Endocrine Abstracts

Background: Severe primary IGF1 deficiency (SPIGFD) is defined in children as a height less than −3sds, low IGF1 levels with normal growth hormone levels. Recombinant IGF1 (rhIGF1, Mecasermin) given twice daily as a subcutaneous injection is the only therapy available to improve the height potential in this group of children. However it may have important side effects including hypoglycaemia, growth of lymphoid tissue and injection site lipohypertrophy.

Aim: To accumulate the UK experience in implementing and monitoring therapy with rhIGF1 and to report short term data on response to treatment. The data from 5 centres (representing 6 of the 7 children on rhIGF1 for SPIGFD in the UK) was collected by a standardised questionnaire.

Results: All 6 children were of South Asian origin. The duration of treatment has ranged from 0 to 2 years (median 0.2 years). The starting dose was 0.04 mg/kg bd; the interval between dose increases was 1 week to 6 months. 2 children have reached the upper dose limit of 0.12 mg/kg bd. Treatment was commenced in hospital in 4 children and blood sugars were mainly monitored at initiation and dose adjustments. 1 child had a reported hypoglycaemia one year into treatment. Injection site hypertrophy or pain was the most common reported adverse event (4 children).

The median age of starting treatment was 10.6 years (range 6,11.7 years). The median height sds in the 5 children with post treatment measurements has increased from −5.3 to −5.1sds.

Conclusion: Recombinant IGF1 therapy appears to be well tolerated in the short term with most adverse events involving the injection sites. There are some early improvements in the height sds and scope for further dose increases still remain. Longer term monitoring remains essential to provide a safety profile and to assess clinical benefits.