Craniopharyngioma

- Publication highlights administration of setmelanotide therapy resulted in a mean percent reduction in BMI of 15% at 16 weeks and 26% at one year of treatment - - Topline data from ongoing pivotal Phase 3 clinical trial in hypothalamic obesity on track for 2Q 2025 - BOSTON, April 29, 2024 (GLOBE NEWSWIRE) -- Rhythm Pharmaceuticals, Inc. (Nasdaq: RYTM), a global commercial-stage biopharmaceutical company focused on transforming the lives of patients and their families living with rare neuroendocrine diseases, today announced the publication of previously disclosed results from its Phase 2 study of setmelanotide for the treatment of hypothalamic obesity. The data are published in the peer-reviewed journal The Lancet Diabetes & Endocrinology. “People with hypothalamic obesity experience rapid, severe weight gain and hyperphagia,” said lead author Christian Roth, M.D., Seattle Children’s Research Institute and Division of Endocrinology, Department of Pediatrics, University of Washington. “In this first study to investigate the use of setmelanotide as a targeted treatment for hypothalamic obesity, we observed a consistent reduction in body weight and hunger in all adherent patients. We believe these findings support setmelanotide as a potential novel and effective treatment option, and we look forward to potentially confirming the results in the ongoing pivotal study.” Acquired hypothalamic obesity is a rare form of extreme obesity that occurs following damage to the hypothalamic region of the brain, which includes the melanocortin-4 receptor (MC4R) pathway and is responsible for controlling physiological functions such as hunger and weight regulation. It most frequently follows the growth or surgical removal of craniopharyngioma, astrocytoma, or other rare brain tumors. Patients experience rapid weight gain, a reduction in energy expenditure, and an increase in hunger leading to severe obesity within six to 12 months following tumor resection. Rhythm enrolled 18 patients in its open-label, 16-week Phase 2 trial designed to evaluate setmelanotide in acquired hypothalamic obesity in patients with a body mass index (BMI) ≥95th percentile (children 6 to <18 years) or ≥35 kg/m2 (adults ≥18 years). The primary endpoint was the proportion of patients who achieved a 5% or greater reduction in BMI after 16 weeks of treatment. Hunger was also assessed daily, as self-reported by individual patients. As previously disclosed, results demonstrated: 89% (16 of 18) of patients achieved the primary endpoint; 78% (14 of 18) of patients achieved a 10% or greater reduction in BMI at 16 weeks; Mean percent reduction in BMI was 15% from baseline; In pediatric patients (n=13), the mean (standard deviation [SD]) BMI Z score at Week 16 was 2.7 (1.3), a reduction of 1.3 (1.0) points from baseline; and Mean (SD) most hunger score at baseline was 6.6 (1.6), compared with 3.7 (2.5) at Week 16, for a reduction of –2.9 (2.3) points or 45% for patients ≥12 years of age (n=11). The publication also includes preliminary data from Rhythm’s long-term extension of the Phase 2 study that were disclosed at ObesityWeek® 2023. These data show patients with hypothalamic obesity (n=12) achieved mean BMI reduction of approximately 26% at one year on setmelanotide treatment. Consistent with prior experience, setmelanotide was generally well tolerated. The most common adverse events (AEs) in the primary trial included nausea (61.1%), vomiting (33.3%), skin hyperpigmentation (33.3%), diarrhea (22.2%), and COVID-19 (22.2%). Two patients discontinued due to AEs and a third patient was non-compliant. There were no serious AEs, no AEs that led to study discontinuation during the trial, and no new safety concerns were observed during the long-term extension trial. In January 2024, Rhythm announced the completion of screening for enrollment in the ongoing pivotal, Phase 3 clinical trial evaluating setmelanotide in patients with acquired hypothalamic obesity. The Company remains on track to obtain topline study results in the first half of 2025. About Rhythm Pharmaceuticals Rhythm is a commercial-stage biopharmaceutical company committed to transforming the lives of patients and their families living with rare neuroendocrine diseases. Rhythm’s lead asset, IMCIVREE® (setmelanotide), an MC4R agonist designed to treat hyperphagia and severe obesity, is approved by the U.S. Food and Drug Administration (FDA) for chronic weight management in adult and pediatric patients 6 years of age and older with monogenic or syndromic obesity due to pro-opiomelanocortin (POMC), proprotein convertase subtilisin/kexin type 1 (PCSK1) or leptin receptor (LEPR) deficiency confirmed by genetic testing, or patients with a clinical diagnosis of Bardet-Biedl syndrome (BBS). Both the European Commission (EC) and the UK’s Medicines & Healthcare Products Regulatory