A Study of the Safety and Efficacy of MK-0773 in Women With Sarcopenia (Loss of Muscle Mass)(MK-0773-005): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Study of the Safety and Efficacy of MK-0773 in Women With Sarcopenia (Loss of Muscle Mass)(MK-0773-005) (NCT00529659), a randomized phase 2 study. The primary outcome is Change From Baseline in Participant Lean Body Mass.

2. Clinical Question

The clinical question is about a measured change in body composition, not about whether an individual participant gained muscle or experienced a functional improvement. The posted primary result is a comparison of group means among participants meeting the full analysis set definition. The study summary describes the overall purpose as evaluating safety, tolerability, and efficacy in women with sarcopenia.

Interpreting the result requires keeping the endpoint and the population in view. Lean body mass is the primary measured outcome; it is distinct from the functional measures listed as secondary outcomes. The registry record does not report a threshold for a clinically important difference in lean body mass, so the statistical estimate alone cannot establish how meaningful its size is to participants. The functional outcomes provide a broader set of measures, but their findings should be understood in light of the primary result and the uncertainty and multiplicity considerations.

3. Trial Design

The registry record describes a Phase IIa randomized, placebo-controlled clinical trial of MK-0773 in patients with sarcopenia. The study title and summary specify women with sarcopenia. It used a double-masked, parallel-group design, with MK-0773 and placebo as the two arms. The record lists enrollment of 170, and the study status is completed.

The study start is recorded as 2007-10 and primary completion as 2009-10. These dates describe the registry record; they do not, on their own, establish when every participant entered, completed treatment, or had an outcome measured. The primary outcome timeframe is baseline to Month 6. The primary analysis population is defined as participants who received at least one dose of study therapy and had a post-randomization lean body mass measurement. The arm counts in that primary analysis are 65 for MK-0773 and 60 for placebo, so these analysis counts are not the same as the overall enrollment figure.

Random allocation is intended to make treatment groups comparable on average, while masking is intended to limit influences on care and assessment related to knowledge of assignment. A parallel-group design means participants were assigned to one study arm rather than being described as crossing between treatments. These general features support a between-group comparison, but they do not remove uncertainty or guarantee that every source of bias is absent.

The registry record does not report the allocation method in more detail, the masking procedures, dose or duration details, adherence, withdrawals, or reasons for missing outcome measurements. It also does not report the trial's original sample-size justification or a detailed statistical analysis plan. Those matters should not be inferred from the study's design label or from the sample-size planning illustration associated with the posted effect.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Before assignment: After a 2-week placebo run-in period, patients were randomized in a 1:1 ratio to receive treatment with either oral MK-0773 50 mg twice daily or matching placebo.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: The full analysis set (FAS) included all participants that received at least one dose of the study therapy and had a post-randomization measurement of lean body mass.

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Change From Baseline in Participant Lean Body Mass, measured over Baseline, Month 6.

The primary endpoint is change from baseline in participant lean body mass, measured in kg at baseline and Month 6. Lean body mass is a continuous measure of body composition. The registry record reports the mean change and standard deviation in each study arm, then presents a between-arm mean difference. This endpoint addresses the study's central question about change in muscle-related body mass, while the separately listed physical performance outcomes capture aspects of function.

Using a continuous measure allows the analysis to represent the average amount of change rather than reducing participants to categories such as improved or not improved. A mean is useful for comparing the overall direction and magnitude of group changes, but it does not describe every participant's response. The standard deviation conveys how spread out individual measurements were around each arm's mean; it is not the uncertainty interval for the difference between arms.

The primary population is the full analysis set defined in the registry record: participants who received at least one dose and had a post-randomization lean body mass measurement. Thus, the reported comparison concerns participants meeting that definition, not necessarily every participant enrolled. The record does not provide a clinically important threshold for this measure or detail how baseline and follow-up measurements were handled beyond the stated change-from-baseline timeframe. Statistical evidence about a mean difference therefore should not be equated with evidence that a difference is clinically important for every participant.

7. Results Posted in the Registry

• MK-0773: mean 1.26 versus 0.29 on control; difference 0.97 (95% CI 0.55 to 1.39), standardized effect d = 0.82; z-test p = <0.001.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Change From Baseline in Participant Short Physical Performance Battery (SPPB)

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • MK-0773: mean 0.92 versus 0.88 on control; difference 0.04 (95% CI -0.52 to 0.60), standardized effect d = 0.02; z-test p = 0.888.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between MK-0773 and the control. The interval gives the range of effects that remain compatible with the data.

