Table 1.
Patient demographics and baseline characteristics (the safety analysis set).
| Part 1A | Part 2A | Parts 1A and 2A | ||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| HER2+ BC or HER2+ GC | HER2+ GC | HER2+ BC | HR+ HER2-low BC | Total | HER2+ BC | Total | ||||||||||||
| Dose, mg/kg | 0.15 n = 2 | 0.5 n = 2 | 1.2 n = 2 | 2.0 n = 4 | 3.0 n = 16 | 4.0 n = 15 | 5.0 n = 6 | Total N = 47 | 3.0 n = 7 | 4.0 n = 6 | 3.0 n = 5 | 4.0 n = 14 | 3.0 n = 12 | 4.0 n = 15 | Total N = 46 | 3.0 n = 14 | 4.0 n = 23 | Total N = 93 |
| Sex | ||||||||||||||||||
| Male | 2 (100.0) | 1 (50.0) | 1 (50.0) | 2 (50.0) | 5 (31.3) | 5 (33.3) | 2 (33.3) | 18 (38.3) | — | — | 0 | 0 | 0 | 0 | 0 | — | — | — |
| Female | 0 | 1 (50.0) | 1 (50.0) | 2 (50.0) | 11 (68.8) | 10 (66.7) | 4 (66.7) | 29 (61.7) | — | — | 5 (100.0) | 14 (100.0) | 12 (100.0) | 15 (100.0) | 46 (100.0) | — | — | — |
| Race | ||||||||||||||||||
| White | 1 (50.0) | 1 (50.0) | 2 (100.0) | 2 (50.0) | 10 (62.5) | 10 (66.7) | 5 (83.3) | 31 (66.0) | — | — | 4 (80.0) | 4 (28.6) | 11 (91.7) | 12 (80.0) | 31 (67.4) | — | — | — |
| Black | 1 (50.0) | 0 | 0 | 0 | 0 | 0 | 0 | 1 (2.1) | — | — | 0 | 1 (7.1) | 0 | 0 | 1 (2.2) | — | — | — |
| Asian | 0 | 0 | 0 | 2 (50.0) | 4 (25.0) | 5 (33.3) | 1 (16.7) | 12 (25.5) | — | — | 1 (20.0) | 9 (64.3) | 1 (8.3) | 3 (20.0) | 14 (30.4) | — | — | — |
| Not reported | 0 | 1 (50.0) | 0 | 0 | 0 | 0 | 0 | 1 (2.1) | — | — | 0 | 0 | 0 | 0 | 0 | — | — | — |
| Median (range) age (y) | 49.0 (35–63) | 65.5 (65–66) | 58.0 (50–66) | 65.0 (64–74) | 56.5 (36–70) | 55.0 (32–70) | 58.5 (39–71) | 58.0 (32–74) | — | — | 52.0 (43–57) | 50.5 (38–67) | 56.0 (42–77) | 51.0 (40–72) | 52.5 (38–77) | — | — | — |
| ECOG PS | ||||||||||||||||||
| 0 | 0 | 0 | 2 (100.0) | 0 | 7 (43.8) | 6 (40.0) | 4 (66.7) | 19 (40.4) | 2 (28.6) | 4 (66.7) | 2 (40.0) | 3 (21.4) | 5 (41.7) | 8 (53.3) | 18 (39.1) | 7 (50.0) | 5 (21.7) | 37 (39.8) |
| 1 | 2 (100.0) | 2 (100.0) | 0 | 4 (100.0) | 9 (56.3) | 9 (60.0) | 2 (33.3) | 28 (59.6) | 5 (71.4) | 2 (33.3) | 3 (60.0) | 11 (78.6) | 7 (58.3) | 7 (46.7) | 28 (60.9) | 7 (50.0) | 18 (78.3) | 56 (60.2) |
| Primary diagnosis | ||||||||||||||||||
| GC | 2 | 2 | 1 | 2 | 7 | 6 | 2 | 22 | 7 | 6 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 22 |
| BC | 0 | 0 | 1 | 2 | 9 | 9 | 4 | 25 | 0 | 0 | 5 | 14 | 12 | 15 | 46 | 14 | 23 | 71 |
| Number of regimens | ||||||||||||||||||
