patients. At this time, AnaptysBio does not intend to utilize its clinical development resources to pursue a Phase 2b clinical trial of etokimab in peanut allergy, however the Company may pursue potential investigator-sponsored trials related to this indication.

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Data from the company’s Phase 1 healthy volunteer trial of ANB019, its wholly-owned anti-interleukin-36 receptor, or IL-36R therapeutic antibody, were presented during May in a poster session at the EAACI Congress 2018 in Munich. In the double-blind, placebo-controlled healthy volunteer Phase 1 trial, 36 subjects were administered a single subcutaneous or intravenous dose of ANB019 ranging between 10 mg and 750 mg, 18 subjects were administered multiple ascending doses of ANB019 intravenously ranging between 40 mg and 300 mg weekly for four consecutive weeks and 18 subjects were dosed with placebo.

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AnaptysBio has initiated a 10-patient open-label Phase 2 trial of ANB019 in GPP, also known as the GALLOP trial and top-line data are anticipated by early 2019. Patients are dosed with a 750mg intravenous loading dose of ANB019 upon enrollment, followed by 100mg subcutaneously-administered monthly doses of ANB019 for a treatment period of up to 16 weeks post enrollment and followed an eight-week follow-up period. The company plans to initiate a placebo-controlled 50-patient multi-dose Phase 2 trial in PPP, also known as the POPLAR trial, where top line data is anticipated in the second half of 2019.

•	Cash, cash equivalents and investments totaled $300.6 million as of June 30, 2018 compared to $324.3 million as of December 31, 2017, for a decrease of $23.7 million. The decrease primarily relates to operating cash outflow for clinical and manufacturing related expenses, as well as personnel costs.

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Research and development expenses were $10.6 million for the three months ended June 30, 2018, as compared to $7.2 million for the three months ended June 30, 2017. The increase was primarily due to continued advancement of the Company’s ANB020 and ANB019 clinical programs and additional personnel-related expenses, including share based compensation, as well as the recognition of lower research and development tax incentives during the three months ended June 30, 2018.

•	General and administrative expenses were $3.8 million for the three months ended June 30, 2018, as compared to $2.4 million for the three months ended June 30, 2017. The increase was primarily attributable to additional personnel-related expenses, including share based compensation, to support the Company’s growth.

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