SOUTH SAN FRANCISCO, CA, USA I May 19, 2025 I CytomX Therapeutics, Inc. (Nasdaq: CTMX), a leader in the field of masked, conditionally activated biologics, today announced that the first patient has been dosed with CX-801 in combination with KEYTRUDA® (pembrolizumab), Merck’s anti-PD-1 therapy, in the ongoing Phase 1 dose escalation study (NCT06462794) evaluating safety and initial clinical activity in patients with metastatic melanoma.
CX-801 is a dually masked interferon (IFN) alpha-2b PROBODY® cytokine. CX-801 has been intentionally designed by CytomX to harness the power of Interferon alpha-2b’s immune stimulating properties in combination with checkpoint inhibition. Interferon alpha-2b has well known single agent anti-cancer activity in multiple tumor types, including in melanoma. However, its use has been limited due to its poor tolerability arising from systemic toxicities. CX-801 is designed to localize the potency of IFN alpha-2b to tumors and reduce systemic toxicities, enabling combination strategies.
CytomX is conducting a focused Phase 1 dose escalation study of CX-801 in metastatic melanoma. The combination arm of the study evaluating CX-801 in combination with KEYTRUDA® has been initiated following successful the clearance of the first three CX-801 monotherapy dose escalation cohorts.
“We are excited to begin evaluating this combination therapy that has the potential to provide significant clinical benefit to patients with PD-1 refractory melanoma, which remains an area of high unmet need,” said Dr. Wayne Chu, M.D., chief medical officer of CytomX Therapeutics. “Utilizing CytomX’s proprietary conditional activation platform to maintain potency and widen interferon’s therapeutic index, CX-801 is well suited to combine with KEYTRUDA® and could become an important component of combination immuno-oncology therapy. We look forward to initial Phase 1a translational and biomarker data in advanced melanoma in the second half of 2025.”
KEYTRUDA® is a registered trademark of Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA
About CytomX Therapeutics
CytomX is a clinical-stage, oncology-focused biopharmaceutical company focused on developing novel conditionally activated, masked biologics designed to be localized to the tumor microenvironment. By pioneering a novel pipeline of localized biologics, powered by its PROBODY® therapeutic platform, CytomX’s vision is to create safer, more effective therapies for the treatment of cancer. CytomX’s robust and differentiated pipeline comprises therapeutic candidates across multiple treatment modalities including antibody-drug conjugates (ADCs), T-cell engagers, and immune modulators such as cytokines. CytomX’s clinical-stage pipeline includes CX-2051 and CX-801. CX-2051 is a masked, conditionally activated ADC directed toward epithelial cell adhesion molecule (EpCAM), armed with a topoisomerase-1 inhibitor payload. CX-2051 has potential applicability across multiple EpCAM-expressing epithelial cancers, including CRC, and was discovered in collaboration with ImmunoGen. CX-801 is a masked interferon alpha-2b PROBODY® cytokine with broad potential applicability in traditionally immuno-oncology sensitive as well as insensitive (cold) tumors. CytomX has established strategic collaborations with multiple leaders in oncology, including Amgen, Astellas, Bristol Myers Squibb, Regeneron and Moderna. For more information about CytomX and how it is working to make conditionally activated treatments the new standard-of-care in the fight against cancer, visit www.cytomx.com and follow us on LinkedIn and X (formerly Twitter).
SOURCE: CytomX Therapeutics
Post Views: 1,484
SOUTH SAN FRANCISCO, CA, USA I May 19, 2025 I CytomX Therapeutics, Inc. (Nasdaq: CTMX), a leader in the field of masked, conditionally activated biologics, today announced that the first patient has been dosed with CX-801 in combination with KEYTRUDA® (pembrolizumab), Merck’s anti-PD-1 therapy, in the ongoing Phase 1 dose escalation study (NCT06462794) evaluating safety and initial clinical activity in patients with metastatic melanoma.
CX-801 is a dually masked interferon (IFN) alpha-2b PROBODY® cytokine. CX-801 has been intentionally designed by CytomX to harness the power of Interferon alpha-2b’s immune stimulating properties in combination with checkpoint inhibition. Interferon alpha-2b has well known single agent anti-cancer activity in multiple tumor types, including in melanoma. However, its use has been limited due to its poor tolerability arising from systemic toxicities. CX-801 is designed to localize the potency of IFN alpha-2b to tumors and reduce systemic toxicities, enabling combination strategies.
CytomX is conducting a focused Phase 1 dose escalation study of CX-801 in metastatic melanoma. The combination arm of the study evaluating CX-801 in combination with KEYTRUDA® has been initiated following successful the clearance of the first three CX-801 monotherapy dose escalation cohorts.
“We are excited to begin evaluating this combination therapy that has the potential to provide significant clinical benefit to patients with PD-1 refractory melanoma, which remains an area of high unmet need,” said Dr. Wayne Chu, M.D., chief medical officer of CytomX Therapeutics. “Utilizing CytomX’s proprietary conditional activation platform to maintain potency and widen interferon’s therapeutic index, CX-801 is well suited to combine with KEYTRUDA® and could become an important component of combination immuno-oncology therapy. We look forward to initial Phase 1a translational and biomarker data in advanced melanoma in the second half of 2025.”
KEYTRUDA® is a registered trademark of Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA
About CytomX Therapeutics
CytomX is a clinical-stage, oncology-focused biopharmaceutical company focused on developing novel conditionally activated, masked biologics designed to be localized to the tumor microenvironment. By pioneering a novel pipeline of localized biologics, powered by its PROBODY® therapeutic platform, CytomX’s vision is to create safer, more effective therapies for the treatment of cancer. CytomX’s robust and differentiated pipeline comprises therapeutic candidates across multiple treatment modalities including antibody-drug conjugates (ADCs), T-cell engagers, and immune modulators such as cytokines. CytomX’s clinical-stage pipeline includes CX-2051 and CX-801. CX-2051 is a masked, conditionally activated ADC directed toward epithelial cell adhesion molecule (EpCAM), armed with a topoisomerase-1 inhibitor payload. CX-2051 has potential applicability across multiple EpCAM-expressing epithelial cancers, including CRC, and was discovered in collaboration with ImmunoGen. CX-801 is a masked interferon alpha-2b PROBODY® cytokine with broad potential applicability in traditionally immuno-oncology sensitive as well as insensitive (cold) tumors. CytomX has established strategic collaborations with multiple leaders in oncology, including Amgen, Astellas, Bristol Myers Squibb, Regeneron and Moderna. For more information about CytomX and how it is working to make conditionally activated treatments the new standard-of-care in the fight against cancer, visit www.cytomx.com and follow us on LinkedIn and X (formerly Twitter).
SOURCE: CytomX Therapeutics
Post Views: 1,484
