Preclinical Data Support Endocyte's Folate Receptor-Targeted Small Molecule Drug Conjugates for Treatment of Triple Negative Breast Cancer

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WEST LAFAYETTE, Ind., Dec. 16, 2013 (GLOBE NEWSWIRE) -- Endocyte, Inc. (Nasdaq:ECYT), a biopharmaceutical company and leader in developing targeted small molecule drug conjugates (SMDCs) and companion imaging agents for personalized therapy in cancer and other serious diseases, today announced preclinical data suggesting the company's folate receptor-targeted SMDCs may provide a possible new treatment alternative for folate receptor expressing triple negative breast cancer (TNBC) patients. The preclinical data were presented on Dec. 12 at the 2013 Cancer Therapy & Research Center – American Association for Cancer Research (CTRC-AACR) San Antonio Breast Cancer Symposium in San Antonio, Texas.

Mice bearing MDA-MB-231 human breast cancer xenografts, a well-established folate receptor-positive TNBC cell line, were treated with vintafolide, EC1456 (a folate-tubulysin SMDC) and EC1744, a folate receptor-targeted SMDC constructed with a potent DNA cross-linking agent. All three SMDCs were highly active against the MDA-MB-231 tumors. Specifically, treatment with vintafolide resulted in 80 percent complete responses in mice, and 80-100 percent cure rates were produced by EC1456 and EC1744 when dosed as single agents. In all cases, the observed anti-tumor activity was not accompanied by any significant weight loss in the animals.

"The folate receptor is highly expressed in the TNBC subtype, and its expression significantly correlates with higher grades of malignancy as well as poor prognoses," said Christopher Leamon, Ph.D., vice president of research at Endocyte and senior author of the study. "Our data suggest that folate-targeted SMDCs hold promise for treating TNBC patients. Furthermore, our companion imaging agent, etarfolatide, may allow us to selectively identify those patients with folate receptor-positive disease in real time. Endocyte is establishing a growing portfolio of folate receptor-targeted SMDCs comprised of potent cytotoxics, such as tubulysin in EC1456, which may provide additional treatment options for patients who become resistant to other drugs or who express lower levels of the folate receptor."

About Vintafolide (MK-8109/EC145)

Vintafolide is an investigational proprietary, injectable, SMDC consisting of folate (vitamin B9) linked to a potent vinca alkaloid chemotherapy agent, desacetylvinblastine hydrazide (DAVLBH). Vintafolide is designed to target the chemotherapy agent to rapidly growing cancer cells that actively take up folate via the folate receptor. The folate receptor is expressed in a wide variety of cancers including ovarian cancer.

Vintafolide (MK-8109/EC145) in combination with pegylated liposomal doxorubicin (PLD) is currently under review with the European Medicines Agency (EMA) for the treatment of adult patients with folate receptor-positive platinum-resistant ovarian cancer. Vintafolide has also been granted orphan drug status by the European Commission. Vintafolide, along with investigational companion imaging agent, etarfolatide, is currently being evaluated in a Phase 3 clinical trial for platinum-resistant ovarian cancer, (PROCEED trial; Identifier NCT01170650) and a Phase 2b trial for non-small cell lung cancer (NSCLC) (TARGET trial; Identifier NCT01577654). A Phase 2 randomized trial of vintafolide in folate receptor-positive triple negative breast cancer is expected to be initiated in the near future.

As part of an exclusive license agreement with Endocyte, Merck is responsible for the development and worldwide commercialization of vintafolide. Endocyte would intend to co-promote vintafolide in the U.S. pending regulatory filing and approval, and is responsible for the development, manufacture and commercialization of etarfolatide worldwide.

About EC1456

EC1456 is an investigational proprietary, injectable, SMDC consisting of folate (vitamin B9) linked to a potent cytotoxic agent, tubulysin B hydrazide (TubBH). EC1456 is wholly owned by Endocyte. TubBH is a member of the tubulysin class of anti-neoplastic agents that inhibit the polymerization of tubulin into microtubules, a critical component during cell division. The targeting ligand folate, essential for cell division, has been investigated with vintafolide. EC1456 is currently being evaluated in a Phase 1 study in patients with advanced solid tumors ( Identifier NCT01999738).

About Etarfolatide (EC20)

Etarfolatide is an investigational folate receptor-targeted companion imaging agent that is being developed as a non-invasive method to identify tumors that express the folate receptor. These tumors are the molecular target of Endocyte's folate receptor-targeted therapeutic compounds such as vintafolide and EC1456. Folic acid is used with etarfolatide for the enhancement of image quality. Etarfolatide is under review with the EMA and has been granted orphan drug status by the European Commission.

About Endocyte

Endocyte is a biopharmaceutical company and leader in developing targeted small molecule drug conjugates (SMDCs) and companion imaging agents for personalized therapy in cancer and other serious diseases. Endocyte uses its proprietary technology to create novel SMDCs and companion imaging agents for personalized targeted therapies. The company's SMDCs actively target receptors that are expressed or over-expressed on diseased cells, relative to healthy cells. This targeted approach is designed to enable the treatment of patients with highly potent drugs into these cells. The companion imaging agents are designed to identify patients whose disease expresses the molecular target of the therapy and who therefore may be more likely to benefit from treatment. For more information, visit

Forward Looking Statements

Certain of the statements made in this press release are forward looking, such as those suggesting the possibility of therapeutic benefit to patients based on preclinical data. Actual results or developments may differ materially from those projected or implied in these forward-looking statements. Factors that may cause such a difference include risks that preclinical data may not be indicative of subsequent clinical trial results and risks related to the safety and efficacy of the company's product candidates. More information about the risks and uncertainties faced by Endocyte, Inc. is contained in the company's periodic reports filed with the Securities and Exchange Commission. Endocyte, Inc. disclaims any intention or obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.

CONTACT: Stephanie Ascher, Stern Investor Relations, Inc., (212) 362-1200, Martina Schwarzkopf, Ph.D., Russo Partners, (212) 845-4292, Tony Russo, Ph.D., Russo Partners, (212) 845-4251,

Source:Endocyte, Inc.