Erlotinib (Tarceva)

Some cancer cells, like other cells in the body express receptors on their surfaces for epidermal growth factor (EGF). EGF is a protein that stimulates cell growth and division. Tyrosine Kinase is the enzyme that mediates the stimulatory effect of EGF to trigger cell division and multiplication.
 

Erlotinib (Tarceva) is a Human Epidermal Growth Factor Receptor Type 1/Epidermal Growth Factor Receptor (HER1/EGFR) tyrosine kinase inhibitor. Thus, it inhibits cancer cells from growth and spread in response to EGF.

Mechanism of action:
 

Erlotinib inhibits the intracellular phosphorylation activation of tyrosine kinase associated with the epidermal growth factor receptor (EGFR).

Uses:
The FDA approves Erlotinib (Tarceva) in the treatment of NSCL and pancreatic cancer.
 

Non-Small Cell Lung Cancer:
Erlotinib (Tarceva) is indicated as a second or third line monotherapy treatment for patients with locally advanced or metastatic Non-Small Cell Lung Cancer after failure of at least one prior chemotherapy regimen.
 

Pancreatic Cancer:
Erlotinib (Tarceva) is indicated as first line therapy in combination with gemcitabine in the treatment of patients with locally advanced, unresectable, or metastatic pancreatic cancer.

Dose and administration:
Tarceva tablets are available in three dosage strengths containing erlotinib hydrochloride (27.3 mg, 109.3 mg, and 163.9 mg) equivalent to 25 mg, 100 mg, and 150 mg erlotinib and other inactive ingredients.
 

Erlotinib is eliminated by hepatic metabolism and biliary excretion. Caution should be taken with drugs that diminish or enhance the hepatic metabolism like clarithromycin, itraconazol, and ketoconazole, or rifampicin phenytoin, and carbamazepine, repectively.

Duration of therapy:
 

Non-Small Cell Lung Cancer:
Tarceva is given at a dose of 150 mg taken at least one hour before or two hours after the ingestion of food. Treatment should continue until disease progression or unacceptable toxicity occurs.

Pancreatic Cancer:
Tarceva is given at a dose of 150 or 100 mg taken same way, in combination with gemcitabine. Treatment should continue until disease progression or unacceptable toxicity occurs.

Toxicity:

Rash and diarrhea are the commonest form of side effects reported in clinical trials. They are usually mild and controlled with medications

Most serious complications reported are:

1. Pulmonary toxicity, Interstitial lung disease (ILD):
Some reports described fatal lung toxicity in patients receiving Erlotinib in the form of ILD-like events included pneumonitis, Acute Respiratory Distress Syndrome, and lung infitration. In the event of any unexplained pulmonary symptoms such as dyspnea, cough, and fever, Tarceva therapy should be interrupted and appropriate treatment should be given till diagnoses is setteled..

2. Diarrhea:

Diarrhea is usually mild in most of the cases although severe diarrhea mandating drug interruption and dose reduction have been reported in clinical trials.
 

3. Skin rash:

Skin rash is another common side effect and can be severe mandating dose modification or discontinuation. Researchers hypothesize that the rash may serve as a biomarker of potential drug activity in most of Tyrosine kinase inhibitors including Tarceva. Some studies using another epidermal growth factor receptor inhibitor (Cetuximab) showed that patients who develop skin rash have a better disease outcome than those who do not develop skin rash. Moreover, experts believe that if your patient did not develop skin rash in 3 or 4 weeks of treatment you better start thinking of another treatment option.

Refrences:

The information provided in this page is based on the drug prescribtion sheet and reliable sources like the FDA website and the NCCN guidelines.