A recent study conducted in Spain demonstrated that for multiple myeloma patients treated with Velcade, prior vincristine-based treatment and the absence of neurological monitoring are factors that may increase the risk of developing nerve damage in their limbs.

The study authors suggested that patients be given a clinical and neurological assessment prior to treatment with Velcade.  If the patients’ resulting score is high enough to suggest the development of a severe form of Velcade-induced nerve damage, patients should continue to be monitored during Velcade therapy.

Velcade ^[1] (bortezomib) is a neurotoxic therapy, meaning it causes damage to the body’s nervous system. As a result, multiple myeloma patients treated with Velcade commonly experience tingling and pain located in their hands and feet from nerve damage in their extremities. This nerve damage is a side effect of the treatment and is referred to as Velcade-induced peripheral neuropathy.

One third of patients may experience Velcade-induced peripheral neuropathy during treatment.  This peripheral neuropathy can be painful, and although it usually diminishes when treatment stops, it has been reported that up to 22 percent of Velcade treated patients may develop nerve damage that compromises their quality of life.

Factors that determine whether a patient will develop nerve damage during treatment with Velcade remain controversial.  However, it has been shown that Velcade dose reductions can minimize nerve damage, prompting researchers to suggest that patients should be monitored for the appearance or worsening of peripheral neuropathy during treatment.

The goal of the current study was to determine the effectiveness of continuous neurological assessment in multiple myeloma patients treated with Velcade.  Researchers also sought to identify factors that increase a patient’s risk of developing Velcade-induced peripheral neuropathy.

The study included 58 patients with relapsed or treatment resistant (refractory) multiple myeloma who received at least one cycle of Velcade treatment.  Patients received Velcade at an initial dose of 1.3 mg/m² on days 1, 4, 8, and 11 for as many as eight 21-day cycles.

Continuous nervous system monitoring during Velcade treatment was performed in 24 of the 58 patients.  These patients were assessed by a neurologist prior to Velcade treatment and again every two cycles up to completion of treatment. Velcade-induced peripheral neuropathy in these patients was compared to that in the 34 patients who were not monitored.

Patients receiving neurological monitoring were given a clinical examination, which included patient reporting of numbness, tingling or pain, or weakness in extremities. It also included a physical exam to evaluate reflexes, strength, and sensation in the extremities.

Nerve conduction studies were also performed at each visit.  These studies are commonly used to evaluate the function of the nervous system and to evaluate numbness, tingling, burning, and weakness in extremities.

Patients were then given a score based on the combination of clinical and nerve conduction evaluations. Patients found to have emerging or worsening peripheral neuropathy during their monitoring received a reduction in their Velcade dosage.

The study authors found that 56 percent of patients who did not receive neurological monitoring during Velcade treatment experienced Velcade-induced peripheral neuropathy compared to 29 percent of patients who were monitored.  Furthermore, severe peripheral neuropathy was experienced by nearly 18 percent of patients who were not monitored compared to 8 percent of patients who were.

Similar to other studies, the majority of patients (62 percent) in this study reported neuropathy symptoms within two treatment cycles. All cases of severe neuropathy were detected within the first four cycles of therapy.

In their analysis, the study authors also found that previous vincristine ^[2] (Oncovin)-based regimens and poor evaluation prior to Velcade treatment were associated with an increased risk of developing Velcade-induced peripheral neuropathy.

For more information, please see the full study in the Journal of the Peripheral Nervous System ^[3].