Pirfenidone is an oral medication approved to slow lung scarring, now studied as a cancer treatment. It can soften the scar-like wall around tumors, potentially helping chemotherapy and the immune system work better. Lab and animal results are promising, mostly alongside chemotherapy, but no human study has yet shown it improves cancer outcomes. (Full Review)

Protocol

Maintenance Dose

801 mg three times daily

2,403 mg/day total, taken with food

Titration

Escalate over 2 weeks

Start low and titrate to the maintenance dose

Setting

Investigational, trial-only

Added to chemotherapy or immunotherapy; off-label for cancer

Time to effect

Chemotherapy Benefit

Weeks to months

Any benefit assessed over chemotherapy cycles

Tumor Response

Every 6–12 weeks

Imaging in a trial setting, aligned with chemotherapy cycles

Benefits

Low: Enhanced chemotherapy penetration and efficacy; reduced tumor scarring; suppression of metastasis and invasion

Speculative: Improved response to immunotherapy; lung cancer risk reduction in fibrosis patients

Contraindications

Severe liver impairment (Child-Pugh Class C)

Severe kidney impairment or end-stage renal disease

Known hypersensitivity to pirfenidone

Strong CYP1A2 inhibitors (fluvoxamine)

Pregnancy and breastfeeding

Key Interactions

CYP1A2 inhibitors (fluvoxamine, ciprofloxacin)

CYP1A2 inducers (cigarette smoke, rifampin, omeprazole)

Antacids, proton-pump inhibitors (omeprazole), NSAIDs

Photosensitizing supplements (St. John's Wort, high-dose niacin)

Hepatotoxic supplements (high-dose green tea extract, kava)

Chemotherapy and immunotherapy (cisplatin, carboplatin/paclitaxel, gemcitabine, doxorubicin, PD-1/PD-L1 inhibitors)

Risk & Side Effects

High: Gastrointestinal disturbance; photosensitivity and skin reactions

Medium: Liver enzyme elevation; fatigue, dizziness, and weight loss

Speculative: Potential to promote tumor progression in some contexts; additive immunosuppression or infection risk

Monitoring

Marker	Target	Why
ALT (alanine aminotransferase)	< 25 U/L (men), < 20 U/L (women)	Detects drug-related liver stress
AST (aspartate aminotransferase)	< 25 U/L	Confirms liver injury alongside ALT
Bilirubin (total)	< 1.0 mg/dL	Flags significant liver dysfunction
eGFR (estimated glomerular filtration rate)	> 90 mL/min/1.73m²	Confirms adequate kidney clearance
CBC (complete blood count)	Within normal limits	Tracks chemotherapy-related toxicity when combined

Cadence: Liver function tests monthly for the first 6 months, then every 3 months; tumor response by imaging every 6–12 weeks in a trial setting.

Qualitative Assessment

Nausea and appetite
Energy levels
Skin reactions
Weight

Pirfenidone to Treat Cancer

Protocol

Benefits

Risk & Side Effects

Monitoring

Qualitative Assessment