Exhibit 10.58

[Biogen Idec Logo]

November 19, 2010 REVISED

Dear Steve:

I am pleased to extend you this offer of employment to join Biogen Idec as
Executive Vice President, Corporate Development and Strategy. This position will
report to me, George Scangos, Chief Executive Officer. The position will be
based at our Weston, Massachusetts facility.

Base Salary: Your starting bi-weekly salary will be $23,076.93, which is
equivalent to an annual salary of $600,000.18, and which will be paid in
accordance with our standard payroll policies.

One-Time Cash Sign-on Bonus: Upon employment, you will receive $350,000 as a
one-time cash bonus. The bonus will be paid to you within two pay periods after
your start date provided that you sign the enclosed Cash Sign-On Bonus
Agreement, which describes the terms and conditions of the cash sign-on bonus.

Annual Bonus Plan: You will be eligible to participate in the Biogen Idec Annual
Bonus Plan, with a target bonus opportunity of 55% of your annualized base
salary. Based upon your start date, your target bonus amount may be pro-rated.
Eligibility details and other terms of the Plan are included in the current
year’s Plan document, which will be made available upon your employment with the
Company.

Long-Term Incentive: You will be granted Cash-Settled Performance Shares (CSPS)
in connection with the commencement of your employment. The approximate grant
date value of your CSPS award will be $1,000,000. You will also be granted
Market Stock Units (MSU) in connection with the commencement of your employment.
The approximate grant date value of your MSU award will be $1,000,000. Your CSPS
and MSU awards will be granted on the first trading day of the month following
your start date.

The actual terms of your CSPS and MSU awards will be communicated to you
following the grant date. Your grants will be awarded under the Biogen Idec Inc.
2008 Omnibus Equity Plan. You are considered a “designated employee,” as defined
in the 2008 Omnibus Equity Plan. Our 2008 Omnibus Equity Plan and Prospectus are
available to you on Biogen Idec’s benefits website at www.mybenergy.com. Please
read these documents for information about your Long-term Incentive grants.

Stock Trading Plan: As an Executive Vice President of the Company, you are
required to enter into a 10b5-1 stock trading plan for all open market trades in
Biogen Idec stock. A 10b5-1 plan allows you to buy or sell Biogen Idec
securities at pre-defined times and/or prices and provides an affirmative
defense against insider trading liability. More information on 10b5-1 trading
plans will be made available upon your employment with the Company.

Employee Benefits: Biogen Idec offers a robust and highly competitive employee
benefits program. As an employee, you will be able to choose from a menu of
options through our flexible benefits program. These benefits include a 401(k)
savings plan; group health care, including medical, dental, prescription drug
and vision coverage; life, dependent life and disability insurance; as well as
flexible spending accounts for eligible medical and dependent care expenses. You
are also entitled to 20 vacation days per year, accrued on a per pay period
basis. Additional benefit offerings include an Employee Stock Purchase Plan
(ESPP) and work/life benefits such as a concierge service and access to
subsidized backup dependent care. Please visit Biogen Idec’s benefits website at
www.mybenergy.com to familiarize yourself with Biogen Idec’s complete benefit
plan offerings.

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Additional Executive Benefits

Supplemental Savings Plan: You will be entitled to participate in Biogen Idec’s
Supplemental Savings Plan (SSP). This plan allows you to make pre-tax deferrals
of up to 80% of your base salary and up to 100% of your Annual Bonus payment and
certain other eligible incentive payments. Your contributions to this plan may
be limited by your contributions towards other plans (e.g., 401(k), ESPP,
medical, etc.). You will be provided with SSP enrollment information upon your
employment with the Company.

Life Insurance: You will be provided life insurance coverage equal to three
times your annual base salary, subject to meeting the medical standards stated
in the group term life insurance policy for U.S. employees. Biogen Idec pays the
premium for this insurance. The IRS requires employers to impute the value of
company-paid life insurance for coverage over $50,000. This imputed income will
be displayed on your pay stub.

