RTB101

ID: rtb101

Aliases: BEZ235-derived mTOR inhibitor, resTORbio RTB101

Type: compound

Route/form: oral investigational tablet in older-adult trials

Status: investigational_failed_phase3_for_rti

Evidence level: human RCT

Best data tier: human controlled/review; exact-use indirect

Support scope: human, context

Source types: clinical_trial_registry, human_rct_negative, human_trial

Linked sources: 3

Broad outcomes: Gut / immune / inflammation, Longevity / mitochondrial / redox, mTORC / autophagy / nutrient signaling

Reading note: These are curation notes anchored to linked sources, not a clinical recommendation or protocol.

Targets / mechanism

• TORC1 / mTOR pathway inhibition
• older-adult antiviral immune-function hypothesis
• PI3K/mTOR pathway ancestry caveat

Optimization domains

• mTORC1
• mTOR
• immune aging
• respiratory infection
• longevity discussion
• safety

Research basis

• RTB101 is useful for the repository because it is a real human geroscience-adjacent mTOR-pathway program, not just animal rapamycin lore.
• Phase 2 respiratory-infection signals were strong enough to justify larger older-adult trials and mechanistic antiviral-immunity discussion.
• It is a cautionary example for mTORC hype because later phase 3 endpoint results did not cleanly validate the early signal.

Limits, risks, and missing evidence

• The phase 2b/phase 3 publication is mixed/negative overall, so RTB101 should not be presented as a validated longevity or immune-enhancement drug.
• It is not simply ?rapamycin in another bottle?; its development history and pathway selectivity complicate interpretation.
• Older-adult RTI endpoints do not establish muscle, fat-loss, cognition, or lifespan benefit.

Risk flags

• investigational
• mixed phase3 signal
• older adult endpoint specific
• not longevity proven
• mtor pathway complexity

Linked papers, labels, and reviews

1. Targeting the biology of ageing with mTOR inhibitors to improve immune function in older adults: phase 2b and phase 3 randomised trials
   human_rct_negative / pubmed_rtb101_phase2b_phase3_2021
   RTB101 older-adult phase 2b/phase 3 publication; important because early RTI/antiviral signals did not translate cleanly into the phase 3 primary endpoint.
2. Effect of RTB101 on Illness Associated With Respiratory Tract Infections in the Elderly
   clinical_trial_registry / clinicaltrials_rtb101_protector1
   ClinicalTrials.gov registry for the PROTECTOR1 phase 3 RTB101 study in adults aged 65 and older.
3. TORC1 Inhibition with RTB101 as a Potential Pan-Antiviral Immunotherapy to Decrease the Incidence of Respiratory Tract Infections Due to Multiple Respiratory Viruses in Older Adults
   human_trial / pmc_rtb101_torc1_rti_2019
   Conference-abstract style human source for the phase 2 RTI signal; useful as context but weaker than the full phase 2b/phase 3 paper.