Acquisition Includes Replidea^TM and Alpharen^TM, Both in Phase 3 Clinical Trials with Kidney Disease Patients

MARKHAM, ON, Jan. 8, 2013 /PRNewswire/ – Cytochroma today announced that it has
entered into a definitive agreement with OPKO Health, Inc. (NYSE:OPK) under which Cytochroma, a privately held pharmaceutical company with
operations in Markham, ON and Bannockburn, IL, will be acquired by
OPKO. Through this transaction, OPKO will acquire worldwide rights to
Cytochroma’s two lead product candidates: Replidea^TM (coded CTAP101 Capsules), a vitamin D prohormone to treat secondary
hyperparathyroidism (SHPT) in patients with stage 3 or 4 chronic kidney
disease (CKD) and vitamin D insufficiency; and, Alpharen^TM (Fermagate Tablets), a non-absorbed phosphate binder to treat
hyperphosphatemia in dialysis patients. Both products are in phase 3
development in the United States. Cytochroma’s officers will join the
OPKO management team, and all other Cytochroma employees will be
retained by OPKO.

Replidea™ has been shown in a phase 2b clinical trial to effectively and
safely treat SHPT and the underlying vitamin D insufficiency in
pre-dialysis patients. Vitamin D insufficiency arises in CKD due to the
abnormal upregulation of CYP24, an enzyme which destroys vitamin D and
its metabolites. Studies in CKD patients have demonstrated that
currently available over-the-counter and prescription vitamin D
products cannot reliably raise blood vitamin D prohormone levels or
effectively treat SHPT.

“OPKO intends to market Replidea™ along with OPKO’s proprietary
point-of-care vitamin D diagnostic test currently in development,”
stated Phillip Frost, MD, OPKO’s CEO and Chairman. “We envision these
remarkable products as part of the foundation for a new and markedly
improved standard of care for chronic kidney disease patients.”

“We are pleased that OPKO and Cytochroma have joined forces to improve
the care of kidney patients,” commented Alan J. Lewis, PhD,
Cytochroma’s Chairman. “The combined companies are well positioned to
become a major new global player in the chronic kidney disease space.”

Alpharen™ has been shown safe and effective in treating
hyperphosphatemia (elevated serum phosphorus) in the phase 2 and 3
clinical trials undertaken to date in dialysis patients.
Hyperphosphatemia exacerbates SHPT and promotes bone disease, soft
tissue mineralization and progression of kidney disease. Approximately
90% of dialysis patients in the United States require regular
treatment. Cytochroma acquired global rights to Alpharen^TM from INEOS Healthcare in 2010.

About Chronic Kidney Disease

CKD is a condition characterized by a progressive decline in kidney
function. The kidney is normally responsible for excreting waste and
excess water from the body, and for regulating various hormones. CKD
is classified in five different stages – mild (stage 1) to severe
(stage 5) disease – as measured by the kidney’s glomerular filtration
rate. According to the National Kidney Foundation, CKD afflicts over
26 million people in the US, including more than eight million patients
with moderate (stages 3 and 4) and severe (stage 5) forms of CKD. In
stage 5 CKD, kidney function is minimal to absent and patients require
regular dialysis or a kidney transplant for survival.

About Vitamin D Insufficiency

Vitamin D insufficiency is a condition in which the body has low vitamin
D stores, characterized by inadequate blood levels of vitamin D
prohormones, collectively known as 25-hydroxyvitamin D. An estimated
70-90% of CKD patients have vitamin D insufficiency, which can lead to
SHPT and resultant debilitating bone diseases.

About Secondary Hyperparathyroidism (SHPT)

SHPT is a condition commonly associated with CKD in which the
parathyroid glands secrete excessive amounts of parathyroid hormone
(PTH). SHPT arises as a result of vitamin D insufficiency or impaired
kidney function that prevents sufficient production of vitamin D
hormones to properly regulate calcium and phosphorus metabolism, and
PTH secretion. Prolonged elevation of blood PTH causes excessive
calcium and phosphorus to be released from bone, leading to elevated
serum calcium and phosphorus, softening of the bones (osteomalacia) and
calcification of vascular and renal tissues. SHPT affects 40-60% of
patients with moderate CKD and approximately 90% of patients with
severe CKD.

About Hyperphosphatemia

Hyperphosphatemia, or elevated serum phosphorus, is common in dialysis
patients and tightly linked to the progression of SHPT. The kidneys
provide the primary route of excretion for excess phosphorus absorbed
from ingested food. As kidney function worsens, serum phosphorus levels
increase and directly stimulate PTH secretion. Stage 5 CKD patients
must reduce their dietary phosphate intake and usually require regular
treatment with phosphate binding agents to lower serum phosphorus to
meet the recommendations of the National Kidney Foundation’s Clinical
Practice Guidelines that serum phosphorus levels should be maintained
at <5.5 mg/dL.

About Cytochroma

Cytochroma is a clinical-stage specialty pharmaceutical company focused
on developing and commercializing proprietary products to treat and
prevent the clinical consequences of vitamin D insufficiency and SHPT
associated with CKD. The Company, founded in 1996 by Martin J.
Petkovich, PhD, Cytochroma’s CSO and Glenville Jones, PhD, former Head
of Biochemistry, Queen’s University, Kingston, ON, specializes in
developing new vitamin D therapies which are designed to safely and
effectively treat patients with stage 3, 4 or 5 CKD. Cytochroma also
has a portfolio CYP24 and phosphate-uptake inhibitors in early stages
of development. Cytochroma’s phase 3 clinical programs are being
funded, in part, by committed financings of nearly $CDN 32 million of
which the first two stages closed in 2012. The lead investors in the
financings were Covington Fund II (Toronto), Business Development Bank
of Canada (Montreal) and GrowthWorks (Toronto). Participating investors
included the Bombardier Trust (Canada) Funds (Montreal), Caisse de
d pôt et placement du Qu bec (Qu bec), Comerica Bank (Toronto), MaRS
Investment Accelerator Fund (Toronto), Partners Group (Zug), Roseway
Capital Sarl (Luxembourg) and VentureLink Innovation Fund (Toronto).

SOURCE Cytochroma