A pilot randomized clinical trial of a peer support intervention for hematopoietic stem cell transplantation.

Introduction

The protracted recovery following hematopoietic stem cell transplantation (HSCT) poses substantial risks to key health-related outcomes, including psychological well-being and quality of life (QOL). 1 , 2 , 3 , 4 Up to 70% of HSCT recipients experience social isolation and loneliness due to immunosuppression-related limitations, 5 and ∼40% report clinically significant anxiety and depression during hospitalization and early recovery. 4 , 6 , 7 , 8 These risk factors, linked to poorer outcomes including reduced survival, 9 often persist into recovery. Conversely, social support and adaptive coping are key psychosocial protective factors associated with reduced distress and improved psychological outcomes, 10 QOL, 11 and survival. 12 Psychosocial interventions have yet to be specifically designed to target pre-HSCT psychosocial protective factors through acute recovery. 13 , 14 , 15

Peer support interventions represent a promising approach to address psychosocial risks and protective factors in HSCT recipients, 16 offering several advantages over existing psychosocial interventions with highly specialized interventionists (eg, mental health providers). 17 , 18 First, peer support leverages the lived experience of HSCT survivors, 19 , 20 whose shared understanding can enhance coping and complement standard transplant psychosocial care. 21 , 22 Second, peer support may benefit both recipients and interventionists, amplifying the potential impact of a peer support intervention. 19 Although peer support has been used in oncology, 23 applications in HSCT have been limited to sharing narratives. 24 , 25 Our previous qualitative work highlighted patients’ preference for live peer connection allowing for a 1-to-1 rapport building, personalized conversation, and a private opportunity to ask individualized questions about the HSCT trajectory. 26 , 27 Moreover, HSCT peer support interventions have not been manualized, theory-driven, or tested in randomized clinical trials (RCTs) to establish efficacy. 16 , 28

To address these gaps, we developed the Supporting Transplant Experiences with Peer Program (STEPP) intervention, a brief, novel, patient-centered, manualized peer support intervention delivered by HSCT survivors. 16 , 19 , 26 , 27 , 28 In this study, we conducted a pilot RCT to evaluate the feasibility and acceptability of STEPP, and to explore preliminary effects on psychosocial outcomes. We hypothesized that STEPP would be feasible, acceptable, and show promising initial effects in reducing psychological distress and enhancing QOL compared with usual care. 26 , 27

Methods

Study design

A detailed description of the study methods has been published. 27 In brief, this study was a single-center pilot RCT at the Dana-Farber Cancer Institute (DFCI). The study was approved by the Dana-Farber/Harvard Cancer Center Institutional Review Board and registered at ClinicalTrials.gov (identifier: NCT06010017 ). 29 We obtained informed consent from all participants and adhered to CONSORT guidelines. 30

Participants

From February 2024 to January 2025, we recruited adults (aged ≥18 years) with hematologic malignancies admitted for autologous or allogeneic HSCT at DFCI who could read and respond in English. Exclusion criteria included: nonmalignant hematologic conditions, second or outpatient HSCT, or acute psychiatric or cognitive disorders that could interfere with the ability to provide informed consent. 31 , 32

Recruitment and enrollment

With oncologist approval, eligible patients were approached by a clinical research coordinator 1 to 2 weeks before their scheduled HSCT admission. Interested individuals provided informed consent, completed baseline assessments, and were enrolled in the study.

Randomization

We conducted 1:1 randomization to STEPP or usual transplant care control using a computer-generated randomization scheme. Randomization was stratified by transplant type (autologous vs allogeneic HSCT) to account for differences in hospitalization and recovery experiences. 33 Assignments were concealed in numbered envelopes. Given the nature of the intervention, blinding was not possible.

