Nephritis, Interstitial

PHILADELPHIA--( BUSINESS WIRE )--GSK plc (LSE/NYSE: GSK) today announced statistically significant and clinically meaningful overall survival (OS) results from Part 1 and progression-free survival (PFS) results from Part 2 of the RUBY/ENGOT-EN6/GOG3031/NSGO phase III trial in adult patients with primary advanced or recurrent endometrial cancer. These data were presented today in a late-breaking plenary session at the Society of Gynecologic Oncology 2024 Annual Meeting on Women’s Cancer (March 16-18). The goal of the RUBY phase III trial program is to evaluate which patients with primary advanced or recurrent endometrial cancer could potentially benefit from treatment with Jemperli (dostarlimab-gxly) plus chemotherapy, with or without the addition of Zejula (niraparib) maintenance. Part 1 of the RUBY phase III trial is investigating dostarlimab-gxly plus standard-of-care chemotherapy (carboplatin-paclitaxel) followed by dostarlimab-gxly compared to chemotherapy plus placebo followed by placebo. Part 2 of the RUBY phase III trial is evaluating dostarlimab-gxly plus standard-of-care chemotherapy, followed by dostarlimab-gxly plus niraparib as maintenance therapy compared to chemotherapy plus placebo followed by placebo. The safety and tolerability profiles of dostarlimab-gxly plus carboplatin-paclitaxel and dostarlimab-gxly plus carboplatin-paclitaxel followed by dostarlimab-glxy plus niraparib were generally consistent with the known safety profiles of the individual medicines. Previous data showed a statistically significant and clinically meaningful improvement in PFS with Jemperli plus chemotherapy versus chemotherapy alone in frontline mismatch repair deficient (dMMR)/microsatellite instability-high (MSI-H) primary advanced or recurrent endometrial cancer. These data led to regulatory approvals for this patient population in the US, EU and certain other countries. Data presented today show additional potential benefit of dostarlimab-gxly plus chemotherapy, with or without the addition of niraparib, in the overall population of patients with primary advanced or recurrent endometrial cancer, including patients with mismatch repair proficient (MMRp)/microsatellite stable (MSS) tumors, for which there are currently no approved immuno-therapy-based regimens. Hesham Abdullah, Senior Vice President, Global Head Oncology, R&D, GSK said : “ The positive data presented today further show how dostarlimab-gxly-based regimens could benefit a broader set of patients with endometrial cancer. The results we’ve seen to date comprise the growing body of evidence supporting the role of dostarlimab-gxly as the backbone of our immuno-oncology development program. Our goal is to continue to identify ways to use dostarlimab-gxly alone and in combination with other therapies to help improve outcomes for patients with limited treatment options.” RUBY Part 1: a statistically significant and clinically meaningful improvement in OS was observed for dostarlimab-gxly plus chemotherapy versus placebo plus chemotherapy, meeting a primary endpoint of the study. Dostarlimab-gxly plus chemotherapy versus chemotherapy alone showed: In the overall population: a statistically significant reduction in the risk of death by 31% (Hazard Ratio [HR]: 0.69; [95% CI: 0.539–0.890]) a clinically meaningful improvement of 16.4 months in median OS (44.6 months vs 28.2 months) In a prespecified exploratory analysis of the MMRp/MSS population: a clinically meaningful trend in reduced risk of death by 21% (HR: 0.79; [95% CI: 0.602–1.044]) a clinically meaningful improvement of seven months in median OS (34.0 months vs 27.0 months) Full OS summaries are shown below. dostarlimab-gxly + carboplatin-paclitaxel placebo + carboplatin-paclitaxel Overall population, Number (N) 245 249 OS, HR (95% CI) 0.69 (0.539–0.890) P -value 1 0.002 OS, median (95% CI), mo. 44.6 (32.6–NR) 28.2 (22.1–35.6) dMMR/MSI-H population 2 , N 53 65 OS, HR (95% CI) 0.32 (0.166–0.629) OS, median 3 (95% CI), mo. NR (NR–NR) 31.4 (20.3–NR) MMRp/MSS2, N 192 184 OS, HR (95% CI) 0.79 (0.602–1.044) OS, median (95% CI), mo. 34.0 (28.6–NR) 27.0 (21.5–35.6) 1 One-sided p-value based on stratified log-rank test. 2 Exploratory analyses of OS in dMMR/MSI-H and OS in MMRp/MSS populations were pre-specified with no planned hypothesis testing. 3 Although the median OS was not reached, at 30 months the estimated reduction in the risk of death was 82.8% for patients who received dostarlimab plus chemotherapy vs. 54.1% for patients who received chemotherapy alone. Matthew Powell, MD, Division of Gynecologic Oncology, Washington University School of Medicine, and US principal investigator of the RUBY trial said: “ RUBY Part 1 is the first clinical trial to show a statistically significant and clinically meaningful improvement in overall survival for an immuno-oncology therapy in combination with chemotherapy in the overall population of patients with primary advanced or recurrent endometrial cancer. As a clinician, I celebrate the results of the RUBY Part 1 trial presented today, which show how dostarlimab-gxly added to chemotherapy could potentially benefit a broader set of patients with this type of cancer.” In RUBY Part 1, grade 3 or higher and serious treatment-emergent adverse events (AEs) were approximately 12% higher in the dostarlimab-gxly plus carboplatin-paclitaxel arm (treatment arm) compared with the placebo plus carboplatin-paclitaxel arm (control arm). The nature and types of immune-related AEs in the dostarlimab-gxly plus chemotherapy safety profile were consistent with the mechanism of action of dostarlimab-gxly and similar to those reported for other PD-(L)1 inhibitors. In the trial, 40.7% of participants in the treatment arm and 16.3% of participants in the control arm had immune-related AEs assessed by the investigator as related to dostarlimab-gxly or placebo, respectively. Discontinuation of dostarlimab-gxly or placebo due to a treatment-emergent AE occurred in 19.1% of patients in the treatment arm and 8.1% of patients in the control arm. GSK expects US Food and Drug Administration regulatory submission acceptance based on RUBY Part 1 data for an expanded indication in the overall population in the first half of this year. RUBY Part 2: addition of niraparib to dostarlimab-gxly in maintenance setting significantly improved PFS in first-line primary advanced or recurrent endometrial cancer compared to chemotherapy alone, meeting the primary endpoint of the trial. Dostarlimab-gxly plus