Overall survival was defined as the time from the date of randomization to the date of death due to any cause. For each participant, prior to data analysis, a reasonable effort was made to obtain the most up-to-date status (date of death or last date known to be alive). For any participant not known to have died as of the data cutoff date, OS was censored at the date the participant was last known to be alive. For any participant who withdrew consent for survival follow-up, OS was censored at the last date for which the participant provided consent for follow-up contact. The Kaplan-Meier method was used to estimate median parameters.

All randomized participants. Censored participants in Doxorubicin + Olaratumab arm = 87 and Doxorubicin + Placebo arm = 91

Overall survival was defined as the time from the date of randomization to the date of death due to any cause. For each participant, prior to data analysis, a reasonable effort was made to obtain the most up-to-date status (date of death or last date known to be alive). For any participant not known to have died as of the data cutoff date, OS was censored at the date the participant was last known to be alive. For any participant who withdrew consent for survival follow-up, OS was censored at the last date for which the participant provided consent for follow-up contact. The Kaplan-Meier method was used to estimate median parameters.

All randomized participants with LMS. Censored participants in Doxorubicin + Olaratumab arm = 42 and Doxorubicin + Placebo arm = 40.

PFS was defined by (Response Evaluation Criteria In Solid Tumors RECIST v.1.1) as the time from the date of randomization to the first date of radiologic disease progression or death due to any cause. Progressive Disease (PD) is at least 20% increase in sum of diameters of target lesions, with reference being the smallest sum on study and plus absolute increase of at least 5 millimeter (mm), or unequivocal progression of non-target lesions, or 1 or more new lesions. Censoring for death or PD due to increase sum of target lesions is defined for each participant as the time from the date of randomization to the first date of radiographic documentation of 1 or more lesions. Censoring for death without progression is defined as the date of death if there is no prior or concurrent radiologic disease progression.

All randomized participants. Censored participants in the Doxorubicin + Olaratumab arm = 39 and the Doxorubicin + Placebo arm =34.

ORR was defined as the percentage of participants achieving a best overall response of complete response (CR) + partial response (PR). CR is the disappearance of all non-target lesions and normalization of tumor marker level. All lymph nodes must be non-pathological in size (<10 mm short axis). PR is at least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum diameters. CR: Disappearance of all target lesions. Any pathological lymph nodes (whether target or non-target) must have reduction in short axis to <10 mm. Tumor marker results must have normalized. Best overall response is classified based on the overall responses assessed by study investigators according to RECIST v1.1.

All randomized participants.

DCR was defined as the percentage of randomized participants achieving a best overall response of CR, PR, or SD per RECIST v.1.1. CR is the disappearance of all non-target lesions and normalization of tumor marker level. All lymph nodes must be non-pathological in size (<10 mm short axis). PR is at least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum diameters. CR: Disappearance of all target lesions. Any pathological lymph nodes (whether target or non-target) must have reduction in short axis to <10 mm. Tumor marker results must have normalized. PD is at least 20% increase in sum of diameters of target lesions, with reference being the smallest sum on study and plus absolute increase of at least 5 mm, or unequivocal progression of non-target lesions, or 1 or more new lesions. SD: neither sufficient shrinkage to qualify for PR nor sufficient increase to qualify for PD, taking as reference the smallest sum diameters while on study.

All randomized participants.

Time to first worsening was calculated as the time from the first study drug dose to the first observation of worsening according to the EORTC QLQ-C30 Scoring Manual (Fayers et al. 2001). The EORTC QLQ-C30 self-reported general cancer instrument consists of 30 total items covered by 1 of 3 dimensions (1 global health status/QoL total score, 5 functional subscales [physical, role, cognitive, emotional, and social]), and 9 symptom subscales [fatigue/nausea/vomiting/pain/dyspnea/insomnia/appetite loss/constipation/diarrhea]). There are 28 questions answered on a 4-point scale where 1=Not at all (best) to 4=Very Much (worst) and 2 questions answered on a 7-point scale where 1=Very poor (worst) to 7= Excellent (best). A linear transformation was used to obtain total score ranging from 0 to 100 where "worsening" was defined as an increase of at least 10 points for the symptom scales or a decrease of at least 10 points for the functional scales and the global health status/QoL scale.

All randomized participants who completed at least 1 baseline assessment and at least 1 subsequent assessment during the study period.

The EQ-5D-5L is a standardized measure of health status used to provide a simple, generic measure of health for clinical and economic appraisal. The EQ-5D-5L consists of a descriptive system of the respondent's health which comprises the following 5 dimensions: (mobility, self-care, usual activities, pain/discomfort, and anxiety/depression). Health status was calculated from a set of item weights to derive a score of 0 to 1, with 1 representing the best health status. United Kingdom (UK) weights were applied. The analysis includes all cycles for which at least 25% of participants in each arm have an assessment. For each participant a change from baseline was calculated for every post-baseline assessment by subtracting the baseline assessment result from the current assessment result. Maximum improvement (over baseline) was determined from the set of all post-baseline change scores.

All randomized participants who had a baseline and a post-baseline measurement.

Time to first worsening of the brief pain inventory short form modified (mBPI-sf) "worst pain score" was defined as the time from the date of the first study drug dose (baseline date) to the first date of a "worst pain" score increase of greater than or equal to (≥) 2 points from baseline. The mBPI-sf is an 11-item instrument used as a multiple-item measure of cancer pain intensity ranging from 0 (no pain or does not interfere) and ranged through 10 (pain as bad as you can imagine or completely interferes).

All randomized participants who completed at least 1 baseline assessment and at least 1 subsequent assessment during the study period.

The duration of overall response was defined for each participant with a best response of CR or PR and measured from the time measurement criteria are first met for CR or PR (whichever is first recorded) until the first date that disease is recurrent or objective disease progression or death due to any cause is observed (taking as reference for PD the smallest measurements recorded on study).

All randomized participants who have evaluable DoR data.

Duration of disease control was defined for each participant with a best response of CR, PR, or stable disease (SD) as the time from randomization to the first date of disease progression or death due to any cause.

All randomized participants who had evaluable DDC data.

The PK systemic clearance parameter estimates from the current analysis are listed together with the population PK model estimates.

All randomized participants who received at least one dose of study drug and had evaluable PK data.

The PK parameter estimates from the current analysis are listed together with the population PK model estimates. The Vss is the sum of central volume of distribution (V1) + peripheral volume of distribution (V2).

All randomized participants who had received at least one dose of study drug and had evaluable PK data.