Usual care control

Participants assigned to usual care did not receive STEPP but, like all patients treated at DFCI, had access to individual meetings with an inpatient HSCT social worker as part of routine care. 34

STEPP intervention development and procedures

A comprehensive description of STEPP development, procedures, interventionist recruitment, and training has been published. 27 Briefly, STEPP is a 5-week manualized phone-delivered peer support intervention consisting of weekly 30- to 60-minute sessions delivered before the conditioning regimen and day 0, from before to after transplant, during which peer support interventionists guide participants through discussions on informational, emotional, and practical social support topics ( supplemental Table 1 ). The intervention modules, informed by previous research on social support for patients with cancer, include reflective exercises and components of established psychotherapeutic approaches such as cognitive behavioral therapy, mindfulness, and positive psychology. 16 , 28 , 35 STEPP was developed by a transdisciplinary team of HSCT recipients, mental health clinicians, oncologists, and researchers with lived experience. 26 , 27 , 36 STEPP was further informed by qualitative studies on HSCT peer support and refined using feedback from patient exit interviews after our previous single-arm proof-of-concept trial. 16 , 26 , 28 Peer support interventionists were matched with participants by transplant type (ie, autologous or allogeneic) to address transplant-specific questions. Peer support interventionists were trained to tailor discussions and shared experiences to each participant’s individual interests, needs, and questions about the transplant process. The initial session was scheduled by the study coordinator; subsequent sessions were arranged by peer support interventionists according to patient preferences and availability, with assistance from the coordinator as needed.

Interventionists recruitment and training

Peer interventionists were adults (aged ≥18 years) who had undergone HSCT at DFCI within the past 2 to 3 years, ensuring stability in their recovery and the ability to meaningfully recall their treatment experiences. Interventionists received extensive training by H.L.A., M.G., and E.P.K. via Zoom version 1.10.3.2581 (Zoom Video Communications, Inc, San Jose, CA) to ensure adequate preparation. 37

Intervention fidelity

All intervention sessions were recorded by interventionists with patient permission. Weekly fidelity assessments were conducted using a standardized checklist adapted from previous supportive interventions to evaluate adherence to manual content, participant engagement, and rapport building. 38 Feedback was provided individually and in monthly 1-hour supervision meetings over Zoom.

Assessment measures

Assessments were administered at baseline (within 14 days before HSCT, before the conditioning regimen and day 0, and before HSCT hospitalization), immediately after STEPP (30 days after HSCT), and 1 month later (60 days after HSCT) to determine the sustained effects of STEPP. 39 At the 60-day post-HSCT assessment time point, participants also reported any previous peer support experiences related to their cancer diagnosis or HSCT.

Sociodemographic and clinical characteristics

At baseline, all participants self-reported sociodemographic characteristics, including sex, race, ethnicity, age, and living situation. Clinical characteristics, including disease- and treatment-related data, were extracted from the electronic health record.

Primary end points: feasibility and acceptability

Feasibility was a priori defined as ≥60% enrollment of eligible patients and ≥60% of STEPP participants completing at least 3 of 5 intervention sessions. 39 , 40 , 41 STEPP intervention acceptability was assessed at day 30 using 7 items of the 8-item Client Satisfaction Questionnaire (CSQ). 42 After reverse-scoring 4 of 8 items, CSQ item scores range from 1 (low satisfaction) to 4 (high satisfaction) and the total score ranges from 8 to 32, with higher total scores indicating greater satisfaction. Acceptability was a priori defined as an average CSQ-8 item score of ≥3 of 4.

Exploratory end points

Anxiety and depression symptoms

The 14-item Hospital Anxiety and Depression Scale was used to assess symptoms of anxiety and depression over the past week. 43 The Hospital Anxiety and Depression Scale includes 2 7-item subscales for anxiety and depression. Total scores on each subscale range from 0 to 21; higher scores indicate more severe symptoms of anxiety or depression.

Posttraumatic stress symptoms

The 17-item Post-Traumatic Stress Disorder Checklist–Civilian Version was used to assess the severity of posttraumatic symptoms related to cancer in the past month. 44 The Post-Traumatic Stress Disorder Checklist–Civilian Version total scores range from 17 to 85, with higher scores indicating more severe posttraumatic stress symptoms.

QOL

The 50-item Functional Assessment of Cancer Therapy–Bone Marrow Transplant 41 was used to assess QOL over the past week. 41 Total scores range from 0 to 148, with higher scores indicating better QOL.

Social support

The 25-item Social Support and Effectiveness Questionnaire was used to assess patients’ perceptions of and satisfaction with social support over the past 3 months. Social Support and Effectiveness Questionnaire total scores range from 0 to 80, with higher scores indicating greater satisfaction with perceived support.

