Osisko Development Provides Infill Drilling Update on Its 13,000-Meter Lowhee Program at Cariboo Gold Project; Intercepts Include 596.40 g/t Gold Over 2.0 Meters from 6.1 Meters Downhole, Including 2,293.56 g/t Gold Over 0.5 Meters from 6.6 Meters Downhole HIGHLIGHTS 11,025 m of infill drilling completed (5,043 m new results) on 10-m drill spacing in 116 drill holes from August 2025 representing ~80% of the total planned ~13 km infill program Highlight intercepts include: 596.40 g/t Au over 2.0 m from 6.1 m downhole (including 2,293.56 g/t Au over 0.5 m from 6.6 m downhole), 21.67 g/t Au over 3.5 m from 96.5 m downhole (including 135.44 g/t Au over 0.5 m from 99.5 m downhole), and 21.97 g/t Au over 2.5 m from 48.7 m downholeResults to date continue to contribute to a more detailed understanding of spatial controls and local variability of the Lowhee Zone An aggregate total of ~12.1 km (~88%) of total planned drill meters have been completed to date, with full assays and QA/QC pending for the remaining, unreported holesInfill program anticipated to conclude in early Q2 2026 MONTREAL, Feb. 11, 2026 (GLOBE NEWSWIRE) -- Osisko Development Corp. (NYSE: ODV, TSXV: ODV) ("Osisko Development" or the "Company") is pleased to announce new infill drilling results from its ongoing 13,000-meter program on 10 meter drill spacing that commenced in August 2025 in the Lowhee Zone of the Company's permitted, 100%-owned Cariboo Gold Project ("Cariboo" or the "Project"), located in central British Columbia ("B.C."), Canada. The six drill hole fans reported herein comprise an additional ~5,043 meters ("m") of underground infill drilling, bringing the total tally of drilling with full results to 11,025 m, or ~80% of the planned total. Chris Lodder, President, stated, "This tighter drill spacing gives us a better understanding of vein corridor spatial geometries and local variability specific to this part of the Lowhee deposit, while reinforcing the importance of continued drilling in underexplored zones. As this work concludes, the resulting information is expected to help refine infill drill requirements and production designs and sequencing in the Lowhee Deposit of the Cariboo Gold Project." In total, an aggregate of approximately 12.1 kilometres ("km"), representing ~88% of the total planned drill meters, has now been completed. Full assay results and associated quality assurance and quality control reviews are pending for the remaining holes not reported herein. Infill drilling activities were suspended following the incident reported on January 23, 2026, with the program now anticipated to conclude in early Q2 2026. DRILL ASSAY HIGHLIGHTS This news release includes assays from fifty-four (54) underground infill HQ diamond drill ("DD") holes (63.5-millimeter diameter) totaling 5,043 m with depths ranging from 51 to 117 m completed between mid-October 2025 and December 2025 (see Table 1). Assays for six (6) complete drill fans were received by January 11, 2026 (Figure 2). Select photon assay highlights include: 596.40 ("g/t") gold ("Au") over 2.0 m in BMU-25-132 from 6.1 m downhole, including: 2,293.56 g/t over 0.5 m from 6.6 m downhole, and90.95 g/t over 0.5 m from 7.6 m downhole 21.67 g/t over 3.5 m in BMU-25-145 from 96.5 m downhole, including: 135.44 g/t over 0.5 m from 99.5 m downhole, and11.88 g/t over 0.6 m from 97.0 m downhole 21.97 g/t over 2.5 m in BMU-25-174 from 48.7 m downhole, including: 88.08 g/t over 0.5 m from 49.7 m downhole, and20.91 g/t over 0.5 m from 50.2 m downhole 9.21 g/t over 4.9 m in BMU-25-157 from 53.9 m downhole, including: 39.26 g/t over 0.5 m from 54.9 m downhole, and19.10 g/t over 0.5 m from 55.9 m downhole, and15.95 g/t over 0.5 m from 55.4 m downhole, and6.88 g/t over 1.0 m from 53.9 m downhole 10.57 g/t over 4.8 m in BMU-25-157 from 84.9 m downhole, including: 95.61 g/t over 0.5 m from 88.7 m downhole, and2.84 g/t over 0.5 m from 80.0 m downhole 10.48 g/t over 4.0 m in BMU-25-140 from 11.0 m downhole, including: 54.01 g/t over 0.5 m from 12.4 m downhole, and28.34 g/t over 0.5 m from 11.9 m downhole 6.91 g/t over 4.5 m in BMU-25-145 from 90.0 m downhole, including: 52.35 g/t over 0.5 m from 92.5 m downhole, and2.36 g/t over 0.7 m from 90.5 m downhole, and2.78 g/t over 0.5 m from 90.0 m downhole, and 2.10 g/t over 0.5 m from 92.0 m downhole 5.94 g/t over 4.7 m in BMU-25-163 from 41.1 m downhole, including: 18.91 g/t over 0.5 m from 43.65 m downhole, and14.44 g/t over 0.65 m from 45.15 m downhole, and8.94 g/t over 0.8 m from 42.0 m downhole, and2.47 g/t over 0.5 m from 44.15 m downhole 15.75 g/t over 1.95 m in BMU-25-148 from 108.1 m, including: 30.84 g/t over 0.7 m from 108.1 m downhole, and11.18 g/t over 0.75 m from 109.3 m downhole 10.46 g/t over 3.0 m in BMU-25-134 from 81.4 m, including: 51.40 g/t over 0.5 m from 82.9 m downhole, and8.10 g/t over 0.5 m from 81.4 m downhole Complete assay highlights, including true width estimates, are presented in Table 1 and drill hole locations and orie