SELLAS Life Sciences Presents Positive Key Immunobiological and Clinical Data from Phase 1/2 Trial of Galinpepimut-S (GPS) in Combination with Keytruda® in WT1+ Platinum-Resistant Advanced Ovarian Cancer at the International Gynecologic Cancer Society 2023 Annual Global Meeting
- Median overall survival for GPS and Keytruda® combination was 18.4 Months compared to 13.8 Months in a Keytruda® single agent study (KEYNOTE-028) and 11-14 Months with standard of care chemotherapy
- Combination of GPS and Keytruda® yielded WT1-specific T-cell immune response and correlated positively in subset of patients with IFNγ and MIP1β biomarkers: 41% longer progression free survival and statistically significant difference: p=0.025
NEW YORK, Nov. 06, 2023 (GLOBE NEWSWIRE) -- SELLAS Life Sciences Group, Inc. (NASDAQ: SLS) (“SELLAS’’ or the “Company”), a late-stage clinical biopharmaceutical company focused on the development of novel therapies for a broad range of cancer indications, today announced final clinical and immunobiological data from the Phase 1/2 clinical trial of galinpepimut-S (GPS) in combination with pembrolizumab (Keytruda®) in Wilms’ tumor-1 (WT1)-positive platinum-resistant ovarian cancer (NCT03761914).
Results are being presented in an e-poster session by Roisin E. O’Cearbhaill, M.D., Research Director, Gynecologic Medical Oncology Service; Clinical Director, Solid Tumor, Cellular Therapy Service; and Associate Attending Physician at Memorial Sloan Kettering Cancer Center, New York, NY, at the 2023 International Gynecologic Cancer Society Annual Global Meeting taking place November 5-7, 2023, in Seoul, South Korea.
GPS is an HLA-unrestricted heteroclitic immunotherapy against WT1, an antigen highly expressed in more than 85% of patients with ovarian cancer. This Phase 1/2 trial was an open-label, multicenter, multi-arm basket study examining the effects of the combination of GPS and pembrolizumab in patients with measurable advanced selected cancers. In the ovarian cancer arm of the study, the effect of the combination was investigated in patients with measurable WT1+ platinum-resistant ovarian cancer relapsed after or refractory to 1st/2nd -or later- line of therapy. Today’s presentation reported clinical efficacy and safety results as well as demographic and disease parameter data in a total of 16 evaluable patients. Historical illustrative comparisons were made between the outcomes in this study and those reported in comparable patients enrolled in the KEYNOTE-028 study, which investigated the effects of pembrolizumab monotherapy.
Study highlights include:
Patient Characteristics
- 17 patients enrolled; 16 safety and efficacy evaluable patients who received at least three doses of GPS and had follow-up cross-sectional imaging (CT/MRI) to determine tumor status.
- Median age was 65 years (50-76).
- Median number of prior lines of systemic therapy was two, while 23.5% of enrolled patients (4/17) had received 3-5 prior lines of therapy.
Efficacy
- Median Overall Survival (OS) was 18.4 months, compared to historical values in comparable patients of 11-14 months with standard of care chemotherapy and 13.8 months with pembrolizumab monotherapy as shown in the KEYNOTE-028 study.
- Median Progression-Free Survival (PFS) was 2.9 months, compared to eight weeks with pembrolizumab monotherapy as shown in the KEYNOTE-028 study.
- Actuarial OS rates at 6, 12, and 18 months were 88%, 68%, and 57%, respectively.
- 43.8% (7/16) of patients achieved stable disease (SD); median duration of SD in these patients was 14.4 months.
- Disease control rate (DCR), which is the sum of overall response rate (ORR) and rate of SD, was 50.1% (8/16 patients) at a median follow-up of 14.4 months; DCR for pembrolizumab alone in KEYNOTE-028 was 37.2%.
- ORR was 6.3%.
- An exploratory analysis of patients harboring tumors with detectable PD-L1 expression, i.e., those with a Combined Positive Score (CPS) >1, suggested the potential correlation between PD-L1 expression as quantified by the CPS in primary tumor samples and median PFS or median OS using two distinct cut-offs (CPS