Mast Cell Activation Disorders

REDWOOD CITY, Calif., March 19, 2024 (GLOBE NEWSWIRE) -- Jasper Therapeutics, Inc. (Nasdaq: JSPR) (Jasper), a biotechnology company focused on development of briquilimab, a novel antibody therapy targeting c-Kit (CD117) in mast cell driven diseases such as chronic spontaneous urticaria (CSU) and chronic inducible urticaria (CIndU), today announced that the first patient has been dosed in Jasper’s Phase 1b/2a (SPOTLIGHT) clinical study of subcutaneous briquilimab for the treatment of CIndU. The SPOTLIGHT study is evaluating a single administration, at two different dose levels, of subcutaneous briquilimab in adult patients with cold urticaria (ColdU) or symptomatic dermographism (SD). “We are excited to announce dosing of the first patient in the SPOTLIGHT study in patients with CIndU, our second clinical program evaluating briquilimab in a mast cell-mediated disease,” said Edwin Tucker, Chief Medical Officer of Jasper. “As with our BEACON study in CSU, we expect the SPOTLIGHT study to establish proof of concept for the depletion of mast cells by briquilimab in CIndU and help us to determine doses and dosing regimens for future registrational studies. We plan to provide enrollment updates as we progress through the study and anticipate reporting preliminary data in the second half of 2024.” The SPOTLIGHT study is expected to enroll approximately 15 patients across 2 dose cohorts. The primary endpoints are safety and tolerability of briquilimab with secondary endpoints focused on efficacy measures and pharmacokinetics. The study is being conducted at four sites in the EU. Jasper anticipates reporting preliminary data from the SPOTLIGHT study in the second half of 2024. “c-Kit inhibitors are a promising class of monoclonal therapeutics with demonstrated efficacy in mast cell driven diseases,” said Marcus Maurer, M.D., Professor of Dermatology and Allergy at Charité – Universitätsmedizin in Berlin. “As a potent and differentiated c-Kit inhibitor, I believe briquilimab has the potential to serve as an important treatment option for patients suffering from CIndU, and I look forward to enrolling patients into the SPOTLIGHT study and additionally into the BEACON study for CSU.” About Briquilimab Briquilimab (formerly JSP191) is a targeted aglycosylated monoclonal antibody that blocks stem cell factor from binding to the cell-surface receptor c-Kit, also known as CD117, thereby inhibiting signaling through the receptor. This inhibition disrupts the critical survival signal, leading to the depletion of the mast cells via apoptosis which removes the underlying source of the inflammatory response in mast cell driven diseases such as chronic urticaria. Jasper is currently conducting clinical studies of briquilimab as a treatment in patients with CSU or with CIndU. Briquilimab is also currently in clinical studies as a treatment for patients with LR-MDS and as a conditioning agent for cell therapies for rare diseases. To date, briquilimab has a demonstrated efficacy and safety pro more than 145 dosed participants and healthy volunteers, with clinical outcomes as a conditioning agent in severe combined immunodeficiency (SCID), AML, MDS, FA, and sickle cell disease (SCD). About Jasper Jasper is a clinical-stage biotechnology company developing briquilimab, a monoclonal antibody targeting c-Kit (CD117) as a therapeutic for chronic mast and stem cell diseases such as chronic urticaria and lower to intermediate risk MDS and as a conditioning agent for stem cell transplants for rare diseases such as SCD, FA and SCID. To date, briquilimab has a demonstrated efficacy and safety pro more than 145 dosed participants and healthy volunteers, with clinical outcomes as a conditioning agent in SCID, AML, MDS, FA, and SCD. For more information, please visit us at . Forward-Looking Statements Certain statements included in this press release that are not historical facts are forward-looking statements for purposes of the safe harbor provisions under the United States Private Securities Litigation Reform Act of 1995. Forward-looking statements are sometimes accompanied by words such as “believe,” “may,” “will,” “estimate,” “continue,” “anticipate,” “intend,” “expect,” “should,” “would,” “plan,” “predict,” “potential,” “seem,” “seek,” “future,” “outlook” and similar expressions that predict or indicate future events or trends or that are not statements of historical matters. These forward-looking statements include, but are not limited to, statements regarding briquilimab’s potential, including with respect to its potential in mast cell driven diseases such as CSU and CIndU and its potential to serve as an important treatment option for patients suffering from CIndU; Jasper’s expectations regarding its Phase 1b/2a SPOTLIGHT study of subcutaneous briquilimab in CIndU, including the expected enrollment, cohorts and site locations, the expected timing for reporting preliminary data, the expectation that the SPOTLIGHT or BEACON studies will establish proof of concept or help Jasper determine doses and dosing regimens for future registrational studies; and Jasper’s expectations regarding its BEACON study in CSU, including the expectation that Jasper will enroll additional patients in the BEACON study for CSU. These statements are based on various assumptions, whether or not identified in this press release, and on the current