A Phase I/II, Dose Finding and Optimization Study of [177Lu]Lu-NeoB in Combination With Capecitabine in Patients With GRPR+, ER+, HER2- Metastatic Breast Cancer After Progression on Previous Endocrine Therapy in Combination With a CDK4/6 Inhibitor.

Registry record from ClinicalTrials.gov (NCT06247995). This is a study registration, not published results. Lead sponsor: Novartis Pharmaceuticals. Recruitment status: ACTIVE_NOT_RECRUITING. Phase: PHASE1, PHASE2. Study type: INTERVENTIONAL. Enrollment: 20 participants (ACTUAL). Conditions: Breast Cancer. Interventions: DRUG: [68Ga]Ga-NeoB; DRUG: [177Lu]Lu-NeoB; DRUG: Capecitabine. Primary outcome measures: Phase I: Incidence and severity of dose limiting toxicities (DLTs) , 42 days after the first administration of [177Lu]Lu-NeoB; Phase I: Incidence and severity of adverse events and serious adverse events for 177-Lu-NeoB in combination with capecitabine , From start of study treatment until 56 days after the last dose of study treatment, assessed up to approximately 33 months; Phase I: Dose modifications for [177Lu]Lu-NeoB in combination with capecitabine , From start of study treatment until the last dose of study treatment, assessed up to approximately 31 months; Phase II: Objective Response Rate (ORR) , From date of randomization until date of progression, death or further antineoplastic therapy, whichever comes first, assessed up to approximately 88 months; Phase II: Clinical Benefit Rate (CBR) , From date of randomization until date of progression, death or further antineoplastic therapy, whichever comes first, assessed up to approximately 88 months; Phase II: Time to Response (TTR) , From date of randomization until first documented evidence of CR or PR (the response prior to confirmation), assessed up to approximately 88 months; Phase II: Duration of Response (DoR) , From first documented evidence of CR or PR (the response prior to confirmation) until time of documented disease progression or death due to any cause, whichever comes first, assessed up to approximately 88 months; Phase II: Progression Free Survival (PFS) , From the date of first dose to the date of confirmed progression or death due to any cause, whichever comes first, assessed up to approximately 88 months; Phase II: Overall Survival (OS) , From the date of first dose until date of death from any cause, assessed up to approximately 88 months. Brief summary: In the phase I part, to determine the recommended doses (RD) and dosing regimens of \[177Lu\]Lu-NeoB in combination with capecitabine in adult patients with gastrin releasing peptide receptor positive, estrogen receptor-positive, human epidermal growth factor receptor-2 negative metastatic breast cancer after progression on previous endocrine therapy in combination with a CDK4/6 inhibitor. In the phase II part, to evaluate the preliminary anti-tumor activity of two different doses/regimens of \[177Lu\]Lu-NeoB in combination with capecitabine (dose optimization).