Study of ADCT-301 in Patients With Selected Advanced Solid Tumors

Ovarian Cancer Clinical Trial

Official title:

A Phase 1b, Open-label, Dose-escalation and Dose-expansion Study to Evaluate the Safety, Tolerability, Pharmacokinetics, and Antitumor Activity of Camidanlumab Tesirine (ADCT-301) as Monotherapy or in Combination in Patients With Selected Advanced Solid Tumors

Clinical Trial Details — Status: Terminated

Administrative data

• NCT number: NCT03621982
• Other study ID #: ADCT-301-103
• Secondary ID: 2019-003132-23
• Status: Terminated
• Phase: Phase 1
• Start date: November 9, 2018
• Est. completion date: December 14, 2022

Study information

• Verified date: June 2024
• Source: ADC Therapeutics S.A.
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

This study evaluates ADCT-301 in patients with Selected Advanced Solid Tumors. Patients will participate in a Treatment Period with 3-week cycles and a Follow-up Period every 12 weeks for up to 1 year after treatment discontinuation.

Description:

This is a Phase 1b, multi-center, open-label study with a dose-escalation part and a dose expansion part. The duration of the study participation for each participant was defined as the time from the date of signed written informed consent to the completion of the followup period, withdrawal of consent, loss to follow-up, or death, whichever occurs first.

The study was include a Screening Period (of up to 21 days), a Treatment Period (with cycles of 3 weeks for a Q3W dosing regimen), and a Follow-up Period (approximately every 12 week visits) for up to 1 year after treatment discontinuation.

Recruitment information / eligibility

• Status: Terminated
• Enrollment: 78
• Est. completion date: December 14, 2022
• Est. primary completion date: December 14, 2022
• Accepts healthy volunteers: No
• Gender: All
• Age group: 18 Years and older

Eligibility

Inclusion Criteria:

1. Written informed consent must be obtained prior to any procedures.

2. Male or female participants aged 18 years or older.

3. Pathologic diagnosis of solid tumor malignancy that is locally advanced or metastatic at time of Screening:

Part 1 Dose escalation camidanlumab tesirine as monotherapy:

Selected advanced solid tumors: colorectal, head and neck, NSCLC, gastric and esophageal cancers, pancreas, bladder, renal cell carcinoma, melanoma, TNBC, and ovarian/fallopian tube cancers

Part 1 Dose-escalation camidanlumab tesirine in combination with pembrolizumab:

Selected advanced solid tumors: colorectal cancer, gastric-esophageal cancer, ovarian /fallopian tube cancer, pancreatic cancer, non-small cell lung cancer, and melanoma.

Note: For colorectal cancer, gastric-esophageal cancer, ovarian/fallopian tube cancer, pancreatic cancers mismatch repair (MMR) / microsatellite stability (MSS) / microsatellite instability (MSI) status was mandatory. If MMR/MSS/MSI status was not available at signature of the informed consent, the test should be performed before Cycle 1 Day 1 (C1D1).

Part 2 Dose expansion camidanlumab tesirine in combination with pembrolizumab:

• Group 1: One of the indications identified in Part 1, for which at least 1 response (PR or CR) was seen.

• Group 2: Participants with advanced solid tumors and MSI-H/dMMR status, who had received a prior regimen containing PD-1/PD-L1 inhibitors, for which the best response was CR, PR, or SD =4 months, and then progressed while under treatment with the PD-1/PD-L1 inhibitor-based regimen.

Note: A maximum of 4 participants with the same indication was allowed in this basket group.

4. Participants who were refractory to or intolerant of existing therapy(ies) known to provide clinical benefit for their condition.

5. Participants with advanced/metastatic cancer, with measurable disease as determined by RECIST v1.1 or immune-related Response Criteria (irRC)/ immune-related Response Evaluation Criteria In Solid Tumors (irRECIST)/ immune-related Response Evaluation Criteria In Solid Tumors (iRECIST)/ immune-modified Response Evaluation Criteria in Solid Tumors (imRECIST) as per Investigator discretion.

6. A) For camidanlumab tesirine as monotherapy: Participant must have a site of disease amenable to biopsy and was willing to undergo fresh biopsy procedures (minimum 3 passes each) prior to first dose, according to the treating institution's guidelines.

