1. HER2+ 或 HER2 弱陽性/微陽性 轉移性乳癌
HER2-positive or HER2-low Metastatic Breast Cancer

2. 腫瘤具有活化型HER2 (ERBB2)突變非小細胞肺癌
Non-small Cell Lung Cancer with Activating HER2 (ERBB2) Mutation

3. 局部晚期或轉移性HER2陽性(IHC 3+或 IHC 2+/ISH陽性)胃癌
Locally Advanced or Metastatic HER2-positive (IHC 3+ or IHC 2+/ISH-positive) Gastric Cancer 

4. HER2陽性(IHC 3+) 實體腫瘤，但仍須執行確認性試驗
HER2-positive (IHC 3+) Solid Tumors, Confirmatory Trials Pending

Antineoplastic Agent, Anti-HER2; Antineoplastic Agent, Antibody Drug Conjugate; Antineoplastic Agent, Monoclonal Antibody; Antineoplastic Agent, Topoisomerase I Inhibitor

Distribution: Vd: Fam-trastuzumab deruxtecan: 2.68 L.
Protein binding: DXd: ~97% (to plasma proteins).
Metabolism: Fam-trastuzumab deruxtecan: Degradation via catabolic pathways into small peptides and amino acids; DXd: Primarily via CYP3A4.
Half-life elimination: Fam-trastuzumab deruxtecan: ~5.4 to 5.7 days; DXd: 5.4 to 6.1 days.
Excretion: Clearance: Fam-trastuzumab deruxtecan: 0.41 L/day; DXd: 18.3 L/hour.

There are no contraindications listed in the manufacturer's US labeling.

Based on the mechanism of action and postmarketing data, exposure to fam-trastuzumab deruxtecan during pregnancy can result in embryo-fetal harm. Advise patients of these risks and the need for effective contraception.

It is not known if fam-trastuzumab deruxtecan is present in breast milk. Due to the potential for serious adverse reactions in the breastfed infant, breastfeeding is not recommended by the manufacturer during therapy and for 7 months after the last fam-trastuzumab deruxtecan dose.

>10%:
Dermatologic: Alopecia (21% to 46%), skin rash (3% to 13%; including bullous rash, dermatitis, erythema multiforme, maculopapular rash, palmar-plantar erythrodysesthesia)
Endocrine & metabolic: Decreased serum albumin (39%), hypokalemia (17% to 35%), weight loss (16% to 17%)
Gastrointestinal: Abdominal pain (9% to 21%), constipation (24% to 35%), decreased appetite (29% to 60%), diarrhea (19% to 32%; grades 3/4: 1% to 2%), dyspepsia (11% to 12%), nausea (61% to 79%; grades 3/4: 3% to 7%), stomatitis (11% to 20%; grades 3/4: 2%), vomiting (26% to 49%; grades 3/4: 2% to 4%)
Hematologic & oncologic: Anemia (31% to 58%; grades 3/4: 7% to 38%),decreased neutrophils (52% to 72%; grades 3/4: 12% to 51%), decreased platelet count (37% to 68%; grades 3/4: 3% to 12%), decreased white blood cell count (60% to 74%; grades 3/4: 4% to 29%), hemorrhage (16%), lymphocytopenia (43% to 70%; grades 3/4: 14% to 28%)
Hepatic: Increased serum alanine aminotransferase (34% to 53%), increased serum alkaline phosphatase (22% to 54%), increased serum aspartate aminotransferase (35% to 67%), increased serum bilirubin (16% to 24%)
Nervous system: Dizziness (10% to 13%), fatigue (32% to 59%; including asthenia and malaise), headache (4% to 22%), peripheral neuropathy (13%; grades 3/4: <1%)
Neuromuscular & skeletal: Musculoskeletal pain (15% to 32%)
Ophthalmic: Dry eye syndrome (11%)
Renal: Increased serum creatinine (15% to 16%)
Respiratory: Cough (10% to 20%), dyspnea (5% to 13%), epistaxis (3% to 13%), interstitial lung disease (6% to 12%; including pneumonitis and respiratory failure), respiratory tract infection (22%; including bronchitis, influenza, lower respiratory tract infection, pneumonia, and respiratory syncytial virus infection), upper respiratory tract infection (4% to 15%)
Miscellaneous: Fever (12% to 24%)

1. Breast cancer, unresectable or metastatic, HER2-positive/low/Ultrlow:
IV: 5.4 mg/kg once every 3 weeks until disease progression or unacceptable toxicity.
2. Colorectal cancer, metastatic, HER2-expressing:
(off-label use): IV: 6.4 mg/kg once every 3 weeks until disease progression or unacceptable toxicity (Siena 2021). Refer to protocol for dosage adjustment details.
3. Gastric cancer, locally advanced or metastatic, HER2-positive:
IV: 6.4 mg/kg once every 3 weeks until disease progression or unacceptable toxicity.
4. Non–small cell lung cancer, unresectable or metastatic, HER2-mutant:
IV: 5.4 mg/kg once every 3 weeks until disease progression or unacceptable toxicity.

CrCl ≥30 mL/minute: No dosage adjustment necessary.
Monitor more frequently for interstitial lung disease in patients with moderate impairment.

Mild (total bilirubin ≤ ULN and any AST > ULN or total bilirubin >1 to 1.5 times ULN and any AST) or moderate (total bilirubin >1.5 to 3 times ULN and any AST) impairment: No dosage adjustment necessary.
Monitor closely for toxicities in patients with moderate impairment.

Store at 2-8℃, do not freeze.