Change From Baseline in Participant Gait Speed

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • MK-0773: mean 6.24 versus 8.91 on control; difference -2.67 (95% CI -8.32 to 2.98), standardized effect d = -0.16; z-test p = 0.354.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between MK-0773 and the control. The interval gives the range of effects that remain compatible with the data.

Change From Baseline in Stair Climbing Power

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • MK-0773: mean 19.68 versus 14.98 on control; difference 4.70 (95% CI -3.03 to 12.43), standardized effect d = 0.21; z-test p = 0.233.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between MK-0773 and the control. The interval gives the range of effects that remain compatible with the data.

The secondary outcomes cover several dimensions of physical function: the Short Physical Performance Battery, gait speed, stair climbing power, and the AM-PAC physical movement score. The posted numerical comparisons are available for the first three listed measures; the AM-PAC outcome is listed among secondary outcomes but a result for it is not reported in the registry record. This means the secondary results do not form a complete account of every functional outcome named in the record.

Across the three posted functional comparisons, estimates differ in direction and all confidence intervals include zero. The pattern is therefore not a consistent set of clear between-arm differences that parallels the primary lean body mass result. This does not demonstrate that body composition and function are unrelated; the registry record does not report an analysis of that relationship. It does mean that the primary body-composition comparison should not be presented as evidence of a corresponding functional change.

These secondary findings also carry less inferential weight because their p-values are unadjusted and the registry record does not report a plan for controlling multiplicity. When researchers examine multiple endpoints, the chance of an apparently notable result among them can increase. A multiplicity procedure may alter the evidential interpretation, but no such adjustment is reported. Secondary outcomes can still help describe the range of measured results and identify questions for further study, but an isolated result should not be treated as definitive evidence without considering the number of comparisons, uncertainty, and whether the outcome was prespecified as primary or secondary.

The registry record does not report secondary analyses beyond the posted results or the AM-PAC numerical findings. Interpretation is consequently limited to the endpoints and summaries available in the record. The secondary pattern neither confirms nor overturns the primary finding; it places that finding in context by showing that clear statistical evidence in the primary measure was not accompanied by equally clear evidence across the posted functional measures.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Change From Baseline in Participant Short Physical Performance Battery (SPPB)
• Change From Baseline in Participant Gait Speed
• Change From Baseline in Stair Climbing Power
• Change From Baseline in Activity Measure for Post Acute Care (AM-PAC) Physical Movement Score

9. Statistical Interpretation

10. Statistical Methods Explained

The posted endpoints are continuous outcomes reported as mean change from baseline. For each arm, the registry results give a number of participants, a mean change, and a standard deviation. A mean difference compares the arm means; its sign depends on which arm's mean is subtracted from the other. In the posted comparisons, the direction is MK-0773 relative to placebo. A positive estimate means the reported mean change was higher in the MK-0773 arm, while a negative estimate means it was lower. This arithmetic description does not assign clinical value to a direction without considering the endpoint.

What does a mean and standard deviation describe?

The mean is the average change in the analyzed group. It is a compact summary and can be useful for comparing groups, but it does not imply that all participants changed by that amount. The standard deviation describes the spread of participant measurements around the arm mean. A larger standard deviation indicates greater dispersion in those observed changes. It is not a standard error and is not a confidence interval for the treatment contrast.

The primary endpoint's means were 1.26 kg for MK-0773 and 0.29 kg for placebo, with standard deviations of 1.09 and 1.29 kg, respectively. The comparison reports a mean difference of 0.97 kg. For a continuous measure, this is expressed in the same unit as the measure. The registry result also gives an unadjusted p-value and a confidence interval for the difference, which address inferential uncertainty rather than the spread of participant-level values.

What does a p-value tell the reader?

In general, a p-value describes how incompatible the observed data are with a specified no-difference model, under the assumptions of the analysis. It is not the probability that the null hypothesis is true, nor does it measure the probability that the result will replicate. The primary unadjusted p-value is < 0.001. The secondary p-values are 0.888, 0.354, and 0.233. Because they are unadjusted, they should be read as individual comparisons rather than as results corrected for examining multiple endpoints.

The registry record does not report a sponsor-conducted inferential analysis for these outcomes. The posted arm summaries can be used for simple, unadjusted comparisons, but those should not be mistaken for a full account of the trial's prespecified analysis. The record does not provide enough detail to state the model, covariate adjustment, assumptions checks, or handling of repeated measurements used in any original sponsor analysis. The registry result's reported population definition does make clear who contributed to the primary comparison.

Why does the confidence interval matter?

In general, a confidence interval gives a range of values compatible with the data and the method used to calculate it. Its width conveys precision: narrower intervals indicate greater precision, while wider intervals indicate more uncertainty about the size of the effect. For the primary comparison, the interval is above zero. The secondary intervals include zero. This distinction helps show why a p-value should not be considered in isolation. The interval also communicates which effect sizes remain plausible under its assumptions, although it does not account automatically for unreported analysis choices or multiplicity.

What is the role of the analysis population?

The primary endpoint population was the full analysis set, defined as participants who received at least one dose of study therapy and had a post-randomization lean body mass measurement. This definition is important because it describes the participants represented by the primary estimate. It does not equal the overall enrollment by definition, and it may exclude participants without the required measurement. The record does not report how many enrolled participants lacked a post-randomization measurement or why, so the potential effect of those exclusions cannot be assessed from the posted record.

The primary arm counts were 65 and 60. Secondary outcome counts vary by endpoint, reflecting the populations with posted measurements for those analyses. The record does not provide further detail on whether missing measurements were imputed or whether sensitivity analyses examined alternative assumptions. In general, missing-data methods matter because an analysis based only on observed measurements can be affected if the chance of having a measurement is related to outcome or study arm.

What can be inferred from the reported analyses?

The posted comparisons are unadjusted summary-statistic comparisons. They provide a direct way to describe the observed arm means and estimated differences, but they do not establish the full analytical strategy used by the sponsor. The record lists no reported secondary analyses. There is also no reported adjustment for baseline covariates, no reported subgroup analysis, and no reported interim analysis. These are statements about what is not reported in the registry record, not claims that such analyses were or were not conducted outside it.

General statistical reasoning also cautions against treating planning illustrations based on an observed effect as evidence about the trial's original design. Such illustrations answer a hypothetical question about participants needed to detect a chosen effect under stated assumptions. They are not estimates of the probability that this completed trial detected a true effect. The original sample-size justification and assumptions are not reported in the registry record.

11. Confidence Intervals and Precision

Precision concerns how tightly the data estimate the difference between group means. A confidence interval expresses uncertainty around that estimate under the calculation method. In general, a narrower interval offers a more precise estimate, while a wider interval leaves more uncertainty about the size and sometimes the direction of the underlying difference.

For lean body mass, the posted mean difference is 0.97 kg, and its confidence interval lies entirely above zero. The result therefore supports a positive difference in mean change under the interval's assumptions. The interval should be considered alongside the estimate: the estimated difference is not known without uncertainty, and the p-value alone does not show the range of effect sizes compatible with the data. The registry record does not report a clinically important threshold, so the interval cannot by itself determine whether its values correspond to meaningful change for participants.

For the three posted functional comparisons, the confidence intervals include zero. This means the data are compatible with no difference as well as with values in either direction represented by the intervals. It does not prove that the true differences are zero, nor does it establish equivalence. The secondary estimates are less conclusive about direction and magnitude than the primary result.

Precision also depends on the analyzed sample and variability. In general, more observations can improve precision when other factors are similar, while greater variation can make estimates less precise. The primary analysis includes 65 participants in the MK-0773 arm and 60 in the placebo arm; the functional endpoint counts are similar but vary by measure. The registry record does not report enough detail to evaluate how missing data, model choices, or any unreported analysis decisions may affect the precision of the original sponsor analysis.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The planning figures describe hypothetical participants per arm for 80% power and 90% power, not total events. The stated assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. Each scenario uses the stated fraction of the observed effect as the effect to detect. The registry record does not report the trial's original sample-size assumptions or justification.

For the primary endpoint, planning for 100% of the observed effect gives 24 participants per arm for 80% power and 32 participants per arm for 90% power. Planning for 75% of the observed effect gives 43 participants per arm for 80% power and 57 participants per arm for 90% power. Planning for 50% of the observed effect gives 95 participants per arm for 80% power and 127 participants per arm for 90% power. These are planning illustrations based on the observed result, not a reconstruction of the study's original design.

