Rhythm Pharmaceuticals Reports Third Quarter 2021 Financial Results -- U.S. and EU regulatory filings submitted for IMCIVREE (setmelanotide) for treatment of Bardet-Biedl and Alstr m syndromes; launch preparations underw

Rhythm Pharmaceuticals Reports Third Quarter

2021 Financial Results

-- U.S. and EU regulatory filings submitted

for IMCIVREE (setmelanotide) for treatment of Bardet-Biedl and Alstr m syndromes; launch preparations underway --

-- Delivered a total of 22 presentations at

three major medical conferences --

-- New presentations include first-ever data

showing improvements in health-related quality of life in rare genetic diseases of obesity --

-- IMCIVREE third quarter net sales reach $1M

-- Management to Host Conference Call at 8:00

BOSTON, November 2, 2021 (GLOBE NEWSWIRE) -- Rhythm

Pharmaceuticals, Inc. (Nasdaq: RYTM), a biopharmaceutical company aimed at developing and commercializing therapies for the treatment

of rare genetic diseases of obesity, today reported financial results and provided a business update for the third quarter ended September

"We continue to execute across our expanding integrated clinical

and commercial strategy to deliver setmelanotide and its potential clinical benefit to patients with rare genetic diseases of obesity,"

said David Meeker, M.D., Chair, President and Chief Executive Officer of Rhythm. "Our team completed regulatory submissions in both

the United States and European Union recently, positioning IMCIVREE (setmelanotide) as the first-ever therapy to address

the unmet needs of hyperphagia and severe obesity that affect the lives of patients and families living with Bardet-Biedl and Alstr m

syndromes. Our initial U.S. commercial experience with POMC, PCSK1, and LEPR deficiency obesities continues to provide valuable learnings

as we expand the number of health care providers testing patients with early-onset, severe obesity and hyperphagia and work with payers

to ensure patients who need therapy can access it. With effective patient services in place, patients have achieved positive responses

and stayed on therapy. We believe these commercial achievements provide a strong foundation for a successful launch in BBS and Alstr m

syndrome in mid-2022."

Dr. Meeker continued, "In parallel, we continue to advance our

robust development strategy for setmelanotide. Including this week's The Obesity Society's ObesityWeek , we

recently delivered a total of 22 presentations that support setmelanotide's potential ability to improve the lives of patients and

the families who care for them. With updated sequencing data from our Uncovering Rare Obesity (URO) testing program complementing

presentations on efficacy and improved quality of life data, we have strong confidence in setmelanotide's potential to deliver meaningful

benefit and our ability to identify patients. We look forward to continuing to execute across our pipeline and deliver on our promise

to transform the care and treatment of rare genetic diseases of obesity."

Third Quarter and Recent Business Highlights:

Bardet-Biedl Syndrome and Alstr m Syndrome:

POMC and LEPR Deficiency Obesities:

Clinical Development Updates

Key Upcoming Milestones:

Rhythm expects to achieve the following near-term milestones:

Third Quarter 2021 Financial Results:

Year to Date 2021 Financial Results:

Financial Guidance: Based

on its current operating plans, Rhythm expects that its existing cash, cash equivalents and short-term investments as of September 30,

2021, will be sufficient to fund its operating expenses and capital expenditure requirements into at least the second half of 2023.

Conference Call Information

Rhythm Pharmaceuticals will host

a live conference call and webcast at 8:00 a.m. ET today to discuss this update, as well as review its third quarter 2021 financial

results and recent business activities. The conference call may be accessed by dialing (844) 498-0570 (domestic) or (409) 983-9726 (international)

and referring to conference ID 2167009. A webcast of the call will be available under "Events and Presentations" in the Investor

Relations section of the Rhythm Pharmaceuticals website at http://ir.rhythmtx.com/. The archived webcast

will be available on Rhythm Pharmaceuticals' website approximately two hours after the conference call and will be available

for 30 days following the call.

