Immunotherapy SBRT Sensitization of the Programmed Death-1 (PD-1) Effect

Blockade of the PD-1/PD-L1 T-cell checkpoint pathway is an effective and well tolerated approach to stimulating the immune response which is a critical option in the treatment of metastatic NSCLC. However, progression free survival (PFS) is increased by only 2-4 months and median overall survival (OS) by 3-9 months.

There is compelling evidence that PFS is increased up to 3 fold and OS by 2 fold in patients receiving a course of radiation therapy while on immunotherapy. Radiotherapy is known to induce immunogenic tumor cell death and upregulation of dendritic cells and antigen presentation leading to activation of cytotoxic T-Cells. Dramatic T-cell activation has been demonstrated where tumor regression occurs outside the radiation treatment field in a phenomenon termed the abscopal effect and is associated with high dose radiation delivered via SBRT.

As such, SBRT activation of T-cells could be complementary to immunotherapy and enhance T-cell mediated killing via PD-L1 blockade which could lead to lasting and durable tumor response with improved progression free survival and overall survival.

Inclusion criteria

• Histologically or cytologically confirmed Stage IV NSCLC according to the 7th AJCC staging manual.
• Eligible for an immunotherapy agent. Patients who progress after drug therapy (3 months) for ALK, EGFR or ROS mutation positive lung cancer are eligible.
• At least 2 lesions that are safely amenable to SBRT. ECOG <=2.
• At least 1 measurable lesion according to Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 criteria for response assessment or at least 1 lesion with FDG avidity and CT correlate that can be monitored for PET-CT response by SUV Max increase or decrease.
• Normal Hepatic and renal function.
• Bone marrow reserve:

• ANC ≥ 1.5 x 109/L
• Hemoglobin ≥9.0 g/dL
• Platelet count ≥75 x 109/L
• Ability to comply with follow-up visits and evaluations, treatment planning and studies and other study related procedures and visits.
• Ability to sign informed consent.

Exclusion criteria

• Patients with active CNS metastases
• Active, known or suspected auto-immune disease.
• Patients with medical conditions that require systemic immunosuppression.
• Patients with a history of interstitial lung disease.
• Prior treatment with immune checkpoint inhibitors/immonotherapy.
• Other active malignancy requiring intervention.
• Prior lung radiation, with the only metastatic targets in the lungs.
• Unresolved toxicity from prior chemotherapy or anti-cancer treatment.
• Current or prior enrollment in clinical trial with an investigational drug within 4 weeks.
• Pregnancy or positive pregnancy test.