Navtemadlin (KRT-232) With or Without Anti-PD-1/Anti-PD-L1 for the Treatment of Patients With Merkel Cell Carcinoma
![]() |
The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Know the risks and potential benefits of clinical studies and talk to your health care provider before participating. Read our disclaimer for details. |
ClinicalTrials.gov Identifier: NCT03787602 |
Recruitment Status :
Recruiting
First Posted : December 26, 2018
Last Update Posted : March 2, 2023
|
- Study Details
- Tabular View
- No Results Posted
- Disclaimer
- How to Read a Study Record
Condition or disease | Intervention/treatment | Phase |
---|---|---|
Merkel Cell Carcinoma | Drug: KRT-232 Drug: Avelumab | Phase 1 Phase 2 |
Study Type : | Interventional (Clinical Trial) |
Estimated Enrollment : | 115 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Masking: | None (Open Label) |
Primary Purpose: | Treatment |
Official Title: | A Phase 1b/2, Open-Label Study Evaluating the Safety and Efficacy of KRT-232 in Patients With p53 Wild-Type (p53WT) Merkel Cell Carcinoma (MCC) Who Have Failed Anti-PD-1 or Anti-PD-L1 Immunotherapy, or in Combination With Avelumab in MCC Patients Who Are Anti-PD-1 or Anti-PD-L1 Treatment Naïve |
Actual Study Start Date : | March 19, 2019 |
Estimated Primary Completion Date : | November 2024 |
Estimated Study Completion Date : | August 2025 |

Arm | Intervention/treatment |
---|---|
Experimental: Cohort 1, Arm 1
KRT-232 will be administered orally, once daily (QD) on Days 1-7 in a 21-day cycle.
|
Drug: KRT-232
KRT-232 is an experimental MDM2 anticancer drug taken by mouth.
Other Name: navtemadlin |
Experimental: Cohort 1, Arm 1b
KRT-232 will be administered orally, once daily (QD) on Days 1-5 in a 23-day cycle.
|
Drug: KRT-232
KRT-232 is an experimental MDM2 anticancer drug taken by mouth.
Other Name: navtemadlin |
Experimental: Cohort 1, Arm 2b
KRT-232 will be administered orally, once daily (QD) on Days 1-5 in a 28-day cycle.
|
Drug: KRT-232
KRT-232 is an experimental MDM2 anticancer drug taken by mouth.
Other Name: navtemadlin |
Experimental: Cohort 1, Arm 3
KRT-232 will be administered orally, once daily (QD) on Days 1-7 in a 21-day cycle.
|
Drug: KRT-232
KRT-232 is an experimental MDM2 anticancer drug taken by mouth.
Other Name: navtemadlin |
Experimental: Cohort 1, Arm 5
KRT-232 will be administered orally, once daily (QD) on Days 1-7 in a 28-day cycle.
|
Drug: KRT-232
KRT-232 is an experimental MDM2 anticancer drug taken by mouth.
Other Name: navtemadlin |
Experimental: Cohort 1 Expansion
KRT-232 will be administered orally, once daily (QD) per Cohort 1 RP2D dose and schedule.
|
Drug: KRT-232
KRT-232 is an experimental MDM2 anticancer drug taken by mouth.
Other Name: navtemadlin |
Experimental: Cohort 2, Arm 1 KRT-232 in combination with avelumab
KRT-232 will be administered orally, once daily (QD) on Days 1-5, in combination with avelumab 800 mg IV on Day 1 and 15 in a 28-day cycle.
|
Drug: KRT-232
KRT-232 is an experimental MDM2 anticancer drug taken by mouth.
Other Name: navtemadlin Drug: Avelumab Avelumab is a PD-L1 blocking antibody anticancer drug administered by intravenous infusion.
Other Name: Bavencio |
Experimental: Cohort 2, Arm 2 KRT-232 in combination with avelumab
KRT-232 will be administered orally, once daily (QD) on Days 1-7, in combination with avelumab 800 mg IV on Day 1 and 15 in a 28-day cycle.
|
Drug: KRT-232
KRT-232 is an experimental MDM2 anticancer drug taken by mouth.
Other Name: navtemadlin Drug: Avelumab Avelumab is a PD-L1 blocking antibody anticancer drug administered by intravenous infusion.
Other Name: Bavencio |
Experimental: Cohort 2 Expansion
KRT-232 will be administered orally, once daily (QD) per RP2D dose and schedule, in combination with avelumab 800 mg IV on Day 1 and 15 in a 28-day cycle.
|
Drug: KRT-232
KRT-232 is an experimental MDM2 anticancer drug taken by mouth.
Other Name: navtemadlin Drug: Avelumab Avelumab is a PD-L1 blocking antibody anticancer drug administered by intravenous infusion.
Other Name: Bavencio |
Experimental: Cohort 3
KRT-232 will be administered orally, once daily (QD) per Cohort 1 RP2D dose and schedule.
|
Drug: KRT-232
KRT-232 is an experimental MDM2 anticancer drug taken by mouth.
Other Name: navtemadlin |
Experimental: Cohort 4
KRT-232 will be administered orally, once daily (QD) per Cohort 1 RP2D dose and schedule.
|
Drug: KRT-232
KRT-232 is an experimental MDM2 anticancer drug taken by mouth.
Other Name: navtemadlin |
- Cohort 1 Part 1: To determine the KRT-232 RP2D. [ Time Frame: 10 Weeks ]The Safety Review Committee (SRC) will determine RP2D for expansion based on safety and tolerability of each arm.
- Cohort 1 Part 2: To determine the objective response rate (ORR) in subjects with p53WT MCC who have failed anti-PD-1 or anti-PDL-1 immunotherapy [ Time Frame: 10 Weeks ]ORR will be assessed per RECIST criteria version 1.1 after all subjects have been treated at the RP2D of KRT 232 and completed the second response assessment.
- Cohort 2 Part 1: To determine the KRT-232 RP2D in combination with avelumab [ Time Frame: 28 Days ]DLTs will be used to establish the MTD of KRT-232 in combination with avelumab. SRC will determine the RP2D based on the safety of combination of KRT-232 with avelumab.
- Cohort 2 Part 2: To determine the objective response rate (ORR) in treatment-naïve subjects with p53WT MCC [ Time Frame: 10 Weeks ]ORR will be assessed per RECIST criteria version 1.1 after all 30 subjects have been treated at the RP2D of in combination with avelumab and have completed the second response assessment.
- Cohort 3: To determine the confirmed overall response rate (ORR) based on IRC assessments in subjects with p53WT MCC are chemotherapy naive and have failed anti-PD-1/PD-L. [ Time Frame: 10 Weeks ]ORR will be assessed per RECIST criteria 1.1 by IRC.
- Cohort 4: To determine the confirmed overall response rate (ORR) based on IRC assessments in subjects with p53WT MCC who have failed anti-PD-1 or anti-PDL-1 immunotherapy and have had least 1 line of prior chemotherapy. [ Time Frame: 10 Weeks ]ORR will be assessed per RECIST criteria 1.1 by IRC.
- To determine the confirmed ORR based on investigator assessment. [ Time Frame: 1 year after last subject enrolled. ]ORR will be assessed per RECIST criteria 1.1 by investigators.
- To determine the duration of response (DoR) [ Time Frame: 1 year after last subject enrolled ]Time from documentation of response (CR or PR as determined by RECIST 1.1) until disease progression.
- To determine Progression-free survival (PFS) [ Time Frame: 1 year after last subject enrolled ]Time from initial treatment until disease progression.
- To determine overall survival (OS) [ Time Frame: 1 year after last subject enrolled ]Time from initial treatment until death from any cause.
- To determine clinical benefit rate (CBR) [ Time Frame: 1 year after last subject enrolled. ]PR, CR or stable disease that last at least 10 weeks, per IRC or investigator assessment.

