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Exhibit 10.8

VERTEX PHARMACEUTICALS INCORPORATED
EMPLOYEE STOCK PURCHASE PLAN
(as amended and restated)

ARTICLE 1
PURPOSE AND DEFINITIONS

        SECTION 1.1.    PURPOSE.    The purpose of the Vertex Pharmaceuticals
Incorporated Employee Stock Purchase Plan is to provide employees with an
opportunity to purchase Common Stock in the Company through payroll deductions,
thereby encouraging employees to share in the economic growth and success of the
Company through stock ownership.

        SECTION 1.2.    DEFINITIONS.    Whenever used in the Plan, unless the
context clearly indicates otherwise, the following terms shall have the
following meanings:

(a)"BENEFICIARY" with respect to a Participant, means the beneficiary designated
by the Participant under the group term life insurance plan maintained by the
Company or such other beneficiary as may be designated by a Participant for
purposes of this Plan.

(b)"BOARD OF DIRECTORS" means the Board of Directors of the Company.

(c)"CODE" means the Internal Revenue Code of 1986, as the same may be amended
from time to time, and references thereto shall include the valid Treasury
regulations issued thereunder.

(d)"COMMITTEE" means the Management Development and Compensation Committee of
the Board of Directors or such other committee of the Board of Directors
designated by the Board of Directors to administer the Company's equity
compensation plans.

(e)"COMMON STOCK" means shares of the $.01 par value common stock of the Company
and any other stock or securities resulting from the adjustment thereof or
substitution therefor as described in Section 3.4.

(f)"COMPANY" means Vertex Pharmaceuticals Incorporated or any successor by
merger, purchase, or otherwise.

(g)"COMPENSATION" means the cash compensation received by an Employee for
services, including pre-tax employee compensation made to the Company's 401(k)
savings plan, but not including overtime or bonuses.

(h)"EFFECTIVE DATE" means July 1, 1992.

(i)"ELECTION" means an election by a Participant to terminate an Offering Period
on the first Purchase Date of such Offering Period, which election shall be made
within such Offering Period and prior to such First Purchase Date and shall be
in writing on a form furnished by the Company for such purpose and shall be made
by having such Participant complete, sign and file such form with the Company in
the manner prescribed by the Company.

(j)"EMPLOYEE" means any person who receives a regular stated compensation from
the Company or a Subsidiary other than a pension, severance pay, retainer, or
fee under contract.

(k)"FAIR MARKET VALUE" of a Share of Common Stock on a particular date shall be
the average of the highest and lowest quoted selling prices on such date (the
"valuation date") on the securities market where the Common Stock of the Company
is traded, or if there were no sales on the valuation date, on the next
preceding date within a reasonable period (as determined in the sole discretion
of the Committee) on which there were sales. In the event

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that there were no sales in such a market within a reasonable period, the fair
market value shall be as determined in good faith by the Committee in its sole
discretion. The Fair Market Value as determined in this paragraph shall be
rounded down to the next lower whole cent if the foregoing calculation results
in fractional cents.

(l)"OFFERING" means the offering of shares of Common Stock to Participants
pursuant to this Plan.

(m)"OFFERING DATE" means each May 15 and November 15. If any such date shall
fall other than on a business day, then the Offering Date shall be the next
succeeding business day.

(n)"OFFERING PERIOD" means either (i) the period from an Offering Date through
the second Purchase Date following such Offering Date or (ii) if a Participant
validly exercises an Election, the period from an Offering Date through the
first Purchase Date following such Offering Date.

(o)"PARTICIPANT" means an Employee who has elected to participate in the Plan.

(p)"PURCHASE DATE" means each May 14 and November 14.

(q)"PLAN" means the Vertex Pharmaceuticals Incorporated Employee Stock Purchase
Plan, an "employee stock purchase plan" within the meaning of Section 423(b) of
the Code, together with any and all amendments thereto.

