Investigation of which patients treated with bortezomib that have increased risk of developing peripheral neuropathy.

The study aims to include 20 patients with multiple myeloma that are initiating bortezomib treatment. The patients must follow their normal treatment cycles while getting blood drawn during their treatment period however maximal 9 cycles.

Blood is dawn before treatment initiation and approximately once per cycle in order to measure neurofilament light chain (NFL) before and during treatment. The primary outcome is to relate the level of NFL during treatment with the level at baseline and as a secondary outcome to relate the level of NFL to the cumulative dose of bortezomib.

Inclusion Criteria:

• Above 18 years of age
• Must speak and understand Danish
• Must be able to and willing to give informed consent
• Diagnosed with myeloma and in need for treatment
• Must not be a candidate for transplantation and must be a candidate for bortezomib treatment.
• Must not previously have been treated with proteasome inhibitors
• Eastern Cooperative Oncology Group (ECOG) Performance status (PS) ≤ 3

Exclusion Criteria:

• Other underlying cancer disease - with exception of a) basal cell carcinoma, b) healed carcinoma in situ cervicis uteri, c) other cancer disease with minimal risk of recurrence or d) prostate cancer with low glean score
• Previous treatment with neurotoxic chemotherapy
• Known polyneuropathy or at diagnosis have polyneuropathy degree 1 with pain or degree 2 without pain.
• Simultaneous amyloidosis/POEMS syndrome
• Patients who have received chemotherapy previously and patients with diabetes, HIV and neurodegenerative diseases.

Must be at least 18 years of age, must understand and speak Danish, must have multiple myeloma and be a candidate for treatment with bortezomib and must not be at candidate for cell transplantation.

Individual participant data cannot be shared due to general data protection regulation (GDPR).