Opinions diverge on CD39 blockade

Surface Oncology’s decision to “pause” clinical development of the anti-CD39 MAb SRF617 is at odds with that taken by Innate Pharma and Astrazeneca, which advanced their own anti-CD39 project, IPH5201, into phase 2 in June. Though Surface insisted that its move was driven by financial concerns, being accompanied by a 20% headcount reduction, the fact is that SRF617 has yet to demonstrate efficacy. At last year’s Esmo a poster showed no responses among 32 subjects given SFR617 monotherapy up to 1.5g, though in seven given a chemo combo there was one partial remission. Innate/Astra have yet to reveal any clinical data with IPH5201, but promise results from a phase 1 Imfinzi combo trial at an upcoming meeting. CD39 is thought to be involved in stimulating T regulatory cells, which can damp down immune response. The pipeline also includes Trishula’s TTX-030, which generated a 61% ORR in combination with budigalimab and chemo in front-line gastric cancer at this year’s AACR meeting, and Arcus’s preclinical AB598. Gilead appears uninterested, having opted in to neither the Arcus project nor TTX-030, which is licensed to Abbvie and was spun into Trishula after Gilead bought 49.9% of its originator, Tizona.

Selected anti-CD39 MAbs
Project Company Detail
IPH5201 Astrazeneca/Innate Pharma (ex Orega Biotech) Ph2 (no CT.gov entry); ph1 +/- Imfinzi completed
SRF617 Surface Oncology Ph2 combo with etrumadenant & zimberelimab, but development "paused"
TTX-030 Abbvie/Trishula (spun out from 49.9% Gilead-owned Tizona) Fully human MAb; ph1 data at AACR 2022
ES002023 Elpiscience Humanised MAb, ph1
JS019 Suzhou Kebo Ruijun (50%-owned by Shanghai Junshi) Fully human MAb, ph1
ES014 Elpiscience Anti-CD39 x TGF-β bispecific, ph1
AB598 Arcus Biosciences Preclinical poster at 2022 Triple meeting revealed this to be an IgG1 Fc-silent MAb
PM1038 Biotheus Peclinical poster at SITC 2021 revealed this to be an anti-CD39 x PD-1 bispecific MAb
Source: Evaluate Pharma.

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