| 1 | 1 (50.0) | 0 | 0 | 0 | 1 (6.3) | 0 | 1 (16.7) | 3 (6.4) | 1 (14.3) | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 3 (3.2) |
| 2 | 1 (50.0) | 0 | 1 (50.0) | 0 | 3 (18.8) | 1 (6.7) | 0 | 6 (12.8) | 3 (42.9) | 1 (16.7) | 2 (40.0) | 0 | 0 | 1 (6.7) | 3 (6.5) | 2 (14.3) | 0 | 9 (9.7) |
| 3–5 | 0 | 0 | 1 (50.0) | 4 (100.0) | 3 (18.8) | 6 (40.0) | 2 (33.3) | 16 (34.0) | 1 (14.3) | 4 (66.7) | 1 (20.0) | 5 (35.7) | 3 (25.0) | 5 (33.3) | 14 (30.4) | 3 (21.4) | 7 (30.4) | 30 (32.3) |
| ≥6 | 0 | 2 (100.0) | 0 | 0 | 9 (56.3) | 8 (53.3) | 3 (50.0) | 22 (46.8) | 2 (28.6) | 1 (16.7) | 2 (40.0) | 9 (64.3) | 9 (75.0) | 9 (60.0) | 29 (63.0) | 9 (64.3) | 16 (69.6) | 51 (54.8) |
| Median (range) | 1.5 (1.0–2.0) | 6.0 (6.0–6.0) | 2.5 (2.0–3.0) | 4.0 (3.0–5.0) | 6.5 (1.0–18.0) | 6.0 (2.0–10.0) | 5.5 (1.0–7.0) | 5.0 (1.0–18.0) | 2.0 (1.0–9.0) | 3.0 (2.0–7.0) | 5.0 (2.0–8.0) | 7.0 (3.0–12.0) | 7.5 (3.0–16.0) | 6.0 (2.0–13.0) | 6.0 (2.0–16.0) | 6.5 (2.0–18.0) | 7.0 (3.0–12.0) | 6.0 (1.0–18.0) |
| Had prior radiotherapy | 1 (50.0) | 2 (100.0) | 1 (50.0) | 2 (50.0) | 8 (50.0) | 12 (80.0) | 4 (66.7) | 30 (63.8) | 1 (14.3) | 4 (66.7) | 3 (60.0) | 11 (78.6) | 10 (83.3) | 14 (93.3) | 38 (82.6) | 10 (71.4) | 19 (82.6) | 68 (73.1) |
| Had prior surgery | 2 (100.0) | 1 (50.0) | 1 (50.0) | 4 (100.0) | 15 (93.8) | 15 (100.0) | 6 (100.0) | 44 (93.6) | 6 (85.7) | 6 (100.0) | 4 (80.0) | 12 (85.7) | 10 (83.3) | 14 (93.3) | 40 (87.0) | 13 (92.9) | 21 (91.3) | 84 (90.3) |
| Prior anti-microtubulin therapies | ||||||||||||||||||
| Yes | 0 | 1 (50.0) | 2 (100.0) | 3 (75.0) | 14 (87.5) | 12 (80.0) | 5 (83.3) | 37 (78.7) | 5 (71.4) | 3 (50.0) | 5 (100.0) | 14 (100.0) | 10 (83.3) | 12 (80.0) | 41 (89.1) | 14 (100.0) | 23 (100.0) | 78 (83.9) |
| Median (range) of number of regimens | - (-, -) | 1.0 (1.0–1.0) | 1.5 (1.0–2.0) | 1.0 (1.0–1.0) | 2.0 (1.0–5.0) | 2.0 (1.0–4.0) | 3.0 (1.0–3.0) | 2.0 (1.0–5.0) | 1.0 (1.0–1.0) | 1.0 (1.0–2.0) | 2.0 (1.0–4.0) | 3.0 (2.0–5.0) | 2.5 (1.0–4.0) | 1.5 (1.0–5.0) | 2.0 (1.0–5.0) | 3.0 (1.0–5.0) | 3.0 (2.0–5.0) | 2.0 (1.0–5.0) |
| Prior chemotherapy | ||||||||||||||||||
| Yes | 2 (100.0) | 2 (100.0) | 2 (100.0) | 4 (100.0) | 16 (100.0) | 15 (100.0) | 6 (100.0) | 47 (100.0) | 7 (100.0) | 6 (100.0) | 5 (100.0) | 14 (100.0) | 12 (100.0) | 14 (93.3) | 45 (97.8) | 14 (100.0) | 23 (100.0) | 92 (98.9) |