expectations of Jasper and are not predictions of actual performance. These forward-looking statements are provided for illustrative purposes only and are not intended to serve as, and must not be relied on by an investor as, a guarantee, an assurance, a prediction or a definitive statement of fact or probability. Many actual events and circumstances are beyond the control of Jasper. These forward-looking statements are subject to a number of risks and uncertainties, including general economic, political and business conditions; the risk that the potential product candidates that Jasper develops may not progress through clinical development or receive required regulatory approvals within expected timelines or at all; the risk that clinical trials may not confirm any safety, potency or other product characteristics described or assumed in this press release; the risk that Jasper will be unable to successfully market or gain market acceptance of its product candidates; the risk that prior study results may not be replicated; the risk that Jasper’s product candidates may not be beneficial to patients or successfully commercialized; patients’ willingness to try new therapies and the willingness of physicians to prescribe these therapies; the effects of competition on Jasper’s business; the risk that third parties on which Jasper depends for laboratory, clinical development, manufacturing and other critical services will fail to perform satisfactorily; the risk that Jasper’s business, operations, clinical development plans and timelines, and supply chain could be adversely affected by the effects of health epidemics; the risk that Jasper will be unable to obtain and maintain sufficient intellectual property protection for its investigational products or will infringe the intellectual property protection of others; and other risks and uncertainties indicated from time to time in Jasper’s filings with the SEC, including its Annual Report on Form 10-K for the year ended December 31, 2023 and subsequent Quarterly Reports on Form 10-Q. If any of these risks materialize or Jasper’s assumptions prove incorrect, actual results could differ materially from the results implied by these forward-looking statements. While Jasper may elect to update these forward-looking statements at some point in the future, Jasper specifically disclaims any obligation to do so. These forward-looking statements should not be relied upon as representing Jasper’s assessments of any date subsequent to the date of this press release. Accordingly, undue reliance should not be placed upon the forward-looking statements. Contacts: Joyce Allaire (investors) LifeSci Advisors 617-435-6602 jallaire@lifesciadvisors.com Alex Gray (investors) Jasper Therapeutics 650-549-1454 agray@jaspertherapeutics.com Lauren Walker (media) Real Chemistry 646-564-2156 lbarbiero@realchemistry.com

PRESS RELEASE SUMMARY OF THE WEBCAST HELD ON MARCH 4, 2024 PROVIDING AN UPDATE ON AB SCIENCE DEVELOPMENT Paris, March 7, 2024, 3pm CET AB Science SA (Euronext - FR0010557264 - AB) is providing a summary of the live webcast held on March 4, 2024, giving an update on AB Science development. The webcast presentation is available on the company’s website, in the section « Press Releases »: https://www.ab-science.com/news-and-media/press-releases/ The presentation covered four topics: Status of conditional approval application of masitinib in ALS with EMA and Health CanadaStatus of the masitinib platform clinical development programStatus of masitinib licensing partnershipStatus of the microtubulin platform clinical development programStatus of masitinib and AB8939 intellectual property Status of conditional approval application of masitinib in ALS with EMA and Health Canada Regarding EMA, the application was filed in August 2022. An Oral Explanation was planned in January 2024, however, CHMP proposed that AB Science submit a written response to the List of Outstanding Issues at D195 of the procedure, instead of addressing these issues through the Oral Explanation, which is unusual. A decision is now expected by the end of Q2 2024.Regarding Health Canada, a Notice of Deficiency-Withdrawal (NOD/w) has been issued and AB Science intends to submit a Request for Reconsideration. This reconsideration process involves new assessors and offers the possibility to have an opinion from a panel of experts. A decision is now expected by the end of Q3/Q4 2024. Of note, the press release dated 26 February 2024 incorrectly stated that Health Canada issued a Notice of Non Compliance – Withdrawal (NON/w) when the decision issued was in fact a Notice of Deficiency – Withdrawal (NOD-W). The issuance of NOD-W or NON-W indicate different regulatory decisions. A NOD-W is issued if, during the scientific review of the response to a Notice of Deficiency (NOD), it is found that the submission/application remains deficient. On the other hand, a Notice of Non-Compliance Withdrawal is issued when, during the scientific review of the response to a Notice of Non-Compliance (NON), it is determined that the submission remains non-compliant. Three key major clinical objections and intended counterarguments for reconsiderations have been presented. They are the following: Amendments Multiple amendments have been made that create uncertainty on the reliability of study data. Several concerns were resolved, namely, changing study status