TPOXX SIDE EFFECTS

  • Generic Name: tecovirimat capsules
  • Brand Name: TPOXX
  • Drug Class: Antivirals, Other
Last updated on MDtodate: 10/12/2022

SIDE EFFECTS

Clinical Trials Experience

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.

The safety of TPOXX has not been studied in patients with smallpox disease.

TPOXX Clinical Trial (Oral Administration)

The safety of TPOXX was evaluated in 359 healthy adult subjects ages 18-79 years in a Phase 3 clinical trial. Of the subjects who received at least one 600 mg dose of TPOXX, 59% were female, 69% were White, 28% were Black/African American, 1% were Asian, and 12% were Hispanic or Latino. Ten percent of the subjects who participated in the study were age 65 or older. Of these 359 subjects, 336 subjects received at least 23 of 28 doses of 600 mg TPOXX in a twice daily (every 12 hours) regimen for 14 days.

Most Frequently Reported Adverse Reactions

The most frequently reported adverse reactions were headache and nausea. Adverse reactions that occurred in at least 2% of subjects in the TPOXX treatment group are shown in Table 1.

Table 1: Treatment-Related Adverse Reactions Reported in ≥ 2% of Healthy Adult Subjects Receiving at Least One Dose of TPOXX Capsules 600 mg

Adverse Reaction TPOXX 600 mg
N = 359 (%)
Placebo
N = 90 (%)
Headache 12 8
Nausea 5 4
Abdominal paina 2 1
Vomiting 2 0
aIncludes abdominal pain, abdominal pain upper, abdominal distension, abdominal discomfort, abdominal pain lower, epigastric pain

 

Adverse Reactions Leading To Discontinuation Of TPOXX

Six subjects (2%) had their treatment with TPOXX discontinued due to adverse reactions.  Each of these subject’s adverse reactions (with severity) is listed below:

  • EEG change, abnormal
  • Mild upset stomach, dry mouth, decreased concentration and dysphoria
  • Mild nausea and fever, moderate diarrhea, severe headache
  • Mild palpable purpura
  • Mild nausea, fever and chills
  • Mild facial redness, facial swelling and pruritus

Less Common Adverse Reactions

Clinically significant adverse reactions that were reported in < 2% of subjects exposed to TPOXX and at rates higher than subjects who received placebo are listed below:

  • Gastrointestinal: dry mouth, chapped lips, dyspepsia, eructation, oral paresthesia
  • General and administration site: pyrexia, pain, chills, malaise, thirst
  • Investigations: abnormal electroencephalogram, hematocrit decreased, hemoglobin decreased, heart rate increased
  • Musculoskeletal and connective tissue: arthralgia, osteoarthritis
  • Nervous system: migraine, disturbance in attention, dysgeusia, paresthesia
  • Psychiatric: depression, dysphoria, irritability, panic attack
  • Respiratory, Thoracic and Mediastinal Disorders: oropharyngeal pain
  • Skin and subcutaneous tissue: palpable purpura, rash, pruritic rash, facial redness, facial swelling, pruritus

TPOXX Clinical Trial (Intravenous Administration)

The safety of multiple doses of 240 mg of TPOXX injection for IV infusion was evaluated in 26 healthy adult subjects ages 23-62 years, inclusive. An additional 6 subjects received placebo. TPOXX injection was administered over a 6 hour period via infusion pump twice daily (every 12 hours) for 7 days. Of the 26 subjects administered TPOXX, 42% were female, 69% were White, 23% were Black/African American, and 42% were Hispanic or Latino.

Most Frequently Reported Adverse Reactions

The most frequently reported adverse reactions included infusion site pain, infusion site swelling, infusion site erythema, infusion site extravasation, and headache. Adverse reactions that occurred in at least 4% of subjects in the TPOXX treatment group are shown in Table 2.

Table 2: Treatment-Related Adverse Reactions Reported in ≥ 4% of Healthy Adult Subjects Receiving at Least One Dose of TPOXX Injection 240 mg

TPOXX 240 mg
N =26 (%)
Placebo
N = 6 (%)
Infusion Site Pain 73 67
Infusion Site Swelling 39 67
Infusion Site Erythema 23 67
Infusion Site Extravasation 19 50
Headache 15 0

 

Adverse Reactions Leading To Discontinuation Of TPOXX Injection

Three subjects (12%) had their treatment with TPOXX injection discontinued due to adverse reactions. One subject had two adverse reactions. Each of these subject’s adverse reactions (with severity) are listed below:

  • Moderate Infusion site extravasation
  • Mild Infusion site extravasation
  • Mild Infusion site swelling and mild infusion site pain

Less Common Adverse Reactions

Clinically significant adverse reactions that were reported in < 4% of subjects exposed to TPOXX injection and at rates higher than subjects who received placebo are listed below:

  • General and administration site: infusion site discomfort, infusion site edema
  • Musculoskeletal and connective tissue: myalgia, arthritis, back pain, muscle tightness
  • Gastrointestinal: diarrhea
  • Eye: photophobia
  • Skin and Subcutaneous Tissue: pruritus generalized

 

SRC: NLM .