The AFERBIO study will evaluates safety and potential benefit of AferBio® in patients with non-small cell lung cancer undergoing at least a second-line palliative monochemotherapy. AferBio® is a fermented supplement in powder form obtained through biotechnological processes developed in Brazil. In this double-blind placebo-controlled randomized clinical trial, participants starting a new palliative regimen will be allocated to AferBio® or placebo. The primary aim will be to compare health-related QOL scores among the arms of the study over time.

Inclusion Criteria:

• Age above or equal to 18 years, and below 75 years;

• Diagnosis of metastatic or recurrent NSCLC, beginning second-line palliative mono-chemotherapy treatment;

• Functional capacity (ECOG-PS) grade 0 - 2;

• Adequate hematological, kidney and liver function, as follows:

  • Total neutrophil count ≥ 1500/μL
  • Platelet count ≥ 100.000/μL
  • Hemoglobin ≥ 9 g/dL
  • Serum bilirubin ≤ 1.5 × upper limit of normal (ULN)
  • Patients with confirmed Gilbert's syndrome and serum bilirubin ≤ 3 × ULN

• Aspartate aminotransferase (AST), alanine transaminase (ALT), alkaline phosphatase ≤ 1.5 × ULN, serum creatinine ≤ 1.5 × ULN, or creatinine clearance ≥ 50 mL/min based on the Cockcroft-Gault equation:

  (140 - age) × (weight in Kkg) × (0.85) 72 × (serum creatinine in mg/dL)

• Absence of any emotional, family-related, sociological, or geographic condition that can potentially hamper adherence to the study protocol and the follow-up schedule;

• Capacity and willingness to adhere to the study visits and tests, and to adhere to the protocol, according to the researcher's evaluation.

Exclusion Criteria:

• Tube feeding, gastrostomy- or jejunostomy;
• Uncontrollable vomiting;
• Sexually active women of reproductive age, except for those who underwent surgical sterilization (e. g., tubal ligation);
• Intestinal obstruction or sub-obstruction;
• Known allergy to any of the components of the investigational product;
• Malabsorption syndrome or other condition that could interfere with enteric absorption;
• History of inflammation of the small or large intestine, previous or currently active (such as Crohn's disease or ulcerative colitis);
• Chronic diarrhea of any cause;
• Diagnosis of any chronic disease that, in the researcher's opinion, will interfere with the participation in the study;
• Known diagnosis of HIV -infection;
• Diagnosis of any chronic disease that changes the immune system and significantly increases the risk of infection;
• The need to use G-CSF already in the first chemotherapy cycle;
• Severe neuropsychiatric disease that prevents the patient from completing the study questionnaires, determined at the researcher's discretion.