(r)"STOCK PURCHASE ACCOUNT," with respect to a Participant, means the account
established on the books and records of the Company or a Subsidiary for such
Participant representing the payroll deductions credited to such account in
accordance with the provisions of the Plan.

(s)"SUBSIDIARY" means any corporation, fifty percent (50%) or more of the total
combined voting power of all classes of stock of which is beneficially owned,
directly or indirectly, by the Company.

ARTICLE II
PARTICIPATION

        SECTION 2.1.    PARTICIPATION REQUIREMENTS.    

(a)COMMENCEMENT OF PARTICIPATION.    Subject to Section 2.2 and Section 3.2(b),
each person who becomes an Employee after the Effective Date may become a
Participant in the Plan on any Offering Date following the date on which such
person becomes an Employee.

(b)ELIGIBILITY OF FORMER PARTICIPANTS.    If a person terminates employment with
the Company after becoming a Participant and subsequently resumes employment
with the Company, such person will again become eligible to participate on the
Offering Date next following such resumption of employment with the Company.

        SECTION 2.2.    EXCLUSIONS.    Notwithstanding any provision of the Plan
to the contrary, in no event shall the following persons be eligible to
participate in the Plan:

(a)Any Employee whose customary employment is twenty (20) hours or less per
week;

(b)Any Employee whose customary employment is for not more than five (5) months
in any calendar year; or

(c)Any Employee who, as of the beginning of an Offering Period, owns (or under
Section 423(b)(3) of the Code would be deemed to own) stock possessing five
percent (5%)

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or more of the total combined voting power or value of all classes of stock of
the Company or a Subsidiary.

ARTICLE III
OFFERING OF COMMON STOCK

        SECTION 3.1.    RESERVATION OF COMMON STOCK.    The Board of Directors
shall reserve 1,748,660 shares of Common Stock for issuance under the Plan after
March 17, 2004, subject to adjustment in accordance with Section 3.4, provided
that no more than 248,660 of such shares shall be issued prior to May 15, 2004.
On May 13, 2008, the Board of Directors shall reserve an additional 2,000,000
shares of Common Stock for issuance under the Plan.

        SECTION 3.2.    OFFERING OF COMMON STOCK.    

(a)GENERAL.    Subject to Section 3.2(b), each Participant in the Plan on an
Offering Date shall be entitled to purchase shares of Common Stock on each
Purchase Date within the Offering Period that begins with such Offering Date
with the amounts deducted from such Participant's Compensation during such
Offering Period pursuant to Article IV, provided, however, that a Participant
shall not participate in more than one Offering Period simultaneously. The
purchase price for such shares of Common Stock shall be determined under
Section 3.3.

(b)LIMITATIONS.    Notwithstanding Section 3.2(a), no employee may accrue rights
to purchase shares of Common Stock attributable to an Offering Period in excess
of $25,000 of fair market value of such shares (measured as of the relevant
Offering Date) for each calendar year during which such rights are outstanding.
For any year, this limit shall be further reduced by the fair market value of
stock (measured as of the relevant Offering Date for such stock) purchasable
under any prior outstanding rights relating to such calendar year under this
Plan and all other Code section 423 employee stock purchase plans of the Company
or any Subsidiary. This paragraph is intended to be consistent with the
limitation of Code section 423(b)(8) and shall be interpreted accordingly.

        SECTION 3.3.    DETERMINATION OF PURCHASE PRICE FOR OFFERED COMMON
STOCK.    The purchase price per share of the shares of Common Stock to be
acquired by a Participant on a Purchase Date pursuant to an Offering shall be
equal to eighty-five percent (85%) of the lesser of:

(a)the Fair Market Value of a share of Common Stock on the Offering Date for
such Offering Period; or

(b)the Fair Market Value of a share of Common Stock on such Purchase Date;

        provided, however, in no event shall the purchase price be less than the
par value of a share of Common Stock.

