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PI3Kα inhibitor

Inavolisib

Itovebi · PI3Kalpha inhibitor

PI3Kα inhibitor · approved 2024 · 4 references

PI3Kalpha inhibitor whose renal-relevant toxicity is metabolic, hyperglycemia and electrolyte shifts, not a defined kidney lesion

Signature injury
Electrolyte Disturbance
Severity
Moderate
Reversibility
Reversible
Onset
Hyperglycemia from PI3Kalpha inhibition is an on-target effect that can appear soon after dosing, sometimes with peak glucose elevations in the hours following ingestion, and typically reverses within days of holding the drug.

Signature kidney injury & incidence

Electrolyte Disturbance.

Direct nephrotoxicity from inavolisib is not prominent and renal-specific data are limited; the headline metabolic toxicity is on-target hyperglycemia. In the INAVO120 phase 3 trial, grade 3 or 4 hyperglycemia occurred in 5.6 percent of the inavolisib group versus 0 percent with placebo, alongside higher rates of stomatitis and diarrhea (which can secondarily cause volume and electrolyte loss). A defined inavolisib-specific kidney lesion with an established electrolyte-event incidence rate is not characterized, so no headline signature rate is charted (the 5.6% grade 3/4 hyperglycemia figure is a metabolic, not electrolyte, signal).

Source: 39476340

Reported injury signatures: Electrolyte Disturbance.

Onset timing & rechallenge

Hyperacute (<24 h) — On-target hyperglycemia appears soon after dosing, sometimes peaking within hours of ingestion, and reverses within days of holding.

Mechanism of kidney injury

PI3Kalpha is a central mediator of insulin signaling, so on-target inhibition causes insulin resistance and hyperglycemia as a class effect, the dominant metabolic toxicity rather than a structural renal lesion. Secondary electrolyte disturbances can arise from the hyperglycemia itself (osmotic shifts and glucosuria-driven losses) and from GI toxicity (stomatitis and diarrhea causing volume depletion with potassium and magnesium loss). True direct tubular or glomerular injury is not a recognized feature of inavolisib.

Clinical presentation

Most commonly new or worsened hyperglycemia detected on glucose monitoring, occasionally severe and recalcitrant, with associated risk of dehydration. Electrolyte abnormalities and prerenal-pattern changes, when present, generally track with hyperglycemia severity and GI fluid losses rather than with an intrinsic kidney lesion.

Management

Manage hyperglycemia per protocol with lifestyle measures and antihyperglycemics (metformin is commonly first-line; insulin's effect may be partly blunted by ongoing PI3K inhibition), and interrupt or dose-modify inavolisib for severe or refractory hyperglycemia. Correct electrolyte abnormalities and replete volume losses driven by GI toxicity. Monitor renal function in the context of these metabolic and volume disturbances rather than expecting a primary nephrotoxic lesion.

Risk factors

  • Pre-existing diabetes, prediabetes, or impaired fasting glucose
  • Obesity and metabolic syndrome
  • Concurrent glucocorticoids
  • Volume depletion from stomatitis/diarrhea (amplifies electrolyte and prerenal risk)

Prevention

  • Optimize glycemic control before the first dose
  • Dietary counseling and early involvement of endocrinology for at-risk patients
  • Proactive management of stomatitis and diarrhea to limit volume and electrolyte losses

Renal dose adjustment

Per the FDA label: no change for mild impairment (eGFR 60-89 mL/min, CKD-EPI); reduce from the 9 mg once-daily standard to 6 mg once daily for moderate (eGFR 30-59) and 3 mg once daily for severe (eGFR <30) impairment. Additional dose modification in practice is driven by hyperglycemia and GI toxicity.

Dialyzability & ESKD dosing

Not characterized. As a small-molecule oral agent, dialytic clearance data are not available; management of hyperglycemic emergencies follows standard metabolic principles.

Differential diagnosis

Distinguish on-target PI3Kalpha-inhibitor hyperglycemia from new-onset diabetes, steroid-induced hyperglycemia, and stress hyperglycemia. Electrolyte and creatinine changes should be attributed to hyperglycemia and GI fluid losses (prerenal physiology) rather than to a primary inavolisib nephrotoxic lesion, which is not an established entity.

