SELLAS Life Sciences Announces Updated Positive Phase 2 Data Reinforcing Meaningful Clinical Benefit of its WT1 Immunotherapeutic Anti-cancer Treatment in Multiple Myeloma Patients

HAMILTON, Bermuda and NEW YORK, March 1, 2017 /PRNewswire/ -- SELLAS Life Sciences Group (SELLAS or the Company), a late-stage biopharmaceutical company developing novel cancer immunotherapies for an extensive list of cancer indications, today reported updated positive Phase II data from its WT1 immunotherapeutic anti-cancer treatment, galinpepimut-S, in multiple myeloma (MM) patients. Consistent with preliminary data, the updated results indicate a meaningful clinical benefit among high-risk MM patients, positioning galinpepimut-S as a potential first-in-class immunotherapeutic cancer treatment. MM patients typically relapse within 12 months after frontline induction therapy, followed by successful autologous stem cell transplantation (ASCT). The results underscore the potential of SELLAS' lead product candidate, galinpepimut-S, to treat a broad range of cancer indications as monotherapy in the setting of minimal residual disease. Galinpepimut-S was licensed from Memorial Sloan Kettering Cancer Center and is a late-stage innovative WT1 targeted immunotherapeutic.

Updated data from the clinical study show an 88% actuarial overall survival (OS) at the 18-month landmark in 18 evaluable patients. All patients had evidence of minimal residual disease (MRD⁺) after ASCT and 15 had high-risk cytogenetics at diagnosis. Combined, these characteristics typically result in low progression-free survival (PFS) rates that do not exceed 12 months following ASCT, even while on maintenance therapy with immunomodulatory drugs or proteasome inhibitors. Current median PFS is 23.6 months, while median OS has not been reached. SELLAS' results compare favorably with an unmatched cohort of MM patients with high-risk cytogenetics published [1] by the UK Medical Research Council (Myeloma IX trial). The Company's galinpepimut-S therapy demonstrated a 2.5-fold increase in median PFS, as well as a 2.6-fold increase  in the PFS rate at 18 months versus the cohort, which included MM patients with high-risk cytogenetics and MRD⁺ status post-ASCT and on continuous thalidomide maintenance.

SELLAS' Phase II study started in June 2014 and has enrolled a total of 20 patients, who are being monitored long-term. All non-progression events are confirmed and ongoing (median follow-up at 18 months for survivors).  

"This treatment has shown the ability to substantially extend the lifespan of patients with high-risk multiple myeloma, which remains a clinical challenge. Based on these results, galinpepimut-S continues to provide strong indication of a meaningful clinical benefit following autotransplantation in high-risk multiple myeloma, particularly in the context of an adverse cytogenetic profile. The need for innovative, efficacious and tolerable therapies among multiple myeloma patients is undisputed and we are excited about the possibility of applying a novel anti-WT1 active immunotherapy in myeloma. We are planning further studies to expand on and confirm our observations among this challenging patient group," said Guenther Koehne, MD, PhD, Attending Physician, Adult Bone Marrow Transplantation Service at MSKCC, Associate Professor of Medicine, Weill Cornell Medical College and Principal Investigator on the trial.

The abstract containing SELLAS' initial data in myeloma has been accepted for an oral presentation at the 43^rd annual meeting of the European Society for Blood and Marrow Transplantation during March 26-29, 2017 in Marseille, France. Scientific abstracts describing SELLAS' follow-up findings - with added emphasis on the dynamics of WT1-specific immune responses - have been submitted for presentation in major oncology meetings.

Dr. Nicholas Sarlis, MD, PhD, Chief Medical Officer of SELLAS, commented: "We are encouraged by continued indications that SELLAS' galinpepimut-S therapy notably delays disease progression in high-risk multiple myeloma patients. We look forward to further updates that will guide future clinical trials and improve clinical outcomes and our understanding of the underlying immune biology with the galinpepimut-S therapy."

Dr. Angelos Stergiou, MD, ScD h.c., Vice Chairman and Chief Executive Officer of SELLAS, said: "This new data further underscores the potential for galinpepimut-S to target an array of tumor types. The data both validate our focus on targeting malignancies with subclinical disease with galinpepimut-S monotherapy, and also support the expansion of our clinical trial program to include combination approaches in addressing a wide variety of cancers."

Galinpepimut-S demonstrated positive Phase II results in acute myeloid leukemia and malignant pleural mesothelioma in 2016, with Phase III programs poised to commence in these tumor types this year.

Earlier this week SELLAS announced a licensing agreement whereby the Company will develop a novel cancer immunotherapy agent using a proprietary Lm-based antigen delivery technology developed by Advaxis, Inc. with SELLAS' patented WT1 targeted heteroclitic peptide antigen composition (galinpepimut-S).

About SELLAS Life Sciences Group

SELLAS Life Sciences is a late-stage biopharmaceutical company focused on the development of novel cancer immunotherapies and therapeutics for a broad range of cancer indications. The Company's lead product candidate, galinpepimut-S, is a cancer immunotherapeutic agent licensed from Memorial Sloan Kettering Cancer Center that targets a broad spectrum of hematologic cancers and solid tumor indications. Galinpepimut-S is poised to enter pivotal Phase 3 clinical trials in patients with AML and Mesothelioma in the first and second half of 2017, respectively.

Galinpepimut-S also is in various development phases in multiple myeloma, ovarian cancer, and soon in other indications as monotherapy or in combination with other immuno-oncology agents.

SELLAS was founded in 2012 and is headquartered in Hamilton, Bermuda, with additional offices in New York City, NY.

1. Rawstron A, et al. J Clin Oncol. 2013;31:2540-7.

SOURCE SELLAS Life Sciences Group