        SECTION 3.4.    EFFECT OF CERTAIN TRANSACTIONS.    The number of shares
of Common Stock reserved for the Plan pursuant to Section 3.1, the maximum
number of shares of Common Stock offered pursuant to Section 3.2(b), and the
determination under Section 3.3 of the purchase price per share of the shares of
Common Stock offered to Participants pursuant to an Offering shall be
appropriately adjusted to reflect any increase or decrease in the number of
issued shares of Common Stock resulting from a stock split, a consolidation of
shares, the payment of a stock dividend, or any other capital adjustment
affecting the number of issued shares of Common Stock. In the event that the
outstanding shares of Common Stock shall be changed into or exchanged for a
different number or kind of shares of stock or other securities of the Company
or another corporation, whether through reorganization, recapitalization,
merger, consolidation, or otherwise, then there shall be substituted for each
share of Common Stock reserved for issuance under the Plan but not yet purchased
by

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Participants, the number and kind of shares of stock or other securities into
which each outstanding share of Common Stock shall be so changed or for which
each such share shall be exchanged.

ARTICLE IV
PAYROLL DEDUCTIONS

        SECTION 4.1.    PAYROLL DEDUCTION ELECTIONS.    Any Employee eligible to
participate in the Plan may elect to have the Company deduct from the
Compensation payable to such Employee during each Offering Period any amount
between one percent (1%) and fifteen percent (15%) of such Participant's
Compensation, in whole multiples of one percent (1%). Such election shall be
made during the thirty day period preceding the Offering Period to which it
first relates. Such election shall become effective as of the first day of such
Participant's first pay period that begins on or after the first day of such
Offering Period and shall remain effective for each successive pay period and
for each subsequent Offering until changed or terminated pursuant to this
Article IV. The percentage deduction specified by the Participant will be
deducted from each payment of Compensation made to the Participant.

        SECTION 4.2.    ELECTION TO INCREASE OR DECREASE PAYROLL
DEDUCTIONS.    Subject to Section 4.4, a Participant who has a payroll deduction
election in effect under Section 4.1 may prospectively increase or decrease
during an Offering Period the percentage amount of the deductions being made by
the Company from such Participant's Compensation (including a decrease to zero)
by delivering to the Company written direction to make such change. Such change
shall become effective as soon as practicable after the Company's receipt of
such written direction and shall remain in effect until changed or terminated
pursuant to this Article IV. A Participant shall be permitted to increase or
decrease the percentage amount of the deductions being made from such
Participant's Compensation only once during each of the portions of an Offering
Period that ends on a Purchase Date; provided, however, a Participant may
terminate the deductions being made from such Participant's Compensation at any
time during such Offering Period. If a Participant terminates deductions, such
Participant cannot resume deductions during that Offering Period.

        SECTION 4.3.    TERMINATION OF ELECTION UPON TERMINATION OF
EMPLOYMENT.    The termination of employment of a Participant for any reason
shall automatically terminate the election of such Participant to have amounts
deducted from such Participant's Compensation pursuant to this Article IV that
is then in effect. Such termination shall be effective immediately following the
pay period during which such termination of employment occurs, but shall not
affect the deduction from Compensation for that pay period.

        SECTION 4.4.    FORM OF ELECTIONS.    Except as otherwise permitted by
the Company, any election by a Participant regarding participation in or
withdrawal from the Plan or deductions from Compensation pursuant to this
Article IV shall be in writing on a form furnished by the Company for such
purpose and shall be made by having such Participant file such form with the
Company in the manner prescribed from time to time by the Company.

ARTICLE V
STOCK PURCHASE ACCOUNTS AND PURCHASE OF COMMON STOCK

        SECTION 5.1.    STOCK PURCHASE ACCOUNTS.    A Stock Purchase Account
shall be established and maintained on the books and records of the Company for
each Participant. Amounts deducted from a Participant's Compensation pursuant to
Article IV shall be credited to such Participant's Stock Purchase Account. No
interest or other increment shall accrue or be payable to any Participant with
respect to any amounts credited to such Stock Purchase Accounts. All amounts
credited to such Stock Purchase Accounts shall be withdrawn, paid, or applied
toward the purchase of Common Stock pursuant to the provisions of this
Article V.