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.
Ages Eligible for Study: | 18 Years and older (Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |
Inclusion Criteria:
- For Cohort 1, 3 and 4 patients must have failed treatment with at least one PD-1 inhibitor or PD-L1 inhibitor for metastatic MCC
- For Cohort 2, patients must not have received any anti-PD-1 or anti-PD-L1 therapy
- For Cohort 3, patients must not have received any prior chemotherapy
- For Cohort 4, patients must have received at least one prior line of chemotherapy
- ECOG performance status of 0 to 1
- Histologically confirmed MCC. Disease must be measurable, with at least 1 measurable lesion by RECIST 1.1
- MCC expressing p53WT based on any CLIA or test approved by local health authority or a validated test (Cohort 1 and 2)
- MCC expressing p53WT based Central Lab test (Cohort 3 and 4)
- Adequate hematological, hepatic, and renal functions
Exclusion Criteria:
- For Cohort 2, subjects must not have autoimmune disease, medical conditions requiring systemic immunosuppression, prior stem cell transplant, or active infection with HBV or HCV.
- Patients previously treated with MDM2 antagonist therapies or p53-directed therapies
- History of major organ transplant
- Patients with known central nervous system (CNS) metastases that are previously untreated
- Grade 2 or higher QTc prolongation (>480 milli-seconds per NCI-CTCAE criteria, version 5.0)

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03787602
Contact: John Mei | 650-542-0136 | jmei@kartosthera.com | |
Contact: Emily Houlihan | 401-954-8042 | ehoulihan@kartosthera.com |

Responsible Party: | Kartos Therapeutics, Inc. |
ClinicalTrials.gov Identifier: | NCT03787602 |
Other Study ID Numbers: |
KRT-232-103 |
First Posted: | December 26, 2018 Key Record Dates |
Last Update Posted: | March 2, 2023 |
Last Verified: | February 2023 |
Studies a U.S. FDA-regulated Drug Product: | Yes |
Studies a U.S. FDA-regulated Device Product: | No |
navtemadlin (KRT-232) |
Carcinoma, Merkel Cell Carcinoma Neoplasms, Glandular and Epithelial Neoplasms by Histologic Type Neoplasms Polyomavirus Infections DNA Virus Infections Virus Diseases Infections Tumor Virus Infections |
Carcinoma, Neuroendocrine Neuroendocrine Tumors Neuroectodermal Tumors Neoplasms, Germ Cell and Embryonal Adenocarcinoma Neoplasms, Nerve Tissue Avelumab Antineoplastic Agents, Immunological Antineoplastic Agents |