| Median (range) of number of regimens | 1.5 (1.0–2.0) | 5.0 (5.0–5.0) | 2.0 (2.0–2.0) | 3.5 (2.0–4.0) | 3.5 (1.0–10.0) | 4.0 (2.0–7.0) | 4.0 (1.0–6.0) | 4.0 (1.0–10.0) | 2.0 (1.0–5.0) | 3.0 (2.0–6.0) | 3.0 (2.0–7.0) | 5.5 (2.0–8.0) | 4.5 (1.0–12.0) | 3.0 (1.0–9.0) | 4.0 (1.0–12.0) | 4.5 (2.0–10.0) | 5.0 (2.0–8.0) | 4.0 (1.0–12.0) |
| Prior HER2-targeted antibody therapies | ||||||||||||||||||
| Yes | 2 (100.0) | 2 (100.0) | 2 (100.0) | 4 (100.0) | 16 (100.0) | 15 (100.0) | 6 (100.0) | 47 (100.0) | 7 (100.0) | 6 (100.0) | 5 (100.0) | 14 (100.0) | 2 (16.7) | 5 (33.3) | 26 (56.5) | 14 (100.0) | 23 (100.0) | 73 (78.5) |
| Trastuzumab | 2 (100.0) | 2 (100.0) | 2 (100.0) | 4 (100.0) | 16 (100.0) | 15 (100.0) | 6 (100.0) | 47 (100.0) | 7 (100.0) | 6 (100.0) | 5 (100.0) | 14 (100.0) | 2 (16.7) | 5 (33.3) | 26 (56.5) | 14 (100.0) | 23 (100.0) | 73 (78.5) |
| Pertuzumab | 0 | 0 | 1 (50.0) | 2 (50.0) | 7 (43.8) | 5 (33.3) | 2 (33.3) | 17 (36.2) | 1 (14.3) | 0 | 4 (80.0) | 7 (50.0) | 1 (8.3) | 1 (6.7) | 13 (28.3) | 10 (71.4) | 12 (52.2) | 30 (32.3) |
| Ado-trastuzumab emtansine (T-DM1) | 0 | 0 | 1 (50.0) | 2 (50.0) | 9 (56.3) | 7 (46.7) | 3 (50.0) | 22 (46.8) | 0 | 0 | 3 (60.0) | 13 (92.9) | 2 (16.7) | 1 (6.7) | 19 (41.3) | 12 (85.7) | 20 (87.0) | 41 (44.1) |
| Prior HER2-targeted small-molecule drugs | ||||||||||||||||||
| Yes | 0 | 0 | 0 | 2 (50.0) | 5 (31.3) | 6 (40.0) | 1 (16.7) | 14 (29.8) | 0 | 0 | 3 (60.0) | 10 (71.4) | 1 (8.3) | 0 | 14 (30.4) | 8 (57.1) | 16 (69.6) | 28 (30.1) |
| Lapatinib | 0 | 0 | 0 | 2 (50.0) | 5 (31.3) | 6 (40.0) | 1 (16.7) | 14 (29.8) | 0 | 0 | 2 (40.0) | 10 (71.4) | 1 (8.3) | 0 | 13 (28.3) | 7 (50.0) | 16 (69.6) | 27 (29.0) |
| Tucatinib | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 (20.0) | 1 (7.1) | 0 | 0 | 2 (4.3) | 1 (7.1) | 1 (4.3) | 2 (2.2) |
Note: Values are n (%) unless stated otherwise.
All patients had prior cancer therapies. No patient received trastuzumab deruxtecan (fam-trastuzumab deruxtecan-nxki, ds-8201a) as prior HER2-targeted antibody therapy. For all groups in Parts 1A and 2A, PF-06804103 was administered once every 3 weeks. Part 1B enrolled 2 patients with HR+ HER2-low BC who received PF-06804103 2.0 mg/kg once every 2 weeks in combination with SOC doses of palbociclib and letrozole (see Supplementary File S1 for more details of Part 1B). No patients were enrolled in Part 2B.
Abbreviations: BC, breast cancer; ECOG PS, Eastern Cooperative Oncology Group performance status; GC, gastric and gastroesophageal cancer; HER2, human epidermal growth factor receptor 2; HR, hormone receptor; SOC, standard of care.