chemotherapy followed by dostarlimab-gxly plus niraparib compared to placebo plus chemotherapy followed by placebo showed: In the overall population: a statistically significant reduction in the risk of disease progression or death by 40% (HR: 0.60 [95% CI: 0.43–0.82]) a clinically meaningful improvement of 6.2 months in median PFS (14.5 months vs 8.3 months) In the MMRp/MSS population: a statistically significant reduction in the risk of disease progression or death by 37% (HR: 0.63 [95% CI: 0.44–0.91]) a clinically meaningful improvement of 6.0 months in median PFS (14.3 months vs 8.3 months) Dr Mansoor Raza Mirza, Chief Oncologist, Copenhagen University Hospital, Denmark, and RUBY principal investigator said : “ In RUBY Part 2, we observed that the use of dostarlimab-gxly in combination with niraparib in the maintenance therapy setting further improved progression-free survival versus placebo for patients with primary advanced or recurrent endometrial cancer. These findings are particularly important for patients who have MMRp/MSS tumors as the data help build on the initial benefit observed with an immuno-oncology plus chemotherapy regimen, reflecting the potential for the addition of niraparib maintenance to address unmet medical need for these patients.” In RUBY Part 2, grade 3 or higher and serious treatment-emergent AEs were approximately 36% and 24% higher, respectively, in the dostarlimab-gxly plus chemotherapy followed by dostarlimab-gxly plus niraparib arm (treatment arm) compared with the placebo plus chemotherapy followed by placebo arm (control arm). In the trial, 36.6% of participants in the treatment arm and 6.3% of participants in the control arm had immune-related AEs assessed by the investigator as related to dostarlimab-gxly or placebo, respectively. No cases of myelodysplastic syndrome/acute myeloid leukemia were reported; other secondary primary malignancies occurred in 1 patient each in both treatment arms. Discontinuation of dostarlimab-gxly or placebo due to a TEAE occurred in 24.1% of patients in the treatment arm and 5.2% of patients in the control arm. Discontinuation of niraparib or placebo due to a treatment-emergent AE occurred in 15.7% of patients in the treatment arm and 4.2% of patients in the control arm. About endometrial cancer Endometrial cancer is found in the inner lining of the uterus, known as the endometrium. Endometrial cancer is the most common gynecologic cancer in developed countries, with approximately 417,000 new cases reported each year worldwide 1 , and incidence rates are expected to rise by almost 40% between 2020 and 2040. 2,3 Approximately 15-20% of patients with endometrial cancer will be diagnosed with advanced disease at the time of diagnosis. 4 About RUBY RUBY is a two-part global, randomized, double-blind, multicenter phase III trial of patients with primary advanced or recurrent endometrial cancer. Part 1 is evaluating dostarlimab-gxly plus carboplatin-paclitaxel followed by dostarlimab-gxly versus carboplatin-paclitaxel plus placebo followed by placebo. Part 2 is evaluating dostarlimab-gxly plus carboplatin-paclitaxel followed by dostarlimab-gxly plus niraparib versus placebo plus carboplatin-paclitaxel followed by placebo. In Part 1, the dual-primary endpoints are investigator-assessed PFS based on the Response Evaluation Criteria in Solid Tumors v1.1 and OS. The statistical analysis plan included pre-specified analyses of PFS in the dMMR/MSI-H and overall populations and OS in the overall population. Pre-specified exploratory analyses of PFS and OS in the MMRp/MSS population and OS in the dMMR/MSI-H populations were also performed. RUBY Part 1 included a broad population, including histologies often excluded from clinical trials and had approximately 10% of patients with carcinosarcoma and 20% with serous carcinoma. In Part 2, the primary endpoint is investigator-assessed PFS in the overall population, followed by PFS in the MMRp/MSS population, and OS in the overall population is a key secondary endpoint. Additional secondary endpoints in Part 1 and Part 2 include PFS per blinded independent central review, PFS2, overall response rate, duration of response, disease control rate, patient-reported outcomes, and safety and tolerability. RUBY is part of an international collaboration between the European Network of Gynaecological Oncological Trial groups (ENGOT), a research network of the European Society of Gynaecological Oncology (ESGO) that consists of 22 trial groups from 31 European countries that perform cooperative clinical trials, and the GOG Foundation, a non-profit organization dedicated to transforming the standard of care in gynecologic oncology. About Jemperli (dostarlimab-gxly) Jemperli is a programmed death receptor-1 (PD-1)-blocking antibody that binds to the PD-1 receptor and blocks its interaction with the PD-1 ligands PD-L1 and PD-L2. 5 Jemperli was discovered by AnaptysBio, Inc. and licensed to TESARO, Inc., under a collaboration and exclusive license agreement signed in March 2014. Under this agreement, GSK is responsible for the ongoing research, development, commercialization, and manufacturing of Jemperli , and cobolimab (GSK4069889), a TIM-3 antagonist. Indications and Important Safety Information for JEMPERLI (dostarlimab-gxly) JEMPERLI, in combination with carboplatin and paclitaxel, followed by JEMPERLI as a single agent, is indicated for the treatment of adult patients with primary advanced or recurrent endometrial cancer (EC) that is mismatch repair deficient (dMMR), as determined by an FDA-approved test, or microsatellite instability-high (MSI-H). JEMPERLI, as a single agent, is indicated for the treatment of adult patients with dMMR recurrent or advanced: EC, as determined by an FDA-approved test, that has progressed on or following prior treatment with a platinum-containing regimen in any setting and are not candidates for curative surgery or radiation, or solid tumors, as determined by an FDA-approved test, that have progressed on or following prior treatment and who have no satisfactory alternative treatment options. This indication is approved under accelerated approval based on tumor response rate and durability of response. Continued approval for this indication may be contingent upon verification and description of clinical benefit in a confirmatory trial(s). Important Safety Information Severe and Fatal Immune-Mediated Adverse Reactions Immune-mediated adverse reactions, which can be severe or fatal, can occur in any organ system or