Efficacy and Safety of Pegfilgrastim in Patients With Severe Congenital Neutropenia

Background Severe congenital neutropenia (SCN) is commonly treated with granulocyte colony‐stimulating factor (G‐CSF) to reduce neutropenia and the associated risk of infections. Pegfilgrastim, a long‐acting form of G‐CSF, provides the benefit of less frequent dosing; however, its application in SCN has not been extensively studied. This study aims to assess the long‐term safety and effectiveness of transitioning SCN patients from standard G‐CSF therapy to pegfilgrastim. Methods We followed eight patients with severe congenital neutropenia (five males, average age 17.8 years) who had been on G‐CSF treatment for at least five years. They were switched to pegfilgrastim injections (3–6 mg every 7–14 days). Dosing was individualized to obtain an absolute neutrophil count (ANC) above 1000/µL in all patients. Over a five‐year follow‐up under treatment with pegfilgrastim, patients were evaluated for ANC levels, infection frequency, adverse effects, and quality of life using the Functional Assessment of Cancer Therapy‐Neutropenia (FACT‐N) questionnaire. In addition, yearly abdominal ultrasounds, bone density every two years, and genetic screening for RUNX1 and the G‐CSF receptor mutations were performed. Results Pegfilgrastim significantly improved ANC levels compared to prior G‐CSF treatment ( p = 0.008). Quality of life (QoL) significantly improved in six patients ( p = 0.016). Varying maintenance dosages were required based on the therapeutic response. Bone pain was common, leading to discontinuation in one patient. Two patients developed hip osteopenia, and one showed progressive splenomegaly. Hospitalization rates and infection frequency remained unchanged. Oral ulcers were decreased overall. Conclusion Pegfilgrastim can be used as an alternative to daily G‐CSF in SCN, providing stable ANC and QoL improvements with individualized dosing. Larger studies are warranted to evaluate its long‐term safety and efficacy. Clinical trial registration This trial is registered at https://irct.behdasht.gov.ir/ in Iranian Registry of Clinical Trials (IRCT) # IRCT20150125020786N3.