Textbook of Personalized Medicine - Second Edition [2015]

83

Companion Diagnostics

Regardless of the name, the combination of diagnosis with therapy will have a
major impact on the diagnostics industry, and the companies that are linking their
diagnostic know-how with therapy are creating a new market place. The fi rst com-
panion diagnostic, Hercep-Test (DAKO), an immunohistochemistry assay used to
identify patients with HER2-positive metastatic breast cancer, was launched in
1998 when it was discovered that patients with HER2 amplifi cation responded bet-
ter to Genentech’s breast cancer therapy, Herceptin. The fi eld of companion diag-
nostics is growing as more and more biomarkers are being discovered and validated.
As of 2014, FDA has recommended companion diagnostics for ~100 drugs and
requires biomarker/companion diagnostic information in the label of 23 approved
drugs (17 for oncology) listed in Table 2.6.

Table 2.6 Drugs requiring biomarker/companion diagnostic information in the label

Drug Therapeutic area Biomarker(s)
Afatinib (Gilotrif) Oncology: NSCLC EGFR: deletion of exon 19 or
substitution in exon 21
Arsenic trioxide Oncology PML/RARα
Atorvastatin Metabolic &
endocrinology

LDL receptor

Brentuximab/Vedotin Oncology CD30
Cetuximab (Erbitux) Oncology EGFR, KRAS
Crizotinib Oncology ELK
Dabrafenib (Tafi nlar) Oncology: melanoma BRAF V600
Dapsone Dermatology & dental G6PD
Dasatinib Oncology Philadelphia chromosome
Fulvestrant Oncology ER receptor
Imatinib (Gleevec) Oncology C-Kit, FIP1L1-PDGFRa fusion,
Philadelphia chromosome,
PDGFR gene rearrangement
Lapatinib Oncology Her2/neu
Maraviroc Antiviral CCR5
Nilotinib Oncology Philadelphia chromosome
Panitumumab Oncology EGFR, KRAS
Sodium phenylacetate & sodium
benzoate

Gastroenterology NAGS; CPS; ASS, OTC, ASL;
ARG
Sodium phenylbutyrate Gastroenterology NAGS; CPS; ASS, OTC, ASL;
ARG
Tamoxifen Oncology ER
Tositumomab Oncology CD20 antigen
Trametinib (Mekinist) Oncology: melanoma BRAF V600
Trastuzumab (Herceptin) Oncology Her2/neu
Vemurafenib (Zelboraf) Oncology BRAF V600
Updated in 2014 from FDA table of pharmacogenomic biomarkers in drug labels, 2012

Combination of Diagnostics and Therapeutics