Efficacy and Safety Study of Niraparib in Melanoma With Genetic Homologous Recombination (HR) Mutation

Inclusion Criteria:

* Have genetic homologous recombination (HR) mutation/ alteration including ARID1A/B, ARID2, ATM, ATR, ATRX, BARD1, BRCA1/2, BAP1, BRIP1, CHEK2, FANCD2, MRN11A, PALB2, RAD50, RAD51, RAD54B
* Disease must have progressed on the standard systemic therapies or they could not have tolerated the standard therapies.
* ECOG PS \>/=1
* Have measurable metastatic disease according to RECIST 1.1
* Prior systemic cytotoxic therapy up to 1 regimens is allowed; There is no limit on the number of prior immunotherapy or targeted therapy regimens.
* All adverse events associated with prior treatment must have resolved to ≤ Grade 1 prior to day 1 of the study drug administration.

Exclusion Criteria:

* Previously treated with a PARP inhibitor
* Symptomatic brain metastasis or active brain lesions ≥6 mm size or those
* Require steroid treatment for brain lesions or leptomeningeal disease
* Systemic cancer therapy within 14 days prior to day 1 of the study drug administration
* Any major surgery ≤ 3 weeks of starting the study and patient must have recovered from any effects of any major surgery
* Investigational therapy administered ≤ 4 weeks, or within a time interval less than at least 5 half-lives of the investigational
* Prior radiotherapy encompassing \> 20% of the bone marrow within 2 weeks; or any radiation therapy within 1 week prior to Day 1 of protocol therapy
* Medical history of immunocompromised condition
* Systemic treatment of another type of cancer ≤ 2 years prior to registration
* Known history of myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML)