Rhythm Pharmaceuticals Reports Second Quarter 2022 Financial Results and Business Update -- Received FDA approval for IMCIVREE (setmelanotide) as the first-ever therapy for patients with Bardet-Biedl syndrome -- -- U.S.

Rhythm Pharmaceuticals Reports Second Quarter

2022 Financial Results and Business Update

-- Received FDA approval for IMCIVREE

(setmelanotide) as the first-ever therapy for patients with Bardet-Biedl syndrome --

-- U.S. launch off to a strong start with more

than 50 IMCIVREE prescriptions written for patients with BBS in first six weeks since FDA approval --

-- EMA's CHMP recommended expansion of

IMCIVREE marketing authorization to include treatment of obesity and control of hunger in patients with genetically confirmed BBS; EC

approval anticipated in the fourth quarter of 2022 --

-- Announced positive interim results from Phase

2 trial in hypothalamic obesity and plans to initiate Phase 3 trial in early 2023 --

-- Entered into non-dilutive revenue interest

financing agreement with Healthcare Royalty Partners for up to $100 million, extending cash runway into second half of 2024 --

-- Management to host conference call today

BOSTON, August 2, 2022 -

Rhythm Pharmaceuticals, Inc. (Nasdaq: RYTM) today reported financial results and provided a business update for the second

quarter ended June 30, 2022.

"Rhythm is executing on our global mission to transform the lives

of patients and families living with hyperphagia and severe obesity caused by rare MC4R pathway diseases," said David Meeker, M.D.,

Chair, President and Chief Executive Officer of Rhythm. "Our commercial launch of IMCIVREE (setmelanotide) in Bardet-Biedl

syndrome (BBS) is off to a strong start, and we continue to make meaningful progress towards securing market access in Europe, for both

our initial indications and, more recently, BBS."

Dr. Meeker added, "We are highly encouraged by the interim

data from our Phase 2 trial evaluating setmelanotide in hypothalamic obesity and the potential role it may play in transforming how this

disease is treated. We look forward to reviewing these data with the U.S. Food and Drug Administration (FDA) and seeking input on a pivotal

Phase 3 trial, which we plan to initiate in the first half of 2023. We are excited to add a potential Phase 3 trial in hypothalamic obesity

to our broad setmelanotide clinical development program, which also includes the ongoing Phase 3 EMANATE trial, Phase 2 DAYBREAK trial,

Phase 3 switch study evaluating a weekly formulation of setmelanotide and our Phase 3 pediatrics trial, which has completed enrollment."

Second Quarter and Recent Business Highlights:

Regulatory and Commercial Updates:

Bardet-Biedl Syndrome:

POMC and LEPR Deficiency Obesities:

Clinical Development Updates:

Key Upcoming Milestones:

In the second half of 2022, Rhythm expects to:

Second Quarter 2022 Financial Results:

Year to Date 2022 Financial Results:

Financial Guidance: Based

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

2022 will be sufficient to fund operations into 2024, and that such existing cash and cash equivalents and short term investments, together

with the second investment tranche under the RIFA with HealthCare Royalty Partners expected in the second half of 2022, will be sufficient

to fund its operating expenses and capital expenditure requirements into at least the second half of 2024.

Conference Call Information

Rhythm Pharmaceuticals will host a live

conference call and webcast at 8:00 a.m. ET today to review its second quarter 2022 financial results and recent business activities.

Participants may register for the conference call here. While not required, it is recommended that participants join the

call ten minutes prior to the scheduled start.

A live webcast of the call will also 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 transforming the lives of patients and their families living with hyperphagia

and severe obesity caused by rare melanocortin-4 receptor (MC4R) pathway diseases. Rhythm's precision medicine, IMCIVREE (setmelanotide),

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 POMC, PCSK1 or LEPR deficiency confirmed by genetic testing, or patients with a

clinical diagnosis of Bardet-Biedl syndrome (BBS). The European Commission (EC) and Great Britain's Medicines & Healthcare

Products Regulatory Agency (MHRA) have authorized IMCIVREE 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. Rhythm received a positive Committee for Medicinal Products for Human Use (CHMP) opinion on its Type II variation application

to the European Medicines Agency 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 in the European Union and a decision from the EC is expected in the

fourth quarter of 2022. 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 45,000 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.

Setmelanotide is a melanocortin-4 receptor (MC4R) agonist. The MC4R is part of the key biological pathway that regulates hunger,

caloric intake and energy expenditure. Variants in genes may impair the function of the MC4R pathway, potentially leading to hyperphagia

and early-onset, severe obesity. Rhythm is developing setmelanotide as a targeted therapy to potentially restore the function of an impaired

MC4R pathway and, in so doing, potentially reduce hunger and weight in patients with rare genetic diseases of obesity.

In the EU and Great Britain, 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.

Rhythm's Type II variation application to the European Medicines

Agency (EMA) for the treatment of obesity and control of hyperphagia in adult and pediatric patients 6 years of age and older with BBS

is under review. The Company is also continuing to advance the most comprehensive clinical research program ever initiated in MC4R pathway

diseases, including the pivotal Phase 3 EMANATE clinical trial evaluating setmelanotide in four independent sub-studies in patients with

obesity due to POMC insufficiency caused by heterozygous variants in the POMC or PCSK1 genes, LEPR insufficiency caused

by heterozygous variants in the LEPR gene, SRC1 deficiency caused by a variant in the NCOA1 gene, and SH2B1 deficiency caused

by a variant in the SH2B1 gene or 16p11.2 deletion encompassing the SH2B1 gene. The Phase 2 DAYBREAK trial is evaluating

setmelanotide in patients with severe obesity and hyperphagia caused by rare variants associated with 10 prioritized MC4R-relevant genes.

Rhythm has also initiated a Phase 3 pediatric trial and a Phase 3 trial evaluating a weekly formulation of setmelanotide.

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 monogenic or syndromic obesity due to:

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

WARNINGS AND PRECAUTIONS

Disturbance in Sexual Arousal: Spontaneous

penile erections in males and sexual adverse reactions in females have occurred. Inform patients that these events may occur and instruct

patients who have an erection lasting longer than 4 hours to seek emergency medical attention.

Depression and Suicidal Ideation:

Depression and suicidal ideation have occurred. Monitor patients for new onset or worsening depression or suicidal thoughts

or behaviors. Consider discontinuing IMCIVREE if patients experience suicidal thoughts or behaviors, or clinically significant or persistent

depression symptoms occur.

Skin Pigmentation and Darkening of

Pre-existing Nevi: Generalized increased skin pigmentation and darkening of pre-existing nevi have occurred. Perform a full

body skin examination prior to initiation and periodically during treatment to monitor pre-existing and new pigmentary lesions.

Risk of Serious Adverse Reactions