Adult participants must be 18 years of age or older

Advanced or metastatic solid tumors excluding primary central nervous system (CNS) tumors

For Module 1 only, Have documented evidence of BRCA1/2 and/or genetic alterations conferring homologous recombination deficiency (HRD) (ATM, BARD1, BRIP1, CDK12, CHEK1, CHEK2, FANCL, PALB2, PPP2R2A, RAD51B, RAD51C, RAD51D, RAD54L, NBN, FANCA)

For Module 2 only, results of MSI and/or MMR testing required.

For Module 2 only, results of BRCA1/2 and HRD gene testing required.

Participant must have progressed on at least one prior line of therapy in the advanced or metastatic setting that is considered an appropriate standard of care, or for which the participant has documented intolerance

For Module 2 only, advanced or metastatic Endometrial Cancer (uterine carcinosarcoma is excluded)

For Module 2 only, Must have progressed on treatment with an anti-PD-1/L1 monoclonal antibody (MAB)

Known primary CNS malignancy

Impairment of GI function or GI disease that may significantly alter the absorption of IDE161

Have active, uncontrolled infection

Clinically significant cardiac abnormalities

Major surgery within 4 weeks prior to enrollment

Radiation therapy within 2 weeks prior to enrollment

Systemic cytotoxic chemotherapy within 4 weeks prior to enrollment

Radioimmunotherapy within 6 weeks of enrollment

Treatment with a therapeutic antibody within 4 weeks prior to enrollment

Treatment with an anti-cancer small molecule within 5 half-lives (t1/2), or 2 weeks, whichever is shorter

Have current active liver or biliary disease

For Module 2 only, History or allogeneic tissue/solid organ transplant

For Module 2 only, Active autoimmune disease that has required systemic treatment in past 2 years

For Module 2 only, History of (noninfectious) pneumonitis/interstitial lung disease that required steroids or has current pneumonitis/interstitial lung disease