Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.
In a randomized, double-blind, parallel arm trial conducted to evaluate the safety of BAT in healthy subjects, and to establish the pharmacokinetic profile of the seven botulinum antitoxin serotypes contained in BAT following intravenous (IV) administration, 40 subjects were randomized to receive either one (n=20) or two vials (n=20) of BAT.
In a second parallel arm, randomized, double-blind pharmacodynamic trial, 26 healthy subjects were randomized to receive either BAT in saline (n=16) or placebo (0.9% saline; n=10).
The most common adverse reactions in all healthy subjects were headache (9%), pruritus (5%), nausea (5%), and urticaria (5%). Other adverse reactions reported in less than 4% of subjects included pyrexia and throat discomfort. All reported adverse reactions were considered mild or moderate. No serious adverse reactions were reported. Two moderate acute allergic reactions that required premature termination of the infusion and treatment were reported. Reactions were predefined as mild if the subject was aware but could tolerate. Moderate reactions were predefined as discomfort enough to interfere with normal daily activity.
A total of 231 subjects with suspected or confirmed botulism were exposed to BAT in an open-label observational expanded access clinical study sponsored by the Centers for Disease Control and Prevention (CDC).
The majority of adult (213/216) and pediatric (13/15) subjects received one dose of BAT. Three adult subjects were exposed to a second dose of BAT, and two pediatric subjects each received two infant doses (10% of the adult dose). The administration of a second dose varied from seven hours to one month after the first dose.
Safety data was actively collected from treating physicians by the CDC. However, no on-site safety monitoring was performed, and the CDC relied on follow-up information provided by the treating physicians to determine the reporting frequencies for adverse reactions. Of the 231 subjects receiving BAT, safety information was available for 228 subjects. Adverse reactions were reported in 10% of all subjects. The most common adverse reactions were pyrexia (4%), rash (2%), chills (1%), nausea (1%), and edema (1%). Other adverse reactions were reported in less than 1% of subjects. No subject experienced anaphylaxis. One subject experienced a serious adverse reaction of hemodynamic instability characterized by bradycardia, tachycardia, and asystole during BAT administration. One subject experienced mild serum sickness (< 1%) with myalgia, arthralgia, and dark urine twelve days after BAT administration.
Table 3Summary of Adverse Drug Reactions (ADR) Reported in Subjects that Received BAT through the CDC Expanded Access Clinical Study | System Organ Class | Preferred Term | Overall (N=228) |
|---|
| No. of Events | No. of Subjects | % of Subjects |
|---|
ALL BODY SYSTEM | OVERALL | 37 | 23 | 10.1 |
Cardiac disorders | Cardiac arrest | 1 | 1 | 0.4 |
Bradycardia | 1 | 1 | 0.4 |
Tachycardia | 1 | 1 | 0.4 |
Gastrointestinal disorders | Vomiting | 1 | 1 | 0.4 |
Nausea | 2 | 2 | 0.9 |
General disorders and administration site conditions | Pyrexia | 9 | 9 | 3.9 |
Chest discomfort | 1 | 1 | 0.4 |
Edema | 2 | 2 | 0.9 |
Chills | 3 | 3 | 1.3 |
Feeling jittery | 1 | 1 | 0.4 |
Immune system disorders | Serum Sickness | 1 | 1 | 0.4 |
Investigations | Blood pressure increased | 1 | 1 | 0.4 |
White blood cell count increased | 1 | 1 | 0.4 |
Psychiatric disorders | Agitation | 1 | 1 | 0.4 |
Anxiety | 1 | 1 | 0.4 |
Renal and urinary disorders | Urinary retention | 1 | 1 | 0.4 |
Respiratory, thoracic and mediastinal disorders | Bronchospasm | 1 | 1 | 0.4 |
Skin and subcutaneous tissue disorders | Erythema | 1 | 1 | 0.4 |
Hyperhidrosis | 1 | 1 | 0.4 |
Rash | 4 | 4 | 1.8 |
Vascular disorders | Hemodynamic instability | 1 | 1 | 0.4 |
Hypotension | 1 | 1 | 0.4 |
All adverse reactions were classified according to MedDRA Version 15.0 and are ranked according to medical significance within a given SOC. |