Biological therapies such as tumour necrosis factor α (TNF-α) blockers are widely used in clinical practice to treat many diseases including rheumatoid arthritis, psoriatic arthritis and plaque psoriasis.1 The administration of biological drugs is usually via subcutaneous self-injection, which has many advantages over intravenous infusions.2 Its advantages include improved flexibility in administration, reduced infusion time and, above all, the possibility of self-administration by the patient or her/his caregivers. The problems that can occur with self-administration concern patient compliance; patients must be adequately educated in self-administration to ensure optimal adherence to therapy and to overcome any resistance related to needle phobia.2 A range of devices, including prefilled syringes (PFS) and prefilled pens (PFP), has been developed to meet the needs of patient compliance.2 These devices have their own special features …