Pembrolizumab after Intensity-Modulated Radiation Therapy for the Treatment of Stage IVB Anaplastic Thyroid Cancer, IMPAACT Study

Inclusion Criteria

• Male/female participants who are at least 18 years of age on the day of signing informed consent with pathologic findings supporting the clinical impression of anaplastic thyroid carcinoma will be enrolled in this study. Diagnosis may include consistent with or suggestive of terminology associated with: anaplastic thyroid carcinoma, undifferentiated carcinoma, squamous carcinoma; carcinoma with spindled, giant cell, or epithelial features; poorly differentiated carcinoma with pleomorphism, extensive necrosis with tumor cells present
• Stage IVB disease (no convincing evidence of metastatic disease outside of the neck) who have unresectable disease are eligible in groups 1 or 2. Previous excisional biopsy is permitted
• Stage IVB disease (no convincing evidence of metastatic disease outside of the neck) who have undergone complete resection of tumor (no convincing evidence of metastatic disease in the neck) are eligible in group 3
• Patient must have completed external beam radiation with or without concomitant cytotoxic chemotherapy to participate in groups 1 and 2. Those who have completed these treatment after surgical resection of primary tumor may participate in group 3
• Patients may enroll only after completing radiation. Study drug may start from 2-6 weeks (+2 weeks) after radiation is completed and can only be started once radiation and chemotherapy-related toxicities are grade 2 or less (with the exception of alopecia). If a subject is consented but adverse event (AE)s are not grade 2 or less by 8 weeks after radiation therapy (RT) is completed, that subject is not eligible and should not start pembrolizumab
• A female participant is eligible to participate if she is not pregnant, not breastfeeding, and at least one of the following conditions applies: * Not a woman of childbearing potential (WOCBP) OR * A WOCBP who agrees to follow the contraceptive guidance during the treatment period and for at least 120 days after the last dose of study treatment
• The participant (or legally acceptable representative if applicable) provides written informed consent for the trial
• Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 1. Evaluation of ECOG is to be performed within 7 days prior to the first dose of study intervention
• Absolute neutrophil count (ANC) >= 1500/uL (specimens must be collected within 10 days prior to the start of study intervention)
• Platelets >= 100 000/uL (specimens must be collected within 10 days prior to the start of study intervention)
• Hemoglobin >= 9.0 g/dL or >= 5.6 mmol/L (specimens must be collected within 10 days prior to the start of study intervention) * Criteria must be met without erythropoietin dependency and without packed red blood cell (pRBC) transfusion within last 2 weeks
• Creatinine =< 1.5 x upper limit of normal (ULN) OR measured or calculated creatinine clearance >= 30 mL/min for participant with creatinine levels (glomerular filtration rate [GFR] can also be used in place of creatinine or creatinine clearance [CrCl]) > 1.5 x institutional ULN (specimens must be collected within 10 days prior to the start of study intervention) * Creatinine clearance (CrCl) should be calculated per institutional standard
• Total bilirubin =< 1.5 x ULN OR direct bilirubin =< ULN for participants with total bilirubin levels > 1.5 x ULN (specimens must be collected within 10 days prior to the start of study intervention)
• Aspartate aminotransferase (AST) (serum glutamic oxaloacetic transaminase [SGOT]) and alanine aminotransferase (ALT) (serum glutamic pyruvic transaminase [SGPT]) =< 2.5 x ULN (=< 5 x ULN for participants with liver metastases) (specimens must be collected within 10 days prior to the start of study intervention)
• International normalized ratio (INR) OR prothrombin time (PT) activated partial thromboplastin time (aPTT) =< 1.5 x ULN unless participant is receiving anticoagulant therapy as long as PT or aPTT is within therapeutic range of intended use of anticoagulants (specimens must be collected within 10 days prior to the start of study intervention)

Exclusion Criteria

• BRAFV600E mutated ATC unless there is a contraindication to BRAF +/- MEK inhibitor therapy. There must be a discussion with the principal investigator (PI) regarding reasons for contraindication and this must be clearly documented
• A WOCBP who has a positive urine pregnancy test within 72 hours prior to first dose of pembrolizumab. A serum pregnancy test will be required
• A male participant must agree to use a contraception of this protocol during the treatment period and for at least 32 weeks (5 terminal half-lives for pembrolizumab plus an additional 90 days) from the last dose of study treatment and refrain from donating sperm during this period
• Has received prior therapy with an anti-PD-1, anti-PD-L1, or anti-PD-L2 agent or with an agent directed to another stimulatory or co-inhibitory T-cell receptor (eg, CTLA-4, OX-40, CD137)
• Has received a live vaccine or live-attenuated vaccine within 30 days prior to the first dose of study drug. Administration of killed vaccines is allowed
• Is currently participating in or has participated in a study of an investigational agent or has used an investigational device within 4 weeks prior to the first dose of study intervention
• Has a diagnosis of immunodeficiency or is receiving chronic systemic steroid therapy (in dosing exceeding 10 mg daily of prednisone equivalent) or any other form of immunosuppressive therapy within 7 days prior to the first dose of study drug
• Has severe hypersensitivity (>= grade 3) to pembrolizumab and/or any of its excipients
• Has active autoimmune disease that has required systemic treatment in the past 2 years (i.e. with use of disease modifying agents, corticosteroids or immunosuppressive drugs). Replacement therapy (eg., thyroxine, insulin, or physiologic corticosteroid replacement therapy for adrenal or pituitary insufficiency, etc.) is not considered a form of systemic treatment and is allowed
• Has a history of (non-infectious) pneumonitis/interstitial lung disease that required steroids or has current pneumonitis/interstitial lung disease, not related to radiation
• Has an active infection requiring systemic therapy
• Has a known history of human immunodeficiency virus (HIV) infection
• Has a known history of hepatitis B (defined as hepatitis B surface antigen [HBsAg] reactive) or known active hepatitis C virus (defined as HCV ribonucleic acid [RNA] qualitative is detected) infection
• Has a history or current evidence of any condition, therapy, or laboratory abnormality that might confound the results of the study, interfere with the participant’s participation for the full duration of the study, or is not in the best interest of the participant to participate, in the opinion of the treating investigator
• Has known psychiatric or substance abuse disorders that would interfere with cooperation with the requirements of the trial
• Is pregnant or breastfeeding or expecting to conceive or father children within the projected duration of the study, starting with the screening visit through 120 days after the last dose of trial treatment
• Has had an allogenic tissue/solid organ transplant