Why Are Silverback Therapeutics Shares Falling On Monday?

Silverback Therapeutics Inc SBTX stock dropped to the lowest level since its IPO in December 2020 in reaction to interim data from SBT6050 Phase 1/1b trial for solid tumors.
The trial in advanced or metastatic HER2-expressing or amplified solid cancer was designed to evaluate SBT6050 as a monotherapy and combined with Merck & Co Inc's MRK Keytruda (pembrolizumab).
Data will be presented at the upcoming European Society for Medical Oncology (ESMO) 2021 Congress.
14 patients were evaluable for the response after treatment of four dose levels of SBT6050 ranging from 0.15 mg/kg to 1.2 mg/kg
The best overall response was PR (n=1), SD (n=3), and PD (n=10).
SBT6050 given alone or in combination with pembrolizumab has a manageable safety profile.
The data in the abstract had a cut-off data date of April 4, 2021.
However, the Company said that the upcoming poster would include additional data with a cut-off date of August 1.
Price Action: SBTX stock is down 22.8% at $15.01 during the market session on the last check Monday.