from phase 2 to phase 3, the fact that multiple amendments may be an inevitability, that amendments were not data-driven, that the study had broad inclusion criteria and there may be a need to limit heterogeneity, and that post-onset decline of 1.1 point per month may be relevant.However, Health Canada was concerned that amendments were late and not sufficiently justified. AB Science intends to justify that the distinction between Normal and Fast progressors was made when the data were entirely blinded and in a sufficiently prospective manner since 88% of the data still needed to be acquired at that time, and that the amendment was justified to minimize expected high missing data due to discontinuations from Fast progressors (confirmed to be >50% at week 48). Missing data The concern regarding non-linearity of the ALSFRS-R data set distribution used for primary analysis (ANCOVA test) was resolved.However, Health Canada was concerned that the treatment of missing data using LOCF methodology could potentially create a bias in favor of treatment. AB Science intends to justify that sensitivity analysis of the primary analysis based on non LOCF recognized methods are successful and convergent (multiple imputational model, jump to reference, copy incremental model), and that the CAFS endpoint, incorrectly assumed by the Agency to be based on LOCF methodology, whereas it is not, approached the conventionally statistically significant outcome of 5% (p=0.0776), even though the study was not powered for this secondary endpoint. Application of EMA guideline on subgroups Health Canada was concerned that the new proposed claim in patients with ALS prior to any complete loss of function is considered post hoc and that overall survival benefit in this claim could have been biased by confounding factors. AB Science intends to justify that in the EMA guidance (EMA/CHMP/539146/2013) on the investigation of subgroups in confirmatory clinical trials, it is written that the guideline is applicable to a subgroup that has not been pre-specified.In this claim, the treatment effect is exceptionally strong based on CAFS (p=0.029) and survival (+22 months p=0.0192). Furthermore, OS is the gold standard endpoint in ALS and is unbiased regardless of post study treatments because no drug has demonstrated OS benefit (except riluzole, which was available to all patients) and because all patients had the same possibility to benefit from tracheostomy or permanent or non-permanent ventilation. Based on the supporting arguments and counterarguments outlined above, AB Science intends to submit a Request for Reconsideration. Other points of concern identified by the agency will also be responded to. Status of the masitinib platform clinical development program Masitinib offers a late stage and diversified platform of 8 indications, primarily centered around neuro-degenerative diseases (namely, amyotrophic lateral sclerosis, progressive form of multiple sclerosis, mild and moderate Alzheimer’s disease) and mast cell diseases (indolent systemic mastocytosis, mast cell activation syndrome), but also sickle cell disease, metastatic castrate refractory prostate cancer eligible to docetaxel, and COVID-19. In amyotrophic lateral sclerosis (ALS), no drug has generated a consensus based on definitive evidence of efficacy. Enrolment in the phase 3 confirmatory masitinib study (AB19001), is slower than that of the previous (AB10015) study, due to design features of the phase 3 (run-in period of 3 months, patient eligibility restricted to moderate ALS severity, exclusion of newly registered drugs and a blinded extension period).In multiple sclerosis (MS), there is no approved drugs for non-active secondary progressive MS and only one for primary progressive MS. Masitinib stands-out as the only non BTK inhibitor in phase 3 clinical development. The confirmatory phase 3 masitinib study (AB20009) is authorized by the FDA and key European countries and initiation is expected in 2024.In Alzheimer’s disease (AD), masitinib is positioned in mild and moderate forms of Alzheimer’s disease, where no novel treatment has been approved. New treatments have been approved in early Alzheimer. The confirmatory phase 3 masitinib study (AB21004) is authorized by FDA and key European countries with initiation expected in 2024.In indolent systemic mastocytosis (ISM), masitinib has a different positioning from other KIT-816 inhibitors and its benefits are optimal on different symptoms such as neurological symptoms, depression but also pruritus and flush. The confirmatory phase 3 masitinib study (AB15003) is on-going and additionally, a phase 2 study (AB20006) is also ongoing in MCAS, another mast cell disease not involving the KIT-816 mutation.In sickle cell disease (SCD), there is an increasing interest with several new drugs being in clinical development; however, unlike masitinib, none target mast cells, which are involved in Vaso Occlusive Crisis. A phase 1/2 study, financed by the RHU program for a budget of 10M€, is planned, with an objective to identify biomarkers of a mast cell signature and to assess the efficacy of masitinib in the treatment of acute and chronic complications. AB Science will be free to continue the development of masitinib in SCD based on phase 2 data with biomarkers.In metastatic castrate refractory prostate cancer (mCRPC) eligible to docetaxel, there is no drug