B) Participants included in the paired-biopsy cohort must in addition be willing to undergo fresh biopsy procedures (minimum 3 passes each) after receiving at least 1 dose of study drug.

C) For camidanlumab tesirine in combination with pembrolizumab: Participant must either had a site of disease amenable to biopsy and must provide fresh tumor biopsy prior to C1D1, or have sufficient available archival tumor tissue (biopsied after their last disease progression, and in the situation where the participant had received no additional anti-cancer therapy between their progression and C1D1). Participants were must willing to undergo fresh biopsy procedures (minimum 3 passes each) after receiving at least 1 dose of study treatment, according to the treating institution's guidelines.

7. ECOG performance status 0-1.

8. Participant with life expectancy = 3 months as per Investigator assessment.

9. Adequate organ function as defined by screening laboratory values within the following parameters:

1. Absolute neutrophil count (ANC) = 1.5 × 10^3/µL (off growth factors at least 72 hours).

2. Platelet count =100 × 10^3/µL without transfusion in the past 10 days.

3. Hemoglobin =9 g/dL (5.6 mmol/L) (prior transfusion allowed).

4. Alanine aminotransferase (ALT), aspartate aminotransferase (AST), or gamma glutamyl transferase (GGT) =2.5 × the upper limit of normal (ULN) if there is no liver involvement; ALT or AST =5 × ULN if there is liver involvement.

5. Total bilirubin =1.5 × ULN (patients with known Gilbert's syndrome may have a total bilirubin up to =3 × ULN with direct bilirubin =1.5 × ULN).

6. Blood creatinine =1.5 × ULN or calculated creatinine clearance =60 mL/min by the Cockcroft-Gault equation.

10. Negative beta-human chorionic gonadotropin (ß-HCG) pregnancy test within 7 days prior to start of study drug for women of childbearing potential (WOCBP).

11. Women of childbearing potential must agree to use a highly effective method of contraception from the time of giving informed consent until at least 9.5 months after the last dose of camidanlumab tesirine or 4 months after last dose of pembrolizumab, whichever is the latest. Men with female partners who were of childbearing potential must agree to use a condom when sexually active or practice total abstinence from the time of giving informed consent until at least 6.5 months after the participant received the last dose of camidanlumab tesirine or 4 months after last dose of pembrolizumab, whichever was the latest.

Exclusion Criteria:

1. Participation in another investigational interventional study.

2. Prior therapy with a CD25 (IL-2R) antibody.

3. Known history of =Grade 3 hypersensitivity to a therapeutic antibody.

4. Participants with prior solid organ or allogeneic bone marrow transplant.

5. History of symptomatic autoimmune disease (e.g., rheumatoid arthritis, systemic progressive sclerosis [scleroderma], systemic lupus erythematosus, Sjögren's syndrome, autoimmune vasculitis [e.g., Wegener's granulomatosis]) (participants with vitiligo, type 1 diabetes mellitus, residual hypothyroidism, hypophysitis due to autoimmune condition only requiring hormone replacement may be enrolled).

6. History of neuropathy considered of autoimmune origin (e.g., polyradiculopathy including Guillain-Barré syndrome and myasthenia gravis) or other central nervous system (CNS) autoimmune disease (e.g., poliomyelitis, multiple sclerosis).

7. History of recent infection (within 4 weeks of C1D1) caused by a pathogen known to be associated with GBS, for example: herpes simplex virus 1/2 (HSV1, HSV2), varicella zoster virus (VZV), Epstein-Barr virus (EBV), cytomegalovirus (CMV), measles, Influenza A, Zika virus, Chikungunya virus, mycoplasma pneumonia, Campylobacter jejuni, enterovirus D68, or severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Note: An influenza test and a pathogen-directed SARS-CoV-2 test (such as polymerase chain reaction [PCR]) were mandatory and must be negative before initiating study treatment (tests to be performed 3 days or less prior to dosing on C1D1; an additional 2 days were allowed in the event of logistical issues for receiving the results on time).

8. Known seropositive and requiring anti-viral therapy for human immunodeficiency (HIV) virus, hepatitis B virus (HBV), or hepatitis C virus (HCV). Note: Testing was not mandatory to be eligible but should be considered in participants with high risk for these infections; testing was mandatory if status was unknown.

