Table 2.
Characteristics of 333 Publications of Registered Stem Cell Clinical Trials that Reported Primary Outcomes Data
| Clinical Trial Characteristic | No. of Publications (n) | No. of Publications with Positive Results n (%) | Completeness Scorea (mean ± SD) |
|---|---|---|---|
| Status | |||
| Completed | 210 | 139 (66.1) | 16.6 ± 3.7 |
| Active not recruiting | 22 | 17 (77.3) | 15.2 ± 3.8 |
| Expanded access no longer available | 2 | 2 (100.0) | 15.5 ± 2.1 |
| Recruitment ongoing | 31 | 23 (74.2) | 14.0 ± 4.1 |
| Unknown | 48 | 34 (70.8) | 15.8 ± 3.1 |
| Enrolling by invitation | 1 | 1 (100.0) | 13.0 ± 0.0 |
| Not yet recruiting, pending | 1 | 1 (100.0) | 12.0 ± 0.0 |
| Suspended, terminated, withdrawn | 18 | 7 (38.9) | 15.6 ± 3.1 |
| Phase | |||
| Phase I, phase I & II | 167 | 125 (74.8) | 15.5 ± 3.7 |
| Phase II, phase II & III | 93 | 59 (63.4) | 16.8 ± 3.8 |
| Phase III, phase III & IV | 12 | 3 (25.0) | 14.5 ± 2.9 |
| Phase IV | 14 | 8 (57.1) | 16.1 ± 2.6 |
| Not applicable or phase 0 | 47 | 29 (61.7) | 16.9 ± 3.9 |
| Graft type | |||
| Allogeneic | 69 | 47 (68.1) | 15.4 ± 3.8 |
| Autologous | 211 | 149 (70.6) | 16.2 ± 3.8 |
| Autologous and allogeneic | 2 | 2 (100.0) | 20.5 ± 0.7 |
| No graft product | 45 | 22 (48.9) | 16.2 ± 3.2 |
| Unspecified | 6 | 4 (66.7) | 15.3 ± 3.1 |
| Cell typeb | |||
| Mesenchymal | 100 | 75 (75.0) | 16.6 ± 3.3 |
| CD34+ fraction | 37 | 31 (81.6) | 16.9 ± 3.6 |
| Endothelial progenitor | 28 | 19 (90.4) | 15.1 ± 2.3 |
| Hematopoietic | 61 | 31 (50.8) | 16.3 ± 4.0 |
| Mononuclear fraction | 52 | 29 (55.8) | 15.1 ± 4.3 |
| Combined | 14 | 10 (71.4) | 15.9 ± 3.9 |
| Others | 41 | 29 (70.7) | 15.4 ± 4.1 |
| Country | |||
| Very high human development | 245 | 160 (65.3) | 16.3 ± 3.6 |
| Medium-high human development | 88 | 64 (72.7) | 15.5 ± 3.9 |
| Funding | |||
| Public | 263 | 173 (65.8) | 15.7 ± 3.8 |
| Industry | 70 | 8 (72.9) | 17.2 ± 3.3 |
| Journal impact factor | |||
| 0–2.98 | 87 | 57 (65.5) | 14.5 ± 3.3 |
| 2.98–3.88 | 139 | 91 (65.5) | 16.3 ± 3.7 |
| 3.88–41.5 | 107 | 76 (71.0) | 17.2 ± 3.8 |
| Year of publication | |||
| Prior to and during 2010 | 223 | 156 (69.9) | 16.2 ± 3.8 |
| After 2011 | 110 | 68 (61.8) | 15.9 ± 3.7 |
| Overall | 333 | 224 (67.3) | 16.0 ± 3.7 |
Ten non-English-language publications were excluded from our analysis of completeness score.
Cell types: hematopoietic cell refers to a graft collected directly from patients used without modification (other than possible cryopreservation and thawing). Mononuclear fraction refers to a hematopoietic cell product purified by density gradient separation or other means that removes granulocytes and red blood cells. CD34+ fraction refers to hematopoietic cell products that underwent purification using a monoclonal antibody to CD34. All these products contain HSCs and are used for hematopoietic engraftment. The other category includes: studies using neural precursors or stem cells (n = 24), CD133 purified HSC or angiogenic cell precursor populations (n = 22), limbal stem cells (n = 16), cell products derived from embryonic stem cell (n = 6), cardiac cells (n = 6), products used in four or fewer trials (n = 43), and trials in which the stem cell product was not specified (n = 20). Specific cell products used in <4 trials included: adrenocortical, bone progenitor, chondrocytes, fibroblasts or fibrocytes, germ cells, oral mucosa and dental cells, pancreatic islet precursors, placental skeletal muscle, and skin or hair follicle stem or precursor cell products.