NEW ORLEANS, April 18, 2016 (GLOBE NEWSWIRE) -- Immunomedics, Inc., (Nasdaq:IMMU) today announced that labetuzumab govitecan, its first-in-class antibody-drug conjugate (ADC), continues to produce encouraging survival results in a multicenter, open-label Phase 2 study in patients previously treated with at least one irinotecan-containing regimen for their metastatic colorectal cancer (mCRC).
Interim median progression-free survival (PFS) and overall survival (OS) for patients who received once-a-week of labetuzumab govitecan at the 8 or 10 mg/kg dose level are summarized below. For the 20 patients with prior treatment with regorafenib, bevacizumab, 5-fluorouracil, irinotecan and oxaliplatin-containing chemotherapies, the median PFS and OS were 3.9 and 6.7 months, respectively.
| Labetuzumab Govitecan Dose | ||||||
| 8 mg/kg once a week | 10 mg/kg once a week | |||||
| Number of Patients | 21 | 17 | ||||
| Median PFS* (months) | 4.8 (3.9 – 6.2) | 4.6 (3.4 – 7.5) | ||||
| Maturity PFS | 90 | % | 67 | % | ||
| Median OS (months) | 7.5 (5.7 – 16.1) | 9.2 (5.9 – 16.0) | ||||
| Maturity OS | 67 | % | 61 | % | ||
* Treatment response was evaluated in accordance with the rules set by the Response Evaluation Criteria In Solid Tumors (RECIST 1.1) using computed tomography as the imaging tool for tumor size measurements.
“Given that regorafenib was approved in the U.S. for the treatment of patients with previously-treated mCRC based on a median PFS of 2.0 months and a median OS of 6.4 months1, I am very encouraged with the results our patients are experiencing with IMMU-130,” stated Dr. Jordan D. Berlin of Vanderbilt-Ingram Cancer Center, Nashville, TN, who presented the updated results at the 2016 Annual Meeting of the American Association for Cancer Research (AACR).
This Phase 2 study evaluated four dosing schedules. A total of 82 patients were enrolled to receive, in the first 2 weeks of a 21-day cycle, labetuzumab govitecan at 8 or 10 mg/kg once-weekly or twice a week at 4 or 6 mg/kg. There was no significant difference in safety and efficacy between the two once-weekly dosing schedules. For patient’s convenience, the once-a-week dose of 10 mg/kg was chosen for future studies in mCRC patients, possibly against regorafenib and/or in patients relapsed or refractory to regorafenib.
Commenting on these results, Cynthia L. Sullivan, President and Chief Executive Officer stated, “IMMU-130 has demonstrated promising activity in this difficult-to-treat cancer population, and we believe it may have even further promise in irinotecan-naïve patients.”
Labetuzumab govitecan remains well tolerated by patients. Among 75 patients with adverse events reported at the AACR conference, grades 3 and 4 adverse events across all doses, with occurrence of 2% or more, included neutropenia at 15%, diarrhea at 7%, and febrile neutropenia at 3%. For the 15 patients who received the ADC at 10 mg/kg once weekly, the designated dose, 33% reported grade 3 or 4 neutropenia but no incidents of febrile neutropenia or diarrhea. Remarkably, despite repeated dosing, no antibody against labetuzumab or its SN-38 conjugate was detected in 460 blood samples (including baseline) drawn from 84 patients.
The Company developed labetuzumab govitecan by conjugating the moderately-toxic drug, SN-38, site-specifically and at a high ratio of drug to labetuzumab, a humanized antibody that recognizes the carcinoembryonic antigen (CEA; CEACAM5 or CD66e) expressed in many solid cancers, including more than 90% of colorectal cancer. SN-38 is the active metabolite of irinotecan (Camptosar), which is used to treat certain solid cancers, particularly metastatic colorectal cancers, as a part of combination therapies, so its pharmacology and properties are well-known.