9. History of Stevens-Johnson syndrome or toxic epidermal necrolysis.

10. Failure to recover to =Grade 1 (Common Terminology Criteria for Adverse Events version 4.0 [CTCAE version 4.0]) from acute nonhematologic toxicity (to =Grade 2 for neuropathy or alopecia), due to previous therapy, prior to screening.

11. Symptomatic CNS metastases or evidence of leptomeningeal disease (brain MRI or previously documented cerebrospinal fluid [CSF] cytology). Previously treated asymptomatic CNS metastases were permitted provided that the last treatment (systemic anticancer therapy and/or local radiotherapy) was completed =4 weeks prior to Day 1 except usage of low dose of steroids on a taper (i.e., up to 10 mg prednisone or equivalent on Day 1 and consecutive days were permissible if being tapered down). Participants with discrete dural metastases are eligible.

12. Clinically significant third space fluid accumulation (i.e., ascites requiring drainage or pleural effusion that is either requiring drainage or associated with shortness of breath).

13. Active diarrhea CTCAE Grade 2 or a medical condition associated with chronic diarrhea (such as irritable bowel syndrome, inflammatory bowel disease).

14. Active infection requiring systemic antibiotic therapy.

15. Active bleeding diathesis or significant anticoagulation (international normalized ratio [INR] =2.0).

16. Breastfeeding or pregnant.

17. Significant medical comorbidities, including uncontrolled hypertension (blood pressure [BP] =160 mmHg systolic and/or =110 mmHg diastolic repeatedly with or without anti hypertensive medication), unstable angina, congestive heart failure (greater than New York Heart Association class II), electrocardiographic evidence of acute ischemia, coronary angioplasty or myocardial infarction within 6 months prior to screening, severe uncontrolled atrial or ventricular cardiac arrhythmia, poorly controlled diabetes, active ulceration of the upper gastrointestinal (GI) tract or GI bleeding, or severe chronic pulmonary disease.

18. Major surgery, radiotherapy, chemotherapy or other anti-neoplastic therapy within 14 days prior to start of study drug (C1D1), except shorter if approved by the Sponsor. For cytotoxic agents that have major delayed toxicity, e.g., mitomycin C and nitrosoureas, 4 weeks is indicated as washout period. For participants received systemic anticancer immunotherapies (as opposed to intralesional) that lead to activation of Teffs and/or increase the Teff/Treg ratio, such as anti-PD-1 antibodies, 4 weeks were indicated as the washout period.

19. Use of any other experimental medication within 14 days prior to start of study drug (C1D1).

20. Participants requiring concomitant immunosuppressive agents or chronic treatment with corticosteroids except:

• replacement dose steroids in the setting of adrenal insufficiency

• topical, inhaled, nasal, and ophthalmic steroids are allowed.

21. Planned live vaccine within 30 days prior to the first dose of study treatment and during study treatment.

22. Congenital long QT syndrome, or a corrected QTcF interval of = 480 ms, at screening (unless secondary to pacemaker or bundle branch block).

23. Active second primary malignancy other than non-melanoma skin cancers, non-metastatic prostate cancer, in situ cervical cancer, ductal or lobular carcinoma in situ of the breast, or other malignancy that the Sponsor's medical monitor and Investigator agree and document should not be exclusionary.

24. Any other significant medical illness, abnormality, or condition that would, in the Investigator's judgment, made the participant inappropriate for study participation or put the participant at risk.

25. For participants treated with camidanlumab tesirine in combination with pembrolizumab:

patients intolerant to checkpoint-inhibitor or with a history of the following = Grade 3 immune-related adverse events: hepatitis, renal, ocular, neurologic, cardiovascular, rheumatologic, and hematologic.

26. For participants treated with camidanlumab tesirine in combination with pembrolizumab:

participants with a history of non-infectious pneumonitis related to prior systemic treatment and that require treatment with steroids within the last 6 months prior to enrollment.

