Akkermansia muciniphila is a naturally occurring bacterium found in the healthy human gastrointestinal tract.

Analysis of the gut microbiota of NSCLC or RCC patients shows that the presence of Akkermansia is associated with the clinical efficacy of immunotherapy. In preclinical models, oral administration of the Akkermansia p2261 strain reverses resistance to PD-1 blockade. In the clinical setting, it is therefore hypothesized that the oral administration of Oncobax®-AK to cancer patients under immunotherapy, but whose gut microbiota is deficient in Akkermansia will restore / improve the efficacy of immunotherapy in patients with NSCLC or RCC.

Inclusion Criteria:

1. Age > 18 years
2. Histologically confirmed Stage IV non-squamous NSCLC or clear cell RCC
3. NSCLC-specific criterion: Best tumor response (by iRECIST) as Stable Disease
4. NSCLC-specific criterion: PD-L1 expression > 50%
5. ECOG Performance Status = 0-1
6. Negative stool PCR test for Akkermansia
7. At least one measurable lesion per iRECIST
8. Hemoglobin ≥ 100 g/L
9. Albumin > 35 g/L
10. Signed informed consent

Exclusion Criteria:

1. Symptomatic brain metastases
2. AST or ALT > 5 x ULN
3. Calculated creatinine clearance < 45 ml/min
4. Auto-immune diseases requiring systemic therapy
5. Immunosuppressive therapy (> 10 mg prednisone/day equivalent)
6. Radiotherapy (> 30 Gy) to the lung(s) within 6 months of signed informed consent
7. Active infection
8. Co-morbidities that may increase the risk of treatment-related adverse events
9. Pregnancy
10. Inability to comply with protocol-specific assessments