8.3 Metastatic RCC & Targeted / Immunotherapy Regimens

8.3 Metastatic RCC & Targeted / Immunotherapy Regimens

RCC may present with synchronous metastases or recur after curative-intent surgery. Common metastatic sites include the lungs, bones, liver, brain and distant lymph nodes. Over the last decade, the management of metastatic clear cell RCC (mRCC) has undergone a dramatic therapeutic revolution: shifting from historical cytokine therapy (interferon-α, interleukin-2) to anti-angiogenic VEGF receptor tyrosine kinase inhibitors (VEGFR-TKIs), and ultimately to dual immune checkpoint inhibitors (ICIs) and combination ICI + VEGFR-TKI regimens that yield durable complete responses and significantly prolong overall survival.

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1. Prognostic Risk Stratification: The IMDC (Heng) Model

Accurate prognostic risk stratification is the mandatory first step before selecting systemic therapy or considering cytoreductive surgery in mRCC. While the historical Memorial Sloan Kettering Cancer Center (MSKCC / Motzer) score guided the cytokine and early TKI era, the International Metastatic RCC Database Consortium (IMDC / Heng) model is the globally accepted standard in contemporary urology.

The Six IMDC Adverse Risk Factors

1. Karnofsky Performance Status (KPS): < 80% (indicates impaired functional independence).
2. Time to Systemic Therapy: < 1 year from the initial histological diagnosis of RCC to the initiation of systemic treatment (reflects aggressive disease biology).
3. Serum Hemoglobin: Less than the laboratory lower limit of normal (LLN).
4. Corrected Serum Calcium: Greater than the laboratory upper limit of normal (ULN); do not substitute a universal 2.50 mmol/L cut-off:
   • Corrected Calcium (mg/dL) = Total Calcium (mg/dL) + 0.8 × [4.0 - Serum Albumin (g/dL)]
5. Platelet Count: Greater than the upper limit of normal (thrombocytosis, driven by IL-6 production).
6. Absolute Neutrophil Count (ANC): Greater than the upper limit of normal (neutrophilia, reflecting systemic inflammatory activation).

IMDC Prognostic Groups & Outcomes

• Favourable Risk: 0 adverse factors.
• Intermediate Risk: 1–2 adverse factors.
• Poor Risk: 3–6 adverse factors.

The original external validation cohort, largely treated in the VEGF-targeted era, had median OS of 43.2, 22.5 and 7.8 months, respectively. These are historical cohort estimates, not individual forecasts under modern ICI combinations.

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2. Cytoreductive Nephrectomy (CN): The Post-CARMENA Paradigm

Historically, two landmark randomized trials in the interferon-α era (SWOG 8949 and EORTC 30947) established upfront cytoreductive nephrectomy (removal of the primary kidney tumour in the presence of metastatic disease) as standard of care, demonstrating a modest 3- to 6-month overall survival benefit. However, the introduction of potent anti-VEGF targeted agents and immune checkpoint inhibitors demanded a rigorous re-evaluation of this surgical premise.

The CARMENA Trial

• Design: A prospective, randomized, open-label, non-inferiority phase 3 trial comparing sunitinib alone versus upfront cytoreductive nephrectomy followed by sunitinib in patients with synchronous clear cell mRCC of MSKCC intermediate or poor risk who were candidates for nephrectomy and systemic therapy.
• Results: Sunitinib alone was non-inferior to cytoreductive nephrectomy followed by sunitinib for overall survival. In the intention-to-treat population, median OS was 18.4 months for sunitinib alone versus 13.9 months for nephrectomy followed by sunitinib.
• Interpretation: In the MSKCC poor-risk subgroup, median OS was 13.3 months with sunitinib alone versus 10.2 months after immediate CN; this was not proof of statistically significant surgical harm. The trial supports avoiding routine immediate CN when systemic treatment is needed, rather than excluding surgery in every metastatic patient.

The SURTIME Trial

• Design: Evaluated immediate cytoreductive nephrectomy followed by sunitinib versus deferred cytoreductive nephrectomy (initiating 3 cycles of sunitinib, followed by nephrectomy in non-progressing responders, followed by continuation of sunitinib).
• Results: Poor accrual left only 99 patients. The 28-week progression-free rate was similar (43% deferred vs 42% immediate). Median OS of 32.4 vs 15.0 months favoured deferral in a secondary, exploratory analysis. Initial systemic therapy can identify early progressors for whom CN is inappropriate.

Contemporary EAU Recommendations for Cytoreductive Nephrectomy

1. Poor risk: Do not perform CN; prioritize appropriate systemic and supportive care.
2. Intermediate risk needing systemic treatment with an asymptomatic primary: Start systemic therapy first. Discuss delayed CN if there is clinical benefit and the patient remains suitable.
3. Selected patients not requiring systemic therapy: Immediate CN can be considered with good performance status, or when oligometastases can all receive complete local treatment. Selection is not restricted to favourable risk or lung metastases.

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3. First-Line Systemic Therapy Landscape

ICI combinations are central to first-line clear cell mRCC treatment. EAU also lists sunitinib or pazopanib as options in favourable-risk disease and recommends them when ICI cannot be received or tolerated. Comorbidity, prior adjuvant therapy, disease tempo and patient preference influence selection.