Related Conditions & MeSH terms

• Bladder Cancer
• Carcinoma
• Carcinoma, Renal Cell
• Colo-rectal Cancer
• Esophageal Cancer
• Fallopian Tube Cancer
• Fallopian Tube Neoplasms
• Gastric Cancer
• Head and Neck Cancer Squamous Cell Carcinoma
• Melanoma
• Non-small Cell Lung Cancer
• Ovarian Cancer
• Pancreas Cancer
• Pancreatic Neoplasms
• Renal Cell Carcinoma
• Triple Negative Breast Neoplasms
• Triple-negative Breast Cancer

Intervention

Drug:
• ADCT-301
intravenous infusion

Biological:
• Pembrolizumab
intravenous infusion

Locations

Country	Name	City	State
Belgium	Institut Jules Bordet	Anderlecht
Belgium	Universitair Ziekenhuis Gent	Gent
United Kingdom	University College London Hospitals NHS Foundation Trust	London	England
United Kingdom	The Christie NHS Foundation Trust	Manchester
United States	The Sarah Cannon Research Institute	Nashville	Tennessee
United States	Smilow Cancer Hospital Phase 1 Unit	New Haven	Connecticut
United States	Stanford Cancer Center	Palo Alto	California
United States	Oregon Health and Science University	Portland	Oregon
United States	The START Center for Cancer Care	San Antonio	Texas

Sponsors (1)

Lead Sponsor	Collaborator
ADC Therapeutics S.A.

