NCT03969004 · CITED IN SOURCE DOCUMENTS

Study of Adjuvant Cemiplimab Versus Placebo After Surgery and Radiation Therapy in Patients With High Risk Cutaneous Squamous Cell Carcinoma

An NCI or FDA source cites this study. A citation does not establish that it applies to an individual diagnosis.

Phase: PHASE3
Status at capture: ACTIVE NOT RECRUITING
Registry last update: 2026-03-27

The primary objective of the study is to compare disease-free survival (DFS) of patients with high-risk cutaneous squamous cell carcinoma (CSCC) treated with adjuvant cemiplimab, versus those treated with placebo, after surgery and radiation therapy (RT). The secondary objectives of the study are: * To compare the overall survival (OS) of high-risk CSCC patients treated with adjuvant cemiplimab, versus those treated with placebo, after surgery and RT * To compare the effect of adjuvant cemiplimab with that of placebo on patients' freedom from locoregional recurrence (FFLRR) after surgery and RT * To compare the effect of adjuvant cemiplimab with that of placebo on patients' freedom from distant recurrence (FFDR) after surgery and RT * To compare the effect of adjuvant cemiplimab with that of placebo on the cumulative incidence of second primary CSCC tumors (SPTs) after surgery and RT * To evaluate the safety of adjuvant cemiplimab and that of placebo in high-risk CSCC patients after surgery and RT * To assess cemiplimab pharmacokinetics and immunogenicity in human serum

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What did the study report?

Outcomes, safety and baseline populations are separate source sections. Quality-of-life measures appear under their original outcome titles.

No posted result sections were captured. Registered plans do not establish that a treatment works.

Who could take part

eligibility Criteria: Key Inclusion Criteria: * For Japan only, men and women ≥21 years old * Patient with resection of pathologically confirmed CSCC (primary CSCC lesion only, or primary CSCC with nodal involvement, or CSCC nodal metastasis with known primary CSCC lesion previously treated within the draining lymph node echelon), with macroscopic gross resection of all disease * High risk CSCC, as defined in the protocol * Completion of curative intent post-operative radiation therapy (RT) within 2 to 10 weeks of randomization * Eastern Cooperative Oncology Group performance status (ECOG PS) ≤1 * Adequate hepatic, renal, and bone marrow function as defined in the protocol Key Exclusion Criteria: * Squamous cell carcinomas (SCCs) arising in non-cutaneous sites as defined in the protocol * Concurrent malignancy other than localized CSCC and/or history of malignancy other than localized CSCC within 3 years of date of randomization as defined in the protocol * Patients with hematologic malignancies (note: patients with chronic lymphocytic leukemia (CLL) are not excluded if they have not required systemic therapy for CLL within 6 months of enrollment) * Patients with history of distantly metastatic CSCC (visceral or distant nodal), unless the disease-free interval is at least 3 years (regional nodal involvement of disease in draining lymph node basin that was resected and radiated prior to enrollment will not be exclusionary) * Ongoing or recent (within 5 years of randomization date) evidence of significant autoimmune disease that required treatment with systemic immunosuppressive treatments, which may suggest risk for immune-related adverse events (irAEs). The following are not exclusionary: vitiligo, childhood asthma that has resolved, type 1 diabetes, residual hypothyroidism that required only hormone replacement, or psoriasis that does not require systemic treatment. * Has had prior systemic anti-cancer immunotherapy for CSCC Note: Other protocol defined Inclusion/Exclusion criteria apply
healthy Volunteers: false
minimum Age: 18 Years
sex: ALL
std Ages: ADULT
OLDER_ADULT

Treatment arms and interventions

arm Groups

intervention Names
Drug: Cemiplimab
label
Cemiplimab
type
EXPERIMENTAL
intervention Names
Drug: Placebo
label
Placebo
type
PLACEBO_COMPARATOR

interventions

arm Group Labels
Cemiplimab
description
Intravenous (IV) infusion over 30 minutes
name
Cemiplimab
other Names
REGN2810
Libtayo
type
DRUG
arm Group Labels
Placebo
description
Intravenous (IV) infusion over 30 minutes
name
Placebo
type
DRUG

Study design

allocation

RANDOMIZED

intervention Model

PARALLEL

masking Info

masking: QUADRUPLE
who Masked: PARTICIPANT
CARE_PROVIDER
INVESTIGATOR
OUTCOMES_ASSESSOR

primary Purpose

TREATMENT

Enrollment

count: 415
type: ACTUAL

Registered outcome plans (not posted results)

primary Outcomes

description
For patients who do not have a tumor recurrence or death, DFS will be censored on the date of last disease assessment.
measure
DFS defined as time from randomization to the first documented disease recurrence (local, regional and/or distant); or death due to any cause.
time Frame
Up to 54 months

