Silverback hits Wall Street with chest-thumping $242M IPO

Immuno-oncology biotech Silverback Therapeutics has more than doubled its original IPO hopes.

The Seattle-based company had looked for a $100 million IPO last month but has got off a major $242 million debut, giving it a fully diluted market value of $758 million.

In the end, it got this major cash swag by offering 11.5 million shares at $21, above the original range of $19 to $20.

Not bad for an early-stage biotech, which will use the cash to bankroll early-phase trials for its lead antibody-drug conjugate and preclinical work for its other programs.

That lead program, SBT6050, targets TLR8 in solid tumors that express the HER2 gene. The antibody makes sure the payload is delivered only to the HER2-expressing cancer cells, while the TLR8 agonist activates immune cells called myeloid cells to attack the tumor and “reprogram” the tumor microenvironment.

Silverback plans to fund the ongoing phase 1 study with the IPO proceeds, including an expansion into specific tumors and a phase 1b study in combination with a PD-1 inhibitor.

The funds will also push a second program toward an IND filing in the fourth quarter of 2021 and into phase 1, according to a securities filing. The treatment, SBT6290, also targets TLR8, but in solid tumors expressing Nectin-4 rather than HER2.

Finally, the IPO will fuel a third TLR8-targeting program, but not in oncology. The ADC combines the payload with a monoclonal antibody targeting ASGR1 for the treatment of chronic hepatitis B infection. It hopes to file an IND for the program, SBT8230, in the second half of 2022, according to its recent Securities and Exchange Commission filing.

Silverback joins a growing list of biotechs that have gunned for $100 million IPO but soared much higher, based largely on a market that is smiling on life science in general, given its newfound hope against the coronavirus (and pretty much the last major thing for investors to bet on and make money when so many other industries are struggling amid the pandemic).

 Silverback will list on the Nasdaq under the symbol "SBTX."