On November 9, 2020 Genexine, Inc. and NeoImmuneTech, Inc. reported the release of data for the dose escalation (DE) phase (Ph1b) of their Ph1b/2 study of GX-I7/NT-I7 (efineptakin alfa), a novel T cell amplifier, in combination with KEYTRUDA (pembrolizumab), a leading checkpoint inhibitor (CPI), for the treatment of heavily pretreated patients with relapsed or refractory triple-negative breast cancer (TNBC) (Press release, Genexine, NOV 9, 2020, View Source [SID1234570550]). These data were shared in a poster presentation at the Society for Immunotherapy of Cancer (SITC) (Free SITC Whitepaper) conference on November 9th, 2020.

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The primary objectives of the DE phase of this study are to evaluate safety and tolerability of GX-I7/NT-I7 in combination with pembrolizumab and to determine the recommended phase 2 dose (RP2D). Two combination schedules of GX-I7/NT-I7 and pembrolizumab were evaluated: 1. Sequential administration of pembrolizumab + GX-I7/NT-I7, after cyclophosphamide (CPA) chemotherapy pre-treatment, and 2. Concurrent administration of pembrolizumab + GX-I7/NT-I7, without CPA chemotherapy pre-treatment.

As of September 30th, 2020, a total of 60 patients have been enrolled and treated in the DE phase of the study. Based on the encouraging efficacy and safety data, the standard dose of pembrolizumab plus 1,200 ug/kg GX-I7/NT-I7 concurrent administration without CPA chemotherapy pre-treatment has been selected as the RP2D. At this level, an objective response rate (ORR) of 28% has been observed.

Both combination schedules were well tolerated, and the most common treatment-related AEs were injection site reaction (n=44, 73.4%), rash (n=26, 43.4%), pyrexia (n=21, 35.0%), ALT/AST increase (n=19, 31.7%), GGT increase (n=12, 20.0%), myalgia (n=12, 20.0%) and nausea (n=11, 18.4%). GX-I7/NT-I7 was dosed up to 1,440ug/kg, however this level was not selected due to one dose-limiting toxicity observed with no additional clinical benefit noted.

"In addition to a well tolerated safety profile, we are pleased to see promising initial efficacy data at the RP2D in the dose escalation phase of this combination study," said Jung Won Woo, Ph.D., Executive Vice President and Head of Research Institute at Genexine. "We look forward to completing the phase 2 portion of the study (dose expansion phase) and confirming the promising efficacy in a large dataset."

NgocDiep Le, M.D., Ph.D., Executive Vice President and Chief Medical Officer of NeoImmuneTech, added: "Metastatic triple-negative breast cancer is an area of significant unmet need, making up 15-20% of breast cancers, and yielding progressively lower response rates and shorter survival after each subsequent relapse. These early efficacy signals in the dose escalation phase of our trial are encouraging and suggest that we may be able to provide a much needed chemo-free treatment option for these patients in dire need."

Additional information on the trial can be found on www.clinicaltrials.gov using the identifier NCT03752723.

KEYTRUDA is a registered trademark of Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, N.J., USA.

About GX-I7/NT-I7 (efineptakin alfa)
GX-I7 (Genexine Code Name) / NT-I7 (NIT Code Name) is the only clinical-stage long-acting human IL-7, and is being developed in oncologic and immunologic indications, where T cell amplification and increased functionality may provide clinical benefit. IL-7 is a fundamental cytokine for naïve and memory T cell development and for sustaining immune response to chronic antigens (as in cancer) or foreign antigens (as in infectious diseases). GX-I7/NT-I7 exhibits favorable PK/PD and safety profiles, making it an ideal combination partner. GX-I7/NT-I7 is being studied in multiple clinical trials in solid tumors and as vaccine adjuvant. Studies are being planned for testing in hematologic malignancies, additional solid tumors and other immunology-focused indications.