Because clinical studies are conducted under widely varying conditions, adverse reaction rates observed cannot be directly compared to rates in other clinical trials and may not reflect the rates observed in practice.
Two separate clinical trials were conducted with PROLASTIN-C: 1.) a 20 week, open-label, single arm safety study in 38 subjects (single-arm open-label trial), and 2.) a 16 week, randomized, double-blind, crossover pharmacokinetic comparability study vs. PROLASTIN in 24 subjects, followed by an 8 week open-label treatment with PROLASTIN-C (randomized double-blinded comparator trial). Thus, 62 subjects were exposed to PROLASTIN-C in clinical trials.
The most serious adverse reaction observed during clinical trials with PROLASTIN-C was an abdominal and extremity rash in one subject. The rash resolved subsequent to outpatient treatment with antihistamines and steroids. Two instances of a less severe, pruritic abdominal rash were observed upon rechallenge despite continued antihistamine and steroid treatment, which led to withdrawal of the subject from the trial.
Grifols assessed the randomized double-blinded comparator trial for adverse reactions (as defined in the footnote to Table 1) occurring during each 8 week double-blind crossover treatment period, as shown in Table 1.
Table 1: Adverse Reactions Occurring during the First 8 Weeks of Each Double-Blinded Treatment| | PROLASTIN®-C No. of subjects: 24 | PROLASTIN® No. of subjects: 24 |
| Adverse Reaction An adverse reaction is defined as any adverse event where either a) the incidence with PROLASTIN-C was greater than with PROLASTIN, or b) the occurrence was within 72 hours of treatment, or c) the event was otherwise considered related or possibly related to the drug. ,Source: the randomized double-blinded comparator trial | No. of Subjects with Adverse Reaction (percentage of all subjects) | No. of Subjects with Adverse Reaction (percentage of all subjects) |
| Upper respiratory tract infection | 3 (12.5%) | 1 (4.2%) |
| Headache | 1 (4.2%) | 2 (8.3%) |
| Pruritus | 1 (4.2%) | 0 |
| Urticaria | 1 (4.2%) | 0 |
| Nausea | 1 (4.2%) | 0 |
| Peripheral edema | 1 (4.2%) | 0 |
| Pyrexia | 1 (4.2%) | 0 |
Table 2 below displays the adverse reaction (defined as per Table 1) rate as a percentage of infusions received during the 8 weeks of each double-blinded treatment.
Table 2: Adverse Reaction Frequency as a Percent of All Infusions during the First 8 Weeks of Each Double-Blinded Infusion Treatment| | PROLASTIN®-C No. of infusions: 188 | PROLASTIN® No. of infusions: 192 |
| Adverse Reaction Source: the randomized double-blinded comparator trial. | No. of Adverse Reactions (percentage of all infusions) | No. of Adverse Reactions (percentage of all infusions) |
| Upper respiratory tract infection | 3 (1.6%) | 1 (0.5%) |
| Headache | 1 (0.5%) | 3 (1.6%) |
| Pruritus | 1 (0.5%) | 0 |
| Urticaria | 1 (0.5%) | 0 |
| Nausea | 1 (0.5%) | 0 |
| Peripheral edema | 1 (0.5%) | 0 |
| Pyrexia | 1 (0.5%) | 0 |
Table 3 below displays the adverse reactions occurring in two or more subjects during the single-arm open-label trial.
Table 3: Adverse Reactions Occurring in Two or More Subjects (>5%) during the 20 Week Single-Arm Open-Label Trial| | PROLASTIN-C No. subjects: 38 |
| Adverse Reaction An adverse reaction is defined as any adverse event that occurred where either a) the occurrence was within 72 hours of treatment, or b) the event was otherwise considered related or possibly related to the drug. ,Source: the single-arm, open-label trial. | No. of subjects with Adverse Reaction (percentage of all subjects) |
| Upper respiratory tract infection | 6 (15.8%) |
| Urinary tract infection | 5 (13.2%) |
| Nausea | 4 (10.5%) |
| Chest pain | 3 (7.9%) |
| Back pain | 2 (5.3%) |
| Chills | 2 (5.3%) |
| Cough | 2 (5.3%) |
| Dizziness | 2 (5.3%) |
| Dyspnea | 2 (5.3%) |
| Headache | 2 (5.3%) |
| Hot flush | 2 (5.3%) |
| Oral candidiasis | 2 (5.3%) |
Ten exacerbations of chronic obstructive pulmonary disease were reported by 8 subjects in the 24 week crossover pharmacokinetic study. During the 16 week double-blind crossover phase, 4 subjects (17%) had a total of 4 exacerbations during PROLASTIN-C treatment and 4 subjects (17%) had a total of 4 exacerbations during PROLASTIN treatment. Two additional exacerbations in 2 subjects (8%) occurred during the 8 week open-label treatment period with PROLASTIN-C. The overall rate of pulmonary exacerbations during treatment with either product was 0.9 exacerbations per subject-year.
Immunogenicity
The detection of antibody formation is highly dependent on the sensitivity and specificity of the assay. Additionally, the observed incidence of antibody (including neutralizing antibody) positivity in an assay may be influenced by several factors including assay methodology, sample handling, timing of sample collection, concomitant medications, and underlying disease. For these reasons, comparison of the incidence of antibodies to PROLASTIN-C with the incidence of antibodies to other products may be misleading.
In the single-arm, open-label safety clinical trial, three treatment naïve subjects out of 36 subjects evaluated developed antibody to Alpha1-PI at week 24 after receiving PROLASTIN-C. A fourth subject (non-naïve) was positive prior to and after receiving PROLASTIN-C, but levels were unchanged during the study. None of the four antibody specimens was able to neutralize the protease inhibitor capacity of PROLASTIN-C. In the randomized, crossover pharmacokinetic clinical trial, none of 24 subjects developed antibodies to PROLASTIN-C.