A Study of mRNA-4106 Administered Alone and in Combination With Immune Checkpoint Blockade in Participants With Solid Tumors

Inclusion Criteria:

• Arm 1, Monotherapy Arm: Histologically confirmed advanced or metastatic cancer (melanoma, non-small cell lung cancer (NSCLC), hepatocellular carcinoma (HCC),esophageal carcinoma, head and neck squamous cell carcinoma (HNSCC), urinary bladdercancer (UBC), colon/rectal adenocarcinomas, gastric, ovarian, cervical, andendometrial carcinomas) with measurable disease as determined by RECIST v1.1 andhave completed or refused all standard therapies (no limit to prior lines oftherapy). Participants must have a tumor lesion amenable to biopsy, or alternativelyarchival tumor tissue is acceptable as long as the collection date is within oneyear of the enrollment date.

• Arm 2, Combination with Nivolumab/Relatlimab Arm: Histologically confirmedunresectable or metastatic melanoma, with measurable disease as determined by RECISTv1.1 and have not had any prior therapy for this cancer in this setting (that is,first-line therapy). Note that prior adjuvant, neoadjuvant, or perioperativemelanoma therapy (that is, anti-CTLA-4, anti-PD1/L1, BRAF/MEK inhibitors, orinterferon) is permitted if disease recurrence did not occur within 3 months fromthe last treatment date.

• Participant has an Eastern Cooperative Oncology Group (ECOG) performance status of ≤1.

• Participant has adequate hematological and biological function.

• Participants who could become pregnant: negative pregnancy test within 24 hoursbefore the first dose of study treatment.

Exclusion Criteria:

• Participant has active central nervous system tumors or metastases

• Participant has received treatment with prohibited medications/treatments (ie,concurrent anticancer therapy including other chemotherapy, hormonal anticancertherapy, biologic therapy, or immunotherapy) or investigational agents within 5half-lives or 14 days prior to the first day of study treatment (Cycle 1 Day 1),whichever is shorter.

• Participant has required the use of immunosuppressive doses of systemic steroids orabsorbed topical steroids (doses >10 mg prednisone daily equivalent) within 2 weeksbefore study treatment administration or currently requiring maintenance doses of >10 mg prednisone or equivalent per day.

• Participant has any plan to receive a live attenuated vaccine during study treatmentor has received a live vaccine within 30 days before the first dose of studytreatment.

• Participant has reversible toxicities from prior cancer therapy that have notrecovered to Grade 1 or baseline. Any unresolved toxicity National Cancer Institute (NCI) Common Terminology Criteria for AEs (CTCAE) Grade ≥2 from previous anticancertherapy with the exception of alopecia, vitiligo, and prespecified laboratoryvalues.

• Participant has any unstable or clinically significant concurrentmedical/psychiatric illness or social situation that would limit compliance withstudy requirements or compromise the ability of the participant to provide writteninformed consent, per the discretion of the Investigator.

• Participant has concurrent enrollment in another clinical study (unless it is anobservational noninterventional clinical study).

Note: Other inclusion and exclusion criteria may apply.