Monitoring

  • Fasting glucose and HbA1c at baseline and periodically
  • Frequent glucose monitoring early in treatment and after dose changes
  • Serum electrolytes (including potassium and magnesium) and volume status, especially with stomatitis/diarrhea
  • Renal function in the setting of hyperglycemia or volume depletion

Key trials & series

  • INAVO120 (NCT04191499; Jhaveri/Turner et al., N Engl J Med 2024): phase 3, inavolisib plus palbociclib-fulvestrant vs placebo plus palbociclib-fulvestrant in PIK3CA-mutated HR-positive/HER2-negative advanced breast cancer; median PFS 15.0 vs 7.3 months (HR 0.43), with grade 3 or 4 hyperglycemia 5.6 percent vs 0 percent
  • Phase I/Ib dose-finding (NCT03006172; Jhaveri et al., J Clin Oncol 2024): established the inavolisib plus palbociclib plus endocrine therapy combination; most frequent treatment-related AEs were stomatitis, hyperglycemia, and diarrhea

Clinical pearls

  • Watch for secondary electrolyte and volume problems from stomatitis and diarrhea, which can produce prerenal changes that mimic kidney injury.
  • Renal-specific literature for inavolisib is limited; the class hyperglycemia evidence (e.g., alpelisib) carries most of the mechanistic weight.

Anticancer mechanism

Inavolisib is a highly potent, selective small-molecule inhibitor of the p110alpha catalytic subunit of PI3K (encoded by PIK3CA) that also promotes degradation of mutant p110alpha. By blocking and depleting oncogenic PI3Kalpha signaling it suppresses the PI3K/AKT/mTOR pathway that drives PIK3CA-mutated, HR-positive/HER2-negative breast cancer. It is used in combination with palbociclib and fulvestrant to overcome endocrine resistance.

Guidelines & consensus

Each recommendation below is this atlas's faithful summary of the source, not a quotation from it — follow the PubMed link for the wording the society published. Summaries may be superseded; consult the current full text and individualize to the patient.

