Spero Therapeutics Receives $25 Million Milestone Payment Triggered by GSK's NDA Submission
Written by Emily J. Thompson, Senior Investment Analyst
Updated: Dec 19 2025
0mins
Should l Buy GSK?
Spero Therapeutics (SPRO) announced that its development partner, GSK (GSK), filed a New Drug Application, NDA, resubmission to the U.S. Food and Drug Administration, FDA, for tebipenem HBr, an investigational oral carbapenem antibiotic being developed for the treatment of complicated urinary tract infections, cUTI, including pyelonephritis. The NDA submission triggers a $25 million milestone payment to Spero, expected to be received in Q1 2026.
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Analyst Views on GSK
Wall Street analysts forecast GSK stock price to fall
6 Analyst Rating
1 Buy
2 Hold
3 Sell
Moderate Sell
Current: 57.810
Low
20.15
Averages
38.72
High
55.60
Current: 57.810
Low
20.15
Averages
38.72
High
55.60
About GSK
GSK plc is a United Kingdom-based biopharma company. The Company’s segments include Commercial Operations and Research and Development. The Company is focused on the science of the immune system and advanced technologies, investing in four core therapeutic areas-respiratory, immunology and inflammation; oncology; human immunodeficiency virus (HIV), and infectious diseases. Its specialty medicines prevent and treat diseases, from asthma, cancer and HIV to autoimmune diseases like lupus. General medicines include inhalers for asthma and chronic obstructive pulmonary disease (COPD) with antibiotics. Its portfolio also includes Efimosfermin, a fibroblast growth factor 21 (FGF21) analog therapeutic in clinical development. The Company also engaged in ozureprubart, a long-acting anti-immunoglobulin E (IgE) monoclonal antibody. The Company also owns HS235, a potential molecule for the treatment of pulmonary hypertension (PH).
About the author
Emily J. Thompson
Emily J. Thompson, a Chartered Financial Analyst (CFA) with 12 years in investment research, graduated with honors from the Wharton School. Specializing in industrial and technology stocks, she provides in-depth analysis for Intellectia’s earnings and market brief reports.
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- Extensive Medical Background: Having served as deputy surgeon general during the Trump administration and playing a key role in the U.S. response to the COVID-19 pandemic, Schwartz brings over 20 years of military experience, including as the Coast Guard's chief medical officer, providing strong credentials for her new role.
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- Health Policy Changes: Schwartz will take over amid controversial health policy changes overseen by Health and Human Services Secretary Robert F. Kennedy Jr., including a comprehensive overhaul of childhood vaccine recommendations, directly impacting public health strategies.
- Extensive Medical Background: Having served as deputy surgeon general during the Trump administration and playing a key role in the U.S. response to the COVID-19 pandemic, Schwartz brings over 20 years of military experience, including as the Coast Guard's chief medical officer, providing strong credentials for her new role.
- Transition from Acting Director: Prior to Schwartz's nomination, Jay Bhattacharya served as acting CDC director, but his term expired last month under federal law, leaving the CDC without a Senate-confirmed leader for months, and Schwartz's appointment is expected to bring new leadership to the agency.
See More
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- Trial Results: GSK's global BEHOLD-1 trial for the Mo-Rez antibody-drug conjugate targeting B7-H4 antigen achieved a 62% objective response rate in platinum-resistant ovarian cancer, indicating broad potential in gynecologic cancer treatment.
- Safety Profile: At the highest doses, no patients in the PROC group discontinued treatment due to treatment-related adverse events, while only 4% of EC patients did, suggesting a favorable safety profile for Mo-Rez in further development.
- Adverse Events Monitoring: The most common treatment-related adverse event was nausea, occurring in 82% of PROC and 75% of EC patients, with grade 3 or higher adverse events reported in 64% and 54% of patients, respectively, aligning with expectations for this therapy class.
