Study was closed due to the recent pandemic and enrollment challenges.

Non-interventional PK sub-study of QUILT-3.032 (CA-ALT-803-01-16) and QUILT-2.005 (CA-ALT-803-01-14)

QUILT-3.032 is a Phase 2, open-label, single-arm, three-cohort, multicenter study of intravesical BCG plus ALT-803 in patients with BCG unresponsive high grade NMIBC. Patients will be enrolled into one of three study cohorts. Cohort A will enroll 80 patients who have histologically confirmed presence of BCG-unresponsive carcinoma in situ (CIS) [with or without Ta or T1 disease]. Cohort B will enroll 80 patients who have histologically confirmed BCG-unresponsive high-grade Ta or T1 disease. Cohort C will enroll up to 23 patients who also have histologically confirmed presence of BCG-unresponsive CIS [with or without Ta/T1 papillary disease]. Patients in Cohorts A and B will receive ALT-803 plus BCG combination treatment. Patients in Cohort C will receive ALT-803 alone. Enrollment of Cohort C will start once the enrollment of Cohort A is complete. Cohorts A, B, and C are independent study cohorts and will be separately evaluated for efficacy. All patients treated in the study will receive via a urinary catheter in the bladder, BCG plus ALT-803 or ALT-803 alone weekly for 6 consecutive weeks during the induction treatment period.

QUILT-2.005 is a phase 2b, randomized, two-cohort, open-label, multicenter study of intravesical ALT-803 plus BCG versus BCG alone, in BCG naïve patients with high-grade NMIBC. Patients will be enrolled into one of two study cohorts and randomized into two arms to be treated with either ALT-803 plus BCG or BCG alone. Cohort A will initially enroll 366 patients who have histologically confirmed CIS (with or without Ta/T1 papillary disease). Cohort B will initially enroll 230 patients who have histologically confirmed high-grade papillary Ta/T1 disease only. Cohorts A and B are two independent study cohorts and will be evaluated separately for efficacy.

PK sub-study: Blood samples to determine serum levels of ALT-803 will be collected on study day 1 prior to dosing, and at post-bladder voiding (+ 15 minutes), 24 (±2), 48 (±4), 72 (±4), 96 (±4) and 168 (±4) hours after dosing administered at study Week 1 and again at the same time points for study Week 6. Six subjects from either cohort A (either study) or cohort C (QUILT 3.032) and six subjects from cohort B (either study) will be sampled initially. Up to an additional 4 subjects for each cohort may also be sampled. Patients enrolled in QUILT 2.005 must have been randomized to receive ALT-803 plus BCG to be eligible for the PK sub-study.

Inclusion Criteria:

• Only subjects who are eligible for and have entered into protocol QUILT-3.032 or QUILT-2.005 may participate in this sub-study.
• Patients enrolled in QUILT-2.005 must have been randomized to receive ALT-803 plus BCG to participate in this sub-study.

Exclusion Criteria:

• Refusal to provide voluntary written informed consent and HIPAA authorization and agree to comply with all protocol-specified procedures and follow-up evaluations.
• Loss of ≥ 475 mL blood volume or blood transfusion of any blood product within 3 months prior to screening.

Six subjects from either Cohort A (either study) or Cohort C (QUILT-3.032) and six subjects from Cohort B (either study) will be sampled initially in this PK sub-study. Up to an additional 4 subjects from each cohort may also be sampled.

Only 1 participant was enrolled in the study.

Any AEs that occurred during the sub-study and were associated with QUILT-3.032 were to be collected and handled per the QUILT-3.032 protocol. This PK sub-study was designed to evaluate the pharmacokinetic (PK) profile of intravesical N-803 in combination with BCG in patients with high grade NMIBC. All AEs were to be reported in the respective main studies, and the only data collected in this study were related to the primary endpoints in QUILT-3.032-2.005-PK.