OncoSec Medical has announced interim data from KEYNOTE-890, an ongoing Phase II study of TAVO (intratumoral IL-12) and KEYTRUDA in patients with pretreated, metastatic, chemotherapy-refractory triple-negative breast cancer (mTNBC).
Patients who earlier failed an average of 3.5 previous lines of chemotherapy were enrolled into the KEYNOTE-890 trial to analyse if TAVO (IL-12), when combined with anti-PD-1 checkpoint inhibitor KEYTRUDA, could offer meaningful clinical activity.
The first five of ten participants with refractory mTNBC (average of 3.5 prior lines of chemotherapy) indicated a quick tumour reduction of 20% or greater at the initial three-month evaluation.
Two patients partially responded, with one having a 66% tumour reduction, including a significant reduction of liver lesions. Four patients had stable disease, out of which three reported a 20% or greater tumour reduction.
When compared with the results of KEYNOTE-086, which demonstrated a 5.3% response rate in mTNBC patients treated with KEYTRUDA monotherapy, KEYNOTE-890 indicates TAVO's ability to unlock KEYTRUDA's potential anti-cancer efficacy.
As of 9 May, four of the six patients who experienced tumour reductions have an ongoing response.
OncoSec clinical strategic advisor and UCSF Clinical Medicine associate professor Alain Algazi said: "These interim data are impressive, especially when considering that all of the patients received numerous prior rounds of chemo / radiation with no success, and the safety profile associated with this platform continues to be unparalleled.
"Metastatic TNBC is a heterogeneous cancer with a poor prognosis where less than 5% of pre-treated patients achieve an objective response to PD-1/PD-L1 checkpoint treatments."
"Therefore, the marked synergy shown in these patients adds even more support for our earlier findings demonstrating that TAVO primes the tumour microenvironment, dramatically improving the clinical results that would have been anticipated with PD-1/PD-L1 checkpoint treatment alone. The combination of TAVO and KEYTRUDA represents a highly promising new therapeutic approach for TNBC and warrants expedited evaluation."
The firm has enrolled more than half of the target of 25 patients.
It expects to complete enrollment and present the clinical data at the San Antonio Breast Cancer Symposium later this year.
OncoSec Medical is a late-stage cancer biotechnology company developing gene-based intratumoral immunotherapies.