About Rhythm Pharmaceuticals

is a commercial-stage biopharmaceutical company committed to transforming the treatment paradigm for people living with rare genetic

diseases of obesity. Rhythm's precision medicine, IMCIVREE (setmelanotide), was approved in November 2020 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 obesity

due to POMC, PCSK1 or LEPR deficiency confirmed by genetic testing and in July and September 2021, respectively, by the European

Commission (EC) and Great Britain's Medicines & Healthcare Products Regulatory Agency (MHRA) for the treatment

of obesity and the control of hunger associated with genetically confirmed loss-of-function biallelic POMC, including PCSK1, deficiency

or biallelic LEPR deficiency in adults and children 6 years of age and above. IMCIVREE is the first-ever FDA-approved and EC- and MHRA-authorized

therapy for patients with these rare genetic diseases of obesity. The Company submitted a supplemental New Drug Application (sNDA) to

the FDA in September 2021 and submitted a Type II variation application to the European Medicines Agency in October 2021 seeking regulatory

approval and authorization for setmelanotide to treat obesity and control of hunger in adult and pediatric patients 6 years of age and

older with BBS or Alstr m syndrome in both the United States and European Union.

Additionally, Rhythm is advancing a broad clinical development program

for setmelanotide in other rare genetic diseases of obesity and is leveraging the Rhythm Engine and the largest known obesity DNA database

-- now with approximately 37,500 sequencing samples -- to improve the understanding, diagnosis and care of people living with severe obesity

due to certain genetic deficiencies. Rhythm's headquarters is in Boston, MA.

IMCIVREE (setmelanotide)

In the United States, IMCIVREE is indicated for chronic weight management in adult and pediatric patients 6 years

of age and older with obesity due to proopiomelanocortin (POMC), proprotein convertase subtilisin/kexin type 1 (PCSK1), or leptin receptor

(LEPR) deficiency. The condition must be confirmed by genetic testing demonstrating variants in POMC, PCSK1,

or LEPR genes that are interpreted as pathogenic, likely pathogenic, or of uncertain significance (VUS).

In the EU, IMCIVREE is indicated for the treatment

of obesity and the control of hunger associated with genetically confirmed loss-of-function biallelic POMC, including PCSK1, deficiency

or biallelic LEPR deficiency in adults and children 6 years of age and above. IMCIVREE should be prescribed and supervised by a physician

with expertise in obesity with underlying genetic etiology.

is not indicated for the treatment of patients with the following conditions as IMCIVREE would not be expected to be effective:

Important Safety Information

WARNINGS AND PRECAUTIONS

Disturbance in Sexual Arousal: Sexual

adverse reactions may occur in patients treated with IMCIVREE. Spontaneous penile erections in males and sexual adverse reactions in females

occurred in clinical studies with IMCIVREE. Instruct patients who have an erection lasting longer than 4 hours to seek emergency medical

Depression and Suicidal Ideation: Some

drugs that target the central nervous system, such as IMCIVREE, may cause depression or suicidal ideation. Monitor patients for new onset

or worsening of depression. Consider discontinuing IMCIVREE if patients experience suicidal thoughts or behaviors.

Skin Pigmentation and Darkening of

Pre-Existing Nevi: IMCIVREE may cause generalized increased skin pigmentation and darkening of pre-existing nevi due to

its pharmacologic effect. This effect is reversible upon discontinuation of the drug. Perform a full body skin examination prior to initiation

and periodically during treatment with IMCIVREE to monitor pre-existing and new skin pigmentary lesions.

Risk of Serious Adverse Reactions

Due to Benzyl Alcohol Preservative in Neonates and Low Birth Weight Infants: IMCIVREE is not approved for use in neonates

USE IN SPECIFIC POPULATIONS

Discontinue IMCIVREE when pregnancy is recognized unless the benefits

of therapy outweigh the potential risks to the fetus.

Treatment with IMCIVREE is not recommended for use while 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 U.S. Full Prescribing

Information, EU SmPC and MHRA SmPC for IMCIVREE.

Forward-Looking Statements

This press release contains forward-looking statements within the