Agency (MHRA) have authorized setmelanotide for the treatment of obesity and the control of hunger associated with genetically confirmed BBS or genetically confirmed loss-of-function biallelic POMC, including PCSK1, deficiency or biallelic LEPR deficiency in adults and children 6 years of age and above. Additionally, Rhythm is advancing a broad clinical development program for setmelanotide in other rare diseases, as well as investigational MC4R agonists LB54640 and RM-718, and a preclinical suite of small molecules for the treatment of congenital hyperinsulinism. Rhythm’s headquarters is in Boston, MA. Setmelanotide Indication In the United States, setmelanotide is indicated for chronic weight management in adult and pediatric patients 6 years of age and older with monogenic or syndromic obesity due to POMC, PCSK1 or LEPR deficiency as determined by an FDA-approved test demonstrating variants in POMC, PCSK1 or LEPR genes that are interpreted as pathogenic, likely pathogenic, or of uncertain significance (VUS) or BBS. In the European Union, setmelanotide is indicated for the treatment of obesity and the control of hunger associated with genetically confirmed BBS or loss-of-function biallelic POMC, including PCSK1, deficiency or biallelic LEPR deficiency in adults and children 6 years of age and above. In Europe, setmelanotide should be prescribed and supervised by a physician with expertise in obesity with underlying genetic etiology. Limitations of Use Setmelanotide is not indicated for the treatment of patients with the following conditions as setmelanotide would not be expected to be effective: Obesity due to suspected POMC, PCSK1 or LEPR deficiency with POMC, PCSK1 or LEPR variants classified as benign or likely benign Other types of obesity not related to POMC, PCSK1 or LEPR deficiency, or BBS, including obesity associated with other genetic syndromes and general (polygenic) obesity. Contraindication Prior serious hypersensitivity to setmelanotide or any of the excipients in IMCIVREE. Serious hypersensitivity reactions (e.g., anaphylaxis) have been reported. WARNINGS AND PRECAUTIONS Skin Pigmentation and Darkening of Pre-Existing Nevi: Generalized increased skin pigmentation and darkening of pre-existing nevi have occurred because of its pharmacologic effect. Full body skin examinations prior to initiation and periodically during treatment should be conducted to monitor pre-existing and new pigmentary lesions. Heart rate and blood pressure monitoring: In Europe, heart rate and blood pressure should be monitored as part of standard clinical practice at each medical visit (at least every 6 months) for patients treated with setmelanotide. Disturbance in Sexual Arousal: Spontaneous penile erections in males and sexual adverse reactions in females have occurred. Patients who have an erection lasting longer than 4 hours should seek emergency medical attention. Depression and Suicidal Ideation: Depression and suicidal ideation have occurred. Patients should be monitored for new onset or worsening depression or suicidal thoughts or behaviors. Consideration should be given to discontinuing setmelanotide if patients experience suicidal thoughts or behaviors, or clinically significant or persistent depression symptoms occur. Hypersensitivity Reactions: Serious hypersensitivity reactions (e.g., anaphylaxis) have been reported. If suspected, advise patients to promptly seek medical attention and discontinue setmelanotide. Pediatric Population: The prescribing physician should periodically assess response to setmelanotide therapy. In growing children, the impact of weight loss on growth and maturation should be evaluated. In Europe, the prescribing physician should monitor growth (height and weight) using age- and sex-appropriate growth curves. Risk of Serious Adverse Reactions Due to Benzyl Alcohol Preservative in Neonates and Low Birth Weight Infants: Setmelanotide is not approved for use in neonates or infants. Serious and fatal adverse reactions including “gasping syndrome” can occur in neonates and low birth weight infants treated with benzyl alcohol-preserved drugs. ADVERSE REACTIONS Most common adverse reactions (incidence ≥20%) included skin hyperpigmentation, injection site reactions, nausea, headache, diarrhea, abdominal pain, vomiting, depression, and spontaneous penile erection. USE IN SPECIFIC POPULATIONS Lactation: Not recommended when breastfeeding. To report SUSPECTED ADVERSE REACTIONS, contact Rhythm Pharmaceuticals at +1 (833) 789-6337 or FDA at 1-800-FDA-1088 or . See section 4.8 of the Summary of Product Characteristics for information on reporting suspected adverse reactions in Europe. Please see the full Prescribing Information for additional Important Safety Information. 