Aktis Oncology (AKTS) investor relations material

Clinical development strategy and trial design

• Initiated a dedicated Phase 1b trial of AKY-2519 in metastatic castration-resistant prostate cancer (mCRPC), enrolling both PLUVICTO-naïve and -experienced patients, with dose escalation at three levels and parallel cohorts.

• A second Phase 1b basket trial targeting B7-H3-expressing tumors (lung, colorectal, and others) is planned for the second half of 2026, with protocol finalized and under regulatory review.

• The two-trial approach enables efficient, indication-relevant data generation for future pivotal studies and broader patient segment evaluation.

• All patients must demonstrate tumor uptake via imaging before enrollment, optimizing targeted dose finding and sequencing insights.

• Strategy is informed by clinical advisory boards and tailored to distinct patient needs.

Rationale and scientific foundation

• B7-H3 is highly expressed in multiple solid tumors, including mCRPC, lung, and breast cancers, and is associated with poor prognosis and non-responsiveness to anti-PD-1 therapy.

• AKY-2519 and its tool compound AKY-3212 show high affinity and selectivity for B7-H3, with promising preclinical data demonstrating tumor retention, anti-tumor effects, and superior efficacy to PSMA-617 in resistant mCRPC models.

• B7-H3 expression is consistent in about 90% of metastatic prostate cancers and is absent in salivary glands and most normal tissues, potentially reducing off-target toxicity.

• Many mCRPC patients are ineligible for or have sub-optimal response to PSMA-targeted therapies, highlighting unmet needs.

• The approach leverages established radioligand therapy centers for prostate cancer and academic centers for the basket trial.

Upcoming milestones and data presentations

• Clinical imaging and dosimetry data for AKY-2519 in prostate and other solid tumors will be presented at ASCO 2026.

• The basket trial is expected to commence in the second half of 2026.

• Preliminary data from the Phase 1b prostate study anticipated in 2027.

• AKY-1189, targeting Nectin-4, will report preliminary Phase 1b data in Q1 2027.

• In-house GMP manufacturing facility to be operational in the second half of this year to support clinical trial demands.