[Third Point LLC Letterhead]


VIA EMAIL AND FEDERAL EXPRESS

April 27, 2006

Mr. David L. Castaldi
Geoffrey F. Cox, Ph.D
Mr. Peter B. Davis
Mr. Richard A. Harvey, Jr.
Leslie Hudson, Ph.D.
Ms. Linda Jenckes
Mr. Thomas H. McLain
Mr. Stephen G. Sundovar

     c/o Mr. Thomas E. Rathjen
     Vice President, Investor Relations
     Nabi Biopharmaceuticals
     5800 Park of Commerce Boulevard, N.W.
     Boca Raton, Florida 33487

To the Board of Directors of Nabi Biopharmaceuticals:

As you should be aware, Third Point LLC filed a Schedule 13D last week in which
we disclosed an 8.4% ownership stake in Nabi, which we have subsequently
increased as of today. If you have not read our filing, and the demands that we
make therein, I strongly urge you to do so immediately. I'd also encourage each
of you to review a history of Third Point's prior "activist investments" to get
an idea of how we have approached similar situations in the past (i.e., when we
determine that a company has substantial asset value that is not reflected in
the stock price due to poor corporate management and board oversight). Any one
of these examples may serve as an object lesson for what the Board and Nabi
management may expect should we not hear promptly from Tom McLain in regards to
the demands made in our Schedule 13D and below.

I would like to expand on some issues raised in our 13D filing, as well as to
disclose certain disturbing issues not previously discussed.

1.   We are deeply concerned that the company intends to continue to use Lehman
     as its investment banker, as evidenced by Tom McLain's statements in a
     Sun-Sentinel article last week. Not only has Lehman presumably presided
     over, and advised on, many of the company's strategic missteps over the
     years, we are also concerned that the longstanding relationship between Mr.
     McLain and the Lehman investment bankers will prevent the company from
     receiving objective advice that will lead to the creation of maximum
     shareholder value. We have been informed by certain prospective buyers of
     Nabi's assets that Nabi's management is "hunkered down" with Lehman, and
     that certain parties felt stonewalled by both Lehman and Nabi's management
     during the alleged ongoing process




     to "explore strategic alternatives" for PhosLo. These same parties were
     apparently similarly stymied when attempting to contact Mr. McLain and/or
     Lehman in recent months to express interest in purchasing other Nabi
     assets. We have also heard that several well-regarded investment banks have
     recently attempted to call Nabi to pursue business relationships and were
     not even given the courtesy of a return call from the company. It seems to
     us that unless the "strategic alternative" being pursued by Lehman and the
     company is to entrench management and maintain the status quo (which would
     be supported by the apparent requirement that all participants in the
     PhosLo process sign restrictive and unusual standstill agreements), Lehman
     has failed to fulfill its fiduciary duty to Nabi's shareholders.
     Accordingly, we demand that Nabi immediately retain an investment bank
     other than Lehman, or in conjunction with Lehman, to explore strategies to
     maximize shareholder value. We do not believe that such a process would be
     run earnestly and objectively, based on the issues noted above, without
     involving a new investment bank.

2.   As we also noted in our filing, until a process to maximize shareholder
     value is undertaken, the company should refrain from selling or partnering
     on any major assets (unless extraordinary shareholder value would be
     created from such a transaction), as we believe that there are parties
     interested in purchasing the entirety of Nabi and that selling or
     partnering on assets could potentially diminish the interest of these
     parties. We also believe that all cash proceeds received by Nabi as the
     result of any asset sales or partnering going forward should promptly be
     paid to shareholders. Management and the board have demonstrated, over many
     years, their inability to turn valuable corporate assets into anything but
     shareholder value destruction and "cash burn." We have no reason to believe
     that this will change going forward. To the contrary, the $25 million "cash
     burn" in the first quarter of 2006, and accompanying management commentary
     congratulating itself for its enhanced focus on shareholder value creation,
     strikes us as both cautionary and delusional. As such, all proceeds from
     corporate dispositions or partnering should be distributed immediately to
     shareholders rather than left in the company for management to dissipate.

3.   We are outraged by both the employee retention and option acceleration
     programs that you recently approved. We believe that the retention program
     was (a) overly generous, both relative to what other similarly-situated
     companies have implemented and in light of the value destroyed by this
     management team; (b) too narrow in terms of the number of employees invited
     to participate, and too weighted towards rewarding the very managers whose
     poor performance is responsible for destroying value, when it is the
     scientific staff who have created the real value, are the ones worthy of
     reward and who should thus be the primary focus of any retention program;
     and (c) propitiously timed to profit insiders by following the release of
     disastrous fourth quarter results, which temporarily depressed the stock
     price, and coming just ahead of the release of the positive StaphVAX news.
     As for the decision to accelerate the vesting of all outstanding options,
     we could understand this decision if Nabi were a company reporting profits
     and therefore having a public valuation based on a multiple of those
     earnings. Sadly, however, these are not issues that Nabi need worry about,
     since the company, as currently managed, has no prospect of making money
     within any acceptable timeframe - which the just-released first quarter


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     results further reinforce. Thus, unvested options have been accelerated on
     behalf of company insiders with no plausible benefit to the stockholders.

In closing, I would like to remind the Board of its fiduciary duties to
represent the financial interest of Nabi's shareholders, not the pecuniary
interest of Nabi's management. Approving the use of incumbent investment bankers
who have not served shareholder interests well in the past, and approving option
and restricted stock programs that gratuitously enrich management and yourselves
at the expense of the company's shareholders, are exactly the types of actions
you are legally charged to avoid, not enable. Under your watch this company has
had a virtually unbroken record of poor quarterly results (which, not
surprisingly, you managed to extend in the first quarter), missed milestones and
trial failures - all leading to significant value destruction for the company's
shareholders. Should this somehow have escaped you, we will happily furnish you
with a timeline demonstrating the repeated disappointments and resultant
dreadful stock price performance.

The good news is that, notwithstanding chronic mismanagement, we believe that
Nabi today still has (a) significant and coveted assets, and (b) parties
interested in buying all or parts of Nabi. Hence, a properly managed sale
process could offer some redemption for Nabi's apparently negligent board by
recovering substantial value for its shareholders. The long-term strategic plan
currently contemplated by management is fraught with far too much execution risk
and uncertainty - especially given the track record of this company. Therefore,
these valuable assets should be monetized in the near-term for the benefit of
the company's owners - and in no case should proceeds from these transactions be
reinvested in high-risk development programs (i.e., your current plan), with
which you've had no tangible success throughout your tenure overseeing this
company.

To reiterate, we insist that new bankers be immediately retained and that a bona
fide public sale process be commenced immediately. Anything less than finally
creating substantial value for Nabi shareholders, rather than continually paying
lip service to it while acting otherwise, is completely unacceptable.

Sincerely,



Daniel S. Loeb
Chief Executive Officer
Third Point LLC


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