Investors hype Silence Therapeutics after cancer drug shows promise in PhIIa

Shares in Silence Therapeutics (AIM:SLN) jumped more than 20% on the back of Phase IIa data. The small trial was designed primarily to assess the safety and pharmacokinetics of the pancreatic cancer drug, but that did little to deter investors from latching on to some encouraging early efficacy data.

Silence Therapeutics CEO Ali Mortazavi

London-based Silence Therapeutics split the participants into two arms, each of which received different doses of its PKN3-targeting RNAi therapeutic Atu027 plus the standard of care, gemcitabine. The excitement of investors stems from the difference in progression-free survival (PFS) between the two arms of the 23-person trial. Participants who received 6 doses of Atu027 over an 8-week period had a median PFS of 1.81 months, while those who took 8 doses over 8 weeks clocked up a PFS of 5.33 months.

The 33% difference in the amount of Atu027 received between the two arms appears to affect PFS, suggesting there is a dose-dependent effect. Silence Therapeutics CEO Ali Mortazavi called the data a "clear signal which requires further investigation" in a statement. The safety profile of Atu027 in the Phase IIa trial means such further investigation will be possible. Silence Therapeutics said Atu027 was "generally well tolerated," with one patient dropping out of each arm because of adverse events. The finding bodes well for the siRNA and delivery technology Silence Therapeutics uses across its pipeline.

Silence Therapeutics is reassessing its other programs in light of the Phase IIa data. In the near term, this entails looking at the protocol for a Phase Ib trial of Atu027 in patients with head and neck cancer. A more detailed look at the pancreatic cancer Phase IIb data also awaits, which will go some way to showing whether investors' enthusiasm for the results was justified.

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