Kolltan Pharmaceuticals Presents Clinical Data for KTN3379 in an Oral Presentation at the 2016 American Society of Clinical Oncology (ASCO) Annual Meeting

Anti-tumor activity and safety data from ongoing Phase 1b clinical trial (KTN3379-CL-001) support initiation of a Phase 2 clinical trial of KTN3379 in head and neck squamous cell carcinoma (HNSCC) and expansion of the Phase 1b BRAF-mutant treatment arm

Durable objective responses were reported in certain patients with resistant tumors treated with KTN3379 in combination with cetuximab or vemurafenib

NEW HAVEN, Conn.--()--Kolltan Pharmaceuticals, Inc., a privately held clinical-stage company focused on the discovery and development of novel antibody-based drugs targeting receptor tyrosine kinases (RTKs) for use in oncology and immunology, today announced the presentation of clinical data related to KTN3379, the Company’s most advanced product candidate for the potential treatment of various solid tumors. These data were discussed in an oral presentation titled, “Safety, pharmacokinetics (PK), pharmacodynamics (PD), and anti-tumor activity in a phase 1b study evaluating anti-ErbB3 antibody KTN3379 in adults with advanced tumors alone and with targeted therapies,” at the 2016 ASCO Annual Meeting, which is taking place in Chicago, IL, June 3-7, 2016. KTN3379 is a novel antibody that blocks the activity of the ErbB3 (HER3) receptor by binding to a unique epitope and effectively locking the ErbB3 receptor in an inactive conformation. In addition, KTN3379 has been engineered to extend serum half-life. These features are believed to contribute to the favorable potency and pharmacology of KTN3379.

“The data presented today are very encouraging and demonstrate that anti-tumor activity was observed in certain extensively pretreated patients when KTN3379 was administered in combination with other targeted therapeutics. The evidence from the Phase 1b clinical trial and several preclinical studies supports the initiation of a Phase 2 clinical trial in HNSCC, and we believe KTN3379 has the potential to provide clinical benefit across multiple tumor types where ErbB3 plays a role in tumor progression and therapeutic resistance. There exists an unmet medical need in cancer patients that have exhausted many or all treatment options, and we plan to advance the clinical development of KTN3379 to address this need,” stated Gerald McMahon, Ph.D., President and Chief Executive Officer of Kolltan.

Study KTN3379-CL-001 (NCT02014909) has two parts. In Part 1, which was the subject of an oral presentation by Dr. Patricia LoRusso at the 26th EORTC-NCI-AACR Symposium on Molecular Targets and Cancer Therapeutics in Barcelona, Spain, KTN3379 was administered to patients with advanced solid tumors as a single agent. In this part of the study, a maximum tolerated dose was not reached and KTN3379 demonstrated favorable tolerability and pharmacology profiles. In Part 2 of the study, the focus of today’s oral presentation, KTN3379 was evaluated in combination with four different targeted therapies. KTN3379 was administered at 15 and 20 mg/kg every three weeks in combination with cetuximab (N=16), erlotinib (N=8), vemurafenib (N=4), or trastuzumab (N=10). Safety monitoring and RECIST-based tumor assessments were conducted. Pharmacokinetic parameters and immunogenicity were evaluated. In addition, archival tumor tissue was tested for mRNA expression of neuregulin (NRG) in baseline tumor samples. Sixty percent of the patients had received at least four prior treatment regimens. Enrollment in the vemurafenib patient cohort is currently being expanded.

Joseph Paul Eder, M.D., Professor of Medicine (Medical Oncology) at the Yale Cancer Center, commented, “The ErbB family of receptors has been among the most successful targets in the treatment of cancer, resulting in therapies that are standard of care across a number of tumor types. The scientific rationale supporting the development of this anti-ErbB3 antibody, including its differentiated features and potency, together with durable responses observed in patients with resistant tumors, warrants the further development of KTN3379 in combination with targeted therapies.”

Ronald Peck, M.D., Chief Medical Officer and Senior Vice President, Clinical Development at Kolltan added, “The responses reported in this trial were impressive, in particular the durable complete response in a HNSCC patient receiving the combination of KTN3379 and cetuximab after disease progression on single agent cetuximab and the durable partial response in a non-small cell lung cancer (NSCLC) patient receiving KTN3379 plus vemurafenib after progressing on another BRAF inhibitor and other prior therapy. These results, as well as extensive preclinical data, support the planned Phase 2 clinical trial of KTN3379 in combination with cetuximab in patients with advanced head and neck squamous cell carcinoma and the ongoing expansion of the Phase 1b BRAF-mutant tumor cohort receiving KTN3379 in combination with vemurafenib.”

