Perspective Therapeutics (CATX) Study update summary

Study design

• Interim Phase 1/2a analysis covered 68 patients across three dose cohorts; patients received up to four doses of [212Pb] VMT-α-NET at 2.5, 5.0 or 6.0 mCi.

• Cohort 4 is enrolling with a frontloaded 6/5/5/4 mCi regimen.

• Data cut-off was 10 Sep 2026; analyses were interim and investigator-assessed, with shorter follow-up in Cohort 3 than Cohort 2.

Efficacy and disease control

• Investigator-assessed ORR, including unconfirmed responses, was 32.6% in Cohort 2 (15/46) and 50.0% in Cohort 3 (10/20); Cohort 3 responses were higher at early assessments.

• Disease control rates were 89.1% in Cohort 2 and 95.0% in Cohort 3.

• Across Cohorts 1–3, estimated PFS was 71.9% at 18 months (95% CI 58.3–81.8); PFS was 86% at 6 months and 74% at 12 months.

• In GEP-NET patients with SSTR2 expression in all target lesions, ORR was 36.8% in Cohort 2 (14/38) and 47.1% in Cohort 3 (8/17).

• Responses were reported across G1, G2 and G3 histological groups; heterogeneous SSTR2 expression may help identify patients to exclude from a registrational study.

Safety and tolerability

• No DLTs, Grade 4 or 5 TEAEs, treatment-related serious AEs, AE-related treatment discontinuations or dysphagia were reported; Grade 3 TEAEs occurred in 20/68 patients (29%).

• No clinically significant myelosuppression was reported; low-grade thrombocytopenia and transient leukopenia were observed, with cell counts typically recovering within a treatment cycle.

• Two patients (2.9%) had Grade 3 acute kidney injury; one case resolved and was considered unlikely related, while the other was assessed as possibly related and remained ongoing.

• Common TEAEs included alopecia (67.6%), fatigue (66.2%), nausea (64.7%) and diarrhoea (42.6%); no myelodysplastic syndrome was reported.