tissue and can occur at any time during or after treatment with a PD-1/PD-L1–blocking antibody, including JEMPERLI. Monitor closely for signs and symptoms of immune-mediated adverse reactions. Evaluate liver enzymes, creatinine, and thyroid function tests at baseline and periodically during treatment. For suspected immune-mediated adverse reactions, initiate appropriate workup to exclude alternative etiologies, including infection. Institute medical management promptly, including specialty consultation as appropriate. Based on the severity of the adverse reaction, withhold or permanently discontinue JEMPERLI. In general, if JEMPERLI requires interruption or discontinuation, administer systemic corticosteroids (1 to 2 mg/kg/day prednisone or equivalent) until improvement to ≤Grade 1. Upon improvement to ≤Grade 1, initiate corticosteroid taper and continue to taper over at least 1 month. Consider administration of other systemic immunosuppressants in patients whose immune-mediated adverse reaction is not controlled with corticosteroids. Immune-Mediated Pneumonitis JEMPERLI can cause immune-mediated pneumonitis, which can be fatal. In patients treated with other PD-1/PD-L1–blocking antibodies, the incidence of pneumonitis is higher in patients who have received prior thoracic radiation. Pneumonitis occurred in 2.3% (14/605) of patients, including Grade 2 (1.3%), Grade 3 (0.8%), and Grade 4 (0.2%) pneumonitis. Immune-Mediated Colitis Colitis occurred in 1.3% (8/605) of patients, including Grade 2 (0.7%) and Grade 3 (0.7%) adverse reactions. Cytomegalovirus infection/reactivation have occurred in patients with corticosteroid-refractory immune-mediated colitis. In such cases, consider repeating infectious workup to exclude alternative etiologies. Immune-Mediated Hepatitis JEMPERLI can cause immune-mediated hepatitis, which can be fatal. Grade 3 hepatitis occurred in 0.5% (3/605) of patients. Immune-Mediated Endocrinopathies Adrenal Insufficiency Adrenal insufficiency occurred in 1.2% (7/605) of patients, including Grade 2 (0.5%) and Grade 3 (0.7%). For Grade 2 or higher adrenal insufficiency, initiate symptomatic treatment per institutional guidelines, including hormone replacement as clinically indicated. Withhold or permanently discontinue JEMPERLI depending on severity. Hypophysitis JEMPERLI can cause immune-mediated hypophysitis. Grade 3 hypophysitis occurred in 0.4% (1/241) of patients receiving JEMPERLI in combination with carboplatin and paclitaxel. Grade 2 hypophysitis occurred in 0.2% (1/605) of patients receiving JEMPERLI as a single agent. Initiate hormone replacement as clinically indicated. Withhold or permanently discontinue JEMPERLI depending on severity. Thyroid Disorders Grade 2 thyroiditis occurred in 0.5% (3/605) of patients. Grade 2 hypothyroidism occurred in 12% (28/241) of patients receiving JEMPERLI in combination with carboplatin and paclitaxel. Grade 2 hypothyroidism occurred in 8% (46/605) of patients receiving JEMPERLI as a single agent. Hyperthyroidism occurred in 3.3% (8/241) of patients receiving JEMPERLI in combination with carboplatin and paclitaxel, including Grade 2 (2.9%) and Grade 3 (0.4%). Hyperthyroidism occurred in 2.3% (14/605) of patients receiving JEMPERLI as a single agent, including Grade 2 (2.1%) and Grade 3 (0.2%). Initiate thyroid hormone replacement or medical management of hyperthyroidism as clinically indicated. Withhold or permanently discontinue JEMPERLI depending on severity. Type 1 Diabetes Mellitus, Which Can Present with Diabetic Ketoacidosis JEMPERLI can cause type 1 diabetes mellitus, which can present with diabetic ketoacidosis. Grade 3 type 1 diabetes mellitus occurred in 0.4% (1/241) of patients receiving JEMPERLI in combination with carboplatin and paclitaxel. Grade 3 type 1 diabetes mellitus occurred in 0.2% (1/605) of patients receiving JEMPERLI as a single agent. Monitor patients for hyperglycemia or other signs and symptoms of diabetes. Initiate treatment with insulin as clinically indicated. Withhold or permanently discontinue JEMPERLI depending on severity. Immune-Mediated Nephritis with Renal Dysfunction JEMPERLI can cause immune-mediated nephritis, which can be fatal. Grade 2 nephritis, including tubulointerstitial nephritis, occurred in 0.5% (3/605) of patients. Immune-Mediated Dermatologic Adverse Reactions JEMPERLI can cause immune-mediated rash or dermatitis. Bullous and exfoliative dermatitis, including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and drug rash with eosinophilia and systemic symptoms (DRESS), have occurred with PD-1/PD-L1–blocking antibodies. Topical emollients and/or topical corticosteroids may be adequate to treat mild to moderate non-bullous/exfoliative rashes. Withhold or permanently discontinue JEMPERLI depending on severity. Other Immune-Mediated Adverse Reactions The following clinically significant immune-mediated adverse reactions occurred in <1% of the 605 patients treated with JEMPERLI or were reported with the use of other PD-1/PD-L1–blocking antibodies. Severe or fatal cases have been reported for some of these adverse reactions. Nervous System: Meningitis, encephalitis, myelitis and demyelination, myasthenic syndrome/myasthenia gravis, Guillain-Barré syndrome, nerve paresis, autoimmune neuropathy Cardiac/Vascular: Myocarditis, pericarditis, vasculitis Ocular: Uveitis, iritis, other ocular inflammatory toxicities. Some cases can be associated with retinal detachment. Various grades of visual impairment to include blindness can occur Gastrointestinal: Pancreatitis, including increases in serum amylase and lipase levels, gastritis, duodenitis Musculoskeletal and Connective Tissue: Myositis/polymyositis, rhabdomyolysis and associated sequelae including renal failure, arthritis, polymyalgia rheumatica Endocrine: Hypoparathyroidism Other (Hematologic/Immune): Autoimmune hemolytic anemia, aplastic anemia, hemophagocytic lymphohistiocytosis, systemic inflammatory response syndrome, histiocytic necrotizing lymphadenitis (Kikuchi lymphadenitis), sarcoidosis, immune thrombocytopenia, solid organ transplant rejection, other transplant (including corneal graft) rejection Infusion-Related Reactions Severe or life-threatening infusion-related reactions have been reported with PD-1/PD-L1–blocking antibodies. Severe infusion-related reactions (Grade 3) occurred in 0.2% (1/605) of patients receiving JEMPERLI. Monitor patients for signs and symptoms of infusion-related reactions. Interrupt or slow the rate of infusion or permanently discontinue