Countries where clinical trial is conducted

United States,  Belgium,  United Kingdom, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Number of Participants Who Experienced Treatment-emergent Adverse Events (TEAEs)	An adverse event (AE) is defined as any untoward medical occurrence in a participant or clinical investigation participant administered a pharmaceutical product, which does not necessarily have to have a causal relationship with this treatment. A TEAE is defined as an AE that occurs or worsens in the period extending from the first dose of study drug to 30 days after the last dose of study drug in this study or start of a new anticancer therapy, whichever is earlier.; Any clinically significant changes from baseline in the safety laboratory values, vital signs, 12-lead electrocardiogram (ECG), and Eastern Cooperative Oncology Group (ECOG) performance status were reported as TEAEs.	Up to 3 years
Primary	Number of Participants Who Experienced TEAEs by Common Terminology Criteria for Adverse Events (CTCAE) Grade	AEs were graded according to CTCAE v4.0 (or more recent). For events not included in the CTCAE criteria, the severity of the AE was graded on a scale of 1 to 5, where 1 is asymptomatic or mild symptoms, 2 is moderate, 3 is severe, 4 is Life-threatening consequences and 5 is death related to an AE.	Up to 3 years
Primary	Number of Participants Who Experienced Treatment-emergent Serious Adverse Events (SAEs)	A SAE is defined as any AE that results in death, is life threatening, requires inpatient hospitalization or prolongation of existing hospitalization (hospitalization for elective procedures or for protocol compliance is not considered an SAE), results in persistent or significant disability/incapacity, is a congenital anomaly/birth defect or important medical events that do not meet the preceding criteria but based on appropriate medical judgement may jeopardize the participant or may require medical or surgical intervention to prevent any of the outcomes listed above.	Up to 3 years
Primary	Number of Participants Who Experienced a SAE by CTCAE Grade	AEs were graded according to CTCAE v4.0 (or more recent). For events not included in the CTCAE criteria, the severity of the AE was graded on a scale of 1 is mild or asymptomatic, 2 is moderate, 3 is severe, 4 is Life-threatening and 5 is death related to an AE.	Up to 3 years
Primary	Number of Participants Who Experienced a Dose Interruption	Dose interruption for participants treated with ADCT-301 as monotherapy and for participants treated with ADCT-301 in combination with pembrolizumab.	Up to 3 years
Primary	Number of Participants Who Experienced a Dose Reduction	Dose reductions for participants treated with ADCT-301 as monotherapy and for participants treated with ADCT-301 in combination with pembrolizumab.	Up to 3 years
Primary	Number of Participants Who Experienced a Dose Limiting Toxicity (DLT)	For the dose-escalation of ADCT-301 as monotherapy, DLT is defined as any of the following events like hematologic DLT and non-hematologic DLT which occur during the 21 days following the first study drug administration period of Part 1, except those that are clearly due to underlying disease or extraneous causes.; For the dose-escalation of ADCT-301 in combination with pembrolizumab, a DLT is defined as any of the following events ike hematologic DLT and non-hematologic DLT which occur during the 21 days following the first study drug administration period of Part 1, except those that are clearly due to underlying disease or extraneous causes.	Day 1 to Day 21
Secondary	Overall Response Rate (ORR) According to the Response Evaluation Criteria In Solid Tumors (RECIST) v1.1.	The ORR was defined as the percentage of participants with a best overall response (BOR) of complete response (CR) or partial response (PR). The overall response category was derived based on response assessment performed on or before the start of subsequent anti-cancer therapy.	Up to 3 years
Secondary	Duration of Response (DOR) as Per RECIST v 1.1	DOR is defined among objective responders (CR or PR) as the time from the earliest date of first response until the first date of either disease progression (based on radiographic or clinical progression at end of treatment [EOT]/end of study [EOS]) or death due to any cause.	Up to 3 years
Secondary	Progression-free Survival (PFS) as Per RECIST v 1.1	PFS defined as the time between start of treatment and the first documentation of recurrence, progression, or death for participants treated with ADCT-301 as monotherapy and for participants treated with ADCT-301 in combination with pembrolizumab.	Up to 3 years
Secondary	Overall Survival (OS)	OS defined as the time between the start of treatment and death from any cause for participants treated with ADCT-301 as monotherapy and for participants treated with ADCT-301 in combination with pembrolizumab.	Up to 3 years
Secondary	Time to Maximum Concentration (Tmax) of ADCT-301 in Serum Total Antibody, PBD-conjugated Antibody, and Unconjugated Warhead SG3199	The pharmacokinetic (PK) profile included determination of Tmax in serum Total antibody, PBD-conjugated antibody, and unconjugated warhead SG3199. For participants treated with camidanlumab tesirine in combination with pembrolizumab, the collection of PK data was stopped upon consultation with the Sponsor if ADCT-301 administration is discontinued and pembrolizumab continues.; Upon consultation with the Sponsor, no further PK samples were collected, ADCT-301 was permanently discontinued and pembrolizumab continues as single agent.	Cycle 1 Day 1 (C1D1), from Pre-dose to 4 hr, 96 hr, 168 hr and 336 hr post dose; Cycle 2 Day 1 (C2D1), from Pre-dose to 4 hr, 48 hr, 96 hr, 168 hr and 336 hr post dose
