This page shows what was measured, who it was measured in, and what that does not settle.
What Daptomycin does in the body
Serious skin or bloodstream infections caused by resistant bacteria, but not pneumonia.
Daptomycin has a fatty tail. With the help of calcium, that tail buries itself in the outer wrapping of a Gram-positive bacterium and pulls the wrapping out of shape, so the cell leaks its contents and dies. The lungs are lined with a soapy substance that keeps the air sacs open, and that substance grabs daptomycin’s fatty tail and holds onto it — so in the lung the drug never reaches any bacteria at all.
What happened in people
It matched older treatment for bloodstream infection and caused less than half as much serious kidney trouble.
✓ Reviewed first-read answer
Where this came from
A person wrote this and a reviewer approved it against this exact record. It carries no effect size.
A reviewer approved this against this record. The reviewed-claim record carrying the exact population and effect size does not exist yet.
No source is stored against this line.
The limit that matters most
It cannot treat pneumonia because substances in the lungs switch it off.
Where it acts
The bacterial cytoplasmic membrane. The human organ that matters most is the lung, where surfactant inactivates the drug, and skeletal muscle, where it causes myopathy.
Kind of result
The kind of result is not recorded
Supervision
Professional supervision is normally required. A regulator classifies this substance in a way that restricts how it is supplied.
What the registries record it as
The substance registry classes this as chemical.
FDA substance registry · NWQ5N31VKK · read 2026-08-29
Its recorded molecular formula is C72H101N17O26, weighing 1620.67.
US prescribing information · 6ec53f7e-9a5f-4b24-84e9-c94325750e32 · read 2026-08-30
Where each sentence above came from
No recorded sentence describes the change this makes in a way that stands on its own. The page opens with what it is taken for instead, and the recorded explanation follows below.
Shown as the opening line on this page.
The limit a reviewer approved as the one that matters most here.
The four opening statements run to 105 words.
Words this page uses
Four words worth knowing first
Chosen from what this page shows, with each one explained before the word it depends on.
Comparator
A comparator is whatever the treatment was measured against.
A picture of it, and where the picture fails
It is like the other runner in a race.
Where that stops being true. A race has one winner. A study can show both arms improved.
What people get wrong. Results are read without asking what the other group got. Beating nothing is not beating a treatment.
The control condition against which the experimental intervention is assessed.
Randomisation
Randomisation means chance decides who gets which treatment.
A picture of it, and where the picture fails
It is like a coin toss deciding the groups.
Where that stops being true. A coin toss is fair once. Fairness here comes from doing it for everyone.
What people get wrong. It is thought to make groups identical. It makes them similar on average, including on things nobody measured.
Allocation of participants to arms by a chance process, so that unmeasured factors are balanced in expectation.
Absolute difference
An absolute difference is how many more people in a hundred were affected.
A picture of it, and where the picture fails
It is like counting heads in two rooms of a hundred.
Where that stops being true. Heads are easy to count. Study results carry a margin of error too.
What people get wrong. It is confused with a percentage change, which can look far larger.
The arithmetic difference in event rates between arms.
Confidence interval
A confidence interval is the range the true answer is likely to sit in.
A picture of it, and where the picture fails
It is like a weather forecast giving a range rather than one number.
Where that stops being true. A forecast range covers tomorrow. This one covers what the study could resolve.
What people get wrong. The middle number is read as the answer. A range crossing zero means no change is still possible.
An interval estimate that would contain the true parameter in a stated proportion of repeated studies.
What happened in people◇Read from sources, not yet reviewed
What happened in people
Each card is one study: the exact question it asked, who was in it, and whether it showed what it set out to show.
Treatment success 42 days after the end of therapy
44.2% (53 of 120) against standard therapy 41.7% (48 of 115); absolute difference 2.4%, 95% CI -10.2 to 15.1, non-inferiority criteria met
Repeated elsewhere
Partially Replicated
What this does not prove. Meeting one endpoint in one population does not carry to other goals or other people.
The limits of this study, and where it came from
Main limit. Success in both arms was below 45%, which is the more striking figure and is rarely quoted. Microbiological failure was more frequent with daptomycin (19 against 11, P=0.17) and reduced daptomycin susceptibility emerged during treatment in 6 of those 19.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Intravenous infusion or injection, once daily and never more often
Interval reported. 95% CI -10
Written into the record, not signed off as a reviewed claim.
Daptomycin against standard therapy in Staphylococcus aureus bacteraemia (NCT00093067) · a recorded source, not a stored snapshot
Clinical response at the test-of-cure visit in the intent-to-treat and clinically evaluable populations
✗ The study did not show it
Who was studied
Pertel 2008 pooled community-acquired pneumonia programme
How many people
834
Study design
Two phase 3, randomised, double-blind, active-controlled trials pooled
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Intent-to-treat 70.9% against ceftriaxone 77.4% (95% CI for the difference -12.4% to -0.6%); clinically evaluable 79.4% against 87.9% (95% CI -13.8% to -3.2%)
Repeated elsewhere
Replicated
What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.
