SCIG dose adjustment in secondary immunodeficiency

Author: V. Dimov, M.D., Allergist/Immunologist at Cleveland Clinic
Reviewer: S. Randhawa, M.D., Allergist/Immunologist and Assistant Professor at NSU

A 72-year-old male was treated for multiple meyeloma 2 years ago. Subsequently, his IgG was found to be 180 mg/dL, IgA 7, IgM and there was insufficient response on the pneumococcus serotypes. At an outside facility, SCIG was started due to poor IV access. There was no history of infections. The diagnosis was secondary immunodeficiency. He has been receiving SCIG (Hizentra) 25 gm every week.

A year later, his IgG is 1200 mg/dL. The reported last dose of SCIG was 3-4 weeks ago (the prescription ran out).

What dose adjustment would you recommend now?

SCIG dose adjustement:

Based on the typical IVIG starting dose of 400 mg/kg/month, the total monthly dose is 400 mg x 65 kg = 26,000 mg (26 g).

According to the Hizentra dosage calculator (Initial recommended dose of Hizentra = 1.53 x Previous IVIg dose(grams)
Number of weeks between scheduled IVIg doses). Based on an IVIg dose of 26grams and 4weeks between IVIg doses, Hizentra weekly dose is: 9.95 g (49.73).

Patient's states the last SCIG dose was 3-4 weeks ago, total IgG is 1200 mg/dL. It is possible that some of the production of IgG by the B cells is recovering.

The recommended new weekly dose of SCIG is 15 g every week. IgG, IgM, IgA levels should be checked in 3 months, just before the SCIG infusion.

SCIG prescription was changed. The infusion nurse was informed.

Mnemonic: Dose of IVIG in PIDD: 4

400-600 mg/kg/month
IgG trough level should be over 400 mg/dL (over 600 mg/dL if bronchiectasis)
4 letter words:

Starting doses for IVIG: 400 to 600 mg/kg/month for a target trough level of at least 500 mg/dL.

How monitor CVID patients on IVIG?

Immunoglobulin levels at 3-6 month intervals
CBC and CMP yearly
Spirometry yearly
CT chest every 3-4 years - only if lung disease suspected or lung functions not normal


Guidelines on Dosing and Treatment Administration for Hizentra Therapy

Related reading

AInotes - Common Variable Immunodeficiency
AInotes - IVIG and Subcutaneous Ig

Published: 07/12/2010
Updated: 03/15/2014

No comments: