Skip to Content

KALBITOR® (ecallantide) Data Presented at American Academy of Allergy, Asthma and Immunology Annual Meeting

-Low Rebound and Relapse Rates Observed in Patients Treated with KALBITOR-

-KALBITOR Study Data Demonstrate Clinically Meaningful Efficacy in Treatment of Acute Laryngeal Attacks of Hereditary Angioedema-

BURLINGTON, Mass.--(BUSINESS WIRE)--Mar 6, 2012 - Dyax Corp. (NASDAQ: DYAX) today announced the presentation of data from KALBITOR® (ecallantide) clinical studies in hereditary angioedema (HAE) at the American Academy of Allergy, Asthma and Immunology (AAAAI) Annual Meeting in Orlando, Florida. The data were presented in four separate poster presentations and included data related to rebound and relapse rates in patients treated with KALBITOR as well as to KALBITOR for the treatment of acute laryngeal attacks of HAE. KALBITOR is indicated for the treatment of acute attacks of HAE in patients 16 years of age and older.

“Taken together, the results presented today enrich the KALBITOR efficacy profile and provide further support for its use against acute attacks of HAE,” stated Henry Li, M.D., Ph.D. of the Institute for Asthma and Allergy in Wheaton, MD. “Notably, low rebound and relapse rates observed among patients treated with KALBITOR evidence sustained relief from HAE attacks, an important consideration in selecting therapy.”

Albert L. Sheffer, II, M.D. of the Brigham and Women's Hospital in Boston, MA, added: “Among the findings of our multi-study evaluation are data demonstrating that treatment with KALBITOR produced clinically meaningful and sustained improvement in laryngeal attacks due to HAE. The larynx is the most serious HAE attack site, and laryngeal attacks will affect nearly half of all individuals with HAE at least once during their lifetime. The availability of an on-demand treatment such as KALBITOR is, therefore, a valuable part of the individual patient's treatment plan.”

“The KALBITOR studies presented demonstrate Dyax's ongoing commitment to HAE,” stated Gustav Christensen, President and Chief Executive Officer at Dyax Corp. “We remain focused on educating the HAE community about the benefits of treatment with KALBITOR, ensuring access to this important therapy, and evolving our plasma kallikrein (bradykinin) mediated angioedema franchise with investments in next-generation products and services.”

In the poster presentation titled, “Rates of Rebound or Relapse Among Acute Attacks of Hereditary Angioedema Treated with Ecallantide in Open-Label, Repeat-Treatment Study,” Dr. Li determined that the rates of rebound and relapse were low among patients treated with KALBITOR. In the study, 144 HAE patients were monitored following treatment with KALBITOR and evaluated using three assessments: the Treatment Outcome Score (TOS), Mean Symptom Complex Severity (MSCS) score, and global response assessment. Treatment episodes showing improvement in all three assessments at 4 hours after dosing, followed by worsening in any assessment at 24 hours were identified as potential cases for further characterization. Rebound was defined as worsening beyond baseline, while relapse was defined as worsening but not beyond baseline. Of the 340 treated attacks with improvement in all three assessments at 4 hours and with data available at 24 hours, 58 were identified as potential cases for further characterization. These cases were then characterized as likely, possible, or unlikely based on number of assessments showing worsening and the quantitative magnitude of change in each assessment. Of the 338 treated attacks in this analysis:


  • 3 (1%) treated attacks were identified as likely rebound and 8 (2%) as likely relapse;
  • 0 (0%) treated attacks were identified as possible rebound and 12 (4%) as possible relapse; and
  • 0 (0%) treated attacks were identified as unlikely rebound and 35 (10%) as unlikely relapse.

Patients treated for multiple attacks showed no consistent pattern of potential rebound/relapse.

In the poster titled, “Ecallantide Reverses Laryngeal Hereditary Angioedema Attacks: Experience from the EDEMA Clinical Development Program,” Dr. Sheffer evaluated the data from four clinical studies of KALBITOR and determined that KALBITOR demonstrated clinically meaningful efficacy for potentially life-threatening laryngeal edema due to HAE. Data was pooled from four clinical studies (EDEMA2, EDEMA3, EDEMA4, and DX-88/19) evaluating 30 mg subcutaneous KALBITOR for the treatment of acute HAE attacks. Efficacy was assessed with two validated, HAE-specific, patient-reported outcomes: Mean Symptom Complex Severity (MSCS) score (negative score indicates improvement; minimally important difference equals -0.3) and Treatment Outcome Score (positive score indicates improvement; minimally important difference equals 30). A total of 98 patients were treated for 220 laryngeal attacks, of which 25% we classified as severe, 62% were classified as moderate, and 13% were classified as mild. Approximately 57% of these patients were treated for one laryngeal attack; 9% were treated for five or more laryngeal attacks. The results demonstrated that the:


  • Mean change in MSCS score was ­1.1 at four hours and -1.6 at 24 hours;
  • Mean TOS was 73.5 at four hours and 85.5 at 24 hours; and,
  • Onset of sustained improvement was reached within four hours by 80% of patients (median time of 113 minutes).

Four serious adverse events were reported: 2 unrelated hospitalizations for HAE, 1 anaphylactic reaction, and 1 hypersensitivity reaction.

Additional KALBITOR data was discussed in the following poster presentations:


  • Efficacy and Safety of Ecallantide Treatment for HAE Attacks in Patients Treated with Both Ecallantide and Placebo, William Lumry, M.D. Allergy and Asthma Research Association Research Center, Dallas, TX
  • Hypersensitivity Reactions to Ecallantide: an Update of the Clinical Trial Experience and Post-Market Surveillance for Treatment of Attacks of Hereditary Angioedema, Timothy J. Craig, D.O., Pennsylvania State University, Hershey, PA

About KALBITOR® (ecallantide)

KALBITOR is a plasma kallikrein inhibitor indicated for the treatment of acute attacks of hereditary angioedema (HAE) in patients 16 years of age and older. KALBITOR, which was discovered and developed by Dyax, is the first subcutaneous treatment available in the U.S. for treating acute HAE attacks.

Important KALBITOR Safety Information

Anaphylaxis has been reported after administration of KALBITOR. Because of the risk of anaphylaxis, KALBITOR should only be administered by a healthcare professional with appropriate medical support to manage anaphylaxis and hereditary angioedema. Healthcare professionals should be aware of the similarity of symptoms between hypersensitivity reactions and hereditary angioedema and patients should be monitored closely. KALBITOR should not be administered to patients with known clinical hypersensitivity to KALBITOR.

For more information about KALBITOR, including full prescribing information, visit

KALBITOR Development HAE Program

The approval of KALBITOR is based on the results of two placebo-controlled Phase 3 clinical studies, known as EDEMA3® and EDEMA4®. Patients having an attack of HAE, at any anatomic location, with at least one moderate or severe symptom, were treated with 30 mg subcutaneous KALBITOR or placebo. Because patients could participate in both trials, a total of 143 unique patients participated. There were 64 patients with abdominal attacks, 55 with peripheral attacks, and 24 with laryngeal attacks. In both trials, the effects of KALBITOR were evaluated using the Mean Symptom Complex Severity (MSCS) score and the Treatment Outcome Score (TOS), two HAE-specific patient-reported outcome endpoints developed by Dyax. These measures evaluated the severity of attack symptoms at all anatomical locations (MSCS score) and response to therapy (TOS). In the EDEMA4 trial at 4 hours, patients treated with KALBITOR demonstrated a greater decrease from baseline in the mean MSCS than placebo (-0.8 vs. -0.4; p = 0.010) and a greater mean TOS (53 vs. 8, p = 0.003). In the EDEMA4 trial at 24 hours, patients treated with KALBITOR also demonstrated a greater decrease from baseline in the mean MSCS than placebo (-1.5 vs. -1.1; p = 0.04) and a greater mean TOS (89 vs. 55, p = 0.03). The results in the EDEMA3 trial were consistent with the EDEMA4 trial results.

Potentially serious hypersensitivity including anaphylaxis, have occurred in patients treated with KALBITOR. In 255 HAE patients treated with intravenous or subcutaneous KALBITOR in clinical studies, 10 patients (3.9%) experienced anaphylaxis. For the subgroup of 187 patients treated with subcutaneous KALBITOR, 5 patients (2.7%) experienced anaphylaxis. Symptoms associated with these reactions have included chest discomfort, flushing, pharyngeal edema, pruritus, rhinorrhea, sneezing, nasal congestion, throat irritation, urticaria, wheezing, and hypotension. These reactions occurred within the first hour after dosing.

The most common adverse reactions occurring in greater-than or equal to 3% of KALBITOR-treated patients and greater than placebo were headache, nausea, diarrhea, pyrexia, injection site reactions, and nasopharyngitis.


Patients and healthcare providers can contact KALBITOR Access® to receive information and work with program staff to research patient insurance coverage for KALBITOR. KALBITOR Access is designed as a one-stop point of contact for information about KALBITOR. The program is staffed with dedicated insurance specialists and nurse case managers who will help coordinate patient treatment and access to KALBITOR. Patients and healthcare providers can call 1-888-4KALBITOR (1-888-452-5248) for information and to utilize these services or visit

About HAE

Hereditary angioedema (HAE) is a rare acute inflammatory condition characterized by episodes of severe, often painful swelling affecting the extremities, gastrointestinal tract, genitalia, and larynx. HAE is caused by low or dysfunctional levels of C1 esterase inhibitor (C1-INH), a naturally occurring molecule that inhibits plasma kallikrein, a key mediator of inflammation, and other serine proteases in the blood. HAE is estimated to affect 1 in 10,000 to 1 in 50,000 individuals. Learn more at

About Dyax

Dyax is a fully integrated biopharmaceutical company focused on the development and commercialization of novel biotherapeutics for unmet medical needs. Dyax's lead product, ecallantide, has been approved under the brand name KALBITOR® in the United States for the treatment of acute attacks of hereditary angioedema (HAE) in patients 16 years of age and older.

Dyax is commercializing KALBITOR in the United States independently, and establishing strategic collaborations to develop and commercialize ecallantide for the treatment of HAE in key regions worldwide. Currently, Dyax has agreements for regions including Europe, Japan, Russia, the Middle East, Israel, North Africa, Australia, New Zealand, Latin America (excluding Mexico) and the Caribbean. Dyax is also exploring other potential indications for ecallantide, either alone or through collaborations, including drug-induced angioedema.

Ecallantide and other compounds in Dyax's pipeline were identified using its patented phage display technology, which rapidly selects compounds that bind with high affinity and specificity to therapeutic targets. Dyax leverages this technology broadly through the Licensing and Funded Research Program (LFRP), which has approximately 70 revenue generating licenses and collaborations for therapeutic discovery, as well as for affinity separations, diagnostic imaging, and research reagents. The success of the Company's LFRP portfolio is illustrated by the program's advanced licensee pipeline that includes 18 candidates in clinical development. Of those candidates, four are in Phase 3 clinical trials, four are in Phase 2 and ten are in Phase 1.

Dyax is headquartered in Burlington, Massachusetts. For online information about Dyax Corp., please visit

Dyax Disclaimer

This press release contains forward-looking statements, including statements regarding the prospects for therapeutic benefits and treatment advantages of KALBITOR for HAE. Statements that are not historical facts are based on Dyax's current expectations, beliefs, assumptions, estimates, forecasts and projections about the industry and markets in which Dyax competes. The statements contained in this release are not guarantees of future performance and involve certain risks, uncertainties and assumptions, which are difficult to predict. Therefore, actual outcomes and results may differ materially from what is expressed in such forward-looking statements. Important factors which may affect the prospects for therapeutic benefits and treatment advantages of KALBITOR for HAE include the risks that: others may develop technologies or products superior to KALBITOR or that are on the market before KALBITOR; KALBITOR may not gain market acceptance; Dyax is dependent on the expertise, effort, priorities and contractual obligations of third parties in the manufacture, marketing, sales and distribution of KALBITOR; and other risk factors described or referred to Item 1A, “Risk Factors” in Dyax's most recent Annual Report on Form 10-K and other periodic reports filed with the Securities and Exchange Commission. Dyax cautions investors not to place undue reliance on the forward-looking statements contained in this release. These statements speak only as of the date of this release, and Dyax undertakes no obligations to update or revise these statements, except as may be required by law.

Dyax, the Dyax logo and KALBITOR are registered trademarks and EDEMA3 and EDEMA4 are registered service marks of Dyax Corp. KALBITOR Access is a service mark of Dyax Corp.


Contact: Dyax Corp.
George Migausky, 617-250-5733
Executive Vice President
and Chief Financial Officer
Jennifer Harsey, 617-250-5741
Manager, Investor Relations
and Corporate Communications



Posted: March 2012