Targeted cancer therapies

Author: A/Prof Amanda Oakley, Dermatologist, Hamilton, New Zealand. January 2018.

This article was supported by an educational grant from Roche New Zealand, distributors of Cotellic™ in New Zealand. Sponsorship does not influence content. 


What are targeted cancer therapies?

Targeted cancer therapies are drugs used to treat certain malignant tumours by blocking the action of certain molecular targets such as genes and proteins. They are classified as small molecules or monoclonal antibodies.

They are also called precision medicines.

How do targeted cancer therapies work?

Targeted cancer therapies interact with a target molecule to prevent tumour cells proliferating.

  • The target molecule may be present in several different types of tumour
  • The molecule may be specific to the tumour (due to mutation) or may be more abundant in the tumour than in normal cells. 
  • This reduces the damage done to surrounding normal cells.
  • Some drugs target fusion proteins, due to chromosomal abnormalities in the tumour.

They are classified as:

  • Hormone therapy
  • Signal transduction inhibitor
  • Gene expression modulator
  • Apoptosis inducer
  • Angiogenesis inhibitor
  • Immunotherapy

Who gets targeted cancer therapies?

Targeted therapies are currently used in dermatology for patients with advanced cancers. They are also in clinical trials as adjuvant therapy (supplementary treatment given to people who are in remission from their cancer but are at high risk of relapse in the future). 

Advanced skin cancers

What targeted therapies are available?

Several targeted therapies are marketed in dermatology to treat advanced skin cancers, and others are in development.

Melanoma

Several products are marketed to treat unresectable metastatic melanoma.

  • Vemurafefenib and dabrafenib target mutant cell growth signalling protein BRAF V600E.
  • Trametinib inhibits the MAPK signalling pathway.
  • Cobimetinib is a MEK inhibitor taken in combination with vemurafenib.
  • Ipilimumab targets cytotoxic T lymphocyte-associated antigen 4 (CTLA-4).
  • Pembrolizumab targets the programmed death 1 (PD-1) receptor.
  • Nivolumab programmed death receptor-1 (PD-1)–blocking antibody.

Basal cell carcinoma

Vismodegib and sonedegib are available treatments for advanced basal cell carcinoma. They target Smoothened, a protein involved in the abnormal Hedgehog signaling pathway.

Squamous cell carcinoma

Several products are being investigated to treat advanced cutaneous squamous cell carcinoma (SCC).

  • Products targeting mutations in the Notch gene and TP53
  • Immune checkpoint inhibitors 

Merkel cell carcinoma

  • Avelumab is available to treat metastatic Merkel cell carcinoma.
  • PD-1 checkpoint inhibitors are under investigation.

Cutaneous T cell lymphoma and Kaposi sarcoma

Targeted treatments used in refractory cutaneous T-cell lymphoma and Kaposi sarcoma are based on the retinoid pathway.

Cutaneous B cell lymphoma

Rituximab targets the CD20 antigen found on B lymphocytes.

Dermatofibrosarcoma protuberans

Imatinib targets BCR-ABL fusion protein. 

What are the side effects of targeted therapy?

Targeted therapies have many side effects including adverse cutaneous reactions. In some cases, side effects are associated with excellent tumour response.

See individual drug topics for more details. 

How effective are targeted therapies?

The efficacy of targeted therapies is variable. They may lose their efficacy over time, having been initially successful at reducing tumour growth and in some cases leading to complete remission.

See individual drug topics.  

New Zealand approved datasheets are the official source of information for these prescription medicines, including approved uses and risk information. Check the individual New Zealand datasheet on the Medsafe website.

 

Related Information

References

On DermNet NZ

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