The most probable AEs caused by Bortezomib (usually transient) are mild to moderate thrombopenia and leukopenia, decreased appetite, gastrointestinal side effects (vomiting, nausea, diarrhea), fatigue, peripheral neuropathy and other neurological symptoms such as headache, dizziness, tremor and hypotension. Intensified immunosuppression may be associated with an increased risk of infection (common: herpes zoster, herpes simplex, pneumonia, bronchitis, sinusitis, nasopharyngitis). Hence, a careful patient follow-up will include a close monitoring for infectious complications (bacterial, viral and fungal infections). Valacyclovir adapted to kidney function will be added to prevent the occurrence of herpes virus infections (herpes zoster).