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, regulatory progress, clinical design or progress, and commercial market for any of our products or product candidates, including setmelanotide to treat hypothalamic obesity; and the ongoing progress of and anticipated timing for our Phase 3 clinical trial. Statements using word such as “expect”, “anticipate”, “believe”, “may”, “will” and similar terms are also forward-looking statements. Such statements are subject to numerous risks and uncertainties, including, but not limited to, whether the conditions for the closing of the investment transaction; our ability to enroll patients in clinical trials, the design and outcome of clinical trials, the impact of competition, the ability to achieve or obtain necessary regulatory approvals, risks associated with data analysis and reporting, our ability to successfully commercialize setmelanotide, our liquidity and expenses, our ability to retain our key employees and consultants, and to attract, retain and motivate qualified personnel, and general economic conditions, and the other important factors discussed under the caption “Risk Factors” in our Annual Report on Form 10-K for the year ended December 31, 2023 and our other filings with the Securities and Exchange Commission. Except as required by law, we undertake no obligations to make any revisions to the forward-looking statements contained in this release or to update them to reflect events or circumstances occurring after the date of this release, whether as a result of new information, future developments or otherwise. Corporate Contact: David Connolly Head of Investor Relations and Corporate Communications Rhythm Pharmaceuticals, Inc. 857-264-4280 dconnolly@rhythmtx.com Media Contact: Adam Daley Berry & Company Public Relations 212-253-8881 adaley@berrypr.com

-- Supplemental cohort of 12 Japanese patients to be added to global Phase 3 hypothalamic obesity trial, with dosing expected to begin in third quarter of 2024 -- -- Significant unmet need with 5,000 to 8,000 patients with hypothalamic obesity estimated to be living in Japan -- BOSTON, Feb. 22, 2024 (GLOBE NEWSWIRE) -- Rhythm Pharmaceuticals, Inc. (Nasdaq: RYTM), a global commercial-stage biopharmaceutical company focused on transforming the lives of patients and their families living with rare neuroendocrine diseases, today announced plans to add a cohort of patients with hypothalamic obesity in Japan to its ongoing global Phase 3 clinical trial of setmelanotide, with dosing expected to begin in the third quarter of 2024. “Following constructive discussions with Japan’s Pharmaceuticals and Medical Devices Agency (PMDA), we are pleased to have developed a clear and efficient plan to support the potential approval of setmelanotide for hypothalamic obesity in Japan,” said David Meeker, M.D., Chair, President and Chief Executive Officer of Rhythm. “With data showing a higher per-capita incidence and prevalence of patients with hypothalamic obesity in Japan compared to the United States and Europe and no approved therapeutic options, there is a major unmet need for a therapy to treat the rapid onset of severe obesity and hyperphagia of hypothalamic obesity.” Rhythm estimates that there are approximately 5,000 to 8,000 patients in Japan with hypothalamic obesity, a rare form of obesity that occurs following damage to the hypothalamic region of the brain, which includes the melanocortin-4 receptor (MC4R) pathway and is responsible for controlling physiological functions such as hunger and weight regulation. The condition most frequently follows the growth and surgical removal or other treatment of craniopharyngioma, astrocytoma, or other rare brain tumors. These individuals often experience rapid weight gain, a reduction in energy expenditure, and an increase in hunger leading to severe obesity within six to 12 months following the hypothalamic lesions. The Company and Japan’s PMDA agreed to add a cohort of 12 Japanese patients to the ongoing trial and, pending completion of the trial, to use these data as part of the Company’s registration package to seek approval from Japan’s Ministry of Health, Labor and Welfare. In addition to efficacy data, Rhythm will collect and submit pharmacokinetics (PK) data from Japanese patients, expediting the typical pathway of collecting such data from an earlier-stage trial in Japanese subjects. Rhythm also announced today that it completed enrollment in the pivotal, 120-patient cohort in its global Phase 3 trial of setmelanotide in hypothalamic obesity with patients, aged 4 years or older with hypothalamic obesity randomized 2:1 to setmelanotide therapy or placebo for a total of 60 weeks, including up to eight weeks for dose titration. As agreed to with both the United States Food and Drug Administration (FDA) and the European Medicines Agency (EMA), Rhythm’s regulatory submissions would be based on data from this cohort. The additional 12-patient Japanese cohort will