Two former executives from Spero Therapeutics have agreed to settle with the Securities and Exchange Commission (SEC) for allegedly misleading investors about the efficacy of the biotech’s lead antibiotic candidate, with a total fine of $187,500.
Ankit Mahadevi, M.D., and Satyavrat Shukla have 30 days to pay their respective penalties of $112,500 and $75,000, according to a Jan. 16 filing from the SEC. Mahadevi was Spero’s president and CEO from 2016 to 2023 and board chair from 2023 to 2025. Shukla was the biotech’s chief financial officer from 2021 to 2023 before taking over Mahadevi’s role as chief exec from 2023 to January 2025.
As part of the settlement, Mahadevi and Shukla are neither admitting nor denying that they committed any wrongdoing. At the time of publication, Spero had not responded to a request for comment from Fierce Biotech.
According to the filing, the trouble began in February 2022, when Spero received criticism from the FDA about its phase 3 trial for tebipenem, an oral antibiotic candidate being tested for urinary tract infections. The drug regulator was evaluating a new drug application for the potential product and became concerned that the trial had inappropriately enrolled patients infected with Enterococcus bacteria. When the trial’s data were reanalyzed with those patients removed, the FDA told Spero that tebipenem’s efficacy vanished.
Tebipenem’s development centered on a different group of bacteria called Enterobacterales. Enterobacterales and Enterococcus are not closely related, with fundamental differences in their structure—Enterobacterales is Gram-negative, while enterococcus is Gram-positive.
This criticism took Spero off guard, the SEC wrote, and over the next two months the biotech tried in vain to change the FDA’s mind about including the enterococcus-infected patients. On March 25, 2022, the agency cancelled a meeting to discuss drug labeling and post-marketing requirements for tebipenem, which typically precedes an approval, and cited the enterococcus issue as the reason.
Despite this clearly negative outcome, on March 31, 2022, Spero wrote in an official SEC filing that the phase 3 trial had “achieved its primary objective as specified in the protocol,” without mentioning that the FDA had conducted its own analysis and that, when certain patients were removed, the primary endpoint was no longer met. The Massachusetts biotech disclosed that the FDA had cancelled the labeling meeting, but didn’t specify why, the SEC wrote.
A subsequent paper in the New England Journal of Medicine and presentation at the European Congress of Clinical Microbiology and Infectious Diseases repeated the claim of tebipenem’s success, according to the SEC, and Mahadevi told investors during a March 31 earnings call that “we continue to believe that we have a very strong application.”
Taken all together, these actions “created the misleading impression” that the FDA’s issues with tebipenem didn’t undermine the data underlying the antibiotic’s approval application, the SEC concluded.
On May 2, 2022, the FDA told Spero that a new phase 3 trial would be necessary, and the next day, the company finally revealed that the FDA had conducted its own analysis while also disclosing that it was halting tebipenem’s development and laying off 75% of staff. The biotech’s stock price predictably plummeted from $3.24 per share to $1.85, according to the Jan. 16 SEC filing.
GSK stepped in and partnered with Spero to run a new phase 3 trial of tebipenem, which was stopped early due to a strong efficacy signal. GSK filed a new NDA for the antibiotic in December 2025, which triggered a $25 million milestone payment to Spero. GSK now holds global rights to commercialize tebipenem everywhere except Asia, where Meiji holds development and commercialization rights.
Mahadevia now serves as the chief experience officer at venture capital firm Curie.Bio. Shukla retired after his Spero tenure ended, according to his LinkedIn profile.