a webcast immunology and allergy clinics of north america

A Webcast

IMMUNOLOGY ANDALLERGY CLINICSOF NORTH AMERICA

IMMUNOLOGY ANDALLERGY CLINICSOF NORTH AMERICA

IMMUNOLOGY AND ALLERGY CLINICS WEBCASTIMMUNOLOGY AND ALLERGY CLINICS WEBCAST

The Art of IgG Replacement in Treating Primary Immunodeficiency Patients


HISTORICAL PERSPECTIVE ON THE THERAPEUTIC USE OF GAMMAGLOBULIN

• 1952 - Treatment of agammaglobulinemia with IM immunoglobulin G (IgG)

• 1966 - Plasma therapy using a “buddy” system

• 1969 - Pepsin-digested Ig for IV use

• 1975 - Initial studies of Ig for use by IV route

• 1981 – Approval of IGIV for use in primary immune deficiencies

• 1994 – Transmission of hepatitis C by IGIV• FDA and GMP introduce solvent/detergent, pasteurization, caprylate to

prevent transmission of lipid envelope viruses

• 1999 – Renal failure by sucrose-containing IGIV products

• 2000 – CJD/new-variant prion disease• Quarantine of IGIV product produces a shortage• Nanofiltration introduced to remove prions

• 2002 – MedWatch for thrombotic events

CJD = Creutzfeldt-Jakob disease; FDA = Food and Drug AdministratIon; GMP = good manufacturing practices; IGIV = intravenous immunoglobulin G; IV = intravenous.


IGIV COMPOSITION

• Donor pool– Derived from 2,000-10,000 donors

• may be as much as 60,000 donors

• Composition– Monomeric IgG (>95%) with small amounts of dimeric and

polymeric IgG1

– Small amounts of IgM and IgA present; varies with product

• Antibody content– One gram of IGIV contains 4x1018 molecules of antibody– >107 specificities to a broad range of bacterial and viral

pathogens

• Stabilized with sugars or amino acids; differs for each product

1. Rütter A, Luger TA. J Am Acad Dermatol 2001;44(6):1010-24.IgA = immunoglobulin A; IgG = immunoglobulin G; IgM = immunoglobulin M; IGIV = intravenous immunoglobulin G.


DOSES OF IGIV FOR PIDD

• Early studies compared IGIV with IGIM

– IM dose: 0.6 cc/kg (~100 mg/kg/mo)

– Initial recommendation for IGIV was 200 mg/kg/mo for first IGIV products

• Late 1980s (Roifman): IgG trough serum levels ≥500 mg/dL reduced frequency of infection and improved pulmonary function1,2

• Recommendation modified in early 1990 to 400 mg/kg to achieve a trough level of ≥500 mg/dl

1. Roifman CM, Gelfand EW. Pediatr Infect Dis J 1988;7(5, suppl):S92-6. 2. Roifman CM, et al. Lancet 1987;i(8541):1075-7.IgG = immunoglobulin G; IGIM = intramuscular immunoglobulin G; IGIV = intravenous immunoglobulin G; IM = intramuscular; PIDD = primary immunodeficiency disease.


DOSES OF IGIV FOR PIDD (cont)

• Quartier et al (Fisher et al)1

– Retrospective study of patients with x-linked agammaglobulinemia (Bruton’s disease)

– Incidence of bacterial infections requiring hospitalization fell from 0.4 to 0.06 per patient per year

• Serum IgG trough levels >500 mg/dL were effective in preventing severe acute bacterial infections

– Patients still developed enteroviral meningoencephalitis and chronic pulmonary disease

• Authors recommended a higher dose to maintain a higher serum IgG trough level (eg, >750 mg/dL to prevent enteroviral disease)

1. Quartier P, et al. J Pediatr 1999;134(5):589-96.IgG = immunoglobulin G; IGIV = intravenous immunoglobulin G; PIDD = primary immunodeficiency disease.


IGIV TherapyBeforeDuring

IgG TROUGH LEVELS AND PNEUMONIA

IRR = 0.726 (CI, 0.658–0.801)

IgG (mg/dL) Incidence (CI)500 0.113 (0.042-0.300)600 0.082 (0.030-0.219)700 0.059 (0.022-0.162)800 0.043 (0.015-0.120)900 0.031 (0.011-0.090)

1000 0.023 (0.008-0.068)

2

1

0.5

0.2

0.1

0.05

0.02

0.01

0.0

Pneu

mon

ia In

cide

nce

per P

atien

t-Ye

ar

Trough IgG (mg/dL)0 200 400 600 800 1000

Orange JS, et al. Clin Immunol 2010;137:21-30.CI = confidence interval; IRR = incidence rate ratio; IgG = immunoglobulin G; IGIV = intravenous immunoglobulin G; IRR = incidence rate ratio.


“BIOLOGIC TROUGH LEVELS”

Titrate IgG trough level to clinical efficacy for an individual patient

Bonagura VR, et al. J Allergy Clin Immunol 2008;122(1)210-2.*Time at which authors assumed care of this patient.IgG = immunoglobulin G; IGIV = intravenous immunoglobulin G; P = pneumonia; S = acute sinusitis.