The limits of this study, and where it came from
Main limit. A post-hoc subgroup of patients who had received up to 24 hours of prior effective therapy showed similar cure rates in both arms, 90.7% against 88.0%. That is a finding about trial enrolment rather than about the drug, and the authors presented it as such.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Intravenous infusion or injection, once daily and never more often
Interval reported. 95% CI for the difference -12
Written into the record, not signed off as a reviewed claim.
Daptomycin against standard therapy in Staphylococcus aureus bacteraemia (NCT00093067) · a recorded source, not a stored snapshot
What we know
RNAWiki holds 2 written-up human studies for this substance, each with the question it asked.
How we know it
Each card names the study, the number of people and what the study set out to measure.
What this does not prove
These summaries were written by a person and have not been signed off as reviewed claims.
Why it matters
A study that failed is as informative as one that worked, and both are here.
What we still do not know
No reviewed claim exists, so no exact population, effect size or interval is published yet.
What it changes in the body◇Read from sources, not yet reviewed
The path through the body
From what a person takes to what changes. A solid line is a step measured in people. A dashed line is a step nobody has measured that way.
Start
Daptomycin
What a person takes: Intravenous infusion or injection, once daily and never more often.
The measurement behind this step
Parenteral only. The once-daily restriction is a safety requirement rather than a convenience: creatine phosphokinase elevations were more frequent when the drug was given more than once a day, and the once-daily schedule is what made a shelved compound marketable. Predominantly renally cleared, with reduced efficacy reported in adults with moderate baseline renal impairment. It must not be used for pneumonia, and its susceptibility testing requires calcium-supplemented medium.
Getting in
Given once a day, and never more often
The drug was abandoned in the 1980s because it damaged muscle. What rescued it was the discovery that giving it once a day rather than in split doses kept the antibacterial effect and largely removed the muscle injury.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
Killing is concentration-dependent while myopathy tracks the time muscle spends exposed, so consolidating the same amount into a single daily administration separates the two. The label states that creatine phosphokinase elevations appeared more frequent when daptomycin was given more than once daily and that it should not be dosed more frequently than once a day.
On its own, daptomycin is strongly negatively charged and a bacterial membrane is negatively charged too, so they repel. Calcium sits between them and neutralises the repulsion, letting the fatty tail reach the membrane.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
Calcium binding neutralises the anionic charge of the cyclic peptide and promotes oligomerisation, allowing the decanoyl tail to insert into phosphatidylglycerol-rich regions of the cytoplasmic membrane. Susceptibility testing must be performed in calcium-supplemented medium, or the result is meaningless.
It disorganises the membrane instead of binding a protein
There is no enzyme to jam. Daptomycin buries itself in the bacterium’s outer wrapping and pulls it out of shape, so the electrical gradient the cell depends on collapses.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
Inserted oligomers cause membrane depolarisation and potassium efflux, disrupting the ion gradients that drive transport and synthesis. Killing is rapid and concentration-dependent and occurs without cell lysis, which reduces release of inflammatory cell-wall fragments compared with beta-lactams.
The cell shuts down rather than exploding, so less bacterial debris is released into the bloodstream.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
Non-lytic killing is unusual for a bactericidal agent and is one proposed advantage in high-burden infection, where beta-lactam-induced lysis releases peptidoglycan and lipoteichoic acid that drive the inflammatory response.
The air sacs of the lung are lined with a soapy substance that keeps them from collapsing. That substance binds daptomycin’s fatty tail and holds it, so the drug never reaches bacteria in the lung. This is the only antibiotic known to be inactivated by a particular organ.
──Measured in people. Written by a person from the study named beside the step. Not signed off as a reviewed claim.
The measurement behind this step
Pulmonary surfactant phospholipids sequester the decanoyl tail required for membrane insertion, abolishing antibacterial activity in vitro and in bronchial-alveolar animal models, while activity is retained in haematogenous pneumonia and inhalation anthrax. Two pooled phase 3 trials in community-acquired pneumonia found clinical cure of 79.4% against ceftriaxone’s 87.9% in evaluable patients, and the label states the drug is not indicated for pneumonia.
It damages muscle and can inflame the lung. Bacteria escape it not by changing a protein but by making their membrane more positively charged, so the calcium-loaded drug is pushed away before it can insert.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
Gain-of-function mutations in mprF increase lysinylation of phosphatidylglycerol and raise membrane positive charge; yycFG/walKR and cls mutations contribute. Emergent reduced susceptibility appeared in 6 of 19 microbiological failures in the registration trial. Labelled harms include myopathy and rhabdomyolysis, eosinophilic pneumonia, DRESS, tubulointerstitial nephritis, peripheral neuropathy, and reduced efficacy in moderate baseline renal impairment.
No suggested links are held for this record, so nothing is hidden from this path.
What we know
The record describes 6 steps from taking it to an effect in a person.
How we know it
Each step names the study behind it in the technical detail beside it.
What this does not prove
A change inside the body is a reason to look. It is not a result in a person.
Why it matters
A reader can see exactly where the chain stops being measured in people.
What we still do not know
No reviewed claim binds any of these steps to a named population.
What is missing or unclear◇Read from sources, not yet reviewed
Were people like you studied?
RNAWiki cannot tell whether a study fits you. It can show who was in it, and where the result stops carrying.
Who was studied
People similar to this profile were included.
Adults and children with complicated skin infection or Staphylococcus aureus bloodstream infection, including right-sided endocarditis.
Who is missing from the studies
Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
What the label states about particular groups
On pediatric, the label states: “Safety and effectiveness in pediatric patients below the age of one year have not been established.”
US prescribing information · 6ec53f7e-9a5f-4b24-84e9-c94325750e32 · read 2026-08-30
On older people, the label states: “Of the 534 adult patients treated with daptomycin for injection in Phase 3 controlled clinical trials of complicated skin and skin structure infections (cSSSI), 27% were 65 years of age or older and 12% were 75 years of age or older.”
US prescribing information · 6ec53f7e-9a5f-4b24-84e9-c94325750e32 · read 2026-08-30
On people who are pregnant, the label states: “Risk Summary Limited published data on use of daptomycin for injection in pregnant women are insufficient to inform a drug-associated risk for major birth defects and miscarriage.”
US prescribing information · 6ec53f7e-9a5f-4b24-84e9-c94325750e32 · read 2026-08-30
On people who are breastfeeding, the label states: “Risk Summary Limited published data report that daptomycin is present in human milk at infant doses of 0.1% of the maternal dose [see Data ] 2,3,4 .”
US prescribing information · 6ec53f7e-9a5f-4b24-84e9-c94325750e32 · read 2026-08-30
Where the result stopped carrying
Eli Lilly shelved the compound in the 1980s over muscle toxicity, and it was only revived when once-daily administration was found to separate efficacy from myopathy
It failed two phase 3 trials in community-acquired pneumonia and the label now states it is not indicated for pneumonia
Reduced susceptibility emerged during the registration trial itself, in patients being treated
It causes eosinophilic pneumonia, an inflammatory lung reaction, in an organ where it cannot treat infection
This is a scope explorer, not a diagnosis engine.
It shows who was studied so you can see whether people similar to you were included.
RNAWiki cannot tell whether a study fits you. It can show who was in it.
What it would be like to take◇Read from sources, not yet reviewed
Why it might seem to do nothing
A real effect and a noticed effect are different things. These are the recorded reasons the two come apart.
It was studied in different people
The people in the studies were not much like the reader.
On this record: Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
The evidence may simply be wrong
Small early studies often do not hold up.
On this record: RNAWiki has not yet published a reviewed conclusion for this use.
The product may not be what it says
Contents of a sold product are not always what the label states.
On this record: This is sold as a supplement, so no agency checked what is in a given tub before it was sold.
Other reasons RNAWiki checked and found nothing for (10)
It was studied for a different goal
The studies measured something else entirely. Nothing in this record points to this reason.
A different form was studied
The studied form is not the form on the shelf. Nothing in this record points to this reason.
There was nothing to correct
Where a level is already normal, topping it up may change nothing. Nothing in this record points to this reason.
Something else had to happen too
In the studies it was paired with training, a diet or another treatment. Nothing in this record points to this reason.
The change is too small to feel
A real change can still sit below what a person notices. Nothing in this record points to this reason.
Day-to-day swing hides it
Sleep, food, stress and time of day move most numbers more than this would. Nothing in this record points to this reason.
Not enough time yet
The studies ran longer than the person has waited. Nothing in this record points to this reason.
It was not taken as studied
Missed days change the result, and studies count them. Nothing in this record points to this reason.
Something else changed at the same time
Two changes at once cannot be told apart afterwards. Nothing in this record points to this reason.
No recorded reason
RNAWiki has nothing stored that would explain it. Nothing in this record points to this reason.
None of these is a reason to take more. Taking more is not a step this page ever suggests.
What it would be like to take◇Read from sources, not yet reviewed
What taking it involves
The recorded facts about getting hold of it and using it. Nothing here is a suggestion about what you should do.