Besides Dr. Berlin, other clinical investigators who participated in this multicenter trial are Drs. Efrat Dotan (first author of the abstract) and Steven J. Cohen, Fox Chase Cancer Center, Philadelphia, PA; Dr. Alexander N. Starodub, Indiana Health Center for Cancer Care, Goshen, IN; Drs. Christopher H. Lieu and Wells A. Messersmith, University of Colorado Cancer Center, Aurora, CO; Dr. Michael J. Guarino, Helen F. Graham Cancer Center & Research Institute, Newark, DE; Dr. John L. Marshall, Georgetown University Hospital, Washington, DC; Dr. Richard M. Goldberg, Ohio State Comprehensive Cancer Center, Columbus, OH; and Dr. J. Randolph Hecht, UCLA Jonsson Comprehensive Cancer Center, Los Angeles, CA.
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About Immunomedics
Immunomedics is a clinical-stage biopharmaceutical company developing monoclonal antibody-based products for the targeted treatment of cancer, autoimmune disorders and other serious diseases. Immunomedics’ advanced proprietary technologies allow the Company to create humanized antibodies that can be used either alone in unlabeled or “naked” form, or conjugated with radioactive isotopes, chemotherapeutics, cytokines or toxins. Using these technologies, Immunomedics has built a pipeline of eight clinical-stage product candidates. Immunomedics’ portfolio of investigational products includes antibody-drug conjugates (ADCs) that are designed to deliver a specific payload of a chemotherapeutic directly to the tumor while reducing overall toxic effects that are usually found with conventional administration of these chemotherapeutic agents. Immunomedics’ most advanced ADCs are sacituzumab govitecan (IMMU-132) and labetuzumab govitecan (IMMU-130), which are in Phase 2 trials for a number of solid tumors and metastatic colorectal cancer, respectively. IMMU-132 has received Breakthrough Therapy Designation from FDA for the treatment of patients with triple-negative breast cancer who have failed at least 2 prior therapies for metastatic disease. Immunomedics has a research collaboration with Bayer to study epratuzumab as a thorium-227-labeled antibody. Immunomedics has other ongoing collaborations in oncology with independent cancer study groups. The IntreALL Inter-European study group is conducting a large, randomized Phase 3 trial combining epratuzumab with chemotherapy in children with relapsed acute lymphoblastic leukemia at clinical sites in Australia, Europe, and Israel. Immunomedics also has a number of other product candidates that target solid tumors and hematologic malignancies, as well as other diseases, in various stages of clinical and preclinical development. These include combination therapies involving its antibody-drug conjugates, bispecific antibodies targeting cancers and infectious diseases as T-cell redirecting immunotherapies, as well as bispecific antibodies for next-generation cancer and autoimmune disease therapies, created using its patented DOCK-AND-LOCK® protein conjugation technology. The Company believes that its portfolio of intellectual property, which includes approximately 286 active patents in the United States and more than 400 foreign patents, protects its product candidates and technologies. For additional information on the Company, please visit its website at www.immunomedics.com. The information on its website does not, however, form a part of this press release.
This release, in addition to historical information, may contain forward-looking statements made pursuant to the Private Securities Litigation Reform Act of 1995. Such statements, including statements regarding clinical trials (including the funding therefor, outcomes, timing or associated costs), out-licensing arrangements (including the timing and amount of contingent payments), forecasts of future operating results, potential collaborations, and capital raising activities, involve significant risks and uncertainties and actual results could differ materially from those expressed or implied herein. Factors that could cause such differences include, but are not limited to, new product development (including clinical trials outcome and regulatory requirements/actions), the Company’s dependence on business collaborations in order to further develop our products and finance our operations, the risk that we or any of our collaborators may be unable to secure regulatory approval of and market our drug candidates, risks associated with the outcome of pending litigation and competitive risks to marketed products, and availability of required financing and other sources of funds on acceptable terms, if at all, as well as the risks discussed in the Company’s filings with the Securities and Exchange Commission. The Company is not under any obligation, and the Company expressly disclaims any obligation, to update or alter any forward-looking statements, whether as a result of new information, future events or otherwise.