Table 2. Combination radiotherapy and immune checkpoint blockade clinical trials in metastatic breast cancer.

HR+/HER2−, hormone receptor-positive/human epidermal growth factor receptor 2-negative; mBC, metastatic breast cancer; mNSCLC, metastatic non-small cell lung cancer; mTNBC, metastatic triple negative breast cancer; NCT, national clinical trial; RT, radiation therapy; SBRT, stereotactic body radiotherapy; SRS, stereotactic radiosurgery.

NCT Number	Phase	N	Status	Tumor Type	Intervention	Sponsor
NCT03004183	2	57	Recruiting	mTNBC or mNSCLC	ADV/HSV-tk + Valacyclovir + Pembrolizumab + SBRT (30 Gy in 5 fractions)	Houston Methodist Cancer Center
NCT03449238	1/2	41	Recruiting	mBC with brain metastases	Pembrolizumab + SRS	Weill Cornell College of Cornell University
NCT03464942	2	52	Recruiting	mTNBC	Atezolizumab + SBRT (20 Gy in 1 fraction or 24 Gy in 3 fractions)	Peter MacCallum Cancer Centre, Australia; Trans Tasman Radiation Oncology Group, TROG
NCT03524170	1	20	Recruiting	HR+/HER2− mBC	M7824 (Anti-PDL1/TGFβ Trap) + RT	MD Anderson Cancer Center
NCT03789097	1/2	56	Recruiting	Multiple tumor types, including mBC	Pembrolizumab + CDX-301 (Flt3 ligand) + RT + Poly ICLC (TLR3 agonist)	Icahn School of Medicine at Mount Sinai
NCT03915678	2	247	Not yet recruiting	Multiple tumor types, including mTNBC	BDB001 (TLR7/8 agonist) + Pembrolizumab + SBRT (27-60 Gy in 3-5 fractions)	Institut Bergonié
NCT04683679	2	56	Not yet recruiting	mTNBC	Olaparib + Pembrolizumab + SBRT (24-27 Gy in 3 fractions)	Memorial Sloan Kettering Cancer Center
NCT04690855	2	23	Not yet recruiting	mTNBC	Talazoparib + Atezolizumab + SBRT (24 Gy in 3 fractions)	Emory Winship Cancer Institute