How it is supplied
Given by a clinician
❝ Quoted from a source
Where this came from
Copied from a source RNAWiki stored, with the source named.
Read from the recorded approval status.
No source is stored against this line.
Form and route
Intravenous infusion or injection, once daily and never more often
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
The form and route recorded on this substance.
No source is stored against this line.
Who oversees it
Professional supervision is normally required. A regulator classifies this substance in a way that restricts how it is supplied.
❝ Quoted from a source
Where this came from
Copied from a source RNAWiki stored, with the source named.
Suppression classes recorded: S7.
No source is stored against this line.
What is in the pack
Parenteral only.
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
Recorded notes on how this is sold. The rest of the recorded wording: The once-daily restriction is a safety requirement rather than a convenience: creatine phosphokinase elevations were more frequent when the drug was given more than once a day, and the once-daily schedule is what made a shelved compound marketable. Predominantly renally cleared, with reduced efficacy reported in adults with moderate baseline renal impairment. It must not be used for pneumonia, and its susceptibility testing requires calcium-supplemented medium.
No source is stored against this line.
Where it is registered
Regulatory records are listed in the technical disclosure at the foot of this page.
# Counted from records
Where this came from
A count of rows RNAWiki holds. It describes our records, not your body.
Register entries are stored per jurisdiction and shown with their dates.
No source is stored against this line.
Why people stop
Not recorded.
∅ Nothing recorded
Where this came from
RNAWiki holds nothing here and says so rather than guessing.
No record of why people stopped taking it is stored for this substance.
No source is stored against this line.
What it would be like to take◇Read from sources, not yet reviewed
What can go wrong
Sorted by where each line came from. A regulator's label and a report somebody sent in are not the same kind of fact.
·Worth asking a clinician aboutWritten into the record from the studies named on this page
Myopathy — muscle aching or weakness with creatine phosphokinase above ten times the upper limit of normal — and rhabdomyolysis with or without acute renal failure, with weekly creatine phosphokinase monitoring advised and more frequent monitoring alongside statins. Eosinophilic pneumonia, managed by discontinuation and consideration of systemic steroids. Anaphylaxis and hypersensitivity, DRESS, tubulointerstitial nephritis and peripheral neuropathy. Use is to be avoided in children under 12 months because of potential nervous and muscular system effects. Persisting or relapsing Staphylococcus aureus infection should prompt susceptibility testing and a search for sequestered foci, because reduced susceptibility can emerge during treatment.
Nobody counted how many people took this and were fine, so this cannot be turned into a rate.
Over a long time. No completed tested study window is recorded, so long-term effects are not established by the registry record.
Groups the studies covered thinly. Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
What is missing or unclear◇Read from sources, not yet reviewed
Does the exact form matter?
Evidence belongs to the exact thing that was tested. A different salt, a different mixture or a different preparation is a different question.
The form that was studied
Intravenous infusion or injection, once daily and never more often
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
The form used in the studies cited on this page.
No source is stored against this line.
What is sold
A recorded note compares this form with the others that are sold. It is kept below, word for word.
§ A fixed RNAWiki sentence
Where this came from
Wording RNAWiki always uses, not a finding about this substance.
The recorded note, unchanged: The once-daily restriction is a safety requirement rather than a convenience: creatine phosphokinase elevations were more frequent when the drug was given more than once a day, and the once-daily schedule is what made a shelved compound marketable. Predominantly renally cleared, with reduced efficacy reported in adults with moderate baseline renal impairment. It must not be used for pneumonia, and its susceptibility testing requires calcium-supplemented medium.
No source is stored against this line.
What is recorded as being sold
64 products list this as an active ingredient in the United States drug directory. 64 of them contain it and nothing else.
FDA National Drug Code directory · 72201-1009 · read 2026-08-29
They are sold as injection, powder, lyophilized, for solution, injection, powder, lyophilized, for suspension, injection, solution, liquid and powder, taken intravenous.
FDA National Drug Code directory · 72201-1009 · read 2026-08-29
The regulator's established pharmacologic class for it is lipopeptide antibacterial [epc] and lipopeptides [cs].
FDA National Drug Code directory · 72201-1009 · read 2026-08-29
47 published labels name it as an active ingredient. 47 of them describe this substance alone, which is where its own label text on this page comes from.
US prescribing information · 6ec53f7e-9a5f-4b24-84e9-c94325750e32 · read 2026-08-29
Those labels are classed as human prescription drug.
US prescribing information · 6ec53f7e-9a5f-4b24-84e9-c94325750e32 · read 2026-08-29
daptomycin is intravenous at 3 DOSAGE FORMS AND STRENGTHS For Injection: 500 mg daptomycin as a sterile, pale yellow to light brown lyophilized powder for reconstitution in a single-dose vial., recorded as fda label in effect 2023-11-14 in the United States.