not affect timing for regulatory submissions in the United States or Europe. The Company remains on track to obtain top-line study results in the first half of 2025. About Rhythm PharmaceuticalsRhythm is a commercial-stage biopharmaceutical company committed to transforming the lives of patients and their families living with rare neuroendocrine diseases. Rhythm’s lead asset, IMCIVREE® (setmelanotide), an MC4R agonist designed to treat hyperphagia and severe obesity, is approved by the U.S. Food and Drug Administration (FDA) for chronic weight management in adult and pediatric patients 6 years of age and older with monogenic or syndromic obesity due to pro-opiomelanocortin (POMC), proprotein convertase subtilisin/kexin type 1 (PCSK1) or leptin receptor (LEPR) deficiency confirmed by genetic testing, or patients with a clinical diagnosis of Bardet-Biedl syndrome (BBS). Both the European Commission (EC) and the UK’s Medicines & Healthcare Products Regulatory Agency (MHRA) have authorized setmelanotide for the treatment of obesity and the control of hunger associated with genetically confirmed BBS or genetically confirmed loss-of-function biallelic POMC, including PCSK1, deficiency or biallelic LEPR deficiency in adults and children 6 years of age and above. Additionally, Rhythm is advancing a broad clinical development program for setmelanotide in other rare diseases, as well as RM-718 and a preclinical suite of small molecules for the treatment of congenital hyperinsulinism. Rhythm’s headquarters is in Boston, MA. Setmelanotide Indication In the United States, setmelanotide is indicated for chronic weight management in adult and pediatric patients 6 years of age and older with monogenic or syndromic obesity due to POMC, PCSK1 or LEPR deficiency as determined by an FDA-approved test demonstrating variants in POMC, PCSK1 or LEPR genes that are interpreted as pathogenic, likely pathogenic, or of uncertain significance (VUS) or BBS. In the European Union, setmelanotide is indicated for the treatment of obesity and the control of hunger associated with genetically confirmed BBS or loss-of-function biallelic POMC, including PCSK1, deficiency or biallelic LEPR deficiency in adults and children 6 years of age and above. In Europe, setmelanotide should be prescribed and supervised by a physician with expertise in obesity with underlying genetic etiology. Limitations of Use Setmelanotide is not indicated for the treatment of patients with the following conditions as setmelanotide would not be expected to be effective: Obesity due to suspected POMC, PCSK1 or LEPR deficiency with POMC, PCSK1 or LEPR variants classified as benign or likely benignOther types of obesity not related to POMC, PCSK1 or LEPR deficiency, or BBS, including obesity associated with other genetic syndromes and general (polygenic) obesity. Contraindication Prior serious hypersensitivity to setmelanotide or any of the excipients in IMCIVREE. Serious hypersensitivity reactions (e.g., anaphylaxis) have been reported. WARNINGS AND PRECAUTIONS Skin Pigmentation and Darkening of Pre-Existing Nevi: Generalized increased skin pigmentation and darkening of pre-existing nevi have occurred because of its pharmacologic effect. Full body skin examinations prior to initiation and periodically during treatment should be conducted to monitor pre-existing and new pigmentary lesions. Heart rate and blood pressure monitoring: In Europe, heart rate and blood pressure should be monitored as part of standard clinical practice at each medical visit (at least every 6 months) for patients treated with setmelanotide. Disturbance in Sexual Arousal: Spontaneous penile erections in males and sexual adverse reactions in females have occurred. Patients who have an erection lasting longer than 4 hours should seek emergency medical attention. Depression and Suicidal Ideation: Depression and suicidal ideation have occurred. Patients should be monitored for new onset or worsening depression or suicidal thoughts or behaviors. Consideration should be given to discontinuing setmelanotide if patients experience suicidal thoughts or behaviors, or clinically significant or persistent depression symptoms occur. Hypersensitivity Reactions: Serious hypersensitivity reactions (e.g., anaphylaxis) have been reported. If suspected, advise patients to promptly seek medical attention and discontinue setmelanotide. Pediatric Population: The prescribing physician should periodically assess response to setmelanotide therapy. In growing children, the impact of weight loss on growth and maturation should be evaluated. In Europe, the prescribing physician should monitor growth (height and weight) using age- and sex-appropriate growth curves. Risk of Serious Adverse Reactions Due to Benzyl Alcohol Preservative in Neonates and Low Birth Weight Infants: Setmelanotide is not approved for use in neonates or infants. Serious and fatal adverse reactions including “gasping syndrome” can occur in neonates and low birth weight infants treated with benzyl alcohol-preserved drugs. ADVERSE REACTIONS Most common adverse reactions (incidence ≥20%) included skin hyperpigmentation, injection site reactions, nausea, headache, diarrhea, abdominal pain, vomiting, depression, and spontaneous penile erection. USE IN SPECIFIC POPULATIONS Lactation: Not recommended when breastfeeding.To report SUSPECTED ADVERSE REACTIONS, contact Rhythm Pharmaceuticals at +1 (833) 789-6337 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. See section 4.8 of the Summary of Product Characteristics for information on reporting suspected adverse reactions in Europe. Please see the full Prescribing Information for additional Important Safety Information. 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 design or progress, potential regulatory submissions, approvals and timing thereof, including our Phase 3 trial of setmelanotide for patients with hypothalamic obesity in Japan, the United States or in Europe, the potential benefits of setmelanotide for patients with hypothalamic obesity, and our business strategy and plans, including regarding commercialization of IMCIVREE. Statements using word such as “expect”, “anticipate”, “believe”, “may”, “will” and similar terms are also forward-looking statements. Such statements are subject to numerous risks and uncertainties, including, but not limited to, our ability to enroll patients in clinical trials, the design and outcome of clinical trials, the impact of competition, the ability to achieve or obtain necessary regulatory approvals, risks associated with data analysis and reporting, our ability to successfully commercialize setmelanotide, our liquidity and expenses, our ability to retain our key employees and consultants, and to attract, retain and motivate qualified personnel, and general economic conditions, and the other important factors discussed under the caption “Risk Factors” in our Quarterly Report on Form 10-Q for the three months ended September 30, 2023 and our other filings with the Securities and Exchange Commission. Except as required by law, we undertake no obligations to make any revisions to the forward-looking statements contained in this release or to update them to reflect events or circumstances occurring after the date of this release, whether as a result of new information, future developments or otherwise. Corporate Contact:David ConnollyHead of Investor Relations and Corporate CommunicationsRhythm Pharmaceuticals, Inc.857-264-4280dconnolly@rhythmtx.com Media Contact:Adam DaleyBerry & Company Public Relations212-253-8881adaley@berrypr.com

BOSTON, Sept. 19, 2023 (GLOBE NEWSWIRE) -- Rhythm Pharmaceuticals, Inc. (Nasdaq: RYTM), a commercial-stage biopharmaceutical company focused on transforming the lives of patients and their families living with hyperphagia and severe obesity caused by rare melanocortin-4 receptor (MC4R) pathway diseases, today announced that the European Medicines Agency (EMA) has issued a positive opinion on the Company’s orphan drug designation request for setmelanotide as a treatment for acquired hypothalamic obesity. “Acquired hypothalamic obesity is a serious disease with severe implications for patients and families and no effective treatment options,” said Yann Mazabraud, Executive Vice President and Head of International at Rhythm. “We are pleased with this EMA positive opinion as it underscores the significant unmet need for these patients and the potential of setmelanotide to bring a precision medicine approach that may benefit patients with this disease across Europe.” EMA orphan drug designation is granted to drugs intended for the treatment, diagnosis, or prevention of life-threatening or chronically debilitating conditions affecting no more than five in 10,000 individuals in the European Union. Rhythm is evaluating setmelanotide in a global Phase 3 clinical trial in acquired hypothalamic obesity and expects to complete patient enrollment in the fourth quarter of 2023. Acquired hypothalamic obesity is a rare form of extreme obesity that occurs following damage to the hypothalamic region of the brain, which includes the MC4R pathway and is responsible for controlling physiological functions such as hunger and weight regulation. It most frequently follows the growth or surgical removal of craniopharyngioma, astrocytoma, or other rare brain tumors. Patients experience rapid weight gain, a reduction in energy expenditure, and an increase in hunger leading to severe obesity within six to 12 months following tumor resection. Rhythm estimates there are approximately 3,500 to 10,000 patients living with acquired hypothalamic obesity in the European countries of Germany, France, Spain, Italy, The Netherlands, and the United Kingdom.1 