SUMMARY: DOSE OF IGIV FOR PATIENTS WITH ANTIBODY DEFICIENCY• 400-600 mg/kg/infusion every 4 weeks1

– Adjust dose and/or interval (q 2-3 weeks) depending on clinical response

– In patients starting with higher serum IgG levels, a rough goal is a serum trough level equal to pretreatment levels plus 300 mg/dL

• Follow clinical response; don’t treat the “numbers”– “Biologic trough levels” for better clinical efficacy– Patients with bronchiectasis require higher dosing2

• When changing the dose, it may take several (3) infusions to equilibrate to a new trough3

• Consider the SC route to eliminate trough levels1. Orange JS, et al. J Allergy Clin Immunol 2006;117(suppl):S525-3. 2. Lucas M, et al. J Allergy Clin Immunol 2010;125(6):1345-60. 3. Lehman HK, Ballow M. In: Leung DYM, et al, eds. Pediatric allergy: principles & practice, 2nd edition. St. Louis: Mosby; 2010. Chap 17.IgG = immunoglobulin G; IGIV = intravenous immunoglobulin G; SC = subcutaneous.


IgG LEVELS: IGIV vs IGSC

Bonilla FA. Immunol Allergy Clin North Am 2008;28(4):803-19.IgG = immunoglobulin G; IGIV = intravenous immunoglobulin G; IGSC = subcutaneous immunoglobulin G.

IGIV IGSC


IgG DOSING: IGSC vs IGIV

• US FDA– To achieve AUC bioequivalence, IGSC must be

dosed higher than IGIV1-3

• 10% and 16% products – 137% of IV dose• 20% product – 153% of IV dose

• European Medicines Agency4 – IGSC is to be dosed at 100% of the IGIV dose

1. Wasserman RL, et al. Clin Exp Immunol 2010;161(3):518-26. 2. Ochs HD, et al. J Clin Immunol 2006;26:265-73. 3. Berger M, et al. Clin Immunol 2011;139:133-41. 4. European Agency for the Evaluation of Medical Products Human Medicines Evaluation Unit. Note for guidance on the clinical investigation of human normal immunoglobulin for subcutaneous and intramuscule use (CPMP.BPWG/283/00). 2002.AUC = area under the curve; IgG = immunoglobulin G; IGSC = subcutaneous immunoglobulin G; IGIV = intravenous immunoglobulin G; US FDA = US Food and Drug Administration.


MECHANISM OF ACTION OF rHuPH201,2

• Hyaluronan forms a barrier to bulk movement of molecules in the interstitial space

• Focal depolymerization of hyaluronan increases hydraulic conductivity in the interstitium and rates of infusion/injection

• Reversible change by virtue of short enzyme half-life and rapid endogenous substrate turnover in the skin

• Increased dispersion decreases residence time in the interstitium

• More rapid uptake leads to better pharmacokinetics resulting in increased bioavailability

1. Day TD. J Physiol 1952;117:1-8. 2. Bookbinder LH, et al. J Controlled Release 2006;114:230-41.


IGSC VS IgHY INFUSIONIGSC Site 15 mL

IGSC + rHuPH20 (IGHy) (approx. 300 mL IgG liquid 10% + rHuPH20)

IGHy IGHy

IGSC = subcutaneous immunoglobulin G.


PHARMACOKINETICS OF ENZYME-FACILITATED IGSC INFUSION (ANIMAL MODEL)

• rHuPH20 increases Cmax and decreases Tmax for large-molecule therapeutics • More rapid absorption (Ka) results in shorter residence time and increased systemic bioavailability

Concentrations of radiolabeled IgG1 (10 mg/kg) administered via IV, SC, or SC + rHuPH20 in rodent model. Gamma counting expressed as counts per minute per mL of blood.

IgG

Ser

um L

evel

s (C

ount

s/m

L)

Time (h)0 10 20 50 604030 80 90 120110100 130

1.81 E+06

1.61 E+06

1.41 E+06

1.21 E+06

1.01 E+06

8.10 E+05

6.10 E+05

4.10 E+05

2.10 E+05

1.00 E+04

IgG 10 mg/kg SC + rHuPH20 IgG 10 mg/kg SC

IgG 10 mg/kg IV

70

IgG = immunoglobulin G; IGSC = subcutaneous immunoglobulin G; SC = subcutaneous; IV = intravenous.Bookbinder LH, et al. J Controlled Release 2006;114:230-241.


AUCs AFTER IGIV AND IGSC + rHUPH20 (IGHy)

--- IGIV― IGSC + rHuPH20 (IgHy)

Misbah S, et al. Clin Exp Immunol 2009;158(suppl 1):51-9.AUC = area under the curve; IgG = immunoglobulin G; IGIV = intravenous immunoglobulin G; IGSC = subcutaneous immunoglobulin G.

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