Self-efficacy for managing cancer

The 17-item Cancer Self-Efficacy Scale was used to evaluate patients’ confidence in handling the effects of their illness and transplant on the day of assessment completion. 45 Cancer Self-Efficacy Scale total scores range from 0 to 170, with higher scores indicating higher levels of self-efficacy.

Positive affect

The 10-item Positive Affect subscale of the Positive and Negative Affect Schedule was used to assess the extent to which patients experienced positive affect over the previous week. Positive and Negative Affect Schedule total scores range from 10 to 50, with higher scores indicating a greater degree of positive affect.

Gratitude

The 6-item Gratitude Questionnaire was used to measure dispositional gratitude. The 6-item Gratitude Questionnaire total scores range from 6 to 42, with higher scores indicating greater gratitude in daily life.

Flourishing

The 8-item Flourishing Scale was used to assess patients’ perceived success in key areas, such as engagement, relationships, self-esteem, meaning and purpose, and optimism. Total scores range from 8 to 56, with higher scores reflecting stronger self-perceived psychological resources and well-being.

Statistical methods

Primary end points

Analyses were conducted using Stata version 18.0 (StataCorp, College Station, TX). Statistical analyses were conducted by H.L.A. and B.C.H., and all authors had access to the primary clinical trial data. Descriptive statistics summarized sociodemographic and clinical characteristics (means and standard deviations [SD] for continuous variables; proportions for categorical variables). Treatment group comparisons (ie, STEPP vs usual care) included all randomized patients who received the transplant regardless of intervention adherence.

Exploratory end points

Longitudinal mixed-effects models with maximum likelihood estimation were used to examine changes in patient-reported outcomes (PROs; eg, anxiety, depression, self-efficacy, positive psychological well-being) at 30 and 60 days after HSCT, controlling for baseline values, transplant type, sociodemographic, and clinical factors. Models included main effects of treatment (STEPP vs usual care), time of study assessments (baseline [within 14 days before HSCT, before conditioning and day 0, and before HSCT hospitalization], day 30 after HSCT, and day 60 after HSCT), and transplant type (autologous vs allogeneic HSCT) as well as the interaction terms (treatment-by-time, transplant-type-by-time, and treatment-by-transplant-type). Missing data were assumed missing at random. Each effect size was estimated as the mean change difference divided by the SD of the change using variance components from the mixed model. Effect size estimates were interpreted according to the following absolute value cutoffs: small (0.177), medium (0.329), and large (0.557). 46 A priori, we defined a P value <.05 as statistically significant.

Power consideration

For feasibility and acceptability end points, power estimates were based on a target sample size of 90 participants, informed by previous trials. 47 , 48 Accounting for an anticipated 10% to 15% attrition due to transplant complications and assuming at least 80% sessions completion, 47 we aimed for a minimum of 40 participants to complete STEPP. With 40 STEPP completers, this provided 99% power (2-sided α = 0.05, binomial proportion test) to show that >50% will complete at least 3 of 5 STEPP sessions.

Results

The CONSORT diagram is presented in Figure 1 . Of 158 potentially eligible patients who underwent HSCT, 117 were approached, 95 consented, and 90 (76.9%) enrolled after completing baseline assessments. Among the 5 patients who consented but did not enroll, 3 did not complete the baseline assessment, 1 revoked consent, and 1 became ineligible due to transplant postponement before baseline completion. After enrolling 90 participants (STEPP, n = 45; usual care, n = 45), 12 became ineligible (3 transplant cancellations, 8 transplant postponements, and 1 randomization error), resulting in a final sample of 78 (STEPP, n = 38; usual care, n = 40).

Participant characteristics

Among 78 participants, the mean age was 58.9 years (SD, 12.3); most were female (n = 45 [57.7%]), White (n = 72 [92.3%]), married (n = 63 [80.8%]), and had completed some college education or higher (n = 69 [88.5%]). Of note, 82% of study participants reported no previous peer support experiences. Baseline sociodemographic and clinical characteristics were balanced between groups ( Table 1 ).