JEMPERLI based on severity of reaction. Complications of Allogeneic HSCT Fatal and other serious complications can occur in patients who receive allogeneic hematopoietic stem cell transplantation (HSCT) before or after treatment with a PD-1/PD-L1–blocking antibody, which may occur despite intervening therapy. Monitor patients closely for transplant-related complications and intervene promptly. Embryo-Fetal Toxicity and Lactation Based on its mechanism of action, JEMPERLI can cause fetal harm. Advise pregnant women of the potential risk to a fetus. Advise females of reproductive potential to use effective contraception during treatment with JEMPERLI and for 4 months after their last dose. Because of the potential for serious adverse reactions from JEMPERLI in a breastfed child, advise women not to breastfeed during treatment with JEMPERLI and for 4 months after their last dose. Common Adverse Reactions The most common adverse reactions (≥20%) in patients with dMMR/MSI-H EC who received JEMPERLI in combination with carboplatin and paclitaxel were rash, diarrhea, hypothyroidism, and hypertension. The most common Grade 3 or 4 laboratory abnormalities (≥10%) were decreased neutrophils, decreased hemoglobin, decreased white blood cell count, decreased lymphocytes, increased glucose, decreased sodium, and decreased platelets. The most common adverse reactions (≥20%) in patients with dMMR EC who received JEMPERLI as a single agent were fatigue/asthenia, anemia, nausea, diarrhea, constipation, vomiting, and rash. The most common Grade 3 or 4 laboratory abnormalities (>2%) were decreased lymphocytes, decreased sodium, increased alanine aminotransferase, increased creatinine, decreased neutrophils, decreased albumin, and increased alkaline phosphatase. The most common adverse reactions (≥20%) in patients with dMMR solid tumors who received JEMPERLI as a single agent were fatigue/asthenia, anemia, diarrhea, and nausea. The most common Grade 3 or 4 laboratory abnormalities (≥2%) were decreased lymphocytes, decreased sodium, increased alkaline phosphatase, and decreased albumin. Please see the full US Prescribing Information for JEMPERLI . About Zejula (niraparib) Zejula is an oral, once-daily poly(ADP-ribose) polymerase (PARP) inhibitor. Indication and Important Safety Information for ZEJULA (niraparib) ZEJULA (niraparib) tablets 100 mg/200 mg/300 mg are indicated: for first-line maintenance treatment of adult patients with advanced epithelial ovarian, fallopian tube, or primary peritoneal cancer who are in a complete or partial response to first-line platinum-based chemotherapy for the maintenance treatment of adult patients with deleterious or suspected deleterious germline BRCA- mutated recurrent epithelial ovarian, fallopian tube, or primary peritoneal cancer who are in a complete or partial response to platinum-based chemotherapy. Select patients for therapy based on an FDA-approved companion diagnostic for ZEJULA Important Safety Information Myelodysplastic syndrome/acute myeloid leukemia (MDS/AML), including cases with a fatal outcome, have been reported in patients who received ZEJULA. In PRIMA, MDS/AML occurred in 6 out of 484 (1.2%) patients treated with ZEJULA, and in 3 out of 244 (1.2%) patients treated with placebo. The duration of therapy with ZEJULA in patients who developed secondary MDS/cancer therapy-related AML varied from 3.7 months to 2.5 years. In NOVA , of patients within the g BRCA mut cohort, MDS/AML occurred in 10 out of 136 (7%) patients treated with ZEJULA and in 2 out of 65 (3%) patients treated with placebo. The duration of therapy with ZEJULA in patients who developed secondary MDS/cancer therapy-related AML varied from 3.6 months to 5.9 years. All patients who developed secondary MDS/cancer therapy-related AML had received previous chemotherapy with platinum agents and/or other DNA-damaging agents, including radiotherapy. For suspected MDS/AML or prolonged hematological toxicities, refer the patient to a hematologist for further evaluation. Discontinue ZEJULA if MDS/AML is confirmed. Hematologic adverse reactions (thrombocytopenia, anemia, neutropenia, and/or pancytopenia) have been reported in patients receiving ZEJULA. The overall incidence of Grade ≥3 thrombocytopenia, anemia, and neutropenia were reported, respectively, in 39%, 31%, and 21% of patients receiving ZEJULA in PRIMA and 29%, 25%, and 20% of patients receiving ZEJULA in NOVA. Discontinuation due to thrombocytopenia, anemia, and neutropenia occurred, respectively, in 4%, 2%, and 2% of patients in PRIMA and 3%, 1%, and 2% of patients in NOVA. In patients who were administered a starting dose of ZEJULA based on baseline weight or platelet count in PRIMA, Grade ≥3 thrombocytopenia, anemia, and neutropenia were reported, respectively, in 22%, 23%, and 15% of patients receiving ZEJULA. Discontinuation due to thrombocytopenia, anemia, and neutropenia occurred, respectively, in 3%, 3%, and 2% of patients. Do not start ZEJULA until patients have recovered from hematological toxicity caused by prior chemotherapy (≤Grade 1). Monitor complete blood counts weekly for the first month, monthly for the next 11 months, and periodically thereafter. If hematological toxicities do not resolve within 28 days following interruption, discontinue ZEJULA, and refer the patient to a hematologist for further investigations. Hypertension and hypertensive crisis have been reported in patients receiving ZEJULA. Grade 3-4 hypertension occurred in 6% of patients receiving ZEJULA vs 1% of patients receiving placebo in PRIMA, with no reported discontinuations. Grade 3-4 hypertension occurred in 9% of patients receiving ZEJULA vs 2% of patients receiving placebo in NOVA, with discontinuation occurring in <1% of patients. Monitor blood pressure and heart rate at least weekly for the first two months, then monthly for the first year, and periodically thereafter during treatment with ZEJULA. Closely monitor patients with cardiovascular disorders, especially coronary insufficiency, cardiac arrhythmias, and hypertension. Manage hypertension with antihypertensive medications and adjustment of the ZEJULA dose if necessary. Posterior reversible encephalopathy syndrome (PRES) occurred in 0.1% of 2,165 patients treated with ZEJULA in clinical trials and has also been described in postmarketing reports. Monitor all patients for signs and symptoms of PRES, which include seizure, headache, altered mental status, visual disturbance, or cortical blindness, with or without associated