US prescribing information · 6ec53f7e-9a5f-4b24-84e9-c94325750e32 · read 2026-08-30
Recorded price in US: 22.68646 USD per one unit as the pricing file counts it — a tablet, capsule, patch or single item, across 21 priced products whose strengths and pack forms differ, as of 2026-08-26, paid by retail pharmacies buying the product, as surveyed by the Centers for Medicare & Medicaid Services. It is not a list price, an insurance price, or what anyone pays at a counter..
Recorded source · 2026-08-26 · read 2026-08-28
Evidence carries across two names for one substance. It does not carry across a salt, a mirror form or a mixture.
What it would be like to take◇Read from sources, not yet reviewed
What you could measure
This one is decided with a clinician, so this section holds questions to ask rather than a plan to run.
Self-experiment planning is not offered for a prescription or clinician-supervised medicine. The questions below are for a clinician or pharmacist.
Questions worth asking
Which of the trials of Daptomycin studied people like me?
What was measured, and for how long?
Was the result a laboratory value or a health outcome?
What would we watch for, and when would we stop?
Tracking can show whether something changed for you. It cannot show what caused it.
RNAWiki records evidence. It does not say whether this substance is right for you.
What is missing or unclear◇Read from sources, not yet reviewed
Claims that go past the evidence
Things said about this substance that sound reasonable, and the exact step that is missing between the evidence and the claim.
✗Goes past the evidence
That the record’s stated indication of pneumonia describes what this drug treats — it names the one organ in which the drug is documented to be inert
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That non-inferiority at 44.2% against 41.7% means the treatment works well; both arms failed more than half their patients
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That less renal dysfunction than a vancomycin-and-gentamicin arm isolates a daptomycin advantage, when the comparator contained two nephrotoxic agents
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That a post-hoc subgroup showing similar cure rates rescues the pneumonia result; the authors offered it as a criticism of trial design
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
What is missing or unclear◇Read from sources, not yet reviewed
What nobody knows yet
Open questions, each with why it is open and what would close it.
How much did people take in the studies?
The sources RNAWiki checked hold nothing for this field.
Why it matters. A result belongs to an amount. Without the amount the result floats free.
What would answer it
A stored source that records it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Missing populations
Which groups were under-represented in the studies has not been recorded.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Missing long-term data
No completed tested study window is recorded.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
No reviewed conclusion
RNAWiki has not yet published a reviewed conclusion for this use.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Missing interaction studies
No interaction was found in the registers checked. Not finding one is not the same as showing there is none.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Formulation uncertainty
Several salts, forms or products of Daptomycin are recorded. Results from one form may not transfer to another.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Mechanism not reviewed
No reviewed mechanism story exists for this substance.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
What happened in people◇Read from sources, not yet reviewed
Check any of this yourself
Every line above traced back to the study it came from. This is the technical layer, and the vocabulary changes here.
Every line above can be traced to the study named beside it. Follow the link and read it.
Non-inferior in Staphylococcus aureus bacteraemia, with half the renal dysfunction
In plain words
In the trial that approved it for bloodstream infection, daptomycin matched the older regimen. What separated them was the kidneys: about one patient in nine on daptomycin had significant kidney trouble, against about one in four on the older combination.
What was measured
Treatment success 42 days after end of therapy, and clinically significant renal dysfunction
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
The trial randomised 124 patients with Staphylococcus aureus bacteraemia with or without endocarditis to daptomycin and 122 to initial low-dose gentamicin plus either an antistaphylococcal penicillin or vancomycin. Treatment success 42 days after the end of therapy in the modified intention-to-treat analysis was 53 of 120 (44.2%) against 48 of 115 (41.7%) — absolute difference 2.4%, 95% CI -10.2 to 15.1, meeting the pre-specified non-inferiority criteria. Success rates were similar in the subgroups with complicated bacteraemia, right-sided endocarditis and MRSA. Clinically significant renal dysfunction occurred in 11.0% against 26.3% (P=.004). Standard therapy was associated with a non-significantly higher rate of adverse events leading to discontinuation, 17 against 8 (P=.06).
Written into the record, not signed off as a reviewed claim
It failed community-acquired pneumonia outright, in two phase 3 trials
In plain words
Two trials tested daptomycin against ceftriaxone in patients hospitalised with pneumonia. It lost both. The published conclusion is that daptomycin is not effective for treating community-acquired pneumonia.
