⁸⁹Zr-Df-IAB22M2C (CD8 PET Tracer) for PET/CT in Patients With Metastatic Solid Tumors

Protocol IAB-CD8-201 is a Phase II, Open Label, Multi-Dose Study of Positron Emission
Tomography (PET/CT) with ⁸⁹Zr-Df-IAB22M2C (CD8 Tracer) in Patients with Metastatic Solid
Tumors. This study will evaluate the safety of repeat doses of ⁸⁹Zr-Df-IAB22M2C, assess and
quantify any detectable changes in ⁸⁹Zr-Df-IAB22M2C uptake from Baseline to post-Treatment,
establish the relationship of ⁸⁹Zr-Df-IAB22M2C uptake in tumors with CD8+ TIL density,
biodistribution, evaluate the variance in participants' gene expression pre- and
post-Treatment, evaluate the correlation of ⁸⁹Zr-Df-IAB22M2C uptake with clinical response by
RECIST (Response evaluation criteria in solid tumors) version 1.1/iRECIST and evaluate the
correlation of ⁸⁹Zr-Df-IAB22M2C uptake with immune infiltrates and other molecular biomarkers
(CD4, CD8, PD-1 and PD-L1) expression by immunohistochemistry (IHC).

The investigational imaging agent to be administered in this study will be ⁸⁹Zr-Df-IAB22M2C
with whole body PET/CT imaging acquired within 1 week prior to the onset of cancer treatment
and 4-5 weeks after start of cancer treatment. Approximately 40 participants are planned to
be enrolled in this clinical study.

Participants should expect to have Convention CT Chest, Abdomen and Pelvis or Magnetic
resonance imaging (MRI) and/or whole body ¹⁸FDG-PET scan performed within 45 days prior to
1st infusion of ⁸⁹Zr-Df-IAB22M2C; PET/CT scans at 24±3 hours after each infusion of
⁸⁹Zr-Df-IAB22M2C; and fresh tumor biopsy (1 to 3 core biopsies) at Baseline and within 0 to 2
weeks after 2nd infusion of ⁸⁹Zr-Df-IAB22M2C and its associated PET/CT scan.

In addition, anti-drug antibody (ADA) blood samples will be collected at the following time
points: at Baseline, prior to receiving the 2nd infusion of ⁸⁹Zr-Df-IAB22M2C, and at
End-of-Study safety follow-up visit.

At each study visit, participants will be questioned concerning any new medications or
changes in current medications including over-the-counter and topical medications.

The safety monitoring practices employed by this protocol are adequate to protect the
participants' safety and should detect all Treatment Emergent Adverse Events (TEAEs). The
safety follow-up (4-5 weeks after the last dose of ⁸⁹Zr-Df-IAB22M2C) and the extended
follow-up (up to 1 year after start of cancer treatment) were also established.

A participant who completes Visit 9 will be considered to have completed the study. All
participants have the right to withdraw at their own request at any point during the study
without prejudice. Although participants do not need to give a reason for requesting
withdrawal from the trial, the Investigator should make a reasonable effort to ascertain the
reason(s), while fully respecting the participant's rights.

A Statistical Analysis Plan (SAP) will be developed and approved before the database is
locked. The SAP will present the detailed statistical methodology to be used in analyzing the
efficacy and tabulating the safety data from this trial. All inferential statistical analyses
will be based on a two-sided test with a Type I error rate of 0.05. The primary analysis of
the primary and secondary outcome measures will be conducted using the Per Protocol (PP)
population. Analyses of safety outcomes will be conducted using the safety population.
Adverse events will be coded using the most recent version of MedDRA. TEAEs will be
summarized by treatment group and by stage in the study, System Organ Class, and preferred
term. In addition, all the data from physical examination, 12 Lead Electrocardiogram (ECG)
and vital signs will also be descriptively summarized. The final statistical analysis of data
will be performed after all clinical monitoring has been completed, all data queries have
been resolved, and all data have been verified (Quality Control checked) prior to formal
database lock. The Sponsor will authorize the final database lock.

For quality control and quality assurance purpose, the Sponsor's designated monitor will
visit the center(s) during the study as well as maintain frequent telephone and written
communication to maintain current personal knowledge of the progress of a study. The
Investigator will permit the Sponsor to monitor the study as frequently as is deemed
necessary and provide access to medical records to ensure that data are being recorded
adequately, that data are verifiable and that protocol adherence is satisfactory. The
Investigator will permit representatives of the Sponsor and/or designated Contract Research
Organization (CRO) to inspect all Case Report Forms (CRFs) and corresponding study
participant original medical records (source documents) at regular intervals throughout the
study. Site inspections serve to verify strict adherence to the protocol and the accuracy of
the data being entered on the CRFs, in accordance with federal regulations. A Monitoring Log
will be maintained at each study site that the monitor will sign, date, and state the type of
visit.

Inclusion Criteria:

Participants will be eligible for enrollment in the study only if they meet ALL of the
following criteria:

1. Patients with metastatic solid tumors with at least one non-radiated lesion.

2. At least 1 measurable lesion documented on CT/MRI (RECIST criteria 1.1) within 45 days
prior to first ⁸⁹Zr-Df-IAB22M2C infusion.

3. At least 1 non-cutaneous lesion that is accessible, per investigator's assessment, and
eligible for biopsy. If only a single RECIST measurable lesion is present,
investigator to determine if the tumor biopsy could interfere with RECIST assessments
of response.

4. Eastern Cooperative Oncology Group (ECOG) performance status ≤ 2.

5. Meeting all clinical safety lab values per institution's standard of care, or
Investigator's discretion, for patients receiving cancer treatment.

6. Age ≥ 18 years.

7. Ability to understand the purposes and risks of the trial and has signed an
IRB-approved informed consent form.

8. Willingness and ability to comply with all protocol required procedures.

9. For men and women of child-producing potential, use of effective double barrier
contraceptive methods during the study, up to 30 days after the last administration of
the investigational product.

Exclusion Criteria:

Participants will be eligible for enrollment in the study only if they meet NONE of the
following criteria:

1. Serious nonmalignant disease or conditions that in the opinion of the investigator
and/or ImaginAb could compromise protocol objectives.

2. Patients with a single RECIST measurable lesion, biopsy of which, per investigator's
assessment, is likely to interfere with RECIST assessments of response.

3. Patients who have any splenic disorders, or had splenectomy, that in the opinion of
the investigator and/or ImaginAb could compromise protocol objectives.

4. Pregnant women or nursing mothers.