SELLAS Announces Positive Follow-up Data from the Randomized Phase 2 VADIS Trial of Nelipepimut-S (NPS) in Women with Ductal Carcinoma In-Situ of the Breast
– Immune Stimulation Augmented by +1,
– Statistically Significant Difference of Duration of Immune Response of NPS vs. Control: p=0.000094 -
– Data to be Presented Today at the San Antonio Breast Cancer Symposium -
NEW YORK, Dec. 11, 2020 (GLOBE NEWSWIRE) -- SELLAS Life Sciences Group, Inc. (Nasdaq: SLS) (“SELLAS” or the “Company”), a clinical-stage biopharmaceutical company focused on the development of novel cancer immunotherapies for a broad range of cancer indications, announced today final data with up to 6 months follow-up from a Phase 2 randomized trial (the VADIS study) of the Company’s nelipepimut-S (NPS) in combination with granulocyte-macrophage colony-stimulating factor (GM-CSF) in women with ductal carcinoma in situ (DCIS) of the breast who are HLA-A2+ or A3+ positive, express HER2 at IHC 1+, 2+, or 3+ levels, and are pre- or post-menopausal. This investigator-sponsored trial randomized patients to receive, prior to surgery, either GM-CSF followed by NPS two weeks later or GM-CSF alone.
Preliminary data previously reported showed that treatment with even a single dose of NPS was capable of newly inducing NPS-specific cytotoxic T-lymphocytes (CTLs) in peripheral blood in DCIS patients. The updated data, based on a 6-month follow-up, demonstrate that CD8+ T-cell responses persist long-term post-NPS treatment, with treated patients retaining and modestly enhancing their antigen-specific immune response. When compared to baseline (BL, prior to investigational agent administration), the relative frequency of NPS-specific CD8 CTLs as a percentage (NPS-CLT%) in peripheral blood at the 1-month and 6-month post-operative time-points increased in the NPS+GM-CSF group (n=9) by 11- and 14-fold: 0.01+
For the NPS+GM-CSF group, the differences in absolute NPS-CTL% mean values between baseline and 1- or 6-months post-vaccination were statistically significant, with p-values of 0.039 and 0.0125, respectively. The relative change in NPS-CTL% mean values at 6 months post-vaccination was +1,300+
“These data confirm that NPS confers long-term immune response in DCIS patients, with continued, and in fact slightly augmented, antigen-specific T-cell response for up to 6 months post-vaccination in a randomized setting,” said Angelos M. Stergiou, MD, ScD h.c., President and Chief Executive Officer of SELLAS. “One of the main limitations of cancer vaccines has traditionally been the short duration of the immune response, especially for CD8+ T-cells. With these new data, we believe that a single course of NPS treatment can result in robust and lasting immunity to HER2-expressing breast cancer. In the VADIS study, immune responses emerged and were sustained even in DCIS patients with low levels of HER (IHC 1+ or 2+) expression. These data further support our belief that NPS, by preferentially inducing adaptive immunity and through its potential synergy with trastuzumab, enhances cell killing.”
The VADIS study enrolled 13 patients, with nine patients receiving NPS plus GM-CSF and four patients receiving GM-CSF only. The NPS-CLT% was measured in the peripheral blood by a sensitive and specific assay using dextramer staining followed by flow cytometry, both at baseline (before vaccination or GM-CSF), as well as at 30 (+7) and 180 (+7) days after surgery. Further data from additional analyses of select histologic and molecular biomarkers will be presented in a future scientific meeting.
There were no drug-related unexpected serious adverse reactions in the study. The overall adverse event profile of the NPS+GM-CSF combination was similar to the adverse event profile seen with GM-CSF alone. Almost all patients in both arms experienced at least Grade 1 toxicities, and the incidence of Grade 2 toxicities was
“These results further support the case for continued development of NPS in HER2-expressing breast cancer, as well as potentially other HER2-bearing cancers,” said Elizabeth A. Mittendorf, MD, PhD, Rob and Karen Hale Distinguished Chair in Surgical Oncology, Director of Research, Breast Surgical Oncology Brigham and Women’s Hospital, Director, Breast Immuno-Oncology Program Dana-Farber/Brigham and Women’s Cancer Center, and the Principal Investigator of the VADIS trial. “In patients with DCIS, a single inoculation with NPS+GM-CSF can induce in vivo immunity and a continued antigen-specific T-cell response. These data provide support for further testing of NPS+GM-CSF in the neoadjuvant and adjuvant settings in an attempt to prevent invasive recurrence in DCIS,” added Dr. Mittendorf.
About the VADIS spotlight poster presentation (PD11-09)
The VADIS data will be presented today, December 11, at the Virtual 2020 Annual San Antonio Breast Cancer Symposium (SABCS)
Title: Vadis trial: phase II trial of Nelipepimut-S peptide vaccine in women with DCIS of the breast.
Authors: O’Shea AE, Clifton GT, Qiao N, Heckman-Stoddard B, Wojtowicz M, Dimond E, Bedrosian I, Weber D, Husband A, Pastorello R, Vornik L, Peoples G, Mittendorf EA.
Presenter: Anne E. O’Shea, MD
Poster Discussion No.: PD11-09
Session Date – Time: Friday, December 11, 2020: 2:15 pm – 3:30 pm CST
Website: www.sabcs.org
About the Phase 2 VADIS Trial
This Phase 2 randomized trial is sponsored and operationalized by the National Cancer Institute (NCI) to study NPS’ potential clinical effects in earlier-stage disease. Patients are randomized to receive, prior to surgery, either GM-CSF followed by NPS two weeks later or GM-CSF alone. The primary endpoint of the trial is the difference in the frequency of newly induced NPS-cytotoxic T lymphocytes (CTL; CD8+ T-cell) in peripheral blood between the two arms of the study, using a dextramer assay. Secondary endpoints to be compared between the two arms include the nature and incidence of adverse events and in vivo immune response to NPS, in additi
