Celtic Pharma Announces Preclinical Findings that XERECEPT(R) Potentiates Significantly the Tumor Inhibition Activity of Avastin(R)

NEW YORK, LONDON and BERMUDA, April 19, 2010 - Celtic Pharmaceutical Holdings L.P. ("Celtic Pharma") today
reported at the AACR 101st Annual Meeting 2010 in Washington, DC the results
from several preclinical studies of XERECEPT(R) in established models for
breast, colon and brain tumors. These animal studies were conducted at Duke
University and the Piedmont Research Center using solid human tumors
including breast and colon xenografts as well as both pediatric and adult
human brain tumor xenografts. All of these models demonstrated statistically
significant tumor regression and prolongation of survival following treatment
with XERECEPT(R) in combination with Avastin(R), compared to Avastin(R)
alone. In the human breast model both Avastin(R) and Xerecept(R) by
themselves produced similar antitumor effects, however, when Avastin(R) was
combined with Xerecept(R), antitumor effect was significantly increased
(p<0.001). The enhanced combination effect was statistically different
(p<0.03) than either result associated with the monotherapies. In the human
colon xenograft model, Xerecept was not active alone against this tumor
model, while Avastin(R) produced a significant tumor growth delay compared to
the vehicle-treated control. However, the combination therapy of Avastin(R)
plus Xerecept(R) significantly increased the overall survival of animals when
compared to treatment with vehicle (p<0.001) or bevacizumab alone (p<0.01).
In the High Grade Pediatric GBM model, Xerecept(R) had activity by itself,
and the combination of Xerecept(R) with bevacizumab was significantly better
than bevacizumab or Xerecept(R) alone. These preclinical findings demonstrate
that XERECEPT(R) has the ability to potentiate or provide a synergistic
enhancement of the antitumor effects of Avastin(R), in these various models.

"We have been seeing anecdotal observations from the Phase III
trials of Xerecept in brain tumor patients that this molecule may be doing
more for some of these patients than just controlling edema. Interestingly,
we have 13 brain tumor patients still on daily Xerecept treatment from the
501 Phase III open label study, with an average of 38 months (range 25 to 53
months) on drug to date" commented Stephen Evans-Freke, Managing General
Partner of Celtic Pharma. "These new preclinical findings of synergistic
activity of Xerecept in combination with Avastin(R) in major tumor types may
indicate a broader role for this molecule than has been understood up to
now".

"From both a medial point of view and a commercial point of
view, this information could have profound implications and certainly merits
further investigation," said John Mayo, Managing General Partner of Celtic
Pharma.

"We are happy to have the opportunity to work with Celtic on
this potential new therapeutic combination for major solid tumor patient
populations," commented Beth Hollister, Corporate Vice President, Charles
River Discovery and Imaging Services and Founder of Piedmont Research Center.
"We look forward to continuing to add to the scientific knowledge base for
this treatment as preparations are made for expanded clinical trials."

XERECEPT(R) is an investigational new drug under development
as a steroid-sparing alternative to dexamethasone for patients with primary
and metastatic brain tumors. Dexamethasone is currently the standard
treatment for peritumoral brain edema, but is associated with debilitating
side effects including diabetes mellitus, hypertension, muscle weakness, bone
loss, impaired wound healing and opportunistic infections.

About Celtic Pharmaceutical Holdings L.P.

Celtic Pharmaceutical Holdings L.P. (Celtic Pharma) is a
global private equity investment firm focused on the biotechnology and
pharmaceutical industries. Celtic Pharma was founded by Stephen Evans-Freke
and John Mayo, CBE and is based in Bermuda, with offices in New York and
London. Celtic Pharma acquires and invests in late stage pharmaceutical
programs and manages these programs through their development to regulatory
approval. Celtic Pharma's aim is to bridge the gap between the established
pharmaceutical companies' new product pipeline crisis and the biotech
industry's capital drought. For further information, please visit Celtic
Pharma's website at www.celticpharma.com.

Forward-Looking Statements

Certain statements in this press release that are not
historical facts, including statements that are preceded by, or followed by,
or that include words such as "may," "expect," "anticipate," "believe," or
"plan," or similar statements, are forward-looking statements that involve
risks and uncertainties, including risks relating to the results of the
clinical trials for XERECEPT(R) and the ability of Celtic Pharma to obtain
regulatory approval for XERECEPT(R). Actual results may differ materially
from those projected. These forward-looking statements represent our judgment
as of the date of the release. We disclaim, however, any intent to update
these forward-looking statements.

    Please Contact With Enquiries:

    Celtic Pharma
    Kathy Armstrong
    Investor Relations
    Tel: +1(212)616-4042
    kathy@celticpharma.com

    Media Contacts:

    FD
    US:
    Robert Stanislaro
    Tel: +1(212)850-5657
    Irma Gomez-Dib
    Tel: +1(212)850-5761

    UK:
    Jonathan Birt /John Dineen
    Tel: +44(0)20-7831-3113

Please Contact With Enquiries: Celtic Pharma, Kathy Armstrong, Investor Relations, Tel: +1(212)616-4042, kathy at celticpharma.com; Media Contacts: FD US: Robert Stanislaro, Tel: +1(212)850-5657, Irma Gomez-Dib, Tel: +1(212)850-5761; UK: Jonathan Birt /John Dineen, Tel: +44(0)20-7831-3113