  • ADQI (2026) — The nephrotoxic effects of anti-cancer therapies: consensus report of the 34th Acute Disease Quality Initiative workgroupProvides expert-based statements (modified Delphi) on preventing and managing cisplatin/platinum-associated AKI, including isotonic IV hydration, attention to volume status and concomitant nephrotoxins, and incorporates evidence that IV magnesium supplementation may reduce cisplatin-associated AKI; emphasizes risk stratification and standardized AKI definitions.Nat Rev Nephrol · PMID 41361704
  • SIRM (2022) — SIRM-SIN-AIOM: appropriateness criteria for evaluation and prevention of renal damage in the patient undergoing contrast medium examinations-consensus statements from Italian College of Radiology (SIRM), Italian College of Nephrology (SIN) and Italian Association of Medical Oncology (AIOM)Recommends eGFR-based renal risk assessment and pre/post-contrast isotonic saline or sodium bicarbonate hydration; advises maintaining a 5-7 day interval between iodinated contrast administration and cisplatin in cancer patients to reduce additive nephrotoxicity.Radiol Med · PMID 35303246
  • KDIGO (2020) — KDIGO Controversies Conference on onco-nephrology: understanding kidney impairment and solid-organ malignancies, and managing kidney cancerIdentifies platinum compounds (especially cisplatin) as leading cytotoxic causes of acute tubular injury, AKI, and electrolyte/magnesium wasting; calls for interdisciplinary onco-nephrology care, accurate GFR estimation, and individualized drug dosing in patients with reduced kidney function.Kidney Int · PMID 33126977
  • KDIGO (2020) — KDIGO Controversies Conference on onco-nephrology: kidney disease in hematological malignancies and the burden of cancer after kidney transplantationAddresses chemotherapy-associated AKI/CKD in hematologic cancer, GFR estimation and chemotherapy dosing in patients with reduced kidney function, and management priorities and research gaps for onco-nephrology care.Kidney Int · PMID 33276867
  • ADDIKD (2025) — Integrating International Consensus Guidelines for Anticancer Drug Dosing in Kidney Dysfunction (ADDIKD) into everyday practiceProvides GRADE-based, drug-specific dose-adjustment recommendations for anticancer agents in kidney dysfunction (illustrated for methotrexate, cisplatin, carboplatin and nivolumab); the recommendations build on Part 1's standardised CKD-EPI eGFR assessment rather than Cockcroft-Gault creatinine clearance.EClinicalMedicine · PMID 40290844
  • ADDIKD (2025) — Aligning kidney function assessment in patients with cancer to global practices in internal medicineThree consensus recommendations: assess kidney function by GFR (measured GFR or CKD-EPI eGFR), classify it using KDIGO categories, and use this uniform approach to dose anticancer drugs — moving cancer medicine away from Cockcroft-Gault estimated creatinine clearance.EClinicalMedicine · PMID 40290845
  • ADDIKD (2025) — A methodology for determining dosing recommendations for anticancer drugs in patients with reduced kidney functionEstablishes that, where RCT evidence is lacking, anticancer drug dosing recommendations in kidney dysfunction should be derived by critically appraising observational literature via GRADE combined with structured international multidisciplinary consensus voting.EClinicalMedicine · PMID 40290846
  • KDIGO (2013) — Diagnosis, evaluation, and management of acute kidney injury: a KDIGO summary (Part 1)Defines/stages AKI by serum creatinine and urine output; emphasizes avoiding nephrotoxins, maintaining euvolemia/perfusion, dose-adjusting drugs to kidney function, and monitoring high-risk patients — the framework applied to nephrotoxic anti-cancer agents.Crit Care · PMID 23394211
  • KDIGO (2024) — Executive summary of the KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease: known knowns and known unknownsEvaluate and risk-stratify CKD, manage to delay progression and its complications, and practise explicit medication management and drug stewardship — the framework the atlas's G1–G5 eGFR banding and every renal dose-adjustment recommendation sit inside. Because the guideline excludes dialysis and transplant recipients by its own statement of scope, its recommendations do not carry to those settings, where this atlas's dialyzability and post-transplant guidance rests on other sources.Kidney Int · PMID 38519239
  • KDIGO (2021) — Executive summary of the KDIGO 2021 Guideline for the Management of Glomerular DiseasesProvides the staging/treatment framework for drug-associated glomerular lesions (e.g., bisphosphonate- and interferon-related collapsing FSGS, VEGF-inhibitor podocytopathy/proteinuria), including immunosuppression and supportive RAAS-blockade strategies.Kidney Int · PMID 34556300
  • KDIGO (2024) — Executive summary of the KDIGO 2024 Clinical Practice Guideline for the Management of ANCA-Associated VasculitisUpdates immunosuppressive induction (rituximab/cyclophosphamide), incorporates avacopan and lower-dose or glucocorticoid-sparing regimens — the management framework for drug- and checkpoint-inhibitor-associated ANCA/pauci-immune glomerulonephritis.Kidney Int · PMID 38388147
  • KDIGO (2024) — Executive summary of the KDIGO 2024 Clinical Practice Guideline for the Management of Lupus NephritisUpdates first-line lupus nephritis therapy to combination immunosuppression with the addition of belimumab or a calcineurin inhibitor (voclosporin) — informs management of immune-complex/lupus-like glomerulonephritis encountered with immunotherapy.Kidney Int · PMID 38182299
  • KDIGO (2025) — Executive summary of the KDIGO 2025 Clinical Practice Guideline for the Management of Immunoglobulin A Nephropathy (IgAN) and Immunoglobulin A Vasculitis (IgAV)Encourages liberal kidney biopsy and stricter proteinuria control (<0.5 g/d, ideally <0.3 g/d) with RAAS blockers, SGLT2 inhibitors, and targeted-release budesonide — the framework for IgA-dominant glomerular lesions, including those triggered by immune-modulating cancer therapy.Kidney Int · PMID 40975525

References

4 peer-reviewed references. Citation metadata via PubMed / NLM.

  1. 1.Inavolisib-Based Therapy in PIK3CA-Mutated Advanced Breast Cancer.Turner NC, Im SA, Saura C, et al. · N Engl J Med · 2024 · PMID 39476340
  2. 2.Phase I/Ib Trial of Inavolisib Plus Palbociclib and Endocrine Therapy for PIK3CA-Mutated, Hormone Receptor-Positive, Human Epidermal Growth Factor Receptor 2-Negative Advanced or Metastatic Breast Cancer.Jhaveri KL, Accordino MK, Bedard PL, et al. · J Clin Oncol · 2024 · PMID 39236276
  3. 3.Oncogenic activation of PIK3CA in cancers: Emerging targeted therapies in precision oncology.Wang Y, Rozen V, Zhao Y, Wang Z · Genes Dis · 2024 · PMID 39717717
  4. 4.Alpelisib-Induced Hyperglycemia.Ekanayake PS, Gerwer J, McCowen K · Acta Endocrinol (Buchar) · 2022 · PMID 35975254
Educational monograph from NephTox (nephtox.com). Not medical advice — verify against current guidelines before any clinical decision.