Withdrawal of hospital outpatient treatments in severe diseases due to unacceptable toxicity: A retrospective study from the register of patients and treatments

Aim: To retrospectively analyse hospital outpatient treatment (HOT) withdrawal due to unacceptable toxicity at our hospital. Information regarding unacceptable toxicity leading to treatment withdrawal was recorded.

Methods: HOT interruptions because of unacceptable toxicity were identified from the Register of Patients and Treatments (RPT) (January 2014 to December 2017). Information regarding the demographic and clinical characteristics of patients, adverse drug reactions (ADRs) and drug treatments was retrieved from electronic health records. Causality and previous knowledge of ADRs were assessed according to the Spanish Pharmacovigilance System algorithm. Information regarding HOT risk management plans (RMPs) and their classification as inverted black triangle medicines was obtained from the European Medicines Agency (EMA).

Results: HOTs were withdrawn due to unacceptable toxicity in 136 (1.5%) registries corresponding to 135 (1.7%) patients. Fifty-one different HOTs (38.6% of those registered) were involved in 240 ADR/HOT pairs: 24 (47%) were additional monitoring medicines and 37 (72.5%) were EMA RMPs. The most frequent medicines involved in ADRs were lenalidomide (30, 12.5%) (mainly neutropenia, thrombocytopenia and bicytopenia), bevacizumab (19, 7.9%) (mainly venous and pulmonary thromboembolism) and sunitinib (13, 5.4%) (mainly thromboembolic events, diarrhoea and worsening of chronic renal failure). Cytopenia (40, 17.3%), diarrhoea (15, 6.5%), asthenia (9, 3.9%) and neuropathy (6, 2.6%) were the most frequent ADRs. All ADRs were severe, 10 (6 patients) had been poorly described or were unknown and only 9 (5 patients) had been reported by spontaneous notification.

Conclusions: Valuable information regarding severe and unknown ADRs was obtained from the RPT. Such registers are useful tools to complement spontaneous ADR notifications.