Patients

Between the 2 participating centers, 67 patients were screened, and 47 patients (44 adults and 3 children) met the eligibility criteria and were enrolled in the study. The patients were predominantly White (89.1%) and not of Hispanic or Latino ethnicity (93.3%). The median (range) age of the three children was 9.0 (8–13) years. All patients (n = 47; 100%) were insured, with the majority enrolled in Medicare (n = 33; 70.2%).

Among the 44 adult patients, 39 (88.6%) were female, the median (range) age was 71.0 (26–82) years, and 32 (72.7%) were aged > 65 years (Table 1). More than 50% of the adult patients were obese or overweight.

Table 1 Patient demographicsa

Owing to the small number of pediatric patients, Tables 1, 2, 3, and 4 present the results of the adult population, with the available pediatric data summarized in the text.

Table 2 Ig20Gly administration at initiation, 6, and 12 monthsaTable 3 Ig20Gly infusion parameters at treatment initiation, 6, and 12 monthsaTable 4 Adverse drug reactionsaMedical History

Most (n = 30; 63.8%) patients had received an IGRT within the 12-month period before starting Ig20Gly treatment, and the remaining patients (n = 17; 36.2%) started de novo on Ig20Gly. Prior IGRTs included 10% IVIG (n = 31), facilitated 10% SCIG with recombinant human hyaluronidase (n = 16), 20% SCIG (n = 9), and unspecified IVIG (n = 1). Reasons provided for switching to Ig20Gly included insurance (n = 6; 20.0%), an unfavorable AE profile with previous treatment (n = 6; 20.0%), preference for less frequent infusions/less travel to an infusion center (n = 4; 13.3%), previous treatment was not effective (n = 2; 6.7%), higher infusion volumes, and preference for at-home use (n = 1; 3.3% each). The reason for switching was not indicated for 8 (26.7%) patients and was listed as “other” for 2 (6.7%) patients.

Most (97.9%) patients had received at least 1 concomitant medication, with 43 (91.5%) patients had received more than 5 medications. The 5 most common classes of concomitant medications patients had received were inhalant adrenergic (61.7%), drugs for peptic ulcer and gastroesophageal reflux disease (57.4%), antihistamines (systemic; 55.3%), cardiac stimulants excluding glycosides (55.3%), and direct-acting antivirals (48.9%). The concomitant use of antithrombotic agents was low (19.1%). All patients had at least 1 comorbidity, which was the most frequent history of infections and infestations (n = 44; 93.6%), followed by respiratory, thoracic, and mediastinal disorders (n = 41; 87.2%), gastrointestinal disorders (n = 38; 80.9%), musculoskeletal and connective tissue disorders (n = 38; 80.9%), and immune system disorders (n = 34; 72.3%). Few patients had a history of deep vein thrombosis (8.5%) and pulmonary embolism (6.4%).

The most common PIDD diagnosis was CVID (74.5%), followed by selective polysaccharide antibody deficiency (12.8%), humoral immune defect (4.3%), ataxia telangiectasia (2.1%), combined immunodeficiency (2.1%), Good syndrome (2.1%), and selective IgG subclass deficiency (2.1%). Median (range) disease duration was 187.0 (5–4717) days and was numerically shorter in IG-de novo patients than in IG-experienced patients (24.0 [5–480] and 805.0 [8–4717] days, respectively). Patient age (median [range]) was similar at PIDD diagnosis for IG-de novo (66.0 [9.0–80.0] years) and IG-experienced patients (66.0 [0.5–77.0] years). The most reported PIDD-related symptom was frequent and recurrent infections (45 [95.7%] patients).

Ig20Gly Administration

Table 2 reports Ig20Gly administration parameters at initiation, 6, and 12 months. Most adult patients received treatment at home across all time points (75.0%, 82.1%, and 84.0% at initiation, 6, and 12 months, respectively). The proportion of adult IG-de novo patients who received treatment at home increased over time (71.4%, 90.0%, and 100.0% at initiation, 6, and 12 months, respectively), while the proportion of adult IG-experienced patients who received treatment at home remained consistent throughout the study (76.9%, 77.8%, and 76.5% at initiation, 6, and 12 months, respectively). All adult patients with available data received assistance with their initiation infusion, and most self-administered Ig20Gly at 6 months (90.0%) and 12 months (88.2%). Similar proportions of adult IG-de novo and IG-experienced patients self-administered Ig20Gly at 6 months (88.9% vs 90.9%, respectively) and 12 months (87.5% vs 88.9%, respectively). The thigh was the most common infusion site for adult patients with available data at all time points (70.4%, 100.0%, and 100.0% at initiation, 6, and 12 months, respectively).

Of pediatric patients (n = 3) with available data, all received their initial infusion at home with nursing assistance. At 6 and 12 months, all 3 pediatric patients infused Ig20Gly at home with assistance from their adult caregiver. Two pediatric patients with available data were reported as having the abdomen as the infusion site.

