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By Jake King

Keryx BioPharmaceuticals (KERX) miscalculated the timing for when its CRO (contract research organization) would deliver Phase III results for Zerenex, the company's phosphate-binder candidate for dialysis patients. Expectations were set for late 2012 (see prior story), however the data still hasn't been released, and shares of KERX have been quiet. We continue to expect positive results, with Zerenex demonstrating very favorable and consistent phosphate binding effects as well as positive iron absorption results (favorable impact on TSAT and ferritin levels) across prior mid- and late-stage clinical trials conducted by the company and its Japanese development and marketing partner, JT Torii (a division of Japan Tobacco).

Reasons for the Phase III data delay include: 1) Trial complexity - many parameters to be measured per patient, such as TSAT, ferritin levels, hemoglobin, and IV iron and ESA (erythropoietin stimulating agent) requirements for patients in the trial; 2) Year-end issues (hurricane Sandy, vacations, etc.); and most importantly, 3) Query resolution, or the process of making sure all the data are entered and accounted for, prior to releasing results. Nevertheless, we believe that queries by the CRO conducting the study have wrapped up and that the company will release results imminently, perhaps later this week. Should the Phase III results demonstrate positive phosphate binding effects only, we believe KERX shares are worth a bit over $5.00 upon releasing the results, and with benefits to a patient's iron levels (anemia benefits), the shares could climb to the double-digit range (See prior report).

As a phosphate binder, Zerenex's differentiating properties will be: 1) fewer pills per day vs. market leader, Renagel; 2) no heavy metal toxicity like competing products Fosrenol and PhosLo; and 3) a non-chewable formulation, which should enable the drug to gain a strong share of the $1.5B phosphate binder market in dialysis alone. Should Zerenex demonstrate that it can meaningfully help manage anemia in dialysis patients, and ultimately in pre-dialysis patients (those with Chronic Kidney Disease), the drug could have multi-hundred million-dollar potential. As we see it, the odds of Zerenex repeating prior clinical results are high, and the upside to KERX could be significant if it does.

KERX continues to prepare for Zerenex NDA. Last week we had a chance to speak with Keryx management and ask about the delay in the Zerenex Phase III clinical trial results. Management noted that the delay has been little more than a misjudgment on the overall timing to finalize patient information from the trial, and that they themselves are still awaiting the results. In the interim, Keryx continues to move forward with the assembly of Zerenex's New Drug Application (NDA). The company is working on all of the modules of the drug application, including the CMC (Chemistry Manufacturing and Controls) section; preclinical data; toxicology studies; and the integrated safety and efficacy database, which is robust based on previous trials and awaits the Phase III results from the ESRD (End Stage Renal Disease) trial. Moving the NDA forward is a positive sign, and assuming that the Phase III data are favorable, the company should be in a position to file an NDA for Zerenex in the U.S. shortly thereafter.

Japanese opportunity for Zerenex may be larger than initially thought; U.S. opportunity could be pure upside. JT Tori, Keryx's Japanese partner for Zerenex, filed a New Drug Application for the drug in Japan on January 7th, and while full details of the application were not disclosed, we now assume that JT Tori may have filed for both ESRD and Chronic Kidney Disease (pre-dialysis patients). Our new assumption is based on reviewing the set of prior studies run by JT Tori, including a Phase III trial in patients with CKD (see here). We previously wrote that the Japanese opportunity for Zerenex could be worth $1 per share to Keryx, but our estimate may be too conservative as it is based only on the ESRD (dialysis) indication.

The market for phosphate binders in Japan is estimated at $335M annually, however, this is only in the ESRD patient population. We assume that Zerenex should take at least 35% of the ESRD treatment market, or $117M in annual sales, given the drug's strong phosphate binding effects and likely anemia benefits. JT Tori is obligated to pay royalties to Keryx in the low double digits (we assume an average of 13%), suggesting that revenues to Keryx could reach approximately $15M annually. Valuing the royalties at a 4x or 5x multiple of sales, and with 72M KERX shares outstanding, the Japanese commercialization of Zerenex in ESRD is thus worth approximately $1 per share to KERX. Considering that the pre-dialysis (CKD) segment is estimated to be 3 to 4 times larger than the ESRD segment as in other countries, potential Zerenex sales, and subsequent revenues to KERX, could be 3x to 4x higher than our initial assumptions. As a result, KERX at ~$3.00 per share may be fairly valued on the Japanese opportunity alone, suggesting that the U.S. opportunity offers significant upside to the stock.

Delay for phosphate binder inclusion into the Medicare dialysis "Bundle" will benefit Zerenex's market debut. When the company put out this press release, KERX shares didn't react much, as Zerenex's Phase III data were not yet released, which clearly takes precedent over any potentially beneficial news for the drug's market opportunity. However, if the company releases positive Phase III results this week for the drug, investors are likely to start factoring in the benefit of Medicare's delay in including phosphate binders as part of the "Bundle." Because phosphate binders will continue to be reimbursed outside of the dialysis bundle for an additional two years (pushed out from 2014 to 2016), dialysis providers will not be as concerned about price, and therefore, Zerenex can be adopted primarily based on its differentiated and superior clinical benefits.

While KERX expects to price Zerenex competitively to gain a rapid foothold in this large market, the lack of interference from bundle constraints removes an important barrier that may have impacted the drug's initial launch ramp. Zerenex is anticipated to be reimbursed under Medicare Part D once approved, and physicians will have two additional years (before dealing with bundle issues) to become familiar with the drug and its benefits relative to competing phosphate binders. We believe this increases the value of Zerenex's U.S. opportunity, and any potential strategic buyers of the company will see the benefit of the delayed bundle effect. Nevertheless, for KERX shares to take advantage of this news, Phase III data need to be favorable. Hence, this is another reason why the stock may rip higher on positive results from the anticipated Phase III trial.

Shares of KERX have sat relatively quiet in the $3.00 range since late last year when Phase III data for Zerenex was set to be released. Results are now expected imminently, and positive phosphate binding data should send the stock up to $5.00 or more, while favorable anemia benefits in ESRD patients on top of strong phosphate binding data could send KERX even higher. On the downside, if the trial data for the U.S. are not robust, we believe the revenue potential for Zerenex in Japan may be able to support the stock at or near current levels as investors better understand this opportunity. Overall, we like the long bet on KERX heading into the Phase III results, and playing the stock with options can limit one's risk on this binary event.

Source: Zerenex Phase III Data Imminent; Odds Still High For Keryx To Succeed With This Drug

Additional disclosure: PropThink is a team of editors, analysts, and writers. This article was written by Jake King. We did not receive compensation for this article, and we have no business relationship with any company whose stock is mentioned in this article. Use of PropThink’s research is at your own risk. You should do your own research and due diligence before making any investment decision with respect to securities covered herein.You should assume that as of the publication date of any report or letter, PropThink, LLC and persons or entities with whom it has relation ships (collectively referred to as "PropThink") has a position in all stocks (and/or options of the stock) covered herein that is consistent with the position set forth in our research report. Following publication of any report or letter, PropThink intends to continue transacting in the securities covered herein, and we may be long, short, or neutral at any time hereafter regardless of our initial recommendation. To the best of our knowledge and belief, all information contained herein is accurate and reliable, and has been obtained from public sources we believe to be accurate and reliable, and not from company insiders or persons who have a relationship with company insiders. Our full disclaimer is available at www.propthink.com/disclaimer.