The results were presented by Gerald Falchook, M.D., Director of Drug Development at Sarah Cannon Research Institute at HealthONE in Denver, Colorado. Following is a summary of the key results:

  • 38 total patients were treated in four cohorts with KTN3379 in combination with the following targeted therapies: cetuximab (N=16), erlotinib (N=8), vemurafenib (N=4), or trastuzumab (N=10);
  • The patient population enrolled in Part 2 of Study KTN3379-CL-001 was generally heavily pretreated, with approximately 97% of patients having received at least one prior treatment regimen and 60% of patients having received at least four prior treatment regimens;
  • The safety profile of the combination therapies was consistent with the safety profiles of the individual agents. The most common treatment related adverse events included diarrhea and rash, which were resolved with medical therapy or dose reduction;
  • Pharmacokinetic data demonstrated that all patients achieved serum concentrations of KTN3379 required for maximal anti-tumor activity in animal tumor models; and
    • Showed a consistent trend towards slower clearance and longer terminal half-life of KTN3379 compared to published data for other anti-ErbB3 antibodies
  • Anti-tumor activity was achieved in several patients with resistant tumors treated with KTN3379 in combination with cetuximab or vemurafenib
    • Cetuximab combination arm:
      • Anti-tumor activity was observed in certain of the nine patients with HNSCC treated with KTN3379 in combination with cetuximab including a patient with a durable complete response (CR) who had undergone extensive prior therapy including chemotherapy, radiation, and multiple surgeries; and
      • The patient with a CR had previously progressed five months after initiating single agent cetuximab. The patient’s CR with KTN3379 in combination with cetuximab persisted for 10.5 months after starting study therapy. The patient’s tumor was found to express the ErbB3 ligand, neuregulin.
    • Vemurafenib combination arm:
      • In four patients with BRAF-mutant cancers that were treated with KTN3379 in combination with vemurafenib, stable disease was reported in one patient with colorectal cancer and durable partial responses (PRs) were reported in two patients with NSCLC; and
      • Notably, one of the two NSCLC PRs was in a patient who underwent extensive prior therapy, which included combination chemotherapy, another BRAF-inhibitor (dabrafenib), and combination immunotherapy (an investigational regimen of an anti-CTLA4 and an anti-PDL-1). Previously, the patient had disease progression within two months of initiating dabrafenib. The patient’s PR persisted for 12 months after starting study therapy. The patient’s tumor was found to express neuregulin.

About KTN3379

KTN3379 is a human monoclonal antibody designed to block the activity of ErbB3 (HER3), a receptor tyrosine kinase (RTK) that belongs to the epidermal growth factor receptor, or EGFR, family. ErbB3 is believed to be an important receptor regulating cancer cell growth and survival. ErbB3 is expressed in many cancers, including head and neck, breast, lung, and gastric cancers, and melanoma. Kolltan is conducting multiple clinical trials evaluating KTN3379 in the treatment of solid tumors (NCT02014909, NCT02456701, and NCT02473731).

About Kolltan Pharmaceuticals

Kolltan, a privately held clinical-stage company, is focused on the discovery and development of novel, antibody-based drugs targeting RTKs for the treatment of cancer and other diseases with significant unmet need. Kolltan’s founders and members of its management team have deep expertise and a proven track record in drug discovery, development, and commercialization of innovative therapeutics, including drugs targeting RTKs. Kolltan is working in close collaboration with the laboratory of Kolltan Co-Founder Dr. Joseph Schlessinger, as well as the Yale University medical and scientific community. The Company has a broad and novel oncology and immunology portfolio of therapeutic biologics targeting multiple RTKs that are advancing in the clinic and are expected to generate multiple near-term milestones.

Forward Looking Statements Disclosure

Any statements in this news release about future expectations, plans, and prospects for Kolltan constitute forward-looking statements. Actual results may differ materially from those indicated by such forward-looking statements as a result of a variety of important factors. Kolltan anticipates that subsequent events and developments may cause its views to change. However, while Kolltan may elect to update these forward-looking statements in the future, Kolltan specifically disclaims any obligation to do so.

Contacts

Media Inquiries:
Burns McClellan
Justin Jackson, 212-213-0006
jjackson@burnsmc.com
or
Investor Inquiries:
Kolltan Pharmaceuticals, Inc.
Jay Campbell, 203-907-0938
jay.campbell@kolltan.com

Contacts

Media Inquiries:
Burns McClellan
Justin Jackson, 212-213-0006
jjackson@burnsmc.com
or
Investor Inquiries:
Kolltan Pharmaceuticals, Inc.
Jay Campbell, 203-907-0938
jay.campbell@kolltan.com