What was measured
Clinical response at test of cure in the intent-to-treat and clinically evaluable populations
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
Two double-blind phase 3 trials randomised adults hospitalised with community-acquired pneumonia to intravenous daptomycin or ceftriaxone once daily for 5 to 14 days. Pooled, the intent-to-treat population held 413 daptomycin and 421 ceftriaxone patients and the clinically evaluable population 369 and 371. Clinical cure in the intent-to-treat population was 70.9% with daptomycin against 77.4% with ceftriaxone (95% CI for the difference -12.4% to -0.6%), and in the clinically evaluable population 79.4% against 87.9% (95% CI -13.8% to -3.2%). Both intervals exclude zero against daptomycin. A post-hoc analysis found that among patients who had received up to 24 hours of prior effective therapy, cure rates were similar — 90.7% against 88.0%, 95% CI -6.1% to 11.5% — which the authors read as a warning about how pneumonia trials enrol rather than as a rescue of the drug.
Written into the record, not signed off as a reviewed claim
The reason it failed: the lung switches it off
In plain words
After the pneumonia trials failed, a laboratory experiment found the explanation. The soapy substance that keeps the air sacs of the lung open binds daptomycin and stops it working. It is the only antibiotic known to be inactivated by a specific human organ.
What was measured
Loss of daptomycin antibacterial activity in the presence of pulmonary surfactant in vitro
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Daptomycin showed an unusual pattern in animal pulmonary models: efficacy in Staphylococcus aureus haematogenous pneumonia and in inhalation anthrax, but no activity against Streptococcus pneumoniae in simple bronchial-alveolar pneumonia. In vitro, daptomycin interacts with pulmonary surfactant, inhibiting its antibacterial activity — an effect specific to daptomycin and consistent with its known mechanism, since surfactant phospholipids sequester the lipid tail that must insert into the bacterial membrane. The authors describe this as the first example of organ-specific inhibition of an antibiotic. The finding is why the label carries an explicit statement that daptomycin is not indicated for pneumonia.
Written into the record, not signed off as a reviewed claim
Reduced susceptibility emerged during the registration trial itself
In plain words
In the trial that approved the drug, more patients on daptomycin failed microbiologically than on the older regimen, and in six of those failures the bacteria had become less susceptible to daptomycin while the patient was on it.
What was measured
Emergent reduced daptomycin susceptibility among microbiological failures in a randomised trial
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
Daptomycin therapy was associated with a higher rate of microbiological failure than standard therapy — 19 patients against 11, P=0.17, not statistically significant. In 6 of the 19 daptomycin microbiological failures, isolates with reduced susceptibility to daptomycin emerged during treatment; reduced susceptibility to vancomycin was similarly noted in isolates from vancomycin-treated patients. The mechanism is now understood as gain-of-function mutation in mprF and related loci, which increases the positive charge of the membrane and repels the calcium-daptomycin complex. The label carries a specific warning about persisting or relapsing Staphylococcus aureus bacteraemia or endocarditis, directing susceptibility testing and a search for sequestered foci of infection.
Written into the record, not signed off as a reviewed claim
It causes the lung disease it cannot treat, and the muscle injury that shelved it
In plain words
Daptomycin cannot treat pneumonia and can cause one — an inflammatory reaction in the lung that looks like infection and is treated by stopping the drug. Separately, it damages muscle, which is why Eli Lilly abandoned it in the 1980s.
What was measured
Not recorded
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
The label carries warnings for anaphylaxis and hypersensitivity, myopathy and rhabdomyolysis, eosinophilic pneumonia, DRESS, tubulointerstitial nephritis, peripheral neuropathy, potential nervous and muscular system effects in children under 12 months in whom use is to be avoided, Clostridioides difficile-associated diarrhoea, persisting or relapsing Staphylococcus aureus infection, and decreased efficacy in adults with moderate baseline renal impairment. Myopathy is defined as muscle aching or weakness with creatine phosphokinase above ten times the upper limit of normal. The label states that in phase 1 and phase 2 studies creatine phosphokinase elevations appeared more frequent when daptomycin was given more than once daily, and that it should therefore not be given more often than once a day — the observation that turned a shelved Lilly compound into a marketed drug.
Source
Daptomycin for Injection United States prescribing information, Warnings and Precautions 5.1 to 5.10 (NDA 021572)
Role in the trial
Not matched to a registered study
Identity check
no open identity hold
Audit mark
caution
Review state
Written into the record, not signed off as a reviewed claim
The enriched record named pneumonia as this drug’s indication
In plain words
The automated record behind this page listed daptomycin’s patient-facing indication as pneumonia. Pneumonia is the one thing this drug is documented not to treat, in two failed trials and an explicit label statement. The error is recorded here rather than quietly corrected.
