A Phase I Study to Assess PSMA+ and PSMA- Tumour Lesions

Crescendo Biologics

Status and phase: Active, not recruiting; Phase 1

Conditions: Advanced and/or Metastatic Solid Tumours

Treatments: Drug: CB307; Drug: Radiolabelled CB307

Study type: Interventional

Funder types: Other; Industry

Identifiers

NCT05836623

CBT307-1-RL

2021-006256-13 (EudraCT Number)

Details and patient eligibility

About

CB307 is a trispecific Humabody® targeting CD137; PSMA; and human serum albumin (HSA) undergoing Phase 1 assessment in patients with PSMA+ solid tumours. This sub study will assess the biodistribution of radiolabelled CB307 in patients with advanced and/or metastatic solid tumours that are PSMA+.

Full description

Phase 1, Open-label, single centre, non-randomised study during which, enrolled patients will undergo a number of PET scans following administration of 89Zr-CB307, in order to assess the uptake of the radiolabelled drug. A post-treatment tumour biopsy for the assessment of PSMA expression will also be taken, if medically feasible, after the last PET scan.

The sub-study consists of 2 parts: an Optimisation Phase (Part A) and an Expansion Phase (Part B).

In Part A, both 89Zr-CB307 and CB307 will be administered to patients. The timing of the scans, post-dose tumour biopsy and CB307 dose will be optimised as determined by the Optimisation Review Committee (ORC).

In Part B (Expansion Phase), 89Zr-CB307 PET scanning will be performed based on the optimal dosing and timing determined in Part A.

The sub-study will continue for 7 days after the tracer injection. Patients will then be enrolled into the main study and will receive Cycle 1 Day 1 (C1D1) CB307 treatment according to the main study protocol.

Enrollment: 5 patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Capable of understanding the written informed consent.
• Aged at least 18 years.
• Not amenable to standard of care.
• ECOG PS of 0 or 1.
• Documented histologically confirmed diagnosis of PSMA+ advanced or metastatic solid tumours.
• Has radiologically measurable disease per RECIST v1.1 or elevated serum PSA for castration resistant prostate cancer patients with only bone metastases.
• Adequate organ function.
• Willing to have a biopsy sample taken immediately after the last PET scan before initiation of the main study.

Exclusion criteria

• Subjects with autoimmune disease or regular immunosuppressants.
• Has discontinued from anti-CTLA 4, anti-PD1 or anti-PD-L1 antibody because of intolerable toxicity.
• Has brain metastasis including leptomeningeal metastasis or primary brain tumour.
• Has current or history of CNS disease.
• Has known active infection.
• Biopsy cannot be safely obtained after the last PET scan, and not provided their consent.

Trial design

Primary purpose: Treatment

Allocation: Non-Randomized

Interventional model: Single Group Assignment

Masking: None (Open label)

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5 participants in 2 patient groups

Part A - Optimisation Phase

Experimental group

Description:

Following administration of 89Zr-CB307, patients will undergo PET scans The timing of the scans and CB307 dose administration will be determined by the Optimisation Review Committee (ORC)

Treatment:

Drug: CB307

Drug: Radiolabelled CB307

Part B - Expansion phase

Experimental group

Description:

89Zr-CB307 PET scanning will be performed based on the optimal dosing and timing determined in Part A by the Optimisation Review Committee (ORC)

Treatment:

Drug: CB307

Drug: Radiolabelled CB307