Lymphoma imaging with a new technetium-99m labelled antibody, LL2

Area of Science:

• Nuclear Medicine
• Oncology
• Immunology

Background:

• Non-Hodgkin's lymphoma and chronic lymphocytic leukaemia are significant B-cell malignancies.
• Accurate lesion detection is crucial for effective lymphoma diagnosis and treatment planning.
• Monoclonal antibodies (MoAbs) offer targeted delivery for diagnostic imaging agents.

Purpose of the Study:

• To evaluate the lesion detection capability of a novel technetium-99m labelled B-cell lymphoma monoclonal antibody (LL2) imaging agent.
• To assess the diagnostic accuracy of 99mTc-LL2 Fab' in patients with B-cell lymphomas.

Main Methods:

• Eight patients with non-Hodgkin's lymphoma and one with chronic lymphocytic leukaemia were studied.
• Patients received an injection of approximately 925 MBq (25 mCi) of 99mTc-LL2 Fab' (1 mg).
• Planar and single photon emission tomography (SPET) imaging were performed at 3-4 hours and 24 hours post-injection.

Main Results:

• The 99mTc-LL2 Fab' agent detected 29 out of 48 known tumour sites across various lymphoma types and grades.
• Excluding one patient with a high tumour burden, detection accuracy increased to 29 of 33 lesions.
• The agent successfully identified gallium-negative lesions in the liver and bone, with one case revealing previously unknown bone involvement.

Conclusions:

• Technetium-99m labelled LL2 Fab' demonstrates significant potential for detecting B-cell lymphoma lesions.
• The imaging agent successfully identified known and unknown tumour sites, including bone metastases.
• Further investigation into LL2 MoAb for radioimmunotherapy is warranted following diagnostic studies.