SITC 2020 – embargo snafu triggers the first movers

The SITC breaks its own embargo, and the ensuing chaos sees Replimune, Iovance and Incyte move.

The Society of the Immunotherapy of Cancer added an extra frisson to its annual meeting by inadvertently revealing full abstracts on its website yesterday, four weeks before the embargo on these was supposed to have lifted.

The mistake was soon rectified, but not before some investors took screenshots and acted on the information, resulting in Replimune surging 47%. Iovance was another early riser, and in common with Replimune it put its data into the public domain once the SITC mistake was noticed. For others the uncertainty will continue, with most of the market being aware only of the presentation titles.

Investors who were not so quick off the mark will argue that this situation is untenable, and Replimune and Iovance’s full disclosure seems the fairest course of action. On the other hand, both companies’ abstracts contain positive data, so it is in their interest to get these out.

Zero responses

This is not the case for Incyte, for instance. Its own SITC abstract, in the brief moment in which it was available, revealed zero responses in 16 patients given the oral, small-molecule PD-L1 inhibitor INCB86550; this was despite T-cell activation and signs of PD-1/PD-L1 interaction blockade. Incyte fell 4%.

Replimune’s 47% surge was triggered by three responses in six subjects given its oncolytic virus project RP2 as monotherapy. Oncolytic viruses are cumbersome and have a poor track record, being largely limited to niche use in melanoma; their remaining utility is in combination, which explains the excitement around Replimune.

Still, RP2 is no ordinary oncolytic virus – it additionally expresses an anti-CTLA-4 molecule. A separate Replimune virus, RP1, is the subject of another SITC presentation, this time in combination with Opdivo.

Selected SITC 2020 abstracts
Company Project Mechanism SITC 2020 abstract detail
Incyte INCB086550 Oral anti-PD-L1 No mention of tumour responses in 16 patients
Alkermes ALKS 4230 IL-2 fusion protein (SC) Artistry-2 trial; needs to replicate IV efficacy
Replimune RP2 Oncolytic virus expressing anti-CTLA-4 50% PR rate in 6 patients on monotherapy
Iovance LN-145 TIL therapy Keytruda combo: 1 CR & 3 PRs in 8 checkpoint-naive HNSCC pts
Xencor XmAb20717 Anti-PD-1xCTLA-4 bispecific 1 CR & 2 PRs in melanoma, 2 PRs in NSCLC, 1 PR in ovarian cancer; 2 treatment-related deaths
Curis CI-8993 Anti-Vista MAb Prelim ph1 data
Biontech/Sanofi SAR441000/BNT311  mRNA encoding IL-12sc, IFα2b, GM-CSF & IL-15sushi Ph1 monotherapy & Libtayo combo data
Biontech/Genmab GEN1046 Anti-PD-L1x4-1BB bispecific First-in-human data
Imcheck ICT01 Anti-BTN3A MAb Data from Eviction trial
Roche Selicrelumab CD40 agonist MAb Ph1/2 data with Tecentriq combo
Roche RO7122290 4-1BB agonist Solid tumour data
Merck KGaA M9241 IL-12/Ab fusion protein Bavencio combo in urothelial cancer
Silverback Therapeutics SBT6050 Anti-Her2/TLR8 agonist conjugate Likely trial design only
Seagen Ladiratuzumab vedotin Anti-ZIP6/LIV-1ADC Monotherapy & Keytruda combo data
Alphamab/Sanofi KN026 + KN046 Anti-Her2 + PD-L1xCTLA-4 bispecifics Prelim data in Her2-mutated tumours
Amgen/Beigene AMG 757 Anti-DLL3 bispecific Ph1 in SCLC
Bioxcel BXCL701 DPP VIII/IX & FAP inhibitor Keytruda combo in prostate cancer
4D Pharma MRx0518  Microbiome regulator Keytruda combo in checkpoint-refractory pts
I-Mab Lemzoparlimab Anti-CD47 MAb Ph1 monotherapy data
Bristol Myers Squibb BMS-986218 Afucosylated anti-CTLA-4 MAb Prelim monotherapy & Opdivo combo data
Scholar Rock SRK-181 TGF-β1 inhibitor Anti-PD-(L)1 combo in checkpoint-unresponsive pts

Iovance closed up 7% yesterday as an SITC abstract revealed a 50% remission rate for its TIL project LN-145, in combination with Keytruda, in head and neck cancer. This might validate TILs in another tumour type, but the fact that patients were checkpoint inhibitor-naive and the lack of a Keytruda-only control limits their relevance.

Like Iovance, Xencor published the entire text of its SITC abstract in a US regulatory filing after the SITC snafu. This concerned the PD-1/CTLA-4 bispecific XmAb20717, and included a 21% ORR at the expansion dose in 29 subjects with prior checkpoint inhibitor exposure; however, there have been two treatment-related deaths among the 109 patients dosed.

Among the multitude of other early clinical results investors will note the large number of bispecifics. There might also be interest in such oddities as 4D Pharma’s microbiome regulator MRx0518 and ICT01, an antibody activating gamma-delta T cells in development by the private French company Imcheck.

However, the chaotic situation where some investors already know data in presentations but others do not looks set to continue until the formal abstract unveiling on November 8. That is unless, of course, the SITC decides that the damage already done warrants full disclosure now.

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