Severance: Under certain circumstances, you will be entitled to receive
severance benefits. Your severance benefits are explained in detail in the
attached executive severance document. If your total severance benefits will
trigger 280G excise taxes, you may elect to have Biogen Idec reduce the amount
of your total payment to reduce your total payments to an amount below the 280G
trigger. To facilitate your decision, Biogen Idec will estimate whether any 280G
excise tax will be owed on severance and the amount of that excise tax.

Tax Preparation, Financial and Estate Planning: You are entitled to
reimbursement of up to $7,500 per calendar year (January 1—December 31) for
expenses incurred due to tax preparation, financial and/or estate planning
services, as well as the purchase of tax preparation and/or financial planning
software. You will be provided with details of this benefit upon your employment
with the Company. Reimbursement must be made no later than the end of the
calendar year following the year in which the expense is incurred, and must be
requested within the deadlines and processes established in the policy.

You are required to satisfy the following contingencies prior to employment at
Biogen Idec.

• Drug Screen: A completed drug-screening test is required within 48 hours of
accepting this offer of employment. Please see the enclosed information
regarding Biogen Idec’s Pre-Employment Drug Testing program. Your employment is
subject to Biogen Idec receiving negative results (i.e., no drugs found) from
your drug test. If you have not received confirmation of your test results from
Human Resources within a week prior to your start date, please contact me to
confirm your test results prior to starting.

• Background Check: Your employment is subject to satisfactory completion of
Biogen Idec’s background check, which includes verification of employment
history, educational and professional licenses, degrees and/or credentials, a
criminal records check, a Social Security Number search and verification of any
other professional qualifications that your position responsibilities at Biogen
Idec may warrant. Completion of your online Application for Employment
authorizes Biogen Idec to conduct these background checks. If you have any
questions about the background check, please contact me.

• New Employee Forms: Upon your acceptance of Biogen Idec’s offer of employment,
please visit our Company website, www.biogenidec.com. Under·’Careers,’
click·’New Employees.’ This site contains the forms you must complete in order
to add you to Biogen Idec’s Payroll and Human Resources systems. Completion of
these forms is required within 48 hours of accepting this offer of employment at
Biogen Idec. Your username is your Social Security Number (without dashes) and
your password will be provided upon your acceptance of this offer.

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• Authorization to Work in the United States: The Federal government requires
you to provide proper identification verifying your eligibility to work in the
United States. Please bring documents necessary to complete the Employment
Eligibility Verification Form I-9 on your first day of employment.

• Signed Proprietary Agreement: In order to protect Biogen Idec’s substantial
investment in creating and maintaining its confidential and proprietary
information, and to maintain goodwill with our customers, vendors and other
business partners, you will be required to sign our ‘Employee Proprietary
Information and Inventions and Dispute Resolution Agreement’ as a condition of
employment. A copy of the Agreement is enclosed with this letter for your
reference. Please sign and return this Agreement with your signed acceptance of
our offer.

Your employment at Biogen Idec is employment at-will. This means that just as
you are free to leave your employment at any time, with or without cause or
notice, Biogen Idec also has the same right to terminate your employment at any
time, with or without cause or notice.

To confirm your acceptance of this offer of employment, please sign and return
this letter and keep the other copy for your records. Review and complete the
enclosed New Employee Checklist with actions required in order to begin your
acceptance process. Your new employee paperwork and drug screen should be
completed within 48 hours of accepting this offer of employment. The New
Employee Checklist provides instructions for your first day of employment.

We are very excited about the prospect of you joining Biogen Idec. We encourage
you to accept this offer of employment by November 12, 2010.

Best regards,

/s/ George Scangos

George Scangos, Ph.D.

Chief Executive Officer

I accept this offer of employment and acknowledge the contingencies of
employment described above, including the at-will nature of my employment.

ACCEPTED:

 

/s/ Steven Holtzman

  

December 4, 2010

  

January 3, 2011

Steven Holtzman

  

Signature Date

  

Start Date