hypertension. Diagnosis requires confirmation by brain imaging. If suspected, promptly discontinue ZEJULA and administer appropriate treatment. The safety of reinitiating ZEJULA is unknown. Embryo-fetal toxicity and lactation: Based on its mechanism of action, ZEJULA can cause fetal harm. Advise females of reproductive potential of the potential risk to a fetus and to use effective contraception during treatment and for 6 months after receiving their final dose of ZEJULA. Because of the potential for serious adverse reactions from ZEJULA in breastfed infants, advise lactating women not to breastfeed during treatment with ZEJULA and for 1 month after receiving the last dose. First-line Maintenance Advanced Ovarian Cancer Most common adverse reactions (Grades 1-4) in ≥10% of all patients who received ZEJULA in PRIMA were thrombocytopenia (66%), anemia (64%), nausea (57%), fatigue (51%), neutropenia (42%), constipation (40%), musculoskeletal pain (39%), leukopenia (28%), headache (26%), insomnia (25%), vomiting (22%), dyspnea (22%), decreased appetite (19%), dizziness (19%), cough (18%), hypertension (18%), AST/ALT elevation (14%), and acute kidney injury (12%). Common lab abnormalities (Grades 1-4) in ≥25% of all patients who received ZEJULA in PRIMA included: decreased hemoglobin (87%), decreased platelets (74%), decreased leukocytes (71%), increased glucose (66%), decreased neutrophils (66%), decreased lymphocytes (51%), increased alkaline phosphatase (46%), increased creatinine (40%), decreased magnesium (36%), increased AST (35%), and increased ALT (29%). Maintenance Recurrent Germline BRCA -mutated Ovarian Cancer Most common adverse reactions (Grades 1-4) in ≥10% of patients who received ZEJULA in NOVA g BRCA mut Cohort were nausea (77%), thrombocytopenia (71%), fatigue (61%), anemia (52%), vomiting (40%), constipation (38%), headache (35%), neutropenia (31%), decreased appetite (22%), hypertension (21%), insomnia (18%), dizziness (18%), dyspnea (17%), dyspepsia (17%), back pain (16%), cough (16%), nasopharyngitis (13%), dry mouth (13%), dysgeusia (13%), urinary tract infection (11%), rash (10%), and anxiety (10%). Common lab abnormalities (Grades 1-4) in ≥25% of patients who received ZEJULA in NOVA g BRCA mut Cohort included: decrease in hemoglobin (85%), decrease in platelet count (81%), decrease in white blood cell count (71%), decrease in absolute neutrophil count (56%), increase in AST (35%), and increase in ALT (25%). Please see the US Prescribing Information for ZEJULA tablets. GSK in oncology Oncology is an emerging therapeutic area for GSK where we are committed to maximizing patient survival with a current focus on hematologic malignancies, gynecologic cancers and other solid tumors through breakthroughs in immuno-oncology and tumor-cell targeting therapies. About GSK GSK is a global biopharma company with a purpose to unite science, technology, and talent to get ahead of disease together. Find out more at us.gsk.com. Cautionary statement regarding forward-looking statements GSK cautions investors that any forward-looking statements or projections made by GSK, including those made in this announcement, are subject to risks and uncertainties that may cause actual results to differ materially from those projected. Such factors include, but are not limited to, those described under Item 3.D “Risk factors” in the company's Annual Report on Form 20-F for 2023. Registered in England & Wales: No. 3888792 Registered Office: 980 Great West Road Brentford, Middlesex TW8 9GS References Faizan U, Muppidi V. Uterine Cancer. [Updated 2022 Sep 5]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available at: www.ncbi.nlm.nih.gov/books/NBK562313/ . Braun MM, et al. Am Fam Physician. 2016;93(6):468-474. International Research on Cancer. Global Cancer Observatory. Cancer Tomorrow. gco.iarc.fr/tomorrow/en/dataviz/ . Accessed 13 July 2022. CMP: CancerMPact® Patient Metrics Mar-2023, Cerner Enviza. Available at www.cancermpact.com . Accessed 29 Feb 2024. Laken H, Kehry M, Mcneeley P, et al. Identification and characterization of TSR-042, a novel anti-human PD-1 therapeutic antibody. European Journal of Cancer. 2016;69, S102. doi:10.1016/s0959-8049(16)32902-1.

On track for topline data from SPR720 Phase 2a proof-of-concept trial in treatment-naive and treatment-experienced non-refractory NTM-PD patients, expected in 2H 2024Initiated enrollment in PIVOT-PO, a pivotal Phase 3 clinical trial of oral Tebipenem HBr in cUTI Submitted IND for SPR206 and received FDA clearance to proceed with Phase 2 clinical trialReiterate expected cash runway into late 2025Conference call and webcast at 4:30pm ET today CAMBRIDGE, Mass., March 13, 2024 (GLOBE NEWSWIRE) -- Spero Therapeutics, Inc. (Nasdaq: SPRO), a multi-asset clinical-stage biopharmaceutical company, focused on identifying and developing novel treatments for rare diseases and multi-drug resistant (MDR) bacterial infections, today announced financial results for the fourth quarter and full year ended December 31, 2023, and provided a business update. “2023 was a productive year for Spero and we have been focused on execution across our programs,” said Sath Shukla, President, and Chief Executive Officer of Spero. “We are well poised to unveil top-line data for SPR720 Phase 2a, which is expected in 2H 2024, and our excitement is fueled by the hope it may bring for the rare disease community grappling with nontuberculous mycobacterial pulmonary disease (NTM-PD). On tebipenem HBr, engaging with the FDA and in collaboration with our partner, GSK, we are actively enrolling patients globally in our Phase 3 PIVOT-PO clinical trial. Positioned as the first oral broad-spectrum carbapenem in the United States for cUTI, we believe this product has the potential to change the treatment paradigm for these patients and underscores Spero’s commitment to innovation. We reiterate our expected cash runway into late 2025 based on our year-end cash balance, along with tebipenem HBr development milestone payments from GSK and our disciplined capital allocation.” Pipeline Update SPR720 SPR720 is an investigational novel, oral, first-line treatment for NTM-PD. Top-line data from the Phase 2a proof-of-concept clinical trial in treatment-naive and treatment-experienced non-refractory NTM-PD patients is expected in 2H 2024. The trial is expected to enroll treatment-naïve or treatment-experienced participants with non-refractory NTM-PD due to Mycobacterium avium complex. The primary endpoint evaluates changes in bacterial load in