Left out of SPAC pack, BioTheryX raises $92M in rare series E to hold over until potential end of year IPO

The SPAC boom missed a target in BioTheryX. 

The clinical stage biopharmaceutical company was talking with special purpose acquisition companies and prepared to sign a deal should one come along in the months since Robert Williamson joined as CEO and president in December. In fact, Williamson almost sponsored a SPAC himself before joining the company.

But, San Diego-based BioTheryX ultimately found a crossover investor lead that “really curtailed our desire to look at and entertain deSPACing,” the CEO said in an interview.

BioTheryX hauled a $92 million series E on Thursday led by Farallon Capital Management with backing from nearly a dozen other new investors and participation from existing ones, as well. The financing gives BioTheryX, founded in 2008, the cash to “weather a lot of storms” and the “flexibility to go public when it’s right, not when we need to,” Williamson said.

“I had misgivings and bounce backs in terms of the glut that I saw coming down the line, as well, but also when I saw BioTheryX, it struck me that it could be quite frankly a good target for deSPACing,” Williamson said.

With heightened attention and scrutiny of SPACs by the SEC in recent months and significant crossover interest, BioTheryX went the late-stage financing route instead.

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Now, the protein degradation-focused company has its sights on hitting key milestones in its IND-enabling molecular glue program BTX-1188 and Phase 1 lead multi-kinase inhibitor BTX-A51. BTX-1188 is expected to enter the clinic in late-September or early-October, said Jamie Donadio, CFO, in a joint interview with Williamson. 

“That’s an important milestone for us to think about as it relates to the timing of the IPO,” said Donadio, who joined BioTheryX in February from Mirati Therapeutics, where he was CFO and senior vice president.

BioTheryX wants to be ready to strike when an opportunity comes for a public listing, which means the company will likely begin the SEC preparation and other IPO groundwork around September or the fourth quarter, the CFO added. 

Williamson and Donadio joined BioTheryX to boost its presence in the market and secure stronger levels of financing to be competitive in the protein degradation landscape. The CEO said he hadn’t heard of BioTheryX until a recruiter found him through a family connection.  

“It struck me that this company had a lot more science and not a lot of money and not a lot of exposure,” Williamson said. The CEO noted that BioTheryX has been working “behind the scenes” on protein degradation with some of the leading scientists in the field, including co-founder David Stirling, Ph.D., a co-founder of Celgene. 

BioTheryX’s drug development team created the IMiD, a cereblon binding “molecular glues,” franchise of compounds for blood cancer while at Celgene. You may recognize the molecular glues better from the blockbuster drugs they spawned: Revlimid, which brought in $12.1 billion for new parent company Bristol Myers in 2020, and Pomalyst, which collected a cool $3.07 billion the same year.

RELATED: Monte Rosa snags $95M to speed lead 'molecular glue' treatment into the clinic 

The "a lot more science" Williamson speaks of can be seen in the company's scientific advisory board, which includes 2004 Nobel Chemistry Laureate Aaron Ciechanover, M.D. BioTheryX decided even more expertise was needed, though, and added three members in April and another one this month.

Protein degradation has caught the attention of Eli Lilly, Roche and other Big Pharmas; led to public offerings of companies like Kymera Therapeutics, C4 Therapeutics and Nurix; and received an outpouring of funding into startups like Monte Rosa and Lycia Therapeutics.  

BioTheryX will broaden its lead multi-kinase inhibitor BTX-A51 into solid tumors within a month or two. The treatment is currently being trialed against liquid tumors in Phase 1, Williamson said. The company is working with MD Anderson, City of Hope and Memorial Sloan Kettering on the program, which is aimed at the treatment of acute myeloid leukemia, myelodysplastic syndromes and solid tumors.  

The fresh funds will also go toward deepening BioTheryX’s platform of molecular glues.