What was measured
That an indication extracted automatically from a label or a trial registry describes what a drug treats — here it named the one organ where the drug is known to be pharmacologically inert
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
The machine-enriched record for this drug carried "Pneumonia" as its patient-friendly indication. The approved indications are complicated skin and skin structure infections and Staphylococcus aureus bloodstream infection including right-sided infective endocarditis. Two pooled phase 3 trials found clinical cure of 70.9% against ceftriaxone’s 77.4% in the intent-to-treat population, with the confidence interval excluding zero, and concluded that daptomycin is not effective for community-acquired pneumonia. The mechanism was subsequently characterised as inactivation by pulmonary surfactant. This is a case where automated indication extraction produced not an incomplete answer but an inverted one, and it is the reason this dossier is flagged as carrying a discrepancy.
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What is not here
7 questions this page could not answer
These sections were prepared and left out because there was nothing to put in them. They are listed rather than hidden, so the gaps in this record are visible.
What was measured, goal by goal — found nothing in the sources checked.
How close this is to real life — found nothing in the sources checked.
Felt, measured, or meaningful — found nothing in the sources checked.
How long anything takes — found nothing in the sources checked.
What it may clash with — found nothing in the sources checked.
Other ways to the same goal — found nothing in the sources checked.
What changed on this page — found nothing in the sources checked.
The record as stored
The full record, for auditing
Everything above is built from what is below. This layer keeps the technical vocabulary, record identifiers and every stored row, so a reader who wants to check the page can.
The older medicine-wide conclusion held in this record
Written for a clinical reader, and about the medicine as a whole rather than about one indication, population and set of trials. RNAWiki does not treat it as a programme conclusion and no reviewer has signed it off in that form. It is here word for word because it is what the record holds.
A calcium-dependent lipopeptide that inserts into the bacterial membrane and disorganises it rather than binding any protein — it was non-inferior to standard therapy in Staphylococcus aureus bacteraemia at 44.2% against 41.7% success with far less renal dysfunction (11.0% against 26.3%, P=.004), and it failed outright in community-acquired pneumonia because pulmonary surfactant binds and inactivates it.
Recorded evidence blocks (7)
Q2
On the Daptomycin label: indicated for what?
"Daptomycin for injection is a lipopeptide antibacterial indicated for the treatment of: • Complicated skin and skin structure infections (cSSSI) in adult and pediatric patients (1 to 17 years of age) ( 1.1 ) and, • Staphylococcus aureus bloodstream infections (bacteremia), in adult patients including those with…": indications and usage on Daptomycin's label. DailyMed label · e6fef9de-e357-4fa3-8839-f483edf1b4d0 · 2026-08-26
Q3
80 registered trials of Daptomycin — at which phases?
Registered studies posting no result
47 of 80
80 registered studies of Daptomycin: 26 phase4, 18 phase2, 15 phase3, 9 phase1, 6 na, 5 na or unstated, 1 early phase1. CLINICALTRIALS_SNAPSHOT · 2026-09-01
82 with a PubMed record
Show the evidence
phase4
26
phase2
18
phase3
15
phase1
9
na
6
na or unstated
5
7 more recorded rows
early phase1
1
completed
44
terminated
22
unknown
9
withdrawn
3
enrolling by invitation
1
recruiting
1
recorded 2026-09-01 · last checked 2026-09-04
Q4
21 of Daptomycin's trials stopped: safety, futility/efficacy, accrual/recruitment, funding/business, other?
safety (1), futility/efficacy (1), accrual/recruitment (14), funding/business (1) and other (4): Daptomycin's stop wording, clustered. CLINICALTRIALS_SNAPSHOT · 2026-09-01
"Study terminated due to low enrollment"; 21 of 80 registered studies
Show the evidence
Trial
NCT00055198
terminated; "Study terminated due to low enrollment"
NCT00401960
terminated; "inadequate enrollment"
NCT00463801
terminated; "Because of inadequate accrual."
NCT00638157
terminated; "commitment completed"
NCT00651131
terminated; "terminated due to slow enrollment"
NCT00695903
terminated; "terminated due to lack of enrollment"
14 further recorded trials
NCT01025271
terminated; "unable to enroll subjects study stopped due to lack of enrollment"
NCT01104662
terminated; "Cubist has reached an agreement with the FDA that enrollment in the DAP-RENSE-08-05 study can stop."
NCT01133600
terminated; "Lack of patient enrollment"
NCT01175707
terminated; "Business decision"
NCT01196169
terminated; "The study is closed to accrual. Enrollment of new patients stopped at the request of CUBIST Pharmaceuticals due to slow rate of enrollment."
NCT01199783
terminated; "Patient number to be enrolled not reachable in prospected time frame, decision to stop the study prematurely was made."
NCT01216241
terminated; "The study has shown futility and the objectives could not be reached without enrolling a very large number of subjects."
NCT01287832
terminated; "Low patient enrollment"
NCT01522105
terminated; "Insufficient patient recruitment"
NCT01734694
terminated; "Independent biostatistician recommended early termination of the trial due to low probability of success."