Feasibility and acceptability

The 76.9% enrollment rate exceeded our a priori feasibility benchmark of 60%. Of those randomized to STEPP, 38 of 38 (100%) completed at least 3 of 5 intervention sessions, and 37 of 38 (97.4%) completed all 5 sessions, with 1 unable to finish due to worsening physical symptoms. Retention rates were also high: 92.3% at 30 days after HSCT, and 84.6% at 60 days. Participants randomized to STEPP reported mean CSQ scores of 3.5, exceeding our a priori threshold of ≥3 of 4 on the average item scores.

Preliminary effects of STEPP on exploratory end points

Table 2 summarizes the preliminary effects of STEPP vs usual care on exploratory outcomes at day 30 after HSCT. At day 30, STEPP participants reported larger reductions in anxiety compared with usual care (difference [Δ], −1.27 [95% confidence interval (CI), −2.93 to 0.38]; d = −0.36). Differences between groups were small based on effect size estimates for depressive symptoms (Δ, −0.07 [95% CI, −1.69 to 1.55]; d = −0.02), posttraumatic stress symptoms (Δ, −0.56 [95% CI, −4.06 to 2.93]; d = −0.07), QOL (Δ, 1.97 [95% CI, −6.50 to 10.4]; d = 0.11), social support (Δ, 0.86 [95% CI, −3.31 to 5.02]; d = 0.10), self-efficacy (Δ, 3.71 [95% CI, −7.42 to 14.9]; d = 0.16), gratitude (Δ, −0.79 [95% CI, −2.64 to 1.07]; d = −0.20), and flourishing (Δ, −0.78 [95% CI, −3.31 to 1.74]; d = −0.14). STEPP participants reported larger reductions in positive affect compared with usual care (Δ, −3.79 [95% CI, −8.04 to 0.45]; d = −0.42) at day 30.

Table 3 summarizes the preliminary effects of STEPP vs usual care at day 60 after HSCT. Compared with usual care, STEPP participants reported larger reductions in anxiety (Δ, −1.89 [95% CI, −3.43 to −0.35]; d = −0.58), depression (Δ, −0.69 [95% CI, −2.03 to 0.66]; d = −0.25), and posttraumatic stress (Δ, −2.11 [95% CI, −5.76 to 1.54]; d = −0.28). STEPP participants also reported greater improvements in QOL (Δ, 7.02 [95% CI, −0.02 to 14.1]; d = 0.48), social support (Δ, 2.75 [95% CI, −0.91 to 6.41]; d = 0.36), and self-efficacy (Δ, 10.5 [95% CI, −0.39 to 21.4]; d = 0.46). Day 60 differences between groups were small based on effect size estimates for positive affect (Δ, −0.37 [95% CI, −4.09 to 3.34]; d = −0.05), gratitude (Δ, 0.10 [95% CI, −1.61 to 1.81], d = 0.03), and flourishing (Δ, 0.19 [95% CI, −2.12 to 2.50]; d = 0.04).

Discussion

To our knowledge, this study is the first to demonstrate the feasibility and acceptability of a structured peer support intervention specifically tailored for patients who underwent HSCT. In this pilot RCT, STEPP proved feasible and well-accepted among recipients of both allogeneic and autologous HSCT, exceeding a priori feasibility and acceptability benchmarks. STEPP showed promising preliminary signals for PROs, including immediate and sustained reductions in anxiety and improvements in depressive and posttraumatic stress symptoms, QOL, social support, and self-efficacy for managing cancer compared with usual care by 60 days after HSCT. Following the National Institute of Health Stage Model for Behavioral Intervention Development, 49 these findings can guide future fully powered randomized efficacy trials evaluating STEPP’s impact on patient-reported psychosocial outcomes. Overall, results highlight STEPP’s feasibility and acceptability, with potential to address critical gaps in psychosocial care for the HSCT population.

