Trastuzumab

Evidence Level: L5

Predicted Indications: 6

Trastuzumab

Pharmacist Assessment Report

Trastuzumab: Malignant cutaneous granular cell skin tumor

One-Sentence Summary

Trastuzumab is a HER2-targeted monoclonal antibody, originally used to treat HER2-positive breast carcinoma. The model’s other predictions for related breast cancer subtypes (progesterone-receptor positive and negative disease) have far stronger support and are summarised below for context.

Quick Overview

Item	Content
Original Indication	Not recorded in the local data
Predicted New Indication	Malignant cutaneous granular cell skin tumor
TxGNN Prediction Score	0.9948
Evidence Level	L5
Australia Market Status	Listed on the PBS Schedule (1 of 1 items) – TGA (ARTG) registration status is not included in this data
Number of PBS Items	1 (valid: 1)
Recommended Decision	Hold

Why is This Prediction Reasonable?

Detailed mechanism of action data is not available in the data compiled for this report. Based on known pharmacology, trastuzumab binds the extracellular domain of HER2, inhibiting HER2 signalling and mediating antibody-dependent cellular cytotoxicity (ADCC). Its efficacy in HER2-positive breast cancer is well established.

Clinical Trial Evidence

Trial Number	Phase	Status	Enrolment	Key Findings
NCT07669610	Phase 3	Not yet recruiting	140	Open-label randomised study of trastuzumab rezetecan (a different HER2-directed ADC) with or without bevacizumab in basal-like, immune-suppressed triple-negative breast cancer. No results, and no direct evidence for trastuzumab.

No ANZCTR identifiers were available in the data compiled for this report.

Literature Evidence

PMID	Year	Type	Journal	Key Findings
19466513	2009	Cohort	Breast Cancer (Tokyo)	Morphological and cytopathological features of basal-like breast carcinoma. Descriptive only, with no treatment evidence.

Australia Market Information

ARTG Number	Product Name	Dosage Form	Approved Indication
ARTG 10383L	Ogivri	Powder for I.V. infusion 150 mg	Not available in the data compiled for this report

Cytotoxicity

Item	Content
Cytotoxicity Classification	Targeted therapy (HER2-directed monoclonal antibody)
Myelosuppression Risk	Low as monotherapy; may add to myelosuppression when combined with chemotherapy
Emetogenicity Classification	Low
Monitoring Items	Cardiac function (LVEF) before and during treatment, FBC when combined with chemotherapy, infusion-related reactions
Handling Protection	Please refer to the Product Information (PI) warnings and precautions

Safety Considerations

Drug Interactions: 94 interactions are recorded. Major-level examples include deferiprone, samarium (153Sm) lexidronam, adalimumab and baricitinib. Moderate-level examples include warfarin, paclitaxel, zidovudine, azathioprine, alemtuzumab and chloramphenicol.
Cardiac toxicity: The literature retrieved for the related predictions discusses trastuzumab-related cardiotoxicity. Cardiac monitoring is a standard guardrail.

For other safety information, please refer to the TGA-approved Product Information (PI).

Conclusion and Next Steps

Decision: Hold

Rationale: The normal breast-like subtype is typically HER2-negative, and the only linked trial tests a different molecule and has not started recruiting. The single paper provides no treatment evidence. The high TxGNN score is not backed by subtype-specific data.

To proceed, the following is needed:

Evidence that normal-like tumours carry HER2 amplification or overexpression, or clinical data in this subtype
Mechanism of action data (MOA)
Package insert warnings and contraindications for the Australian product, and the approved indication text for ARTG 10383L

Context from other predictions:

Rarer tumours (for example ectomesenchymoma, score 0.9948, and HHV-8-related tumours, score 0.9946, L5, Hold): prediction only, with no trials or literature.
Disclaimer

This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.