About Rhythm Pharmaceuticals Rhythm is a commercial-stage biopharmaceutical company committed to transforming the lives of patients and their families living with hyperphagia and severe obesity caused by rare melanocortin-4 receptor (MC4R) diseases. Rhythm’s lead asset, IMCIVREE (setmelanotide) is approved by the U.S. Food and Drug Administration (FDA) and authorized by the European Commission (EC) and the UK’s Medicines & Healthcare Products Regulatory Agency (MHRA) for use in accordance with product labeling. Additionally, Rhythm is advancing a broad clinical development program for setmelanotide in other rare MC4R pathway diseases, as well as a preclinical suite of investigational candidates for the treatment of congenital hyperinsulinism. Rhythm’s headquarters is in Boston, MA. Setmelanotide IndicationIn the United States, setmelanotide is indicated for chronic weight management in adult andi pediatric patients 6 years of age and older with monogenic or syndromic obesity due to POMC, PCSK1 or LEPR deficiency as determined by an FDA-approved test demonstrating variants in POMC, PCSK1 or LEPR genes that are interpreted as pathogenic, likely pathogenic, or of uncertain significance (VUS) and BBS. In the European Union, setmelanotide is indicated for the treatment of obesity and the control of hunger associated with genetically confirmed Bardet-Biedl syndrome (BBS) or genetically confirmed loss-of-function biallelic proopiomelanocortin (POMC), including PCSK1, deficiency or biallelic leptin receptor (LEPR) deficiency in adults and children 6 years of age and above. In Canada, setmelanotide is indicated for the treatment of obesity due to Bardet-Biedl syndrome (BBS) or genetically-confirmed biallelic pro-opiomelanocortin (POMC), proprotein convertase subtilisin/kexin type 1 (PCSK1), or leptin receptor (LEPR) deficiency due to variants interpreted as pathogenic, likely pathogenic, or of uncertain significance in adults and children 6 years of age and above. Limitations of Use Setmelanotide is not indicated for the treatment of patients with the following conditions as setmelanotide would not be expected to be effective: Obesity due to suspected POMC, PCSK1 or LEPR deficiency with POMC, PCSK1 or LEPR variants classified as benign or likely benignOther types of obesity not related to POMC, PCSK1 or LEPR deficiency, or BBS, including obesity associated with other genetic syndromes and general (polygenic) obesity. In Europe, Setmelanotide should be prescribed and supervised by a physician with expertise in obesity with underlying genetic etiology. WARNINGS AND PRECAUTIONS Skin Monitoring: Setmelanotide may lead to generalized increased skin pigmentation and darkening of pre-existing naevi because of its pharmacologic effect. Full body skin examinations should be conducted annually to monitor pre-existing and new skin pigmentary lesions before and during treatment with setmelanotide. Heart Rate and Blood Pressure Monitoring: Heart rate and blood pressure should be monitored as part of standard clinical practice at each medical visit (at least every 6 months) for patients treated with setmelanotide. Prolonged Penile Erection: Spontaneous penile erections have been reported in clinical trials with setmelanotide. Patients who have a penile erection lasting longer than 4 hours should be instructed to seek emergency medical attention for potential treatment of priapism. Depression: In clinical trials, depression has been reported in patients treated with setmelanotide. Patients with depression should be monitored at each medical visit during treatment with setmelanotide. Consideration should be given to discontinuing setmelanotide if patients experience suicidal thoughts or behaviors. Pediatric Population: The prescribing physician should periodically assess response to setmelanotide therapy. In growing children, the impact of weight loss on growth and maturation should be evaluated. The prescribing physician should monitor growth (height and weight) using age- and sex-appropriate growth curves. Excipients: This medicinal product contains 10 mg benzyl alcohol in each ml. Benzyl alcohol may cause allergic reactions. Patients who are pregnant or breastfeeding should be advised of the potential risk from the excipient benzyl alcohol, which might accumulate over time and cause metabolic acidosis. This medicinal product should be used with caution in patients with hepatic or renal impairment, because of the potential risk from the excipient benzyl alcohol which might accumulate over time and cause metabolic acidosis. Sodium: This medicinal product contains less than 1 mmol sodium (23 mg) per dose, that is to say essentially “sodium-free.” ADVERSE REACTIONS The most frequent adverse reactions are hyperpigmentation (51%), injection site reaction (39%), nausea (33%), and headache (26%). USE IN SPECIFIC POPULATIONS