Antiviral NL-CVX1 efficiently blocks infection by SARS-CoV-2 viral variants of concern (VOC) Maria Rebelo, PhD Gonçalo Bernardes Lab Instituto de Medicina Molecular Lisboa, Portugal mariarebelo@medicina.ulisboa.pt Exhibit 99.1

Disclosures Hui-Ling Yen, PhD: received donation from Saiba AG and has performed contract research for Neoleukin Therapeutics, Inc. Wen Su, PhD: has no conflict of interest to declare. Gonçalo Bernardes, PhD: consultant and scientific advisor of Neoleukin Therapeutics, Inc. Ownership of Neoleukin options and stock. Maria Rebelo, PhD: has no conflict of interest to declare. Laurie Tatalick, DVM, PhD, DACVP: Consultant for Neoleukin Therapeutics, Inc. Ownership of Neoleukin options and stock. Matthew Walker, PhD: employee of Neoleukin Therapeutics, Inc. Ownership of Neoleukin options and stock. Marianne Riley, BS: employee of Neoleukin Therapeutics, Inc. Ownership of Neoleukin options and stock. Kevin Yu, BS, MS: employee of Neoleukin Therapeutics, Inc. Ownership of Neoleukin options and stock. Luis M Blancas-Mejia, PhD: employee of Neoleukin Therapeutics, Inc. Ownership of Neoleukin options and stock Daniel-Adriano Silva, PhD: scientific advisor of Neoleukin Therapeutics, Inc. Ownership of Neoleukin options and stock. David Shoultz, PhD, MBA: employee of Neoleukin Therapeutics, Inc. Ownership of Neoleukin options and stock. Cong Tang, MD, PhD: has no conflict of interest to declare. Ana R. Coelho, PhD: has no conflict of interest to declare

SARS-CoV-2 enter the cell by binding to the ACE2 receptor on the surface of human cells via the spike protein De novo decoy binds to SARS-CoV-2 spike protein, preventing the virus to bind to ACE2 receptor and thus inhibiting viral entry into cells NL-CVX1 is a potent de novo protein that blocks SARS-CoV-2

NL-CVX1 is a potent de novo protein that blocks SARS-CoV-2 − 20 − 10 0 M R E (x 1 0 ) – 3 25 50 75 100 Temperature (°C) 0 200 400 600 Time (s) KD<=3.5 nM0 0.1 0.2 R e sp o ns e 10 − 12 10 − 10 10 − 8 10 − 6 10 − 4 Concentration (M) 0 50 100 % B in d in g In hi b iti on hACE2 CTC-445 CTC-445.2 CTC-445.2d Low nanomolar affinity for the RBD of SARS-CoV-2 High thermodynamic stability Outcompetes binding of SARS-CoV-2 RBD to hACE2 I hACE2 CTC-445 CTC-445.2 CTC-445.2dNL-CVX1 Cite as: T. W. Linsky et al., Science 10.1126/science.abe0075 (2020).

NL-CVX1 demonstrates promising lung PK following a single dose and is well-tolerated with daily administration Linsky TW, et al. Science. 2020;370(6521):1208-1214. In vivo results 0 12 24 36 48 Time (h) 1 10 100 1000 10000 C o n c. ( ng /m L ) Lung pharmacokinetics • NL-CVX1 was present for >24 hours in the lungs and respiratory tract of mice. • NL-CVX1 was well-tolerated by mice with daily intranasal administration NL-CVX1

K18hACE2 transgenic mice Our K18hACE2 mouse model of SARS-CoV-2 infection

0 2 4 6 8 10 12 14 16 18 20 60 80 100 120 Days after inoculation % b od y w ei gh t c ha ng e Vehicle CVX1_25 ug CVX1_100 ug CVX1_250 ug 0 3 6 9 12 15 18 21 0 50 100 Days after inoculation % o f s ur vi va l Vehicle CVX1_25 ug CVX1_100 ug CVX1_250 ug Clinical observations in vivo A single dose of NL-CVX1 protects mice from lethal SARS-CoV-2 infection

Veh icl e CVX1_ _2 5 ug CVX1_ _1 00 u g CVX1_ 25 0 ug -10 0 10 20 30 R el at iv e m R N A e xp re ss io n (N g en e) Veh icl e CVX1_ _2 5 ug CVX1_ _1 00 u g CVX1_ 25 0 ug -5 0 5 10 15 20 R el at iv e m R N A e xp re ss io n (E g en e) Veh icl e CVX1_ _2 5 ug CVX1_ _1 00 u g CVX1_ 25 0 ug 0.0 5.0×103 1.0×104 1.5×104 2.0×104 2.5×104 P F U /le ft lu ng Lung viral load from in vivo experiments A single dose of NL-CVX1 prevents detectable viral load in the lungs of mice • No plaque forming units observed in either the 100 ug or 250 ug dose groups • No detection of the nucleocapsid (N) gene in either the 100 ug or 250 ug dose groups • No detection of the envelope (E) gene in either the 100 ug or 250 ug dose groups