STEPP’s feasibility and acceptability are further demonstrated by high consent, enrollment, and retention rates compared with other psychosocial intervention trials in this population, 36 , 47 , 50 despite the physical and emotional challenges of HSCT hospitalization and recovery. 4 , 6 , 7 Most participants completed all 5 sessions, reflecting strong engagement. We also confirmed the feasibility of training survivors of HSCT to deliver a structured psychosocial intervention and assessing intervention fidelity with rigor comparable to that applied to interventions led by mental health professionals. 51 , 52 This trial could serve as a model for implementing structured peer support in other underserved oncological populations. Acceptability rates from this pilot RCT indicated high patient satisfaction with STEPP (eg, rating STEPP as “excellent” and being “very satisfied”), potentially reflecting the value of STEPP for facilitating a connection between current recipients and survivors of HSCT and helping to normalize the challenges and overall experience of the transplant process. Another unique advantage is its remote delivery, enhancing accessibility for socially isolated HSCT recipients. Future work will directly assess STEPP’s impact on social isolation and loneliness during hospitalization and recovery.

Preliminary effects on PROs revealed promising signals for STEPP’s effects on psychological distress, QOL, social support, and self-efficacy for managing cancer. STEPP’s preliminary effects on anxiety may reflect decreased physiological and cognitive arousal at completion (day 30 after HSCT) and continuing through day 60. Similar to previous work, 53 , 54 , 55 STEPP’s timing and emphasis on coping may have reduced participants’ psychological distress during a particularly stressful period. If replicated in a future full-scale RCT, STEPP has potential to help reduce distress without relying on scarce specialty-trained psychosocial and supportive care clinicians. 56 Emerging signals of benefit on other measures of psychological distress (eg, depressive and posttraumatic stress symptoms) and on QOL, social support, and self-efficacy by day 60 may reflect enhanced adaptation during early post-HSCT recovery and opportunities to practice skills after discharge. Contrary to expectations, a short-term decline in positive affect was observed immediately after intervention but was negligible by day 60. This may reflect STEPP’s impact on increasing emotional awareness and expression while reducing avoidance, consistent with findings from other psychosocial interventions. 57 , 58 STEPP’s effects on PROs require further investigation in a larger, fully powered efficacy RCT with longer follow-up and measures assessing skills practice. Future trials should examine potential mediators and moderators to determine how and for whom STEPP works best. 59

Several study limitations should be considered. First, although a sample of 78 was sufficient for assessing feasibility and acceptability, larger, fully powered trials are needed to evaluate STEPP’s efficacy for improving PROs especially as it pertains to clinical benchmarks to inform clinical decision-making. Second, the study was conducted at a major academic medical center with extensive psychosocial resources, limiting generalizability to settings with fewer services. Future research should test STEPP in diverse clinical and community settings to assess its broader impact. Third, materials were only available in English. Given the unique support needs of patients from non-English speaking and underserved backgrounds, 60 , 61 future work should culturally adapt STEPP with feedback from clinicians and patients. Fourth, the duration of STEPP’s effect should be assessed in future trials, as no follow-up is planned beyond this pilot. Lastly, because of the intervention’s nature, participants and staff were not blinded to randomization, potentially introducing bias.

In summary, STEPP is feasible and acceptable for patients undergoing HSCT, showing promising signs for improving PROs. It represents a potentially scalable, accessible approach to bridging critical psychosocial care gaps in this population. The next essential step is a fully powered, multisite efficacy trial to evaluate STEPP’s effects on patient-reported psychosocial outcomes.

Conflict-of-interest disclosure: A.E.-J. serves as a consultant for Incyte Corporation, GlaxoSmithKlein, and Novartis. The remaining authors declare no competing financial interests.

Acknowledgments

A.E.-J. is a Scholar of Clinical Research for the Leukemia and Lymphoma Society. H.L.A. is supported by the Robert Wood Johnson Foundation, American Society for Hematology Harold Amos Medical Faculty award, and the Doris Duke Charitable Foundation’s Clinician Scientist Development award.

Authorship

Contribution: H.L.A. conceptualized the study; E.P.K. and H.L.A. curated the data; B.C.H. and H.L.A. conducted the formal analysis; H.L.A. acquired funding, performed the investigation, developed the methodology, administrated the project, created the visualization, and wrote the original draft; E.P.K., M.G., and H.L.A. supervised the study; and all authors reviewed and edited the manuscript and provided final approval of the manuscript, and agree to be accountable for all aspects of the work.

Footnotes

Original data are available from the corresponding author, Hermioni L. Amonoo ( hermioni_amonoo@dfci.harvard.edu ), on request.

The full-text version of this article contains a data supplement.

Supplementary Material

Supplemental Table

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