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                                                                   EXHIBIT 10.29

              EXECUTIVE SEVERANCE - SENIOR/EXECUTIVE VICE PRESIDENT

As a Senior Vice President or Executive Vice President, you are entitled to
severance benefits in the event your employment with Biogen Idec is terminated
by Biogen Idec other than for cause. The severance benefits will be comprised of
(i) a lump sum payment and (ii) upon completion of the appropriate forms,
continuation of your participation in Biogen Idec's group medical and dental
insurance plans. The lump sum payment, equivalent to at least nine months of
annual base salary and a prorated portion of your target annual performance
bonus, will be calculated as follows:

                      [9 + (A x 2)] x B = lump sum payment

where: A   is number of full years of service with Biogen Idec, but (A x 2) not
           more than 9
       B   is monthly annual compensation (i.e., one-twelfth of sum of annual
           base salary plus target annual performance bonus modified by your
           most recent individual performance incentive factor).

The lump sum payment (less state and federal income and welfare taxes and other
mandatory deductions under applicable laws) will be paid to you promptly
following the later of (i) the termination of your employment with Biogen Idec
and (ii) the effective date of a general release in favor of Biogen Idec (see
below). Your participation in Biogen Idec's group medical and dental insurance
plans will continue until the earlier of (x) the date you become eligible to
participate in the medical and dental insurance plans of a third party employer
or (y) the date that is [9 + (A x 2)] months following the termination of your
employment with Biogen Idec; and only to the same extent such insurance is then
provided to regular employees of Biogen Idec (including payment by you of a
portion of the insurance premiums). For example:

         If your employment with Biogen Idec is terminated after two months, you
         will receive a lump sum payment equal to nine months of your monthly
         annual compensation and continue to participate in Biogen Idec's group
         medical and dental plans for nine months, unless you become eligible to
         participate in a third party employer's medical and dental plans before
         that date.

         If your employment with Biogen Idec is terminated after five years, you
         will receive a lump sum payment equal to 18 months of your monthly
         annual compensation and continue to participate in Biogen Idec's group
         medical and dental plans for 18 months, unless you become eligible to
         participate in a third party employer's medical and dental plans before
         that date.

For purposes of the severance arrangement, "cause" means (i) your engagement in
misconduct that is injurious to Biogen Idec, monetarily or otherwise, (ii) your
conviction of a felony by a court of competent jurisdiction, (iii) your
commission of any act of fraud or embezzlement relating to the property of
Biogen Idec, or (iv) your material violation of any obligations of
confidentiality, nondisclosure and non-competition owed to Biogen Idec.

Payment and provision of the severance benefits described above are conditioned
on your execution of a general release in favor of Biogen Idec, in form and
substance reasonably acceptable to Biogen Idec, in respect of any and all claims
relating to your employment and the termination of your employment with Biogen
Idec. If you retire or terminate your employment with Biogen Idec or Biogen Idec
terminates your employment for cause or you do not provide the requisite general
release, then you shall not be entitled to receive the severance benefits
described above.