A single dose of NL-CVX1 protects mice from lethal SARS-CoV-2 infection Source: Pedro Ruivo, iMM Non-infected Vehicle 25 µg 100 µg 250 µg • Proliferative epithelium • Pulmonary edema • Mononuclear inflammatory cell and neutrophil infiltration, with occasional necrotic and dying cells. • Mild pulmonary edema and mononuclear cell infiltrates observed • Mild pulmonary edema • No changes

0 5 10 15 20 25 60 80 100 120 Days after re-challenge % b od y w ei gh t c ha ng e WT_Vehicle 100 ug + WT Primary prophylaxis with NL-CVX1 protects against a second SARS-CoV-2 infection 30 days later 0 5 10 15 20 25 80 100 120 Days after re-challenge % b od y w ei gh t c ha ng e Alpha_vehicle 250µg + alpha

NL-CVX1 outcompetes hACE2 and efficiently binds to RBD of SARS-CoV-2 VOC ELISA competition assay Biolayer interferometry (OCTET) binding assays • NL-CVX1 binds at high picomolar to low nanomolar concentrations to RBD of SARS-CoV-2 VOC • NL-CVX1 outcompetes binding of SARS-CoV-2 RBD to hACE2

NL-CVX1 efficiently binds the Delta VOC with a low dissociation rate ELISA competition assay Biolayer interferometry (OCTET) binding assays • NL-CVX1 binds at high picomolar to low nanomolar concentrations to RBD of SARS-CoV-2 VOC • NL-CVX1 outcompetes binding of SARS-CoV-2 RBD to hACE2

NL-CVX1 neutralizes pseudoviruses with SARS-CoV-2 VOC spike proteins Original (Wuhan-1) Alpha variant (B.1.1.7) Beta variant (B.1.351) Gamma variant (P.1) IC50 (ng/mL) 13.2 9.7 1500 136 1 0 -2 1 0 -1 1 0 0 1 0 1 1 0 2 1 0 3 0 2 5 5 0 7 5 1 0 0 1 2 5 T e s t- ite m (µ g /m L ) N e u tr a li z a ti o n ( % ) Gamma variant Original (Wuhan-1) Alpha variant Beta variant N eu tr al iz at io n (% ) NL-CVX1 (µg/mL) • NL-CVX1 retains neutralizing activity against all VOC tested. • When compared to the original strain, the Alpha VOC displayed the highest sensitivity to NL-CVX1

NL-CVX1 is efficacious in vitro against SARS-CoV-2 VOC Original (Wuhan-1) Alpha variant (B.1.1.7) Beta variant (B.1.351) Gamma variant (P.1) TCID50 EC50 (nM) 4.6 1.9 1384 18.8 PCR EC50 (nM) 3.1 1.7 > 4000 16.8 Source: Su Wen and Hui-Ling Yen, HKUMed 10 -4 10 -3 10 -2 10 -1 10 0 10 1 2 4 6 8 Concentration (mM) Lo g 1 0T C ID 50 /m L NL-CVX1 (Lineage NL-CVX1 (B.1.351) EC50 = 1384 nM NL-CVX1 (B.1.1.7) EC50 = 1.858 nM NL-CVX1 (P • NL-CVX1 showed comparable efficacy against the Alpha and Gamma VOC. • Higher concentrations of NL-CVX1 were required for neutralization of the Beta VOC. 10 -4 10 -3 10 -2 10 -1 10 0 10 1 4 6 8 10 12 Concentration (mM) Lo g 1 0 R N A c op ie s/ m L Gamma variant Original (Wuhan-1) Alpha variant Beta variant

• NL-CVX1 is a de novo human ACE2 decoy protein that neutralizes SARS-CoV-2 in vitro and in animal models. • NL-CVX1 is effective against VOC tested in vitro at different concentrations. • Binding to the Delta variant spike protein and low dissociation rate is encouraging. • Single intranasal dose not only protects mice from to SARS-CoV-2 but also protects from a second experimental infection a month later. Summary and conclusions

Future directions • Investigate in vivo efficacy of NL-CVX1 against new VOC in K18hACE2 mice. • Characterize the underlying immune response that protects mice from secondary SARS-CoV-2 exposure. • Evaluate the nature of antibodies developed by mice following primary prophylactic exposure to NL-CVX1 and SARS-CoV-2 infection

Acknowledgments Hui-Ling Yen Su Wen Sin Fun Sia Ka Tim Choy Prathanporn Kaewpreedee Daniel Adriano Silva Thomas W. Linsky Jonathan Drachman Laurie Tatalick Matthew Walker Marianne Riley Kevin Yu Luis M. Blancas-Mejia David Shoultz Gonçalo Bernardes Cong Tang Ana R Coelho Marta Miranda Pedro Ruivo Iolanda Moreira Pedro Simas Juan Lama Isabel Cisneros