secondary Outcomes

measure
Overall survival (OS), defined as time from randomization to the date of death. A patient who has not died will be censored on the last known date as alive.
time Frame
Up to 78 months
description
For patients who do not have a LRR or death, FFLRR will be censored on the date of last disease assessment.
measure
FFLRR defined as time from randomization to the date of first locoregional recurrence (LRR). Patients who died without a preceding LRR will be censored on the date of death.
time Frame
Up to 54 months
description
For patients who do not have a DR or death, FFDR will be censored on the date of last disease assessment.
measure
Freedom from distant recurrence (FFDR), defined as time from randomization to the date of first distant recurrence (DR). Patients who died without a preceding DR will be censored on the date of death.
time Frame
Up to 54 months
measure
Cumulative occurrence of second primary cutaneous squamous cell carcinoma tumor (SPTs) for each patient from randomization to occurrence of first primary endpoint event or end of study.
time Frame
Up to 54 months
measure
Incidence and severity of treatment-emergent adverse events (TEAE)
time Frame
Up to 78 months
measure
Incidence of deaths
time Frame
Up to 78 months
measure
Incidence of laboratory abnormalities
time Frame
Up to 78 months
measure
Cemiplimab concentrations in serum
time Frame
Up to 78 months
measure
Anti-drug antibodies (ADA) in serum
time Frame
Up to 78 months

Full study description

brief Summary: The primary objective of the study is to compare disease-free survival (DFS) of patients with high-risk cutaneous squamous cell carcinoma (CSCC) treated with adjuvant cemiplimab, versus those treated with placebo, after surgery and radiation therapy (RT). The secondary objectives of the study are: * To compare the overall survival (OS) of high-risk CSCC patients treated with adjuvant cemiplimab, versus those treated with placebo, after surgery and RT * To compare the effect of adjuvant cemiplimab with that of placebo on patients' freedom from locoregional recurrence (FFLRR) after surgery and RT * To compare the effect of adjuvant cemiplimab with that of placebo on patients' freedom from distant recurrence (FFDR) after surgery and RT * To compare the effect of adjuvant cemiplimab with that of placebo on the cumulative incidence of second primary CSCC tumors (SPTs) after surgery and RT * To evaluate the safety of adjuvant cemiplimab and that of placebo in high-risk CSCC patients after surgery and RT * To assess cemiplimab pharmacokinetics and immunogenicity in human serum
detailed Description: Cemiplimab is a monoclonal antibody. Antibodies are proteins naturally found in the blood. A monoclonal antibody is a special antibody that is manufactured as a medication to target specific proteins in the body that may be involved in cancer. Cemiplimab works by blocking programmed death-1 (PD-1), a cell receptor on immune cells. By blocking PD-1, it is expected that the immune cells will attack cancer cells. The study is being conducted in participants that have had surgery and radiation therapy for a type of skin cancer called cutaneous squamous cell cancer, and who have a risk that this cancer may come back. The main purpose of the study is to determine if cemiplimab will prevent cutaneous squamous cell cancer (CSCC) from returning after surgery and radiation. Currently, we know that certain types of CSCC have a high chance of coming back after surgery and radiation. At this time, there is no approved treatment to give patients after surgery and radiation to prevent high-risk CSCC from coming back. We are investigating if the addition of cemiplimab will decrease the chance of these high-risk cancers coming back. The study will also investigate if cemiplimab may help participants live for longer. The study has two parts. Part 1: participants will receive every 3 weeks via intravenous infusion (drip into a vein) either cemiplimab (study drug) or placebo (similar to the study drug but without active medicine). After 12 weeks of treatment, cemiplimab or placebo will be given every 6 weeks. Part 1 of the study includes a screening period (up to 28 days), a treatment period (approximately 48 weeks), an end of treatment visit (approximately 30 days after completion of study drug treatment period) and a post-treatment follow-up period (approximately up to 5 years or until skin cancer returns or the study ends). Part 2 of the study is optional and provides the participant with the option to receive cemiplimab if the cancer comes back if the participant was initially receiving placebo. There is no placebo in Part 2 of the study. If the cancer comes back, the study doctor will discuss with participants if they are eligible to participate in the optional part 2 of the study. Part 2 of the study includes a brief screening period, a treatment period (approximately 96 weeks) and an end of treatment visit (approximately 30 days after the completion of the study drug treatment period).

Source references

references

citation
Rischin D, Porceddu S, Day F, Brungs DP, Christie H, Jackson JE, Stein BN, Su YB, Ladwa R, Adams G, Bowyer SE, Otty Z, Yamazaki N, Bossi P, Challapalli A, Hauschild A, Lim AM, Patel VA, Walker JL, De Liz Vassen Schurmann M, Queirolo P, Canueto J, Ferreira da Silva FA, Stratigos A, Guminski A, Lin C, Damian F, Flatz L, Taylor AE, Carr DR, Harris S, Kirtbaya D, Quereux G, Rutkowski P, Basset-Seguin N, Khushalani NI, Robert C, Ju H, Joseph C, Bansal S, Chen CI, Seebach F, Yoo SY, Lowy I, Goncalves P, Fury MG; C-POST Trial Investigators. Adjuvant Cemiplimab or Placebo in High-Risk Cutaneous Squamous-Cell Carcinoma. N Engl J Med. 2025 Aug 21;393(8):774-785. doi: 10.1056/NEJMoa2502449. Epub 2025 May 31.
pmid
40454639
type
DERIVED