sputum samples from baseline to the end of the 56-day treatment period. Key secondary endpoints include assessments of clinical response, quality of life, pharmacokinetics, and safety and tolerability. For more information on the trial, see ClinicalTrials.gov identifier NCT05496374.A paper Efficacy of SPR720 in murine models of non-tuberculous mycobacterial pulmonary infection (Nicole Cotroneo et al) was published in Journal of Antimicrobial Chemotherapy in February 2024.A paper Nontuberculous mycobacterial pulmonary disease and the potential role of SPR720 (Kevin Winthrop et al) was published in Expert Review of Anti-infective Therapy in October 2023. Tebipenem HBr Tebipenem HBr is an investigational oral carbapenem antibiotic being developed for the treatment of complicated urinary tract infection (cUTI) including acute pyelonephritis (AP) to help patients avoid hospitalizations or reduce duration of in-patient therapy. Spero commenced enrollment in PIVOT-PO, a global, randomized, double-blind, Phase 3 clinical trial of tebipenem HBr in patients with cUTI, including AP in December 2023. The trial compares oral tebipenem HBr with intravenous imipenem cilastatin, in hospitalized adult patients with cUTI/AP. The primary endpoint is the number of patients with overall response (a combination of clinical cure and favorable microbiological response) at the Test-of-Cure (TOC) visit. The trial is expected to enroll approximately 2,648 patients, with enrollment completion anticipated in 2H 2025. For more information on PIVOT-PO, refer to ClinicalTrials.gov ID NCT06059846. In July 2023, Spero received written agreement from the U.S. Food and Drug Administration (FDA), under a Special Protocol Assessment (SPA), on the design and size of PIVOT-PO. The FDA has indicated that positive and persuasive results from PIVOT-PO, supported with confirmatory evidence of efficacy, could be sufficient to support approval of tebipenem HBr as a treatment for cUTI, including pyelonephritis, for a limited use indication. Under the terms of its license agreement with GSK, in December 2023, upon dosing the first patient, Spero earned $95 million in development milestones payable in four equal installments over two years. Spero also received a $30 million development milestone payment following the SPA. Further details on the agreement with GSK can be found here. SPR206 SPR206 is an innovative, investigational IV-administered direct-acting next generation polymyxin that has shown antibiotic activity against MDR Gram-negative pathogens, including carbapenem-resistant Enterobacteriaceae, Acinetobacter baumannii and Pseudomonas aeruginosa in preclinical studies. An Investigational New Drug (IND) application has been cleared by the FDA to advance SPR206, to treat MDR Gram-negative bacterial infections, into a Phase 2 clinical trial in participants with hospital-acquired or ventilator-associated bacterial pneumonia.The results from the Phase 1 bronchoalveolar lavage (BAL) study of SPR206 were published in a paper Pharmacokinetics of SPR206 in Plasma, Pulmonary Epithelial Lining Fluid, and Alveolar Macrophages following Intravenous Administration to Healthy Adult Subjects (Keith Rodvold et al) in Antimicrobials and Chemotherapy in July 2023. A paper Safety and pharmacokinetics of SPR206 in subjects with varying degrees of renal impairment (Jon B. Bruss et al) was published in Antimicrobials and Chemotherapy in October 2023. Corporate Highlights Satyavrat “Sath” Shukla successfully transitioned to President and Chief Executive Officer (CEO) of the company, and a member of the Board of Directors in August 2023. Mr. Shukla had previously been Chief Financial Officer and Treasurer of the company. Mr. Shukla succeeded Spero’s prior CEO and President, Ankit Mahadevia, M.D., who became Chair of the Board of Directors in August 2023.Esther Rajavelu was appointed as Chief Financial Officer, Chief Business Officer, and Treasurer in November 2023. Ms. Rajavelu brings over 20 years of experience working in the biotech and financial sectors focused on growth strategy, M&A, and financing. Fourth Quarter and Full Year 2023 Financial Results Spero reported net income of $51.2 million for the fourth quarter and an overall net income of $22.8 million, for the year ended December 31, 2023, or a diluted net income per share of common stock of $0.96 and $0.43, respectively. Net income for the fourth quarter and net loss for the year ended December 31, 2022, was $26.8 million and $(46.4) million, or $0.55 and $(1.23) per share of common stock, respectively.Total revenue for the fourth quarter of 2023 was $73.5 million, compared with total revenue of $47.4 million for the fourth quarter of 2022. The revenue increase for the fourth quarter of 2023 was primarily due to $71.8 million in collaboration revenue related to our agreements with GSK and Pfizer. Total revenue for the year ended December 31, 2023 was $103.8 million, compared to $53.5 million for the year ended December 31, 2022. The revenue increase for the year ended December 31, 2023, was primarily due to the aforementioned collaboration revenue related to our agreements with GSK and Pfizer.Research and development expenses for the fourth quarter of 2023 were $16.6 million, compared to $15.1 million of research and development expenses for the same period in 2022. Research and development expenses for the year ended December 31, 2023 were $51.4 million, compared to $47.6 million for the year ended December 31, 2022. The increase in research and development expenses year-over-year was primarily due to increased clinical activity during the period related to the ongoing Phase 2a clinical trial of SPR720, offset by personnel-related costs.General and administrative expenses for the fourth quarter of 2023 were $6.4 million, compared to $6.5 million of general and administrative expenses for the same period in 2022. This year-over-year decrease was primarily due to changes in personnel-related costs, offset by increased professional and consulting fees. General and administrative expenses for the year ended December 31, 2023, were $25.6 million, compared to $36.5 million for the year ended December 31, 2022, with lower expenses in 2023 compared to 2022 primarily due to decreases in both personnel-related costs and professional and consulting fees.As of December 31, 2023, Spero had cash and cash equivalents of $76.3 million. Since the year-end closing of financials, the company received $23.8 million, the first tranche of the $95.0 million