registered in combination with docetaxel and there is an unmet medical need after failure to hormonotherapy and eligible to docetaxel. A first phase 3 study of masitinib in combination with docetaxel was positive. Submission of a confirmatory phase 3 study is planned in 2024, following scientific advice received from EMA and FDA, who both recommended to demonstrate benefit on radiographic progression free survival with no need to prove efficacy on overall survival.In COVID-19, read-out of two phase 2 studies is expected in 2024, the first evaluating masitinib anti-inflammatory activity in hospitalized patients in need of oxygen with moderate and severe COVID-19, and the second one evaluating masitinib anti-viral activity in ambulatory or hospitalized patients with symptomatic mild and moderate COVID-19 and with comorbidities. Status of masitinib licensing partnership Discussions for masitinib licensing with a pharmaceutical company are ongoing and the process is expected to be completed by the end of 2024. The scope of the license is mainly neurodegenerative indications, including ALS. The discussions are with companies that do not condition the signature of a binding offer to a positive opinion from EMA and Health Canada in ALS. AB Science is currently aiming to develop a liquid formulation for masitinib in ALS. A liquid formulation would be beneficial for ALS patients because they have difficulties in swallowing. A liquid formulation is beneficial for the masitinib development plan as differential pricing will be facilitated between ALS (liquid formulation) and other indications (tablets). The development of any new formulation will require bioequivalence studies and is expected to take two years. Status of the microtubulin platform clinical development program The microtubule destabilizer agents (MDAs) platform is focused in haemato-oncology with two drugs, AB8939 and AB12319. AB8939 has the potential to improve acute myeloid leukemia (AML) treatment based on three differentiating features of its mechanism of action. AB8939 is not metabolized by an enzyme called myeloperoxidase, produced by the disease itself, unlike other MDAs.AB8939 avoids multidrug resistance because it does not bind and is not transported by PgP/BRCP, so it is not washed out from the cells, unlike other MDAs.AB8939 has a strong synergistic effect with reference treatment azacitidine, called Vidaza. The phase 1 study of AB8939 has completed its first step (determination of maximum tolerated dose following 3 consecutive days of AB8939 treatment), and key agencies have authorized this study to proceed with the next step (determination of maximum tolerated dose following 14 consecutive days of AB8939 treatment). The phase 1 is expected to be completed in 2024 and a phase 2 will be initiated in 2025 with an intention to design the study to support accelerated approval. Status of masitinib and AB8939 intellectual property Masitinib intellectual property rights are protected until 2036 in mastocytosis, until 2037 in ALS, and potentially until 2041 in MS and ALZ and 2042 in prostate cancer. AB8939 intellectual property rights in AML are secured until 2036 through a ‘composition of matter’ patent and potentially until 2044 in AML with chromosome abnormality (MECOM) through a ‘second medical use’ patent. About AB ScienceFounded in 2001, AB Science is a pharmaceutical company specializing in the research, development and commercialization of protein kinase inhibitors (PKIs), a class of targeted proteins whose action are key in signaling pathways within cells. Our programs target only diseases with high unmet medical needs, often lethal with short term survival or rare or refractory to previous line of treatment. AB Science has developed a proprietary portfolio of molecules and the Company’s lead compound, masitinib, has already been registered for veterinary medicine and is developed in human medicine in oncology, neurological diseases, inflammatory diseases and viral diseases. The company is headquartered in Paris, France, and listed on Euronext Paris (ticker: AB).Further information is available on AB Science’s website: www.ab-science.com. Forward-looking Statements - AB ScienceThis press release contains forward-looking statements. These statements are not historical facts. These statements include projections and estimates as well as the assumptions on which they are based, statements based on projects, objectives, intentions and expectations regarding financial results, events, operations, future services, product development and their potential or future performance. These forward-looking statements can often be identified by the words "expect", "anticipate", "believe", "intend", "estimate" or "plan" as well as other similar terms. While AB Science believes these forward-looking statements are reasonable, investors are cautioned that these forward-looking statements are subject to numerous risks and uncertainties that are difficult to predict and generally beyond the control of AB Science and which may imply that results and actual events significantly differ from those expressed, induced or anticipated in the forward-looking information and statements. These risks and uncertainties include the uncertainties related to product development of the Company which may not be successful or to the marketing authorizations granted by competent authorities or, more generally, any factors that may affect marketing capacity of the products developed by AB Science, as well as those developed or identified in the public documents published by AB Science. AB Science disclaims any obligation or undertaking to update the forward-looking information and statements, subject to the applicable regulations, in particular articles 223-1 et seq. of the AMF General Regulations. For additional information, please contact: AB ScienceFinancial Communication & Media Relations investors@ab-science.com Attachment Summary Webcast March 4 2024 VEng VF

