Table 3.
Best overall response and confirmed objective response based on RECIST v1.1 (the mITT population).a
| Part 1A | Part 2A | Parts 1A and 2A | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| HER2+ BC or HER2+ GC | HER2+ BC | HR+ HER2-low BC | Total | HER2+ BC | Total | |||||||||
| Dose, mg/kg | <2.0 n = 6 | 2.0 n = 4 | 3.0 n = 14 | 4.0 n = 14 | 5.0 n = 5 | Total N = 43 | 3.0 n = 4 | 4.0 n = 11 | 3.0 n = 10 | 4.0 n = 11 | Total N = 36 | 3.0 n = 12 | 4.0 n = 19 | Total N = 79 |
| CR | 0 | 0 | 0 | 1 (7.1) | 1 (20.0) | 2 (4.7) | 0 | 0 | 0 | 0 | 0 | 0 | 1 (5.3) | 2 (2.5) |
| PR | 1 (16.7) | 0 | 3 (21.4) | 5 (35.7) | 2 (40.0) | 11 (25.6) | 1 (25.0) | 5 (45.5) | 1 (10.0) | 3 (27.3) | 10 (27.8) | 2 (16.7) | 8 (42.1) | 21 (26.6) |
| SD | 2 (33.3) | 4 (100.0) | 6 (42.9) | 8 (57.1) | 2 (40.0) | 22 (51.2) | 3 (75.0) | 5 (45.5) | 3 (30.0) | 8 (72.7) | 19 (52.8) | 7 (58.3) | 9 (47.4) | 41 (51.9) |
| Non-CR/Non-PD | 1 (16.7) | 0 | 1 (7.1) | 0 | 0 | 2 (4.7) | 0 | 0 | 0 | 0 | 0 | 1 (8.3) | 0 | 2 (2.5) |
| PD | 2 (33.3) | 0 | 3 (21.4) | 0 | 0 | 5 (11.6) | 0 | 1 (9.1) | 6 (60.0) | 0 | 7 (19.4) | 1 (8.3) | 1 (5.3) | 12 (15.2) |
| NEb | 0 | 0 | 1 (7.1) | 0 | 0 | 1 (2.3) | 0 | 0 | 0 | 0 | 0 | 1 (8.3) | 0 | 1 (1.3) |
| OR (CR+PR) | 1 (16.7) | 0 | 3 (21.4) | 6 (42.9) | 3 (60.0) | 13 (30.2) | 1 (25.0) | 5 (45.5) | 1 (10.0) | 3 (27.3) | 10 (27.8) | 2 (16.7) | 9 (47.4) | 23 (29.1) |
| 95% CIc of OR | 0.4–64.1 | 0.0–60.2 | 4.7–50.8 | 17.7–71.1 | 14.7–94.7 | 17.2–46.1 | 0.6–80.6 | 16.7–76.6 | 0.3–44.5 | 6.0–61.0 | 14.2–45.2 | 2.1–48.4 | 24.4–71.1 | 19.4–40.4 |
| DC (CR+PR+SD+ Non-CR/Non-PD) | 4 (66.7) | 4 (100.0) | 10 (71.4) | 14 (100.0) | 5 (100.0) | 37 (86.0) | 4 (100.0) | 10 (90.9) | 4 (40.0) | 11 (100.0) | 29 (80.6) | 10 (83.3) | 18 (94.7) | 66 (83.5) |
| 95% CI of DC | 22.3–95.7 | 39.8–100.0 | 41.9–91.6 | 76.8–100.0 | 47.8–100.0 | 72.1–94.7 | 39.8–100.0 | 58.7–99.8 | 12.2–73.8 | 71.5–100.0 | 64.0–91.8 | 51.6–97.9 | 74.0–99.9 | 73.5–90.9 |
Note: Values are n (%) unless stated otherwise.
Abbreviations: BC, breast cancer; CI, confidence interval; CR, complete response; DC, disease control; GC, gastric and gastroesophageal cancer; HER2, human epidermal growth factor receptor 2; HR, hormone receptor; mITT, modified intent-to-treat; NE, not evaluable; OR, objective response; PD, progressive disease; PR, partial response; RECIST, Response Evaluation Criteria in Solid Tumors; SD, stable disease; SOC, standard of care.
aThe mITT population included patients who received ≥1 dose of PF-06804103 with adequate baseline assessment and ≥1 post baseline assessment (for SD or Non-CR/Non-PD, ≥5 weeks after treatment start date), disease progression, or death before the first tumor assessment. 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. One patient in Part 1B was evaluable for OR and was assessed as achieved PR (see Supplementary File S1 for more details of Part 1B). No patients were enrolled in Part 2B.
bThe reason for NE was SD too early, that is, <5 weeks of treatment.
cClopper–Pearson method used.