A Phase 1 Study of IM-1021 in Participants With Advanced Cancer

Inclusion Criteria:

1. Informed consent signed by the participant prior to conducting study-specificprocedures

2. ≥18 years of age

3. Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1, or 2

4. Histological or cytological diagnosis of: Part A: advanced B-cell lymphomas or solid tumors, of the following subtypes: B-cell Lymphomas:

• Mantle cell lymphoma (MCL)

• Diffuse large B-cell lymphoma (DLBCL) (including Richter's transformation)

• Follicular lymphoma

• Small lymphocytic lymphoma (SLL) Solid Tumors:

• Pancreatic cancer

• Non-squamous non-small cell lung cancer (NSCLC)

• Malignant mesothelioma

• Epithelial ovarian cancer. Participants with fallopian tube and/or peritonealmalignancies are also eligible.

• Triple-negative breast cancer.

• Liposarcoma Other, unlisted histologies, if approved by the Sponsor Medical Monitor Part B Cohorts B1, B2, and B3: Histological or cytological diagnosis of the cohort-specific disease indication.Indications may include those listed in Inclusion Criterion 4.a

5. Participants must have adequate organ function.

6. Participants must have a negative pregnancy test, be willing to practice highlyeffective methods of birth control, use condoms, and refrain from oocyte/spermdonation, as applicable, as detailed in the protocol.

7. Participants must be refractory to or have relapsed after at least one priorstandard therapeutic regimen. Participants must be relapsed or refractory to, havedeveloped an intolerance to, or not be candidates for available therapies withestablished benefit. Participants with B-cell malignancies should have received atleast two lines of therapy, including available therapies with established benefit.Participants with SLL should have received at least three prior lines of therapy.

8. Participants must have measurable disease as per the relevant response assessmentframework: Lugano Classification for lymphoma (except SLL) , per iwCLL criteria forSLL , and per RECIST v.1.1 for solid tumors.

Exclusion Criteria:

1. Previously treated with an ADC with a topoisomerase-1 inhibitor payload.

2. Previously received a ROR1-targeted therapy (eg, ADC, cell therapy, or monoclonalantibody).

3. History of an anaphylactic reaction to irinotecan or ≥ grade 3 GI toxicity to prioririnotecan.

4. Life expectancy < 12 weeks.

5. Prior solid organ transplant.

6. Participants with symptomatic ascites or pleural effusion. Participants who areclinically stable for at least 2 weeks following treatment for these conditions (including therapeutic thoraco- or paracentesis or catheter) are eligible.

7. Participant has a known active central nervous system (CNS) primary tumor ormetastases and/or carcinomatous meningitis. Participants with previously treatedbrain metastases may participate provided they are clinically stable for at least 4weeks prior to study entry, have no radiological evidence of new or enlarging brainmetastases, and are off steroids or on a stable dose up to an equivalent ofprednisone 10 mg/day for at least 15 days prior to first dose of study medication.Participants who have symptoms consistent with CNS metastasis must have a negativemagnetic resonance imaging (MRI) during the screening period.

8. Participant has a known history of malignant primary brain tumor, or another primarysolid or hematologic malignancy (other than that under study), unless theparticipant has undergone potentially curative therapy with no evidence of thatdisease for at least 2 years. Exception: The time requirement does not apply toparticipants who underwent successful definitive resection of certain cancers.

9. Participant has certain other significant medical conditions including cardiac,pulmonary, and infectious disease as detailed in the protocol.

10. Participant is pregnant, breastfeeding, or expecting to conceive within theprojected duration of the study.