PregnancyThere are no data from the use of setmelanotide in pregnant women. Animal studies do not indicate direct harmful effects with respect to reproductive toxicity. However, administration of setmelanotide to pregnant rabbits resulted in decreased maternal food consumption leading to embryo-fetal effects. As a precautionary measure, setmelanotide should not be started during pregnancy or while attempting to get pregnant as weight loss during pregnancy may result in fetal harm. If a patient who is taking setmelanotide has reached a stable weight and becomes pregnant, consideration should be given to maintaining setmelanotide treatment as there was no proof of teratogenicity in the nonclinical data. If a patient who is taking setmelanotide and still losing weight gets pregnant, setmelanotide should either be discontinued, or the dose reduced while monitoring for the recommended weight gain during pregnancy. The treating physician should carefully monitor weight during pregnancy in a patient taking setmelanotide. Breast-feeding It is unknown whether setmelanotide is excreted in human milk. A nonclinical study showed that setmelanotide is excreted in the milk of nursing rats. No quantifiable setmelanotide concentrations were detected in plasma from nursing pups. A risk to the newborn/infant cannot be excluded. A decision must be made whether to discontinue breastfeeding or to discontinue/abstain from setmelanotide therapy taking into account the benefit of breastfeeding for the child and the benefit of therapy for the mother. Fertility No human data on the effect of setmelanotide on fertility are available. Animal studies did not indicate harmful effects with respect to fertility. To report SUSPECTED ADVERSE REACTIONS, contact Rhythm Pharmaceuticals at +1 (833) 789-6337. See Summary of Product Characteristics’ APPENDIX V for a list of European national reporting systems to communicate adverse reactions. Please see the full Prescribing Information for additional Important Safety Information. Forward-looking StatementsThis 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 progress of setmelanotide and the potential benefits and expectations of receipt of a positive opinion on the Company’s orphan drug designation request for setmelanotide as a treatment for acquired hypothalamic obesity; and expectations regarding the prevalence of patients living with acquired hypothalamic obesity. Statements using words such as “expect”, “anticipate”, “believe”, “may”, “will” and similar terms are also forward-looking statements. Such statements are subject to numerous risks and uncertainties, including, but not limited to, risks relating to our liquidity and expenses, our ability to enroll patients in clinical trials, the design and outcome of clinical trials, the ability to achieve necessary regulatory approvals, risks associated with data analysis and reporting, failure to identify and develop additional product candidates, unfavorable pricing regulations, third-party reimbursement practices or healthcare reform initiatives, risks associated with the laws and regulations governing our international operations and the costs of any related compliance programs, our ability to obtain or maintain orphan drug designations for setmelanotide or to obtain or maintain exclusivity in any use, the impact of competition, risks relating to product liability lawsuits, inability to maintain our collaborations, or the failure of these collaborations, our reliance on third parties, risks relating to intellectual property, our ability to hire and retain necessary personnel, the impact of the COVID-19 pandemic and general economic conditions on our business and operations, including our preclinical studies, clinical trials and commercialization prospects, and the other important factors discussed under the caption “Risk Factors” in our Quarterly Report on Form 10-Q for the three months ended June 30, 2023 and our other filings with the Securities and Exchange Commission. Except as required by law, we undertake no obligations to make any revisions to the forward-looking statements contained in this release or to update them to reflect events or circumstances occurring after the date of this release, whether as a result of new information, future developments or otherwise. Corporate Contact: David Connolly Executive Director, Investor Relations and Corporate Communications Rhythm Pharmaceuticals, Inc. 857-264-4280 dconnolly@rhythmtx.com Media Contact: Adam Daley Berry & Company Public Relations 212-253-8881 adaley@berrypr.com 1 Rhythm’s European prevalence estimate for hypothalamic obesity is limited to the EU4, UK and the Netherlands. The total 2020 population estimates for the six key countries (Germany, France, Spain, Italy, Netherlands, and UK) of 339,295,304 was used to reach a final prevalence of 0.1-0.3 in 10,000 patients.