The FDA recently approved Pfizer to market Xalkori (crizotinib), targeted to
treat patients with late stage, non-small-cell lung cancer (NSCLC) who express mutations of the
anaplastic lymphoma kinase (ALK) gene. Concurrently, the FDA has also approved a companion
diagnostic test to help determine if the patient expresses the ALK gene mutation. This represents a rather new and exciting trend in
chemotherapy treatment as Xalkori is the 2nd targeted chemotherapy agent approved by the
FDA along with a test this year (Genentech Inc.’s Zelboraf™ used for late-stage melanoma
in patients with BRAF V600E mutation was approved along with a companion test in August 2011).
EML4-ALK is a genetic mutation representing the fusion of the echinoderm
microtubule-associated protein-like 4 (EML4) and ALK
estimated that 2-7% of patients with NSCLC have EML4-ALK mutations, representing about 10,000
patients in the United States alone. Patients
expressing EML4-ALK mutations are resistant to treatment with currently available growth factor
receptor inhibitors (ie. Tarceva®, erlotinib), however, it has been shown in clinical trials
that treatment with crizotinib (an ALK inhibitor) has improved response rates to nearly 60% of
patients, compared to ~10% of patients treated with second line chemotherapy.
One of the challenges facing practitioners had been that no standard
FDA-approved test for detecting EML4-ALK mutations was available per the NCCN guidelines for
NSCLC. Now with the new FDA approval of the Vysis
ALK Break Apart FISH Probe kit as a companion test, providers will now have a gold-standard tool to
use in determining patient qualification for this new medication.
One of the issues that will certainly arise is the cost of targeted
therapies. It is estimated that treatment with Xalkori
will cost roughly $9600/month. This is far out
of the financial reach of the vast majority of patients, although Pfizer is currently offering a
patient assistance program for uninsured or underinsured patients which may help a greater number
of patients have access to the drug. The high cost
associated with this new drug is not unique, either.
The previously mentioned Zelboraf comes with its own steep price tag of $56,400 for a
6-month course of treatment. Even considering
planned patient assistance programs, it is clear that these new, innovative genomic-based targeted
therapies will come at a significant cost, making accessibility to the general population limited
at best. While these therapies surely represent
advances in our understanding of the role of genomics in providing patient-specific therapy, only
time will tell if the benefits will outweigh the costs enough to continue advancing medicine in
1. FDA news release. FDA Approves Xalkori with companion diagnostic for a type of
late-stage lung cancer. Found at: http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm269856.htm#.TlzssAv9VpM.email. Accessed 30 August 2011.
2. NCCN Clinical Practice
Guidelines in Oncology: Non-Small-Cell Lung
Cancer. Found at:
http://www.nccn.org/professionals/physician_gls/pdf/nscl.pdf. Accessed 30 August 2011.
3. Kwak E, et al. Anaplastic Lymphoma Kinase Inhibition in Non-Small-Cell Lung
Cancer. NEJM; 363:1693-1703. 28 October 2010. Found at: http://www.nejm.org/doi/full/10.1056/NEJMoa1006448. Accessed 30 August 2011.
4. ALK Inhibitor Xalkori
FDA-Approved: New Era, with New Challenges. Global Resource for Advancing Cancer Education. Found at: http://cancergrace.org/lung/2011/08/27/alk-inhibitor-xalkori-crizotinib-fda-approved-new-era-with-new-challenges/.
Accessed 30 August 2011.
5. US FDA approves Roche skin
cancer drug Zelboraf. Thomson Reuters. Found at: http://www.reuters.com/article/2011/08/17/roche-zelboraf-idUSN1E77G0BW20110817. Accessed 30 August 2011.