Treatment Resulted in Rapid, Clinically Meaningful, and Statistically Significant Improvements Across Multiple Signs and Symptoms in the Intention-to-Treat Population Complete Results to be Presented at the Association for Research in Vision and Ophthalmology Annual Meeting 2024 TL-925 is a First-in-Class Topical (Eye Drop) BTK Inhibitor Targeting Mast Cell-mediated Ocular Inflammation and Allergy REDWOOD CITY, Calif.--(BUSINESS WIRE)-- Telios Pharmaceuticals, Inc., a clinical stage biopharmaceutical company committed to improving the lives of patients with inflammatory diseases, today announced topline results from its Phase 2 study assessing TL-925, a first-in-class topical Bruton’s tyrosine kinase (BTK) inhibitor for individuals with moderate to severe dry eye disease (DED). This proof-of-concept, multicenter, randomized, double-masked study evaluated the safety, tolerability, and efficacy of TL-925 versus vehicle control, when dosed twice daily for 28 days. A total of 107 subjects with moderate to severe DED were enrolled. TL-925 was safe and well tolerated and the intention-to-treat analysis demonstrated clinically meaningful and statistically significant efficacy relative to vehicle control across multiple signs and symptoms. The rapid onset of efficacy across multiple ocular regions, coupled with favorable and consistent results in different environments confirm TL-925’s differentiated pro a safe, well-tolerated, and effective treatment for patients with DED. Complete results will be presented at the upcoming Association for Research in Vision and Ophthalmology (ARVO) Annual Meeting 2024, to be held from May 5-9, 2024, in Seattle, Washington. Poster: 2965 - A0124 Title: TL-925, a First-in-Class, Topical, Bruton’s Tyrosine Kinase Inhibitor in Subjects with Moderate to Severe Dry Eye Disease Session: 316 Date & Time: May 7, 2024, 08:30 - 10:15 “We are thrilled by these findings and honored to have been selected to share our groundbreaking research with the ophthalmology community at ARVO,” said Jesse McGreivy, CEO of Telios Pharma. “Our team is excited about advancing TL-925 through the next stages of clinical development with the aim of further demonstrating its ability to address the underlying cause of dry eye disease, an underdiagnosed and often poorly managed condition that affects many millions of people worldwide.” “I am highly encouraged by the breadth of positive results from this Phase 2 study and hopeful about the potential for TL-925 to impact the underlying pathology of DED,” said George Ousler, lead investigator and Senior Vice President at Ora Inc., the world’s leading full-service ophthalmic research organization, which oversaw the trial. “The results are among the most impressive that I have seen in my years working on dry eye clinical development programs. TL-925 is a promising and much needed novel approach for the treatment of DED.” A Phase 2b study of TL-925 in DED has been initiated based on these results and is currently enrolling patients. Consistent with TL-925’s efficacy in DED, a separate Phase 2 study evaluating the safety and efficacy of TL-925 in individuals with allergic conjunctivitis (AC) has recently shown clinically meaningful and statistically significant improvements in both itching and redness. These data will be presented at a medical congress later this year. “DED and AC are two of the most common ocular inflammatory disorders and often coexist, presenting unique treatment challenges,” said Gail Torkildsen, MD, a board-certified ophthalmologist at Andover Eye Associates and principal investigator in both studies. “Positive efficacy results in DED and AC demonstrate that TL-925 can effectively and rapidly halt the cycle of inflammation; these data also validate TL-925’s potential to target the underlying inflammatory mechanisms driving these diseases. It is increasingly apparent that TL-925 may represent a significant leap forward for the effective treatment of DED and AC.” About Telios Pharma, Inc. Telios Pharma is a privately held clinical stage biopharmaceutical company with a first-in-class topical and oral BTK program targeting mast cell-mediated inflammation and allergy. About TL-925 Dry eye disease, a chronic inflammatory disorder of the lacrimal unit, causes ocular discomfort, pain, and visual disturbances. Mast cells, found in the lacrimal functional unit, are key initiators and amplifiers of the inflammatory cascade. TL-925, an ophthalmic formulation of the potent, irreversible BTK inhibitor TL-895 prevents mast cell activation and degranulation, blocks the cytokine-driven inflammatory response, and restores lacrimal unit homeostasis, offering the potential for disease modification. Our novel approach to treating DED targets BTK, which has been shown to be critical for mast cell activation and immune response.