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        SECTION 5.2.    PURCHASE OF COMMON STOCK.    

(a)GENERAL.    As of each Purchase Date, the amount to the credit of a
Participant in such Participant's Stock Purchase Account shall be used to
purchase from the Company on such Participant's behalf the largest number of
whole shares of Common Stock which can be purchased at the price determined
under Section 3.3 with the amount then credited to such Participant's Stock
Purchase Account, subject to the limitations set forth in Article III on the
maximum number of shares of Common Stock such Participant may purchase. As of
such date, such Participant's Stock Purchase Account shall be charged with the
aggregate purchase price of the shares of Common Stock purchased on such
Participant's behalf. No brokerage or other fees are to be charged upon a
purchase. Stock transfer taxes, if any, shall be paid by the Company. The
remaining balance, if any, credited to such Participant's Stock Purchase Account
shall be carried forward and used to purchase shares of Common Stock on the next
succeeding Purchase Date; provided that any excess balance remaining in a
Participant's Stock Purchase Account after the application of the limitations in
Section 3.2 shall be refunded to the Participant.

(b)ISSUANCE OF COMMON STOCK.    The shares of Common Stock purchased for a
Participant as of a Purchase Date shall be deemed to have been issued by the
Company for all purposes as of the close of business on such date. Prior to such
date, none of the rights and privileges of a stockholder of the Company shall
exist with respect to such shares of Common Stock. As soon as practicable after
such a Purchase Date the Company shall issue and deliver, or shall cause its
stock transfer agent to issue and deliver, a certificate for the number of
shares of Common Stock purchased for a Participant, which certificate shall be
issued in the Participant's name or, if so specified by the Participant, in the
name of the Participant and such other person as the Participant shall designate
as joint tenants with right of survivorship. In lieu of issuing a certificate,
the Company may elect to deliver to the Participant a statement which shall
indicate the number of shares of Common Stock purchased for such Participant and
the aggregate number of shares of Common Stock held on behalf of such
Participant under the Plan.

(c)INSUFFICIENT COMMON STOCK AVAILABLE.    If, as of any Purchase Date, the
aggregate Stock Purchase Accounts available for the purchase of shares of Common
Stock pursuant to Section 5.2(a) would purchase a number of shares of Common
Stock in excess of the number of shares of Common Stock then available for
purchase under the Plan, (i) the number of shares of Common Stock which would
otherwise be purchased for each Participant on such date shall be reduced
proportionately to the extent necessary to eliminate such excess, (ii) the
remaining balance to the credit of each Participant in each such Participant's
Stock Purchase Accounts shall be distributed to each such Participant, and
(iii) the Plan shall terminate automatically upon the distribution of the
remaining balance in such Stock Purchase Accounts.

        SECTION 5.3.    WITHDRAWAL FROM PLAN PRIOR TO PURCHASE OF COMMON
STOCK.    In the event (i) a Participant elects in writing for any reason to
withdraw from the Plan during an Offering Period or (ii) a Participant's
employment with the Company terminates for any reason prior to the end of an
Offering Period, then the entire amount remaining to the credit of such
Participant in such Participant's Stock Purchase Account shall be distributed to
such Participant (or, if such Participant is deceased, to such Participant's
Beneficiary) as soon as administratively practicable after such withdrawal or
termination of employment (as the case may be).

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ARTICLE VI
COMMITTEE

        SECTION 6.1.    POWERS OF THE COMMITTEE.    The Committee shall
administer the Plan. The Committee shall have all powers necessary to enable it
to carry out its duties under the Plan properly. Not in limitation of the
foregoing, the Committee shall have the power to construe and interpret the Plan
and to determine all questions that shall arise thereunder. The decision of the
Committee upon all matters within the scope of its authority shall be final and
conclusive on all persons, except to the extent otherwise provided by law.

