NEW YORK (Map) - NEW YORK, June 3 /PRNewswire-FirstCall/ -- Keryx Biopharmaceuticals, Inc. (Nasdaq: KERX) today announced that phase 2 results of perifosine (KRX-0401) in patients with relapsed/refractory Waldenstroms macroglobulinemia (WM) was presented at the 44th Annual Meeting of the American Society of Clinical Oncology. In a poster presentation held earlier today, Dr. Irene Ghobrial, Instructor of Medicine at the Dana-Farber Cancer Institute (DFCI) in Boston, MA, discussed the phase 2 results on the single agent clinical activity of perifosine in patients with both relapsed and/or refractory Waldenstroms macroglobulinemia. The presentation was entitled:

Abstract 8546: A PHASE II TRIAL OF THE NOVEL ORAL AKT INHIBITOR PERIFOSINE (KRX-0401) IN RELAPSED AND/OR REFRACTORY WALDENSTROMS MACROGLOBULINEMIA (WM).

Thirty-seven patients (median age 65 yrs) with advanced WM (76% had at least two prior treatments) were enrolled, with most patients (>75%) previously treated with at least one course of therapy on rituximab. All patients were scheduled to receive 150 mg of perifosine daily in a 28 day cycle for at least 6 cycles. Toxicities were generally well managed and tolerated with Grade 1 & 2 GI related toxicities occurring in 30% of the patients. Thirty-six patients were evaluable for response, assessed by criteria established at the second consensus panel for WM, with results as follows:

Response N Median Duration of Therapy(wks) Partial Response 2(5%) 60+, 24+ Minimal Response 10(28%) 36(range 9 - 68+) ORR (PR + MR) 12(33%) Stable Disease 22(61%) Progression 2(5%) PR: > 50% reduction in IgM / MR: > 25% reduction in IgM

11/36 patients remain on treatment and the median Time to Progression (TTP) has not been reached (8 cycles with a range of 2 - 17+). In summary, the investigators conclude that single agent perifosine showed encouraging activity with manageable toxicity in patients with relapsed/refractory Waldenstroms macroglobulinemia. An overall response rate of 33% (CR + PR + MR) was reported with an additional 61% of patients achieving stable disease (SD).

"The phase 2 data presented today further confirms pre-clinical results suggesting the promising activity of perifosine in Waldenstrom's macroglobulinemia," stated Dr. Ghobrial. "We are encouraged by the activity of single agent perifosine in the treatment of patients with advanced Waldenstrom's macroglobulinemia, and the manageable toxicity profile seen to date.

Michael Weiss, CEO of Keryx Biopharmaceuticals, commented "We are encouraged by this new data for perifosine, which continues to show activity across multiple forms of cancer. There is no FDA approved agent for the treatment of Waldenstroms macroglobulinemia and we believe that perifosine may offer a novel treatment option for these patients. We look forward to continuing to explore the potential for perifosine in the treatment of Waldenstroms macroglobulinemia as well as several other cancers, including multiple myeloma, renal cell carcinoma and brain cancer, both as a single agent and in combination with other novel agents."

Copies of the posters are available by request to Keryx Biopharmaceuticals.

KRX-0401 (Perifosine) Mechanism of Action and Profile

KRX-0401 (Perifosine) is a novel, potentially first-in-class, oral anti-cancer agent that modulates Akt and a number of other key signal transduction pathways, including the JNK and MAPK pathways, all of which are pathways associated with programmed cell death, cell growth, cell differentiation and cell survival. The effects of perifosine on Akt are of particular interest because of the importance of this pathway in the development of most cancers, the evidence that it is often activated in tumors that are resistant to other forms of anticancer therapy, and the difficulty encountered thus far in the discovery of drugs that will inhibit this pathway without causing excessive toxicity. High levels of activated Akt (pAkt) are seen frequently in many types of cancer and have been correlated with poor prognosis in patients with soft-tissue sarcoma, gastric, hepatocellular, endometrial, prostate, renal cell, head and neck cancers and hematological malignancies, as well as glioblastoma. The majority of tumors expressing high levels of pAkt were high-grade, advanced stage or had other features associated with poor prognosis. High pAkt is often seen in tumors that are resistant to conventional cancer treatments, including radiotherapy, chemotherapy, endocrine therapy, and especially therapy with some of the newer biologicals.

To date, over 1,700 patients have been treated with KRX-0401 in trials conducted both in the United States and Europe. Its safety profile is distinctly different from that of most cytotoxic agents. It does not appear to cause myelosuppression (depression of the immune system that may lead to life threatening infections), thrombocytopenia (a decrease in platelets that may result in bleeding), skin rash, flu-like symptoms or alopecia (hair loss); all of these toxicities occur frequently with many of the currently available treatments for cancer. The main side effects of perifosine are nausea, vomiting, diarrhea and fatigue, but these are either mild or non-existent in lower doses that have induced tumor regression. Responses have been seen with both daily and weekly regimens. At the doses studied, the daily regimens were better tolerated.

In Phase 1/2 trials, KRX-0401 has induced tumor regressions and/or caused disease stabilization in a variety of tumor types. KRX-0401 has shown single agent partial responses in renal cell and hepatocellular carcinoma, soft tissue sarcoma, GIST tumors, mesothelioma, and carcinoma of the appendix. There is also evidence of activity in hematological malignancies, especially multiple myeloma. Disease stabilization, defined as time on treatment without progression for at least 6 months has been seen in 20 tumor types, including metastatic renal cell cancer, hepatocellular carcinoma, melanoma, carcinoid, prostate, head and neck, breast, and small cell lung cancer. Responding patients, including stable disease, have been treated for various durations up to more than three years.

KRX-0401 (perifosine) is in-licensed by Keryx from Aeterna Zentaris, Inc. (Nasdaq: AEZS; TSX: AEZ) in the United States, Canada and Mexico.

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 is currently in Phase 2 clinical development for the treatment of hyperphosphatemia (elevated phosphate levels) in patients with end-stage renal disease, or ESRD. 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 has an in-licensing and acquisition program designed to identify and acquire additional drug candidates. 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 the Phase 1 and Phase 2 clinical trials for KRX-0401; we may not be able 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 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: 212.531.5965 E-mail: lfischer@keryx.com