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                                                                   EXHIBIT 10.47

             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 is terminated by
Biogen 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
at Biogen's expense of your participation in Biogen'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, 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 termination of your employment with Biogen. Your participation in
Biogen'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; and only
to the same extent such insurance is then provided to regular employees of
Biogen. For example:

          If your employment with Biogen 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'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 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'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 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, or (iv) your material violation of any obligations of confidentiality
and nondisclosure owed to Biogen.

Payment and provision of the severance benefits described above are conditioned
on your execution of a general release in favor of Biogen, in form and substance
reasonably acceptable to Biogen, in respect of any and all claims relating to
your employment and the termination of your employment with Biogen. If you
retire or terminate your employment with Biogen or Biogen 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.