Secondary	Area Under the Concentration-time Curve From Time Zero to the Last Quantifiable Concentration (AUC0-last) of ADCT-301 in Serum Total Antibody, PBD-conjugated Antibody, and Unconjugated Warhead SG3199	PK profile included AUC0-last of ADCT-301 in Serum total antibody, PBD-conjugated antibody, and unconjugated warhead SG3199. For participants treated with ADCT-301 in combination with pembrolizumab, the collection of PK data was stopped upon consultation with the Sponsor if ADCT-301 administration was discontinued and pembrolizumab continues.; Upon consultation with the Sponsor, no further PK samples were collected, ADCT-301 was permanently discontinued and pembrolizumab continues as single agent.	C1D1, from Pre-dose to 4 hr, 96 hr, 168 hr and 336 hr post dose; C2D1, from Pre-dose to 4 hr, 48 hr, 96 hr, 168 hr and 336 hr post dose
Secondary	Area Under the Concentration-time Curve From Time Zero to Infinity (AUCinf) of ADCT-301 in Serum Total Antibody, PBD-conjugated Antibody, and Unconjugated Warhead SG3199	The PK profile included AUCinf of ADCT-301 in serum total antibody, PBD-conjugated antibody, and unconjugated warhead SG3199. For participants treated with ADCT-301 in combination with pembrolizumab, the collection of PK data was stopped upon consultation with the Sponsor if ADCT-301 administration was discontinued and pembrolizumab continues.; Upon consultation with the Sponsor, no further PK samples were collected, ADCT-301 was permanently discontinued and pembrolizumab continues as single agent.	C1D1, from Pre-dose to 4hr, 96hr, 168 hr and 336 hr post dose; C2D1, from Pre-dose to 4 hr, 48 hr, 96 hr, 168 hr and 336 hr post dose
Secondary	Area Under the Concentration-time Curve From Time Zero to the End of the Dosing Interval (AUCtau) ADCT-301 in Serum Total Antibody, PBD-conjugated Antibody, and Unconjugated Warhead SG3199	The PK profile included AUCtau ADCT-301 in serum total antibody, PBD-conjugated antibody, and unconjugated warhead SG3199. For participants treated with ADCT-301 in combination with pembrolizumab, the collection of PK data was stopped upon consultation with the Sponsor if ADCT-301 administration was discontinued and pembrolizumab continues.; Upon consultation with the Sponsor, no further PK samples were collected, ADCT-301 was permanently discontinued and pembrolizumab continues as single agent.	C1D1, from Pre-dose to 4 hr, 96 hr, 168 hr and 336 hr post dose; C2D1, from Pre-dose to 4 hr, 48 hr, 96 hr, 168 hr and 336 hr post dose
Secondary	Accumulation Index (AI) of ADCT-301 in Serum Total Antibody, PBD-conjugated Antibody and Unconjugated Warhead SG3199	The PK profile included AI of ADCT-301 in serum total antibody and PBD-conjugated antibody. For participants treated with ADCT-301 in combination with pembrolizumab, the collection of PK data was stopped upon consultation with the Sponsor if ADCT-301 administration was discontinued and pembrolizumab continues.; AI is the ratio of accumulation of a drug under steady state conditions (i.e., after repeated administration) as compared to a single dose.; Upon consultation with the Sponsor, no further PK samples were collected, ADCT-301 was permanently discontinued and pembrolizumab continues as single agent.	C2D1, from Pre-dose to 4 hr, 48 hr, 96 hr, 168 hr and 336 hr post dose
Secondary	Clearance (CL) of ADCT-301 in Serum Total Antibody, PBD-conjugated Antibody and Unconjugated Warhead SG3199	The PK profile included the CL of ADCT-301 in serum total antibody and PBD-conjugated antibody. For participants treated with ADCT-301 in combination with pembrolizumab, the collection of PK data was stopped upon consultation with the Sponsor if ADCT-301 administration was discontinued and pembrolizumab continues.; Upon consultation with the Sponsor, no further PK samples were collected, ADCT-301 was permanently discontinued and pembrolizumab continues as single agent.	C1D1, from Pre-dose to 4 hr, 96 hr, 168 hr and 336 hr post dose; C2D1, from Pre-dose to 4 hr, 48 hr, 96 hr, 168 hr and 336 hr post dose
Secondary	Apparent Terminal Elimination Half-life (Thalf) of ADCT-301 in Serum Total Antibody, PBD-conjugated Antibody, and Unconjugated Warhead SG3199	The PK profile included the Thalf of ADCT-301 in serum total antibody and PBD-conjugated antibody. For participants treated with ADCT-301 in combination with pembrolizumab, the collection of PK data was stopped upon consultation with the Sponsor if ADCT-301 administration was discontinued and pembrolizumab continues.; Upon consultation with the Sponsor, no further PK samples were collected, ADCT-301 was permanently discontinued and pembrolizumab continues as single agent.	C1D1, from Pre-dose to 4 hr, 96 hr, 168 hr and 336 hr post dose; C2D1, from Pre-dose to 4 hr, 48 hr, 96 hr, 168 hr and 336 hr post dose
Secondary	Maximum Concentration (Cmax) of ADCT-301 in Serum Total Antibody, PBD-conjugated Antibody and Unconjugated Warhead SG3199	The PK profile included determination of Cmax in serum Total antibody, PBD-conjugated Antibody and Unconjugated Warhead SG3199. For participants treated with ADCT-301 in combination with pembrolizumab, the collection of PK data was stopped upon consultation with the Sponsor if ADCT-301 administration was discontinued and pembrolizumab continues.; Upon consultation with the Sponsor, no further PK samples were collected, ADCT-301 was permanently discontinued and pembrolizumab continues as single agent.	C1D1, from Pre-dose to 4 hr, 96 hr, 168 hr and 336 hr post dose; C2D1, from Pre-dose to 4 hr, 48 hr, 96 hr, 168 hr and 336 hr post dose
Secondary	Number of Participants With Anti-drug Antibody (ADA) Response in Serum	ADA testing included number of participants with positive pre-dose ADA response, number of participants with post-dose ADA response only, and number of participants with positive ADA response at any time. Collection of ADA was stopped if ADCT-301 administration was discontinued. For participants treated with ADCT-301 in combination with pembrolizumab, unless there was a penultimate observation of positive ADA response, no other collection of ADA data was necessary if ADCT-301 administration was discontinued.; Upon consultation with the Sponsor, ADA samples were not collected anymore if ADCT-301 was permanently discontinued and pembrolizumab continues as single agent.	C1D1, from Pre-dose to 336 hr post dose.