Patients With 100 Percent Folate Receptor-Positive Tumor Lesions Experienced Substantial Progression-Free Survival When Treated With Vintafolide
New Data Presented at AACR-SNMMI Joint Conference on State-of-the-Art Molecular Imaging in Cancer Biology and Therapy
SAN DIEGO, March 1, 2013 (GLOBE NEWSWIRE) -- Endocyte, Inc. (Nasdaq:ECYT), a biopharmaceutical company developing targeted small molecule drug conjugates (SMDCs) and companion imaging diagnostics for personalized therapy in cancer and other serious diseases, today announced a new analysis demonstrating that the investigational diagnostic imaging agent etarfolatide (EC20) can identify ovarian cancer and non-small cell lung cancer (NSCLC) patients who could benefit from folate receptor-targeted therapeutics, such as the novel investigational cancer candidate vintafolide (MK-8109/EC145). Patients with all target tumor lesions positive as assessed by etarfolatide imaging, FR(100%) experienced substantial progression-free survival (PFS) compared to patients with 10 to 90 percent of target lesions positive for folate receptor, FR(10-90%), when treated with single-agent vintafolide. Additional data demonstrate etarfolatide's potential to predict in which tissues or lesions folate receptor-targeting drugs will accumulate and therefore potentially respond to folate receptor-targeted therapy. These results were presented at the first AACR-SNMMI Joint Conference on State-of-the-Art Molecular Imaging in Cancer Biology and Therapy in San Diego, Calif."Etarfolatide allows for a non-invasive, full-body assessment of target lesions that over-express the folate receptor in real time, providing physicians with deeper information that guides patient selection for the investigational folate receptor-targeted therapy, vintafolide," said Phillip Kuo, M.D., Ph.D., associate professor, radiology, medicine and biomedical engineering, University of Arizona Cancer Center. "These studies, conducted in heavily pre-treated patients, provide additional support that this personalized therapy approach enables the identification of patients who will most likely benefit from folate receptor-targeted therapy." Vintafolide and etarfolatide are currently being evaluated in a Phase 3 randomized, double-blind clinical trial for platinum-resistant ovarian cancer (PROCEED trial; ClinicalTrials.gov Identifier NCT01170650) and a Phase 2b trial in patients with NSCLC (TARGET trial; ClinicalTrials.gov Identifier NCT01577654). Endocyte recently announced that the European Medicines Agency (EMA) has accepted for review the marketing authorization application (MAA) filings for vintafolide and etarfolatide for the targeted treatment of patients with folate receptor-positive ovarian cancer in combination with pegylated liposomal doxorubicin (PLD). Both vintafolide and etarfolatide have been granted orphan drug status by the European Commission. In abstract number 41, " 99mTc-etarfolatide (EC20) SPECT imaging for the identification of ovarian and non-small cell lung cancer patients who are most likely to benefit from folate receptor-targeted agent vintafolide (EC145)," heavily pre-treated ovarian cancer and non-small cell lung cancer patients in two single-arm Phase 2 trials were imaged with etarfolatide single-photon emission computed tomography (SPECT) scans to assess etarfolatide uptake in target lesions and then treated with single-agent vintafolide. Vintafolide was administered in an induction phase (1.0 mg intravenous [IV] bolus daily x 5 days for 3 weeks of a 4-week cycle x 2 cycles) followed by a maintenance phase (2.5 mg IV bolus daily x 3 days, weeks 1 and 3 of a 4-week cycle). Patients received therapy until disease progression or unacceptable toxicity. Among both NSCLC and ovarian cancer patients with at least one target tumor lesions positive as assessed by etarfolatide imaging, the greatest efficacy was observed in FR(100%) patients compared to the FR(10 to 90%) patients: (15.2 versus 7.4 weeks in ovarian cancer patients and 31.1 versus 7.3 weeks in NSCLC patients). The PFS hazard ratios with 95 percent confidence interval between the two folate receptor subgroups were 0.797 (0.362, 1.756) and 0.326 (0.115, 0.919) for the ovarian cancer and NSCLC studies, respectively. The FR(100%) subgroup also had greater than 50 percent improvement in disease control rate (ovarian cancer, 57.1 percent versus 36.4 percent; NSCLC, 57.1 percent versus 14.3 percent) and overall survival (ovarian cancer, 63.6 versus 41.7 weeks; NSCLC, 47.2 versus 14.9 weeks) compared with FR(10-90%) patients. The overall survival hazard ratios (95 percent confidence interval) between the two folate receptor subgroups were 0.574 (0.213, 1.542) and 0.539 (0.209, 1.395) for the ovarian cancer and NSCLC studies, respectively. Furthermore, analyses of tumor lesions showed that the percentage of lesions that were decreased (at least 20 percent decrease in size from baseline) or stable (less than 20 percent increase in size from baseline) was greater in folate receptor-positive lesions than in folate receptor-negative lesions, supporting the target-specific mechanism of action of vintafolide. There were no drug-related grade 4 toxicities reported. The most common drug-related adverse events (all grades) were constipation (47 percent and 33 percent in ovarian cancer and NSCLC studies, respectively) and fatigue (37 percent for both ovarian cancer and NSCLC).