A Phase 1b/2, First-in-Human, Dose Escalation and Expansion Study of XMT-1536 In Patients With Solid Tumors Likely to Express NaPi2b

Trial ID # NCT03319628
Phase Ib/II
Drug Class Antibody Drug Conjugates: NaPi2b
Drug Name Upifitamab rilsodotin
Alternate Drug Names XMT-1536, UpRi
Drugs in Trial Upifitamab rilsodotin
Eligible Participant

Platinum resistant ovarian cancer

Patients Enrolled

97; 90% Pt-R; 70% w/ prior Bev; 59% w/ prior PARP inhibitor

Therapy Setting


Study Design

Open-Label, Non-randomized


ORR, DCR, DoR, evaluated per RECIST


All treatment doses (n=75):
ORR: 23% (2CR, 15PR)
DCR: 72% (2CR, 15PR, 3uPR, 34SD)

Dose group 36 (33-38 mg/m2) (n=25):
ORR: 36% (2CR, 7PR)
DCR: 72% 

Dose group 43 (38-43 mg/m2)(n=48):
ORR: 17% (8PR)
DCR: 73%

Exploratory analysis, NaPi2b High, TPS≥75:
All doses (n=38):
ORR: 34% (2CR, 11PR); DCR: 87% (2CR, 11PR, 1uPR, 19SD); DoR (n=13): 5 months
Dose group 36 (33-38 mg/m2) (n=16):
ORR: 44% (2CR, 5PR); DCR: 75%
Dose group 43 (38-43 mg/m2)(n=22):
ORR: 27% (6PR); DCR: 95%

Clinically Significant Adverse Events

Dose group 43 vs Dose group 36:
Serious AE: overall (27 vs 14%)
Grade 3-4 AE: pneumonitis (n=4 vs n=0)


UpRi (XMT-1536) is well tolerated and shows promising signs of anti-tumor activity in platinum resistant ovarian cancer; UpRi at the 36mg/m2 dose demonstrates robust clinical activity with a differentiated safety profile


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