TABLE 1.
Clinicopathologic Features in RET Fusion-Positive TC and RET-Mutant Medullary Thyroid Cancer (MTC)
| Characteristic | RET Fusion-Positive TC | RET-Mutant MTC | ||
|---|---|---|---|---|
| Treatment Naïve (n = 24)a | Previously Treated (n = 41) | Cabozantinib/Vandetanib Naïve (n = 143)b | Previously Treated (n = 152) | |
| Age, years, median (range) | 60.5 (20-84) | 58.0 (25-88) | 57.0 (15-87) | 58.0 (17-90) |
| Sex, No. (%) | ||||
| Female | 10 (41.7) | 23 (56.1) | 60 (42.0) | 55 (36.2) |
| Male | 14 (58.3) | 18 (43.9) | 83 (58.0) | 97 (63.8) |
| Race, No. (%) | ||||
| White | 18 (75.0) | 24 (58.5) | 124 (86.7) | 137 (90.1) |
| Asian | 1 (4.2) | 12 (29.3) | 8 (5.6) | 2 (1.3) |
| Black | 0 | 3 (7.3) | 2 (1.4) | 2 (1.3) |
| Native Hawaiian or other Pacific Islander | 0 | 0 | 1 (0.7) | 0 |
| American Indian or Alaska Native | 0 | 0 | 0 | 1 (0.7) |
| Other | 3 (12.5) | 2 (4.9) | 7 (4.9) | 10 (6.6) |
| Missing | 2 (8.3) | 0 | 1 (0.7) | 0 |
| Smoking status, No. (%) | ||||
| Never | 12 (50.0) | 28 (68.3) | NR | NR |
| Former | 10 (41.7) | 13 (31.7) | NR | NR |
| Current | 1 (4.2) | 0 | NR | NR |
| Missing | 1 (4.2) | 0 | NR | NR |
| ECOG performance status, No. (%) | ||||
| 0 | 14 (58.3) | 11 (26.8) | 69 (48.3) | 42 (27.6) |
| 1 | 9 (37.5) | 27 (65.9) | 68 (47.6) | 99 (65.1) |
| 2 | 1 (4.2) | 3 (7.3) | 6 (4.2) | 11 (7.2) |
| TC histologic subtype, No. (%) | ||||
| Papillary TC | 23 (95.8) | 31 (75.6) | — | — |
| Poorly differentiated TC | 1 (4.2) | 5 (12.2) | — | — |
| Anaplastic TC | 0 | 4 (9.8) | — | — |
| Hurthle cell TC | 0 | 1 (2.4) | — | — |
| MTC | 0 | 0 | 143 (100) | 152 (100) |
| No. of prior systemic regimens, (%) | ||||
| 0 | 6 (25.0) | 0 | 116 (81.1) | — |
| 1 | 10 (41.7) | 10 (24.4) | 22 (15.4) | 73 (48.0) |
| 2 | 3 (12.5) | 8 (19.5) | 5 (3.5) | 37 (24.3) |
| ≥3 | 5 (20.8) | 23 (56.1) | 0 | 42 (27.6) |
| Previous regimen,c No. (%) | ||||
| Chemotherapy | — | 8 (19.5) | 5 (3.5) | 16 (10.5) |
| Immunotherapy | — | 3 (7.3) | 5 (3.5) | 13 (8.6) |
| Multikinase inhibitor | — | 35 (85.4) | 9 (6.3) | 152 (100) |
| Otherd | 18 (75.0) | 30 (73.2) | 9 (6.3) | 16 (10.5) |
| RET fusion, No. (%) | ||||
| CCDC6 | 15 (62.5) | 25 (61.0) | — | — |
| NCOA4 | 7 (29.2) | 8 (19.5) | — | — |
| Other | 2 (8.3) | 7 (17.1) | — | — |
| Unknown | 0 | 1 (2.4) | — | — |
| RET mutation type, No. (%) | ||||
| M918T | — | — | 86 (60.1) | 99 (65.1) |
| Extracellular cysteine mutation | — | — | 34 (23.8) | 24 (15.8) |
| V804 M/L | — | — | 6 (4.2) | 8 (5.3) |
| Other | — | — | 17 (11.9) | 21 (13.8) |
| CNS metastases at baseline,e No. (%) | ||||
| Yes | 1 (4.2) | 12 (29.3) | 3 (2.1) | 11 (7.2) |
| No | 23 (95.8) | 29 (70.7) | 140 (97.9) | 141 (92.8) |
| Patients who received at least one dose of 160 mg twice daily, No. (%) | 23 (95.8) | 40 (97.6) | 141 (98.6) | 144 (94.7) |
Abbreviations: ECOG, Eastern Cooperative Oncology Group; EGFR, epidermal growth factor receptor; MTC, medullary thyroid cancer; mTOR, mammalian target of rapamycin; NR, not reported; RET, REarranged during Transfection; TC, thyroid cancer; VEGF, vascular endothelial growth factor.
Treatment naïve refers to therapies other than radioactive iodine.
Cabozantinib/vandetanib naïve included treatment-naïve patients (n = 116) and patients who were not previously treated with cabozantinib/vandetanib (n = 27).
Patients may have received more than one prior systemic therapy.
Other prior systemic therapies included radioactive iodine, mTOR inhibitor, EGFR inhibitor, VEGF/VEGF receptor inhibitor, hormonal therapy, and selective RET inhibitor.
Includes both measurable and nonmeasurable CNS metastases.