Infusion Parameters Overall Adults

IG dose (mean [SD]) for adult patients was similar over time, with a slightly higher dose at 12 months (13.4 [5.9], 13.1 [5.6], and 14.2 [5.8] g at initiation, 6, and 12 months, respectively). The mean (SD) infusion rate was 79.7 (27.8), 64.7 (32.2), and 74.6 (27.7) mL/h per infusion at initiation, 6, and 12 months, respectively. Several patients (including 2 patients at initiation, 3 patients at 6 months, and 1 patient at 12 months) received treatment at a rate ≥ 120 mL/h, using 2 infusion sites (Table 3). The mean (SD) number of infusion sites per infusion at Ig20Gly initiation was 1.7 (0.5). Infusion duration (mean [SD]) was similar across time, with a slightly higher duration at 12 months (50.5 [17.0], 50.7 [17.5], and 54.3 [21.5] min at initiation, 6, and 12 months, respectively). The prescribed infusion frequency for adults with available data was weekly or biweekly at initiation (57.1% vs 42.9%), 6 months (50.0% vs 50.0%), and 12 months (44.2% vs 55.8%). The need for dose adjustments among adult patients was minimal (10 instances) within the 12-month study duration (Table 3).

IG-De Novo Adults

In the adults who started IGRT de novo, the mean (SD) IgG level was 714.5 (141.3) mg/dL at Ig20Gly initiation. IG dose (mean [SD]) increased from initiation (8.2 [1.2] g) to 12 months (10.3 [3.7] g; Table 3). The infusion rate (mean [SD]) also increased from initiation (55.3 [21.1] mL/h) to 12 months (79.0 [33.7] mL/h; Table 3). The mean (SD) number of infusion sites per infusion was approximately 2 throughout the study period (Table 3). The infusion duration (mean [SD]) slightly decreased over time (49.3 [16.7] and 44.4 [14.2] min at initiation and 12 months, respectively; Table 3).

IG-Experienced Adults

The mean (SD) IgG level in the adults who switched from another IGRT was 719.6 (309.9) mg/dL, similar to IG-de novo adults. IG dose (mean [SD]) was similar across time, with a slightly higher dose at 12 months (15.9 [5.6], 15.3 [5.8], and 16.5 [5.6] g at initiation, 6, and 12 months, respectively). At Ig20Gly initiation, adult IG-experienced patients used a mean (SD) of 1.8 (0.4) infusion sites per infusion (Table 3). Unlike the IG-de novo adults, infusion rate (mean [SD]) decreased over time (94.0 [20.5] and 68.0 [15.5] mL/h at initiation and 12 months, respectively), and infusion duration (mean [SD]) increased (51.2 [17.9] and 69.2 [22.9] min at initiation and 12 months, respectively; Table 3).

Pediatric Patients (n = 3)

The mean (SD) IG dose administered in children was 5.7 (1.5), 6.3 (2.1), and 6.3 (2.1) g at initiation, 6, and 12 months, respectively. For pediatric patients with available data at initiation (n = 2), the mean (SD) infusion rate was 60.0 (6) mL/h (no pediatric data were available at 6 months), and the mean (SD) infusion duration at initiation was 30.0 (0) min (no pediatric data were available at 6 or 12 months). The prescribed infusion frequency was weekly or biweekly at initiation (33.3% vs 66.7%), 6 months (50.0% vs 50.0%), and 12 months (33.3% vs 66.7%). No pediatric patients required dose adjustments during the study period. Overall, 1 child required additional therapy due to hospital formulary limitations during hospitalization (gammagard liquid 10%).

Healthcare Resource Utilization

There were no emergency department visits during the study. One adult patient had 3 hospital visits (due to pneumonia, flu, and interstitial lung disease); each visit had a duration of less than 1 day. Twenty-one adult patients (IG-de novo, n = 9; IG-experienced, n = 12) had a median (range) of 4.0 (1–5) physician visits, with many patients on a 3-month follow-up schedule. Infections were reported in 6 adult patients during the 12-month study period. One pediatric patient was admitted to the hospital for an issue unrelated to the study, and no pediatric patients had physician visits.

Infections

Six patients (all adults) had a mean (SD) of 2.3 (1.8) infections. Three (6.4%) patients each had 1 infection, and 1 (2.1%) patient each had 2, 4, or 5 infections.

Tolerability

A total of 46 ADRs occurred in 16 (36.4%) adult patients (Table 4). ADRs were most frequently categorized as general disorders and administration site conditions (44 events in 15 adult patients). The most common (> 2 events) ADRs were infusion site pain, infusion site erythema, infusion site pruritus, and infusion site reaction. None of the ADRs were associated with treatment discontinuation or a change in dose. Three ADRs resulted in further action: 1 event (infusion site extravasation) was followed by a switch in needle size; 1 event (infusion site rash) was followed by a change of infusion site from the leg to the abdomen; and 1 patient received concomitant medication for an infusion site rash.

Among pediatric patients (n = 3), 5 ADRs occurred in 1 (33.3%) patient, including infusion site pain (1 event in 1 patient) and infusion site erythema (4 events in 1 patient), none of which were associated with treatment discontinuation or a change in dose.

Safety

A total of 336 AEs (defined as any medical condition that occurred over the study period) were reported in 47 (100.0%) patients, with the majority considered not related to PIDD (1 event in 1 [2.1%] patient was considered to be associated with PIDD). Concomitant medication was required for 37 (78.7%) patients who experienced AEs, and none of the AEs led to Ig20Gly discontinuation. There were 21 serious AEs (SAEs) reported in 13 (27.7%) patients: none led to treatment discontinuation and were not considered associated with PIDD; 12 required concomitant medication in 10 (21.3%) patients. A total of 105 TEAEs were experienced by 44.7% of patients, with system organ classes reported in > 10% of patients that were general disorders and administration site conditions (49 events in 13 [27.7%] patients) and infections and infestations (10 events in 8 [17.0%] patients).