Safety, PK and Efficacy of QXL138AM in Patients With Solid Tumors and Multiple Myeloma

Inclusion Criteria:

1. Participants with Solid Tumors

• Histopathologically confirmed diagnosis of an advanced, unresectable, ormetastatic solid tumor (ovarian, pancreatic, urothelial, renal, hepatocellular,gastrointestinal (GI), lung, prostate, and breast cancer).

• Have progressed despite standard therapies, or for whom conventional therapy isnot effective or tolerable, as judged by the Investigator. Patients must haveno available therapeutic options known to confer clinical benefit for theirtumor type.

2. Participants with Multiple Myeloma

• Have progressed despite standard therapies, or for whom conventional therapy isnot effective or tolerable, as judged by the Investigator.

• Patients must have failed at least 3 prior therapies for myeloma and shouldhave had prior exposure to a proteosome inhibitor, an IMiD, and ananti-CD38-directed therapy.

2. Male or female participants ≥18 years of age at the time of informed consent 3. AnEastern Cooperative Oncology Group (ECOG) performance status scale of 0, 1, or 2 atScreening 4. Must have at least 1 measurable lesion by RECIST version 1.1 (solidtumors only), or evaluable disease by IMWG Uniform Response Criteria (multiplemyeloma only) 5. Adequate organ function and bone marrow reserve 6. Adequate cardiacfunction as estimated by left ventricular ejection fraction 7. Female participantsof child-bearing potential must:

• Have a negative serum pregnancy test at screening and a negative pregnancy test atWeek 1 Day 1 prior to first dose of QXL138AM, AND

• Agree to use at least 1 highly effective method of contraception for the duration ofstudy participation, and for 120 days after last dose of QXL138AM.

8. Male participants of child-bearing potential must:

• Agree to use at least 1 highly effective method of contraception for the duration ofstudy participation, and for 120 days after last dose of QXL138AM, AND

• Refrain from sperm donation prior to the first dose of investigational productthrough 120 days following the last dose of QXL138AM.

Exclusion Criteria:

1. New York Heart Association Class III or IV cardiac disease, myocardial infarctionwithin the past 6 months, unstable arrhythmia, a history of risk factors forTorsades de Pointes (TdP), including heart failure, hypokalemia, and family historyof long QTc syndrome, or evidence of ischemia on ECG. Symptomatic ischemic heart disease or unstable angina pectoris; or history ofcardiac angioplasty, cardiac stenting, or coronary artery bypass graft. A clinicallysignificant baseline prolongation of QT/QTcF interval at screening.

2. The use of concomitant medications that may significantly prolong the QT/QTcinterval.

3. Active, uncontrolled bacterial, viral, or fungal infections requiring systemictherapy.

4. Known hypersensitivity to the investigational product or components (anti-CD138 IgG1antibody, Interferon A2a and/or the formulation excipients: histidine, sucrose,arginine, polysorbate 80).

5. Female participant is lactating.

6. Any other clinically significant comorbidities.

7. Received prior anticancer therapy within 28 days or 5x the half-life (whichever isshorter) prior to the first dose of investigational product.

8. Participants who received wide-field radiation therapy within 4 weeks prior to firstdose of investigational product, (2 weeks for limited field radiation therapy)

9. Major surgery within 30 days before first dose of investigational product

10. Chronic use of systemic corticosteroids of more than 20 mg/day of prednisone orequivalent.

11. Active, clinically significant liver disease such as Hepatitis B or C, autoimmunehepatitis, or cirrhosis (Child Hugh Stage B or C).

12. Current or history of mood disorder such as major depression per DSM-5 within pasttwo years not controlled with current therapy.

13. Active autoimmune disorders not controlled with current therapy.

14. Active endocrine disorders including hypothyroidism, hyperthyroidism, hypoglycemia,hyperglycemia, and diabetes mellitus not controlled with current therapy.