Galecto : ATS 2023 poster - The Anti-Fibrotic Effect of GB0139, a Small Molecule Galectin-3 Inhibitor, in Precision Cut Lung Slices from Idiopathic Pulmonary Fibrosis Tissue

The Anti-Fibrotic Effect of GB0139, a Small Molecule Galectin-3 Inhibitor, in

Precision Cut Lung Slices from Idiopathic Pulmonary Fibrosis Tissue

A.C. MacKinnon1, L.A. Borthwick2, R.J. Slack3

1Galecto Biotech AB, BioQuarter, Edinburgh, UK 2Fibrofind Ltd, William Leech Building, Medical School, Newcastle University, Newcastle upon Tyne, UK, 3Galecto Biotech AB, Stevenage Bioscience

Catalyst, Stevenage, UK.

Introduction

GB0139 is an inhaled, small molecule inhibitor of galectin-3(Gal-3) that is currently in phase 2b studies for IPF

Results

In vitro characterization of GB0139 (biochemical & cellular)

GB0139

GB0139 Gal-3 Affinity & Kinetics (SPR)

Ex vivo IPF BAL cells

(NCT03832946). Gal-3 has been shown to be a key driver of lung fibrosis1 and in this study the anti- fibrotic effect of GB0139 was investigated in idiopathic pulmonary fibrosis (IPF) precision cut lung slices (PCLuS).

	Human ±SD (n)	Mouse ±SD (n)
FP KD (nM)	2.1 ± 0.1 (4)	54 ± 17 (3)

Response (RU)

10

8

6

4

2

0

12	41 nM
10	14 nM

					(RU)	8		KD = koff/kon = 3.9 nM
					Response	6	4.6 nM
					4	1.5 nM
						2	0.5 nM
	KD = 3.7 nM				0	kon = 2.0 x 107 M-1s-1	koff = 0.08 s-1
0	10	20	30	40	50	-2	-20 0 20 40 60	80 100 120 140 160
		[GB0139] nM				Time (s)

% inhibition of Gal-3 (IPF AM ex vivo)

100

80

60

40

20

0

-8	-7	-6	-5
	Log [GB0139] M

Methods

Human fibrotic lung tissue was sourced ethically from human explants from three patients with IPF undergoing lung transplantation. All patients had their IPF diagnosis confirmed based on medical history and evaluation of their explanted lung tissue by a board-certified respiratory pathologist. Tissue was inflated with 2-3 % low boiling point agarose and allowed to set at 4°C. PCLuS were then cut at 400 μm on a vibrating microtome and cultured in DMEM media. PCLuS were rested for 48 h prior to treatment with inhibitors for 6 days with media replaced every 24

GB0139 demonstrates high affinity for Gal-3 & inhibits Gal-3 expression ex vivo on IPF BAL cells (IC50 = 361 ± 108 nM (mean ± SD, n=3 patients)).

Ex vivo precision cut IPF lung slice

Method for generation of PCLuS from human IPF lungs

Secreted galectin-3 (Daily Average Change)

	40
Galectin-3 change vs. vehicle	20
0
-20
-40
%
	-60

Pirfenidone

μ

μ

μ

Vehicle

ALK5i

Nintedanib

GB0139GB0139GB0139

M

10

μ

M

M

M

M

mM

1

3

10

5

5 .

μ

.

2

2

Secreted fibrotic markers (Daily Average Change)

h. Soluble mediators released were measured daily via standard ELISAs. In addition, analysis of experimental proteomics data derived from MS testing on the PCLuS were completed.

Results

GB0139 caused a concentration- dependent reduction in Gal-3 in IPF PCLuS. This was associated with a reduction in markers of fibrosis (Co1α1, hyaluronic acid, TIMP-1,

Patient Demographics

IPF Donor	Age	Sex	FEV1
1	62	Male	1.85
2	64	Male	2.37
3	65	Male	1.53

Translational pharmacology of GB0139 in IPF

% change vs. vehicle

40

20

0

-20

-40

-60

Pirfenidone

μ

μ

μ

M ALK5i

Nintedanib

GB0139

GB0139 GB0139

10

μ

M

M

M

M

5mM

1

3

10

5

.

.

μ

2

2

●Col1α1 ●HA ●TIMP-1

●MMP-7●Galectin-3

MMP-7) comparable to pirfenidone and nintedanib. A number of pathways were perturbed by down- regulated proteins that included

transcriptional activity of

SMAD2/SMAD3 and platelet activation, signalling and aggregation.

Conclusions

GB0139 demonstrates Gal-3 target engagement that results in an anti- fibrotic effect comparable to approved IPF therapies in PCLuS, at concentrations achieved in the lung when dosed in IPF patients2. In addition, GB0139 inhibited pathways in PCLuS that correlate with biomarker changes observed in IPF2 and COVID193 clinical studies.

References

1. MacKinnon AC et al. Am. J. Respir. Crit. Care Med. 2012;185(5):537-546.
2. Hirani N et al., Eur. Respir. J., 2021:57:2002559.
3. Gaughan EE et al., Am J Respir Crit Care Med 2022; 207(2):138-149.

Phase Ib - GB0139 dose-dependently reduces

galectin-3 in the lungs of IPF patients

			p = 0.0173
baseline)		p = 0.017
150
(%	125
100
Gal-3
75
surface
50
	25
AM	0
Placebo	GB0139		GB0139		GB0139
		mg
	3mg	3mg	10
	0
	.

Phase Ib - GB0139 inhibits IPF fibrotic markers in

humans at concentrations equivalent to ex vivo PCLuS

	300		●PDGF-BB
biomarkerPlasma baseline)(%			●PDGF-AA
200		●PAI-1
		●MMP-8
			●YKL-40
			●CCL-2
	100
	0
	Placebo	GB0139
	3	mg

Phase Ib - GB0139 ex vivo PCLuS vs. clinical target

engagement in IPF patients

(%baseline)	10 μM GB0139 = Max IPF PCLuS activity
120
100				0% inhibition
				0.3 mg
80
				3 mg
					10 mg
Gal-3	60
			50% inhibition
40
surface	20
0				100% inhibition
-20
AM
0	25	50	75	100	125

[GB0139] in AM ∝M

Pathways perturbed by proteins downregulated by 10 µM

GB0139 across all IPF PCLuS patients

This work was sponsored by Galecto Biotech AB, Inc.