in development milestones from GSK. Based on its current operating plans, Spero expects that its cash and cash equivalents, together with other non-dilutive funding commitments, will be sufficient to fund its operating expenses and capital expenditure requirements into late 2025. For further details on Spero’s financials, refer to Spero’s Annual Report on Form 10-K, filed with the U.S. Securities and Exchange Commission (SEC) today. Conference Call and Live Webcast Today at 4:30 pm EST Spero will host a conference call and webcast today at 4:30 p.m. ET. To access the call, please dial 1-877-704-4453 (domestic) or 1-201-389-0920 (international) and refer to conference ID 13744458 or click on this Link and request a return call. The conference call will also be webcast live and can be accessed through this website link, and on Spero's website at www.sperotherapeutics.com on the "Events and Presentations" page under the "Connect" tab. An archived webcast will be available on Spero's website for 30 days following the presentation. Tebipenem HBr Research SupportSelect tebipenem HBr studies have been funded in part with federal funds from the Department of Health and Human Services; Administration for Strategic Preparedness and Response; Biomedical Advanced Research and Development Authority, under contract number HHSO100201800015C. Government Agency Research Support The views expressed in this press release are those of the authors and may not reflect the official policy or position of the Department of the Army, Department of Defense, or the U.S. Government. Department of Defense Select SPR206 studies are supported by the Office of the Assistant Secretary of Defense for Health Affairs, through the Joint Warfighter Medical Research Program under Award No. W81XWH 19 1 0295. Opinions, interpretations, conclusions, and recommendations are those of the author and are not necessarily endorsed by the Department of Defense. National Institute of Allergy and Infectious Disease Select SPR206 studies have been funded in whole or in part with Federal funds from the National Institute of Allergy and Infectious Diseases, National Institutes of Health, Department of Health and Human Services, under Contract No. 75N93021C00022. About Spero TherapeuticsSpero Therapeutics, headquartered in Cambridge, Massachusetts, is a multi-asset clinical-stage biopharmaceutical company focused on identifying and developing novel treatments for rare diseases and MDR bacterial infections with high unmet need. For more information, visit www.sperotherapeutics.com. Forward Looking Statements This press release may contain forward-looking statements. These statements include, but are not limited to, statements about the design, initiation, timing, progress and results of Spero's preclinical studies and clinical trials and its research and development programs, as well as the regulatory path forward for tebipenem HBr and potential FDA approval, the potential commercialization of tebipenem HBr, the potential receipt under the GSK license agreement of milestone payments and royalties on future sales of tebipenem HBr, and Spero’s cash runway. In some cases, forward-looking statements can be identified by terms such as "may," "will," "should," "expect," "plan," "aim," "anticipate," "could," "intent," "target," "project," "contemplate," "believe," "estimate," "predict," "potential" or "continue" or the negative of these terms or other similar expressions. Actual results may differ materially from those indicated by such forward-looking statements as a result of various important factors, including whether tebipenem HBr, SPR720 and SPR206 will advance through the clinical trial process on a timely basis, or at all, taking into account the effects of possible regulatory delays, slower than anticipated patient enrollment, manufacturing challenges, clinical trial design and clinical outcomes; whether the results of such trials will warrant submission for approval from the FDA or equivalent foreign regulatory agencies; whether the FDA will ultimately approve tebipenem HBr and, if so, the timing of any such approval; whether the FDA will require any additional clinical data or place labeling restrictions on the use of tebipenem HBr that would delay approval and/or reduce the commercial prospects of tebipenem HBr; whether a successful commercial launch can be achieved and market acceptance of tebipenem HBr can be established; whether results obtained in preclinical studies and clinical trials will be indicative of results obtained in future clinical trials; Spero's reliance on third parties to manufacture, develop, and commercialize its product candidates, if approved; Spero’s need for additional funding; the ability to commercialize Spero's product candidates, if approved; Spero's ability to retain key personnel; Spero’s ongoing leadership transitions; whether Spero's cash resources will be sufficient to fund its continuing operations for the periods and/or trials anticipated; and other factors discussed in the "Risk Factors" set forth in filings that Spero periodically makes with the SEC. The forward-looking statements included in this press release represent Spero's views as of the date of this press release. Spero anticipates that subsequent events and developments will cause its views to change. However, while Spero may elect to update these forward-looking statements at some point in the future, it specifically disclaims any obligation to do so. These forward-looking statements should not be relied upon as representing Spero's views as of any date subsequent to the date of this press release. Investor Relations Contact:Ashley R. RobinsonManaging Director, LifeSci Advisors, LLCarr@lifesciadvisors.com(617) 775-5956 Media Inquiries: media@sperotherapeutics.com Spero Therapeutics, Inc.Condensed Consolidated Balance Sheet Data(in thousands)(Unaudited) December 31, December 31, 2023 2022 ChangeCash, cash equivalents and marketable securities $76,333 $109,107 $(32,774)Other assets 106,057 15,695 90,362 Total assets $ 182,390 $ 124,802 $ 57,588 Total liabilities $75,496 $48,868 $26,628 Total stockholder's equity 106,894 75,934 30,960 Total liabilities and stockholders' equity $ 182,390 $ 124,802 $ 57,588 Spero Therapeutics, Inc.Condensed Consolidated Statements of Operations(in thousands, except share and per share data)(unaudited) Three Months Ended December 31, Year Ended December 31, 2023 2022 2023 2022 Revenues: Grant revenue $1,698 $1,087 $7,046 $4,930 Collaboration revenue - related party 71,603 46,076 95,802 46,076 Collaboration revenue 223 278 933 2,503 Total revenues 73,524 47,441 103,781 53,509 Operating expenses: Research and development 16,558 15,089 51,440 47,593 General and administrative 6,433 6,495 25,554 36,483 Impairment of long-term asset — — 5,306 — Restructuring — (67) — 11,630 Total operating expenses 22,991 21,517 82,300 95,706 Loss from operations 50,533 25,924 21,481 (42,197)Other income (expense) 1,046 847 3,923 (4,218)Net income (loss) before income taxes 51,579 26,771 25,404 (46,415)Income tax expense (387) — (2,598) — Net income (loss) attributable to common shareholders of Spero Therapeutics, Inc. $51,192 $26,771 $22,806 $(46,415) Net loss per share attributable to common shareholders per share, basic $0.97 $0.55 $0.43 $(1.23)Net loss per share attributable to common shareholders per share, diluted $0.96 $0.55 $0.43 $(1.23) Weighted average shares outstanding, basic: 52,999,491 48,715,409 52,703,467 37,585,075 Weighted average shares outstanding, diluted: 53,108,270 48,942,616 52,989,030 37,585,075

Key Hires in CMC/Technical Operations, Business Development, and Finance MALVERN, Pa.--(BUSINESS WIRE)-- Venatorx Pharmaceuticals, a private, pre-commercial pharmaceutical company focused on improving health outcomes for patients with multidrug-resistant bacterial infections and hard-to-treat viral infections, announced expansion of its leadership team with three key industry veterans: Jason Burdette joining as Senior Vice President, CMC and Technical Operations: Armand Girard as Chief Business Officer; and Tamra Adams, and Chief Financial Officer. These appointments come as the Company expands its remit from pure R&D to encompass support of commercialization. "Jason, Armand and Tamra bring a breadth of experience that will be instrumental to Venatorx as we continue to advance our portfolio and maximize the value of our assets," said Christopher J. Burns, Ph.D., President and CEO of Venatorx. "These additions to our senior leadership team are critical to ensure we are prepared for our NDA resubmission and are strategically positioned for continued success." Jason Burdette – Senior Vice President, CMC and Technical Operations – Burdette started at Venatorx in late 2023 and is an experienced leader with more than 30 years in the pharmaceutical industry across process chemistry, formulation and process development, manufacturing, supply chain management, and technical operations. He joined Venatorx from Aimmune/Nestle Health Science where he was a Senior Vice President and Head of Technical Operations. At Aimmune/Nestle Health Science, Burdette was responsible for formulation and process development, analytical development, CMC, manufacturing science and technology, quality control, quality assurance, supply chain, and product distribution. Before this, he was the Senior Vice President of Technical Operations with Paratek Pharmaceuticals and over the years has worked at Eagle Pharmaceuticals, Shire with aaiPharma, Elan Pharmaceuticals, Sandoz, and Mylan Pharmaceuticals. Burdette earned a bachelor's degree in chemistry and an MBA from West Virginia University. Armand Girard – Chief Business Officer – Girard is a seasoned biopharmaceutical executive with multiple product approvals and launches over his 25 years of experience in strategic planning, corporate development, clinical development, and business development. He has extensive partnering experience having completed collaborations, licenses, acquisitions, and spinouts by and between leading pharmaceutical and biotech companies. Girard joined Venatorx from GlycoMimetics where he was the Chief Business Officer. At GlycoMimetics, he was responsible for corporate strategy, partnering, and managing the company's corporate and institutional alliances supporting the development of uproleselan. Previously, he was Vice President, Technical Assessment and Senior Director for Business Development at Shire Pharmaceuticals to build the product pipeline and support Shire's strategic venture arm through investments. He received his undergraduate degree from Lehigh University and an MBA from St Joseph's Haub School of Business Executive Pharmaceutical Marketing Program. Tamra Adams – Chief Financial Officer – Adams has over 25 years of financial management experience. Most recently, she was CFO at Antios Therapeutics, a clinical-stage biopharmaceutical company that was developing innovative therapies to treat and cure HBV. Adams helped lead a $107 million financing and was responsible for IPO readiness, including filing the S-1. Before joining Antios, she founded Accounting Concepts, Inc., a firm that provided CFO, accounting, and financial services to emerging growth companies in the biopharmaceutical and information technology industries. Before that, Adams was the Senior Financial Executive at Silverstorm Technologies and began her career at Ernst & Young, followed by Goldman Sachs. She received her undergraduate degree from the State University of New York at Albany and received her CPA license in New York State. About Venatorx Pharmaceuticals, Inc. Venatorx is a private, late-stage clinical pharmaceutical company focused on improving health outcomes for patients with multidrug-resistant bacterial infections and hard-to-treat viral infections. Venatorx’s lead program, cefepime-taniborbactam, is a clinical-stage antibiotic that successfully completed a Phase 3 study in adults with complicated urinary tract infections (cUTI), including pyelonephritis. In October 2022, BARDA awarded a contract of up to $318M for development and procurement of cefepime-taniborbactam for the treatment of melioidosis and multi-drug resistant infections. Venatorx is also developing an oral antibacterial, ceftibuten-ledaborbactam (formerly known as VNRX-7145), for the treatment of cUTI, including pyelonephritis, caused by certain bacteria in adult patients with limited treatment options; this product is completing Phase 1 and will advance directly to a global Phase 3 cUTI clinical trial. For more information about Venatorx and its anti-infectives portfolio, please visit . Forward Looking Statements This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. All statements contained in this press release that do not relate to matters of historical fact should be considered forward-looking statements, including without limitation statements regarding the potential, safety, efficacy, and regulatory and clinical development of Venatorx Pharmaceuticals’ product candidates.