FDA approves inavolisib combination for PIK3CA-mutated, endocrine-resistant HR-positive breast cancer

Evidence stage: Later-Stage HumanRegulatory status: FDA-approved for the exact stated cancer/useGuideline status: Not addressed

The FDA approved inavolisib (Itovebi), in combination with palbociclib and fulvestrant, for adults with endocrine-resistant, PIK3CA-mutated (as detected by an FDA-approved test), HR-positive, HER2-negative, locally advanced or metastatic breast cancer whose disease recurred during or within 12 months of completing adjuvant endocrine therapy, with no prior systemic therapy for metastatic disease — based on the randomized, double-blind, placebo-controlled, phase 3 INAVO120 trial (ClinicalTrials.gov NCT04191499; primary publication DOI 10.1056/NEJMoa2404625). INAVO120 randomized 325 patients 1:1 to the inavolisib combination or placebo combination; the primary analysis reported a significantly longer progression-free survival with the inavolisib combination, and a later, more mature analysis (DOI 10.1056/NEJMoa2501796) reported a statistically significant overall-survival benefit as well. This is an approval of a 3-drug combination regimen, not of inavolisib alone, and requires PIK3CA companion-diagnostic testing before use — it does not apply to PIK3CA-wild-type, HER2-positive, or later-line/heavily pretreated populations. Hyperglycemia is a known class effect of PI3K inhibitors and was common in the inavolisib arm (a meaningful share Grade 3/4); stomatitis and diarrhea also occurred at higher rates than placebo.

What This Means

In the randomized, double-blind, placebo-controlled INAVO120 trial, adding inavolisib to palbociclib and fulvestrant significantly delayed disease progression compared with palbociclib and fulvestrant alone, in a PIK3CA-mutated, endocrine-resistant, first-line metastatic breast cancer population; a later, more mature follow-up analysis also reported a statistically significant overall-survival benefit for the inavolisib combination.

What This Doesn't Mean

This is an approval of a 3-drug combination regimen, not of inavolisib as a standalone drug, and requires PIK3CA companion-diagnostic testing before use. It does not apply to PIK3CA-wild-type, HER2-positive, or later-line/heavily pretreated metastatic breast cancer populations.

Why It Matters

Gives a defined, biomarker-selected population an additional first-line option with both a progression-free-survival benefit and, per the later analysis, a statistically significant overall-survival benefit — a relatively high evidentiary bar for this drug class to have met.

Promise & Proof

Proof — strength of the evidence 5 / 5
  • Base score from evidence stage: Later-Stage Human.
  • FDA-approved for the exact stated cancer/use.
Promise — potential significance if later evidence holds up 3 / 5
  • Baseline — a validly-evidenced story starts here; every further point below is an explicit, checkable reason.
  • The record includes substantive editorial reasoning about why this discovery matters.
  • A distinct follow-on/confirmatory study or trial is already cited as a secondary source — the field is already building on this finding.

These two ratings are automatically computed from this story's own structured evidence fields and are shown separately on purpose — they are never combined into one score. They describe this record, not a medical recommendation: they do not establish medical certainty, do not substitute for reading the cited sources, and are recalculated whenever the underlying evidence changes.

Population / Applicability

Studied in: Adults with endocrine-resistant, PIK3CA-mutated (as detected by an FDA-approved test), HR-positive, HER2-negative, locally advanced or metastatic breast cancer, whose disease recurred during or within 12 months of completing adjuvant endocrine therapy (or while still on adjuvant endocrine therapy after at least 2 years), with no prior systemic therapy for metastatic disease — used in combination with palbociclib and fulvestrant, never as a standalone drug. (Adults)

Hyperglycemia is a known class effect of PI3K inhibitors and was common in the inavolisib arm, with a meaningful share reaching Grade 3/4 severity — this must be disclosed, not minimized. Stomatitis and diarrhea also occurred at meaningfully higher rates than placebo. PIK3CA companion-diagnostic testing is required before use.

Full evidence details
Study design
Randomized controlled trial
Sample size
325

Funding & Conflicts

Trial sponsor: Genentech/Roche (per multiple independent secondary sources; original disclosure statement itself not independently re-read).

Regulatory status by jurisdiction

United States (FDA)

Status
FDA-approved for the exact stated cancer/use
Indication
Adults with endocrine-resistant, PIK3CA-mutated, HR-positive, HER2-negative, locally advanced or metastatic breast cancer, as detected by an FDA-approved test, following recurrence on or after completing adjuvant endocrine therapy, in combination with palbociclib and fulvestrant.
Biomarker requirement
PIK3CA mutation
Decision date
2024-10-10
Source
Regulator record (opens in a new tab)

Guideline positions

Guideline

Position
Not addressed
Last verified
2026-08-13

Primary evidence supporting this story

Additional context

Why Should I Trust This?

  • 1 source at Tier 2 — Peer-reviewed primary research, trial registries, regulatory documents, official conference abstracts
  • Last reviewed: 2026-08-13

This panel summarizes real, checkable facts about this record's own sources and review status — it is not a trust score, and reading it is not a substitute for reading the cited sources yourself.

Discovery Timeline

Every recorded change to this record's content or publication status, in order.

  1. Status change — Status changed from "Legacy / Unverified" to "In editorial review".
  2. Status change — Status changed from "In editorial review" to "Verified".

Last reviewed

Related discoveries

FDA approves inavolisib combination for PIK3CA-mutated, endocrine-resistant HR-positive breast cancer

https://cancerdiscoveries.com/discoveries/fda-approves-inavolisib-combination-for-pik3ca-mutated-endocrine-resistant-hr-positive-breast-cancer/

Evidence stage: Later-Stage Human

What This Means

In the randomized, double-blind, placebo-controlled INAVO120 trial, adding inavolisib to palbociclib and fulvestrant significantly delayed disease progression compared with palbociclib and fulvestrant alone, in a PIK3CA-mutated, endocrine-resistant, first-line metastatic breast cancer population; a later, more mature follow-up analysis also reported a statistically significant overall-survival benefit for the inavolisib combination.

What This Doesn't Mean

This is an approval of a 3-drug combination regimen, not of inavolisib as a standalone drug, and requires PIK3CA companion-diagnostic testing before use. It does not apply to PIK3CA-wild-type, HER2-positive, or later-line/heavily pretreated metastatic breast cancer populations.

Why It Matters

Gives a defined, biomarker-selected population an additional first-line option with both a progression-free-survival benefit and, per the later analysis, a statistically significant overall-survival benefit — a relatively high evidentiary bar for this drug class to have met.

Primary sources

  • INAVO120 trial primary progression-free-survival results: inavolisib-based therapy in PIK3CA-mutated advanced breast cancer (NEJM) — https://doi.org/10.1056/NEJMoa2404625 (DOI 10.1056/NEJMoa2404625)

Date verified: 2026-08-13

Correction status: No correction or retraction