NCT01756924
terminated; "This study has been terminated; alternative study designs are being considered. Fusidic acid remains available under an Expanded Access Protocol."
NCT01975662
terminated; "slow accrual of participants"
NCT02168816
terminated; "The study was stopped for feasibility (i.e., low recruitment)"
NCT02208063
terminated; "Halted due to lack of statistical power. No safety concerns identified."
recorded 2026-09-01 · last checked 2026-09-04
Q5
Daptomycin's half-life is 0 to 24 hours — which schedules were studied?
0 to 24 hours, the half-life Daptomycin's label states: "Table 11: Mean (SD) Daptomycin Pharmacokinetic Parameters in Healthy Adult Volunteers at Steady-State Dose *† (mg/kg) Pharmacokinetic Parameters ‡ AUC 0-24 (mcg•h/mL) t 1/2 (h) V ss (L/kg) CL T (mL/h/kg) C max (mcg/mL) 4 (N=6) 494 (75) 8.1 (1.0) 0.096 (0.009) 8.3 (1.3) 57.8 (3.0) 6 (N=6) 632 (78) 7.9 (1.0) 0.101…" DailyMed label · e6fef9de-e357-4fa3-8839-f483edf1b4d0 · 2026-08-26
Show the evidence
half lifepharmacokinetics
0 to 24 hours; Table 11: Mean (SD) Daptomycin Pharmacokinetic Parameters in Healthy Adult Volunteers at Steady-State Dose *† (mg/kg) Pharmacokinetic Parameters ‡ AUC 0-24 (mcg•h/mL) t 1/2 (h) V ss (L/kg) CL T (mL/h/kg) C max (mcg/mL) 4 (N=6) 494 (75) 8.1 (1.0) 0.096 (0.009) 8.3 (1.3) 57.8 (3.0) 6 (N=6) 632 (78) 7.9 (1.0) 0.101 (0.007) 9.1 (1.5) 93.9 (6.0) 8 (N=6) 858 (213) 8.3 (2.2) 0.101 (0.013) 9.0 (3.0)…
metabolismpharmacokinetics
Metabolism In in vitro studies, daptomycin was not metabolized by human liver microsomes.
recorded 2026-08-26 · last checked 2026-09-04
Q6
Which running trial of Daptomycin could settle lifespan?
NCT05137119 measures All-cause mortality at 90 days after platform entry, reading out 2028-12-01.
1 open trial; n 8000; "Staphylococcus Aureus Network Adaptive Platform Trial"
Show the evidence
TrialNCT05137119
"Staphylococcus Aureus Network Adaptive Platform Trial"; n 8000; "All-cause mortality at 90 days after platform entry"; 2028-12-01
Q7
Which 24 trials of Daptomycin posted no result?
Posted no result
24 of 24 completed trials
Registrations
NCT00538694, NCT00540072, NCT00093067, NCT00136292, NCT00295178 and NCT00426933, and 18 more
Completion dates
oldest 2001-09-30; newest 2024-08-21
Show the evidence
Trial
NCT00538694
2001-09-30
NCT00540072
2002-02-27
NCT00093067
2005-02
NCT00136292
2006-08-09
NCT00295178
2006-08-09
NCT00426933
2007-09
14 further recorded trials
NCT00490737
2008-05-12
NCT00679835
2008-11-20
NCT00858325
2009-03
NCT01080963
2012-03
NCT01211470
2012-03
NCT01019395
2012-03-20
NCT00507247
2012-09
NCT02052388
2014-10
NCT01626560
2015-03
NCT02097953
2016-07
NCT02660346
2018-01-30
NCT03004066
2019-03-31
NCT02972983
2019-09
NCT01792804
2020-03-26
Q8
At the median, Daptomycin's trials enrolled 46.5 people — anything larger?
Median enrolment
46.5
Largest enrolment
8000
Registered trials counted
76
Where it is registered
Where it’s registered
Withdrawn in United States, 2020, for "Presence of Particulate Matter" (openFDA drug enforcement Class I recall)
ClinicalTrials.gov — US Government work · mixed register set; per-register licences in docs/specs/corpus-20k-sources.md · openFDA / DailyMed — US Government work · openFDA enforcement — US Government work
✗ required summary fields resolved: 4 required field(s) not terminal: Why people use it, Best-supported result, Biggest unanswered question, Human evidence
✓ public claims reviewed: 0 reviewed claim(s); drafts are never rendered
✓ source coverage passed: 5 source rows
✓ no critical contamination: no quarantine open
✓ canonical metadata passed: slug and display name present
✓ no raw internal fields: enforced by the copy-contract test over the rendered page
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