ANTHIM
Clinical safety rating
cautionComprehensive clinical and safety monograph for ANTHIM (ANTHIM).
Comprehensive clinical and safety monograph for ANTHIM (ANTHIM).
FDA: Treatment of chronic lymphocytic leukemia (CLL) (not approved; withdrawn from market)Off-label: None
Oblimersen is an antisense oligonucleotide that inhibits the production of Bcl-2 protein, promoting apoptosis in cancer cells.
| Metabolism | Metabolized by exonucleases to shorter oligonucleotides. |
| Excretion | Renal: approximately 50% as unchanged drug; biliary/fecal: minimal (<10%) |
| Half-life | Terminal elimination half-life: approximately 21 days (range 12–31 days); supports monthly dosing for post-exposure prophylaxis |
| Protein binding | Approximately 57% bound to plasma proteins (including albumin and immunoglobulins) |
| Volume of Distribution | Volume of distribution: approximately 0.16–0.20 L/kg; indicates limited extravascular distribution, consistent with a monoclonal antibody |
| Bioavailability | Intravenous: 100% bioavailability; no other routes are approved or clinically relevant |
| Onset of Action | Intravenous: onset of clinical effect occurs within hours to days; maximal serum concentration achieved by end of infusion |
| Duration of Action | Duration of therapeutic effect: up to 1 month after a single IV dose; due to long half-life, protective neutralizing antibody levels persist for ≥4 weeks |
| Molecular Weight | 148000 |
800 mg IV over 90 minutes, then 400 mg IV over 90 minutes at 2 and 4 weeks post-first dose.
| Dosage form | INJECTABLE |
| Renal impairment | No dose adjustment required for mild to moderate renal impairment (CrCl ≥30 mL/min). Insufficient data for severe renal impairment (CrCl <30 mL/min) or ESRD. |
| Liver impairment | No dose adjustment required for mild to moderate hepatic impairment (Child-Pugh A or B). Insufficient data for severe hepatic impairment (Child-Pugh C). |
| Pediatric use | For patients weighing 10 kg to <40 kg: 14 mg/kg IV (max 800 mg) over 90 minutes, then 7 mg/kg IV (max 400 mg) over 90 minutes at 2 and 4 weeks post-first dose. For patients ≥40 kg: same as adult dosing. |
| Geriatric use | No specific dose adjustment recommended; clinical studies did not include sufficient numbers of patients aged ≥65 years to determine whether they respond differently. Use with caution. |
| 1st trimester | No human data available; animal studies show no evidence of fetal harm at doses up to 5 times the human dose. Use only if benefit outweighs risk. |
| 2nd trimester | No human data available; animal studies show no evidence of fetal harm. Use only if benefit outweighs risk. |
| 3rd trimester | No human data available; animal studies show no evidence of fetal harm. Use only if benefit outweighs risk. |
Clinical note
Comprehensive clinical and safety monograph for ANTHIM (ANTHIM).
| Placental transfer | Likely minimal due to high molecular weight (148 kDa); not studied in humans. |
| Breastfeeding | Unknown if distributed in human milk; limited data suggest low excretion due to high molecular weight. Caution advised. |
| Lactation Rating | L3 |
| Teratogenic Risk | ANTHIM (obiltoxaximab) is a monoclonal antibody. Embryo-fetal developmental studies in monkeys showed no adverse effects at doses up to 17 times the human dose. However, human data is limited. As a IgG1 monoclonal antibody, it is expected to cross the placenta increasingly after the first trimester. The risk is likely low but cannot be excluded. Use only if clearly needed. |
| Fetal Monitoring | Monitor for infusion reactions (e.g., rash, hypotension, fever) during administration. For anthrax infection, standard monitoring for infection progression including vital signs, respiratory status, and signs of toxemia. No specific fetal monitoring indicated unless maternal deterioration occurs. |
| Fertility Effects | Animal studies with obiltoxaximab have not been conducted to evaluate fertility. No known effects on human fertility reported. As a monoclonal antibody, it is unlikely to directly affect reproductive organs. |
■ FDA Black Box Warning
None.
| Serious Effects |
Hypersensitivity to anthrax immune globulin or any excipient
| Precautions | Myelosuppression, Infusion reactions, Tumor lysis syndrome, Electrolyte abnormalities, Cardiotoxicity |
| Food/Dietary | No known food interactions. ANTHIM is administered intravenously, and food intake does not affect its pharmacokinetics. |
| Clinical Pearls | ANTHIM (obiltoxaximab) is a monoclonal antibody indicated for inhalational anthrax. It should be administered as soon as possible after suspected or confirmed exposure. Premedication with diphenhydramine may reduce infusion reactions. Monitor for anaphylaxis and infusion-related reactions. Efficacy is established in animal models due to ethical limitations. |
| Patient Advice | ANTHIM is used to treat or prevent inhalational anthrax, which can be fatal if not treated. · You will receive this medication as an intravenous (IV) infusion over 1.5 hours. · You may experience side effects such as pain or swelling at the infusion site, headache, itching, or feeling tired. · Serious allergic reactions can occur; tell your healthcare provider immediately if you develop rash, hives, difficulty breathing, or swelling of the face or throat. · Because ANTHIM is made from mouse proteins, it can cause allergic reactions in some people. · This medication should not replace a recommended vaccination program for anthrax. |
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