        SECTION 6.2.    INDEMNIFICATION OF THE COMMITTEE.    The Company agrees
to indemnify and hold harmless the members of the Committee against any
liabilities, loss, costs, or damage that they may incur in acting as such
members and to assume the defense of any and allocations, suits, or proceedings
against the members of the Committee, to the extent permitted by applicable law.

ARTICLE VII
AMENDMENT AND TERMINATION

        SECTION 7.1.    AMENDMENT OF THE PLAN.    The Company expressly reserves
the right, at any time and from time to time, to amend in whole or in part any
of the terms and provisions of the Plan; provided, however, no amendment may
without the approval of the shareholders of the Company increase the number of
shares of Common Stock reserved under the Plan.

        SECTION 7.2.    TERMINATION OF PLAN.    The Company expressly reserves
the right, at any time and for whatever reason it may deem appropriate, to
terminate the Plan. The Plan shall continue in effect until terminated pursuant
to (i) the preceding sentence or (ii) Section 5.2(c). Upon any termination of
the Plan, the entire amount credited to the Stock Purchase Account of each
Participant shall be distributed to each such Participant.

        SECTION 7.3.    PROCEDURE FOR AMENDMENT OR TERMINATION.    Any amendment
to the Plan or termination of the Plan may be retroactive to the extent not
prohibited by applicable law. Any amendment to the Plan or termination of the
Plan shall be made by the Company by resolution of the Board of Directors
(subject to Section 7.1) and shall not require the approval or consent of any
Participant or Beneficiary in order to be effective.

ARTICLE VIII
MISCELLANEOUS

        SECTION 8.1.    ADOPTION BY A SUBSIDIARY.    A Subsidiary may, with the
approval of the Board of Directors and the board of directors of such
Subsidiary, elect to adopt the Plan as of a date mutually agreeable to the Board
of Directors and the board of directors of such Subsidiary. Any such adoption of
the Plan by a Subsidiary shall be evidenced by an appropriate instrument of
adoption executed by such Subsidiary.

        SECTION 8.2.    AUTHORIZATION AND DELEGATION TO THE BOARD OF
DIRECTORS.    Each Subsidiary that hereafter adopts the Plan authorizes the
Board of Directors (i) to amend or terminate the Plan without further action by
said Subsidiary as provided in Article VII and (ii) to perform such other acts
and to do such other things as the Board of Directors is expressly directed,
authorized, or permitted to perform or do as provided herein.

        SECTION 8.3.    TRANSFERABILITY OF RIGHTS.    Rights under the Plan are
not transferable by a Participant other than by will or the laws of descent and
distribution and are exercisable during a Participant's lifetime only by the
Participant.

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        SECTION 8.4.    NO EMPLOYMENT RIGHTS.    Participation in the Plan shall
not give any employee of the Company or any Subsidiary any right to remain
employed or, upon termination of employment, any right or interest in the Plan,
except as expressly provided herein.

        SECTION 8.5.    COMPLIANCE WITH LAW.    No shares of Common Stock shall
be issued under the Plan prior to compliance by the Company to the satisfaction
of its counsel with any applicable laws.

        SECTION 8.6.    CONSTRUCTION.    Article, Section, and paragraph
headings have been inserted in the Plan for convenience of reference only and
are to be ignored in any construction of the provisions hereof. If any provision
of the Plan shall be invalid or unenforceable, the remaining provisions shall
nevertheless be valid, enforceable, and fully effective. It is the intent that
the Plan shall at all times constitute an "employee stock purchase plan" within
the meaning of Section 423(b) of the Code, and the Plan shall be construed, and
interpreted to remain such. The Plan shall be construed, administered,
regulated, and governed by the laws of the United States to the extent
applicable, and to the extent such laws are not applicable, by the laws of The
Commonwealth of Massachusetts. Without limiting the foregoing, all Participants
for an Offering Period shall have the same rights and privileges with respect to
their rights to acquire Common Stock under the Plan for such period, subject to
the express terms hereof.

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Exhibit 10.8