This research study is a Phase I clinical trial, which tests the safety of an investigational drug and also tries to define the appropriate dose of the investigational drug to use for further studies. Investigational means that the drug is being studied.~The FDA (the U.S. Food and Drug Administration) has not approved niraparib for this specific disease but it has been approved for other uses.~The FDA has approved osimertinib as a treatment option for this disease.~Niraparib is a type of drug called a PARP inhibitor, which blocks DNA (the genetic material of cells) damage from being repaired or may prevent damage from occurring in the first place. In cancer treatment, inhibiting PARP may help kill cancer cells through deadly DNA damage. PARP inhibition may be a treatment option for participants with this type of cancer due to altered repair and protection of tumor DNA.~Osimertinib is an inhibitor of the epidermal growth factor receptor (EGFR). In this type of cancer there is a mutation in the EGFR which is allowing the cancer to grow when it is not supposed to. Osimertinib blocks mutated EGFR, which may cause tumor regression (when the tumor starts to shrink) and prevent the spread of the cancer.~In this research study, the investigators are looking to see whether the combination of niraparib and osimertinib is safe and well tolerated and what the best dose of niraparib is in participants with EGFR-Mutated Advanced Lung Cancer. The investigators also hope that the combination of niraparib and osimertinib will stop the cancer from growing and spreading.
This research study is studying a combination of drugs as a possible treatment for EGFR-Mutated Advanced Lung Cancer.~The names of the study drugs involved in this study are Niraparib and Osimertinib.