In plain terms, 80% power is the planned chance of detecting the specified effect under the stated assumptions if that effect is real; 90% power is a higher planned chance under the same conditions. Achieving the higher target generally requires more participants. The illustration also shows that planning to detect a smaller effect requires more participants than planning to detect a larger one. The figures are not observed power: they do not describe the probability that the completed trial found a true effect, and they should not be used as a substitute for interpreting the estimate and its confidence interval.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = 0.970; pooled standard deviation σ = 1.190.
2. n = 2 × (1.96 + 0.842)² × 1.190² / 0.970² = 23.6, rounded up to 24 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- 0.97                      # observed difference in means
sigma <- 1.19013663217802                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(529659)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 24 (80% power), 32 (90% power)
 75% of observed effect: n per arm = 43 (80% power), 57 (90% power)
 50% of observed effect: n per arm = 95 (80% power), 127 (90% power)
power.t.test: 24.6 
Simulated power at n = 24 per arm: 0.789 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Multiplicity, Missing Data and Analysis Populations

Multiplicity arises when a study tests more than one outcome or makes multiple comparisons. Even if each individual test uses a conventional significance threshold, examining several results increases the possibility that at least one will appear statistically notable by chance. Researchers may address this through a prespecified hierarchy, family-wise error control, false discovery procedures, or other approaches. The registry record does not report a multiplicity adjustment or a hierarchy for interpreting the listed outcomes. The posted p-values should therefore be read as unadjusted comparisons, especially for secondary endpoints.

The primary outcome is identified as change in lean body mass, while the registry record lists functional measures as secondary outcomes. This distinction gives the primary comparison a different interpretive role from the secondary findings, but it does not establish the exact testing strategy used in the original protocol. The record does not report a full statistical analysis plan, interim analyses, stopping rules, or whether any outcomes were changed or added after study initiation. These matters are not reported in the registry record and should not be inferred.

Missing-data information is also limited. The primary full analysis set required at least one dose and a post-randomization lean body mass measurement. The record does not report how many participants lacked such a measurement, the reasons for missingness, or the methods used to address missing data. It does not report sensitivity analyses that would show how the result changes under different assumptions about missing outcomes. Missing data can matter when participants with absent measurements differ systematically from those whose outcomes are observed.

The arm counts contributing to the primary endpoint are 65 for MK-0773 and 60 for placebo, while the registry lists enrollment of 170. The difference in these counts does not itself explain why some enrolled participants are absent from the primary analysis; the reasons and disposition are not reported in the registry record. The registry record also does not provide a detailed account of the randomized analysis population or confirm that a separate intention-to-treat analysis was performed. These omissions limit assessment of how robust the posted endpoint result is to population definitions and analysis choices.

15. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: alanine aminotransferase increased (2.5%), aspartate aminotransferase increased (2.5%), cardiac failure congestive (1.2%), supraventricular tachycardia (1.2%), abdominal distention (1.2%).

The safety results report serious adverse events in 12 of 81 participants at risk in the MK-0773 group and 9 of 89 at risk in the placebo group. Other adverse events are reported for 50 of 81 participants at risk in the MK-0773 group and 52 of 89 at risk in the placebo group. These are counts of participants, with the relevant at-risk group sizes stated in the registry record; they should not be confused with the primary efficacy analysis counts.

The registry record lists serious adverse event terms including Alanine aminotransferase increased and Aspartate aminotransferase increased, each at 2.5%; Cardiac failure congestive and Supraventricular tachycardia, each at 1.2%; and Abdominal distention and Abdominal pain upper, each at 1.2%. These are the listed terms and percentages, not a complete description of clinical course or severity for each participant.

Death counts are not reported in the registry record. The posted counts alone do not establish whether a difference in safety risk exists, and they do not give enough information to assess event timing, duration, relatedness, or all potential adverse events. They describe the reported safety experience in this study and should be interpreted with those limits in mind.

16. What the Result Does, and Does Not, Mean

The main statistical result is a higher mean change in lean body mass in the MK-0773 group than in the placebo group over the stated baseline-to-Month-6 timeframe. The estimated mean difference is 0.97 kg, and the unadjusted p-value is < 0.001. The interval for that estimate lies above zero. Taken together, these posted statistics provide evidence of a difference in average change in the analyzed groups under the assumptions of the comparison.

That conclusion is narrower than a claim about every participant or every outcome. Group means do not show how many individuals experienced an increase, how changes were distributed, or whether a particular participant would have a similar result. The primary endpoint is lean body mass, not a direct report of physical function. The functional comparisons have intervals that include zero, and the registry record does not report an analysis linking body composition changes with functional changes.

The result also does not determine clinical importance. The registry record does not report a threshold for a meaningful lean body mass change, and statistical evidence alone cannot supply one. Nor does the posted primary comparison establish the full benefit-risk profile: safety results are limited to the reported event counts and terms, with death counts not reported in the registry record.

Interpretation is restricted to the study population and analysis definition. The primary endpoint involved participants who received at least one dose and had a post-randomization measurement. The registry record does not report details needed to assess all missing data, analysis assumptions, or multiplicity. Consequently, the posted result is informative about the observed group comparison, but it does not establish what would happen in other populations, under other conditions, or for outcomes not reported. It is a statistical finding, not medical advice or a basis for an individual treatment decision.

17. Why This Trial Matters Statistically

This trial illustrates why a clinical result should be read at the level of its endpoint, population, and uncertainty. Its primary outcome is a continuous body-composition measure, summarized with arm means and standard deviations and compared using a mean difference. That presentation makes the scale and direction of the estimated difference explicit, while the confidence interval indicates that the estimate is not exact.

It also illustrates the importance of distinguishing a primary measure from functional outcomes. The primary comparison shows a difference in mean lean body mass change, whereas the posted functional comparisons do not provide similarly clear evidence of between-arm differences. A body-composition result should not automatically be interpreted as a functional result. Keeping related but distinct outcomes separate prevents an overstatement of what the data establish.

The registry record further demonstrates how incomplete reporting can constrain statistical interpretation. The full analysis set is defined, and outcome counts are posted, but the original sample-size rationale, detailed statistical plan, multiplicity handling, and missing-data methods are not reported. Without those details, readers can describe the posted summaries and simple comparisons, but cannot fully evaluate every design and analysis decision.

Finally, planning illustrations based on the observed effect are useful for understanding how assumed effect size and power targets relate to hypothetical enrollment needs. They do not reveal the trial's original design assumptions and are not observed power. Separating planning calculations from trial results helps avoid a common interpretive error: treating a retrospective illustration as proof that a completed study was adequately designed or that its result is certain.

18. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The registry record offers a limited account of the analysis underlying the posted results. It does not report the original sample-size justification, full statistical analysis plan, detailed allocation procedures, or methods used for missing data. The sponsor's inferential analyses are not reported in the registry record, and the posted unadjusted comparisons do not replace those analyses. As a result, important details about modeling, covariate adjustment, and sensitivity checks cannot be evaluated.

The primary analysis population excludes participants who did not meet the full analysis set definition, which required receipt of at least one dose and a post-randomization lean body mass measurement. The reasons that some enrolled participants are not represented in the primary arm counts are not reported in the registry record. The record does not describe withdrawals, measurement availability, or whether missingness differed by group. This limits assessment of selection and missing-data effects.

Multiplicity is another limitation. Multiple secondary outcomes are listed, but the record does not report a correction or testing hierarchy. The AM-PAC physical movement score is named as a secondary outcome, but its numerical result is not reported in the registry record. The available functional results therefore do not cover every listed secondary measure, and their unadjusted p-values require cautious interpretation.

Safety reporting is also bounded by the posted information. Serious and other adverse event counts are listed, along with selected serious event terms, but the record does not provide event timing, duration, relatedness, or death counts. Finally, no threshold for clinically important change in lean body mass is reported. Statistical significance therefore cannot be translated directly into clinical importance from this record alone.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: A Study of the Safety and Efficacy of MK-0773 in Women With Sarcopenia (Loss of Muscle Mass)(MK-0773-005) — NCT00529659.
• Registry record last updated 2015-02-16; status last verified 2015-01.
• Results first posted 2012-07-02.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

22. Record Summary

The registry record describes a completed Phase IIa, randomized, double-masked, parallel-group, placebo-controlled study of MK-0773 in women with sarcopenia. Enrollment was 170. The primary endpoint was change from baseline in lean body mass, measured in kg at Month 6. The full analysis set included participants who received at least one dose and had a post-randomization lean body mass measurement.

Mean change was 1.26 kg for 65 participants in the MK-0773 group and 0.29 kg for 60 participants in the placebo group. The posted mean difference was 0.97 kg, with an unadjusted p < 0.001. The three posted functional comparisons have confidence intervals that include zero. Safety results include serious adverse events in 12 of 81 participants at risk for MK-0773 and 9 of 89 for placebo; death counts are not reported in the registry record.

The registry record does not report the original sample-size justification, detailed analysis plan, multiplicity procedure, or missing-data methods. These omissions limit interpretation beyond the posted summaries.