SecProbe.io

April 12, 2013

Via E -mail
Jeffrey M. Leiden
Chief Executive Officer
Vertex Pharmaceuticals Incorporated
130 Waverly Street
Cambridge, MA  02139 -4242

Re: Vertex Pharmaceuticals Incorporated
 Form 10 -K for the Fiscal Year Ended December  31, 2012
 Filed March 1,  2013
 File No. 000-19319

Dear M r. Leiden :

We have reviewed your filing and have the following comments.  In our comment s, we
ask you to provide us with information so we may better understand your disclosure.

Please respond to this letter within 10 business days by providing the requested
information or by advising us when you will provide the requested response.  If you  do not
believe a commen t applies to your facts and circumstances, please tell us why in your response.
Please furnish us a letter on EDGAR under the form type label CORRESP that keys your
response s to our comment s.

After reviewing the information provided, we may raise additional comments and/or
request that you amend your filing.

General

1. We note that you incorporate by reference into Part III of your Form 10 -K certain
information from your definitive proxy statement fo r your 2013 annual meeting of
shareholders. Please note that we may have further comments after reviewing this
information and we will not be able to clear our review of your filing until we have the
opportunity to resolve any resulting comments.

Notes to Consolidated Financial Statements

I. Intangible Assets and Goodwill
Intangible Assets
Alios Collaboration, page F -27

2. You state “there was no impairment to the program in the third quarter of 2012 because of
the advancement of ALS -2200 .”  Please tell us why ALS -2200 and ALS -2158 were not

Jeffrey M. Leiden
Vertex Pharmaceuticals Incorporated
April 12, 2013
Page 2

 separately valued at the date of acquisition.   Cite the accounting guidance used in your
determination.

P. Income Taxes, page F -34

3. With respect to the tax rate reconciliation, please clarify for us :

 The nature of  the foreign rate differential  that increases the provision each year presented
and to what  foreign operations the differential relates considering that you incurred
foreign  pre-tax losses  each year ; and
 The nature of  the unbenefited operating losses , to what operations (United States versus
foreign) it relates  and why it decr eases  the tax provision  in 2012 and 2011.

Provid e us proposed revised  disclosure  to be included in future filings  addressing the se items.

4. You state it is not “practical” to determine the amount of unrecognized deferred U.S. federal
income tax liability. Please provide us proposed  disclosure to be included in future filings
that complies  with ASC 740 -30-50-2.c. which requires disclosure of the amount of
unrecognized deferred tax liability, if practicable, or a statement that determination is not
practicable .

We urge all persons who are responsible for the accuracy and adequacy of the disclosure
in the filing to be certain that the filin g include s the information the Securities Exchange Act of
1934 and all applicable Exchange Act rules require.   Since the company and its management are
in possession of all facts relating to a company’s disclosure, they are responsible for th e accuracy
and adequacy of the disclosures they have made.

In responding to our comment s, please provide a written statement from the company
acknowledging that:
 the company is responsible for the adequacy and accuracy of the disclosure in the filing;
 staff comment s or changes to disclosure in response to staff comment s do not foreclose
the Commission from taking any action with respect to the filing; and
 the company may not assert staff comment as a defense in any proceeding initia ted by the
Commission or any person under the federal securities laws of the United States.

 You may contact Tabatha Akins, Staff Accountant, at (202) 551 -3658 or Joel Parker ,
Account ing Branch  Chief , at (202) 551 -3651 if you have any questions regarding the
comments.   In this  regard, do not hesitate to contact me at (202) 551 -3679.

Sincerely,

  /s/ Jim B. Rosenberg

Jim B. Rosenberg
Senior Assistant Chief Accountant