Keryx Biopharmaceuticals Reports Single Agent Phase 2 Data of KRX-0401 Demonstrating Activity in Treatment of Advanced Metastatic Renal Cell Cancer

NEW YORK — Keryx Biopharmaceuticals, Inc. (Nasdaq: KERX) today announced data on the clinical activity of KRX-0401 (perifosine), the Company’s Akt-inhibitor for cancer, as a treatment for advanced renal cell carcinoma.

Abstract #5034, entitled, “Phase II study of perifosine in metastatic renal cell carcinoma (RCC) progressing after prior therapy (Rx) with a VEGF receptor,” was presented earlier today in a poster session at the 45th Annual Meeting of the American Society of Clinical Oncology (ASCO), taking place in Orlando, Florida. Later this afternoon, the data will also be presented by Dr. Brian Rini, Associate Professor of Medicine at the Cleveland Clinic Taussig Cancer Institute, in a poster discussion during the Genitourinary Cancer session.

The study enrolled a total of 50 patients, of which 46 patients were evaluable for response. Evaluable patients were defined as those who had greater than 7 days of treatment. The primary endpoint of this study was clinical benefit, defined as response rate (RECIST), and progression-free survival (PFS) in RCC patients who failed a prior VEGF receptor inhibitor (sunitinib or sorafenib). Safety of perifosine in this patient population was evaluated as a secondary endpoint. Best response to single agent perifosine was as follows:

Group N PR SD > 12 wks CBR* Median PFS

N (%) N (%) N (%) (SD or >)

All Pts 46 5 (11%) 16 (35%) 21 (46%) 33 weeks

[95% CI (24, 60)]

*CBR: Clinical Benefit Rate defined as patients with Stable Disease or Partial Response

The median PFS for all 46 patients was 12.5 weeks [95% CI (11.9, 19)]. The median overall survival has not been reached with 33 of 46 patients (72%) still alive.

Also of interest was the patient subgroup who had failed both a VEGF receptor inhibitor (sunitinib or sorafenib) and an mTOR inhibitor (either everolimus or temsirolimus). For this group, best response and median PFS to single agent perifosine was as follows:

Group N PR SD > 12 wks CBR Median PFS

N (%) N (%) N (%)

VEGF + mTOR 16 1 (6%) 7 (44%) 8 (50%) 16 weeks

[95% CI (11.7, 33.6)]

Three patients out of the group of patients previously treated with and failed both a VEGF and an mTOR inhibitor remain on active treatment, now out 5, 9 and 17 months.

Commenting on the data, Principal Investigator Nicholas Vogelzang, MD, Professor and Head of the Genitourinary Cancer Program at the Nevada Cancer Institute, stated, “perifosine demonstrated impressive single agent activity with an overall partial response rate of greater than 10%, which compares favorably to that of mTOR inhibitors, and was well tolerated. We are particularly intrigued by the group of patients previously treated with both an mTOR and VEGF receptor inhibitor, which had a median PFS of 16 weeks. Given the manageable safety profile and demonstrated efficacy, we believe a direct comparison to 2nd or 3rd line mTOR treatment and a study combining perifosine with mTOR inhibition should be considered.”

Ron Bentsur, Chief Executive Officer of Keryx, commented, “We believe that this single agent activity for perifosine once again demonstrates that perifosine is an active, novel agent with the potential to provide clinical benefit to patients with 2nd or 3rd line metastatic renal cell cancer. We are grateful to Dr. Vogelzang, Dr. Hutson and the other renal cell cancer experts for their leadership in this study and we look forward to evaluating future trial designs in patients with advanced renal cell carcinoma.”

A copy of abstract #5034 is currently available and can be viewed on-line through the ASCO website: http://www.asco.org/. A copy of the poster presented earlier today may be obtained by contacting the Company.

About Renal Cell Carcinoma (RCC)

Of all kidney tumors, 85% are classified as renal cell carcinoma (RCC) and of all patients with RCC, 25% present with advanced disease. Advanced RCC is resistant to such standard treatments as radiation therapy and chemotherapy, and the initial treatment for most patients is surgical removal of the kidney. If the cancer is confined to the kidney, the five-year survival rate is 60 to 70 percent; but the survival rate is considerably lower after the cancer has metastasized to other parts of the body. Even with the recent approval of several biological therapies for the treatment of advanced metastatic RCC (VEGF inhibitors, sunitinib and sorafenib, and mTOR inhibitors everolimus and temsirolimus), the National Cancer Institute reports a rising incidence of RCC with incidence and mortality rates more than twice as high in men as in women. In 2009, an estimated 49,000 new cases of RCC and 11,000 deaths attributable to RCC are expected in the US.

About Keryx Biopharmaceuticals, Inc.

Keryx Biopharmaceuticals is focused on the acquisition, development and commercialization of medically important, novel pharmaceutical products for the treatment of life-threatening diseases, including renal disease and cancer. Keryx is developing Zerenex((TM)) (ferric citrate), an oral, iron-based compound that has the capacity to bind to phosphate and form non-absorbable complexes. Zerenex has recently completed a Phase 2 clinical program as a treatment for hyperphosphatemia (elevated phosphate levels) in patients with end-stage renal disease. The Company is also developing KRX-0401 (perifosine), a novel, potentially first-in-class, oral anti-cancer agent that modulates Akt, a protein in the body associated with tumor survival and growth. KRX-0401 also modulates a number of other key signal transduction pathways, including the JNK and MAPK pathways, which are pathways associated with programmed cell death, cell growth, cell differentiation and cell survival. KRX-0401 is currently in Phase 2 clinical development for multiple tumor types. The Company also actively engages in business development activities that include seeking strategic relationships for its product candidates and for the Company, as well as evaluating compounds and companies for in-licensing or acquisition. Keryx is headquartered in New York City.

Cautionary Statement

Some of the statements included in this press release, particularly those anticipating future clinical and business prospects for KRX-0401, may be forward-looking statements that involve a number of risks and uncertainties. For those statements, we claim the protection of the safe harbor for forward-looking statements contained in the Private Securities Litigation Reform Act of 1995. Among the factors that could cause our actual results to differ materially are the following: our ability to successfully complete clinical trials for KRX-0401; our ability to meet anticipated development timelines for KRX-0401 due to recruitment, clinical trial results, manufacturing capabilities or other factors; and other risk factors identified from time to time in our reports filed with the Securities and Exchange Commission. Any forward-looking statements set forth in this press release speak only as of the date of this press release. We do not intend to update any of these forward-looking statements to reflect events or circumstances that occur after the date hereof. This press release and prior releases are available at http://www.keryx.com. The information in our website and in the American Society of Clinical Oncology’s website is not incorporated by reference into this press release and is included as an inactive textual reference only.

KERYX CONTACT:

Lauren Fischer

Director, Investor Relations

Keryx Biopharmaceuticals, Inc.

Tel: 212.531.5962

E-mail: [email protected]