- Future Trial Plans: Based on the promising efficacy and safety data, GSK plans to launch five pivotal phase III trials in 2026, with a recommended dose of 5.8 mg/kg to further validate Mo-Rez's clinical application.
See More
GSK's Bold Move into Oncology with Five Late-Stage Trials
- Oncology Trial Strategy: GSK is launching five late-stage clinical trials simultaneously for its promising cancer drug Mo-Rez, including three for ovarian cancer and two for endometrial cancer, indicating a significant shift in the company's historically criticized drug development pipeline towards a more aggressive oncology focus.
- Leadership Impact: Since the appointment of new CEO Luke Miels in September, GSK's stock has surged approximately 50%, as he emphasizes the need for bolder decision-making, reflecting a strategic pivot to address investor concerns over the company's previous conservative approach.
- Competitive Strategy Shift: This strategy mirrors tactics employed by rivals like AstraZeneca, which has advanced in oncology since GSK stepped back in 2015; GSK's re-entry into the field through acquisitions and focus on gynecologic and blood cancers demonstrates its repositioning in the market.
- Promising Early Results: Early data presented at a recent oncology conference showed encouraging response rates of 62% in ovarian cancer patients and 67% in endometrial cancer patients, suggesting Mo-Rez's potential as a blockbuster drug and enhancing GSK's prospects in the oncology sector.
See More
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- Expanded Committee Role: HHS Secretary Robert F. Kennedy Jr. has signed new rules that significantly expand the CDC Vaccine Advisory Committee's role, moving beyond domestic vaccine recommendations to encompass a broader range of public health initiatives, aiming to enhance the comprehensiveness and effectiveness of vaccine policy.
- Focus on Safety Research: The new rules emphasize identifying gaps in vaccine safety research, including adverse effects post-vaccination, reflecting a heightened concern for vaccine safety that could influence public trust and acceptance, thereby impacting vaccination rates.
- Assessment of New Technologies: The committee is now tasked with considering novel vaccine platforms, such as mRNA vaccines, which were utilized in COVID-19 vaccines, indicating a focus on future vaccine technology developments that may drive innovation and progress in vaccine research.
- Transparent Decision-Making: The new rules mandate a transparent, evidence-driven decision-making process for the committee, requiring the review of clinical data and expert consultations to ensure the scientific validity of vaccine recommendations, which will help enhance public trust in CDC guidance.
See More
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- Approval Withdrawal: The FDA has announced the withdrawal of GSK's Wellcovorin drug approval, which was previously promoted by the Trump administration for autism treatment, indicating a stringent regulatory review process in the pharmaceutical market.
- Market Exit Announcement: GSK has informed the FDA that Wellcovorin (leucovorin calcium) tablets are no longer marketed, and the company ceased sales in 1999, reflecting a lack of optimism regarding the drug's market potential.
- Waiver of Hearing Rights: GSK has chosen to waive its opportunity for a hearing, demonstrating acceptance of the FDA's decision and indicating a strategic shift in the company's drug development focus towards other pharmaceuticals.
- Availability of Alternatives: The FDA noted that approved generic formulations of leucovorin can now be used to treat cerebral folate transport deficiency in patients with specific genetic variants, highlighting the presence of effective alternative treatment options in the market.
See More
GSK Withdraws Autism Drug Application
- Application Withdrawal: GSK has requested the U.S. FDA to withdraw its application for leucovorin calcium, a drug previously touted by President Trump as a potential autism treatment, indicating the company's negative outlook on the drug's market potential.
- Market Stagnation: GSK has not marketed leucovorin calcium since 1999, suggesting a complete lack of commercial interest in the drug, which may impact its reputation in related therapeutic areas.
- FDA Approval Status: Although the FDA approved the drug for cerebral folate transport deficiency last month, it did not approve it for autism, reflecting regulatory caution regarding the drug's efficacy in treating autism.
- Company Statement: A GSK spokesperson stated that the company never intended to sell the drug again, further confirming its strategic shift away from leucovorin calcium towards other therapeutic areas.
See More