Dual Immune Checkpoint Inhibition (ICI + ICI)

• Regimen: Nivolumab (anti-PD-1) plus Ipilimumab (anti-CTLA-4) (CheckMate 214 trial).
• Dosing: Nivolumab 3 mg/kg IV plus Ipilimumab 1 mg/kg IV every 3 weeks for 4 induction doses, followed by single-agent Nivolumab maintenance.
• Clinical Indications: Standard first-line therapy for IMDC Intermediate- and Poor-Risk patients.
• Efficacy: Demonstrates significant overall survival superiority over sunitinib in intermediate/poor risk (5-year OS ~43% vs 31%) and achieves a complete response (CR) rate of 11% to 12%, with durable long-term treatment-free remissions.
• Favourable Risk: Initial CheckMate214 response and PFS results favoured sunitinib. Longer follow-up showed durable complete responses with nivolumab–ipilimumab, leading EAU2026 to list it as an alternative. This subgroup was exploratory; the EU first-line authorization for the combination remains intermediate/poor risk.

Combination ICI plus VEGFR-TKI Regimens

Combining an anti-PD-1 antibody with an anti-angiogenic VEGFR-TKI produces synergistic anti-tumour activity: VEGF blockade normalizes abnormal tumour vasculature and reverses endothelial cell-mediated immune suppression, enhancing T-cell tumoral infiltration. These regimens demonstrate broad clinical efficacy across all IMDC risk categories (Favourable, Intermediate, and Poor):

1. Pembrolizumab + Axitinib (KEYNOTE-426 trial):
   • Combines anti-PD-1 (pembrolizumab 200 mg IV q3w) with a potent, selective VEGFR-1/2/3 inhibitor (axitinib 5 mg PO BID).
   • Superior OS, PFS, and objective response rate (original ORR 59.3% vs 35.7%) compared to sunitinib monotherapy.
2. Nivolumab + Cabozantinib (CheckMate 9ER trial):
   • Combines nivolumab (240 mg IV q2w) with cabozantinib (40 mg PO daily; inhibits VEGFR2, MET, and AXL).
   • Doubled median progression-free survival (16.6 vs 8.3 months) and significantly reduced the risk of death compared to sunitinib.
3. Pembrolizumab + Lenvatinib (CLEAR trial):
   • Combines pembrolizumab (200 mg IV q3w) with lenvatinib (20 mg PO daily; targets VEGFR1-3, FGFR1-4, PDGFRα, RET, and KIT).
   • In the original CLEAR analysis, median PFS was 23.9 vs 9.2 months with sunitinib; ORR was 71% and complete response 16%.

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4. Second-Line and Subsequent Therapies

Upon disease progression following first-line ICI-based therapy, subsequent therapeutic selection depends on the prior regimen administered:

• After ICI combinations: Use an appropriate unused VEGFR-TKI, commonly cabozantinib (monotherapy dose 60 mg PO daily). METEOR established its survival benefit after prior VEGF-targeted therapy, rather than directly after modern ICI combinations. Lenvatinib–everolimus is another selected later-line option.
• Tivozanib: TIVO-3 demonstrated better PFS than sorafenib after two or three previous regimens. This later-line evidence differs from its EU authorization for first-line treatment or after one cytokine regimen in VEGFR/mTOR-inhibitor-naive patients.
• Belzutifan (Welireg): Oral HIF-2α inhibitor. LITESPARK-005 improved PFS and response versus everolimus after ICI and VEGFR-TKI treatment, without a significant OS advantage. The EU monotherapy indication requires progression after at least two lines including a PD-(L)1 inhibitor and at least two VEGF-targeted therapies. Monitor for anemia and hypoxia.

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5. Management of Treatment-Related Toxicities

Immune-Related Adverse Events (irAEs)

Immune checkpoint inhibitors unleash autoimmune attacks across any physiological organ system:

• Colitis & Enteritis: Diarrhea, abdominal pain or bleeding requires assessment for infection and immune toxicity. Withhold ICI for grade2 disease and use corticosteroids when indicated. Severe disease warrants admission and methylprednisolone-equivalent 1–2 mg/kg/day. Under the European nivolumab–ipilimumab product information, grade3/4 colitis requires permanent discontinuation; grade3 during nivolumab monotherapy can instead be withheld pending recovery. Steroid-refractory or severely ulcerative colitis may need infliximab 5 mg/kg or vedolizumab with specialist input.
• Autoimmune Hepatitis: Manifests as asymptomatic elevations in AST, ALT, and bilirubin. Managed with high-dose corticosteroids. Infliximab is strictly contraindicated in autoimmune hepatitis due to severe idiosyncratic hepatotoxicity; the immunosuppressant of choice for steroid-refractory hepatitis is mycophenolate mofetil.
• Endocrinopathies: Hypophysitis (pituitary inflammation with secondary adrenal/thyroid failure), primary adrenal insufficiency, and thyroiditis. Hormone deficits often persist and require replacement; when adrenal and thyroid deficiencies coexist, give glucocorticoid before levothyroxine. Withhold ICI during unstable illness; controlled endocrinopathy does not necessarily require permanent discontinuation.

VEGFR-TKI Class Toxicities

• Common adverse effects: Secondary arterial hypertension (managed with ACE inhibitors or calcium channel blockers), palmar-plantar erythrodysesthesia (hand-foot skin reaction: painful erythematous blisters on weight-bearing points, managed with keratolytics and dose reduction), fatigue, diarrhea, stomatitis, and hypothyroidism.

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6. IMDC Risk Criteria & First-Line Therapy Algorithm