Stockholm, Sweden

Calliditas Announces Primary Endpoint Successfully Met in Phase

3 NefIgArd Trial Evaluating Nefecon in IgA Nephropathy

Calliditas Therapeutics AB (Nasdaq: CALT, Nasdaq Stockholm: CALTX)

("Calliditas") today announced positive topline results from the global, randomized, double-blind, placebo-controlled Phase

3 clinical trial NefIgArd, which investigated the effect of Nefecon (TARPEYO /Kinpeygo (budesonide) delayed release capsules)

versus placebo in patients with primary IgA nephropathy (IgAN).

"This is truly a great outcome for IgAN patients. This reflects

sustained impact on kidney function across the entire study population with a treatment which was specifically designed to treat IgAN

by downregulating pathogenic IgA1 antibodies at their presumed source and we believe this dataset supports regulatory filing for full

approval based on the Phase 3 study population," said CEO Ren e Aguiar-Lucander.

"These data show the kidney function protection delivered by

Nefecon and demonstrate that the approach offers patients a truly disease modifying treatment with sustained reductions in proteinuria

over two years and continued eGFR benefit. Importantly Nefecon was well tolerated and together with the proteinuria and eGFR data mean

that Nefecon has cemented its place as a key treatment option for patients with IgA nephropathy at risk of progressive kidney function

loss," said Dr Jonathan Barratt, Mayer Professor of Renal Medicine at Leicester University.

"These data establish that there is an option for patients with

IgA nephropathy to specifically target their illness and to safely slow and delay progression of their kidney disease. The sustained

effects on proteinuria and on eGFR are impressive and clinically meaningful," said Richard Lafayette, Professor of Medicine (Nephrology)

at Stanford University.

This data readout from Part B provides longer term data from the Phase

3 NefIgArd trial, which read out topline data on Part A in November 2020. An additional 29 Chinese patients, required for local Chinese

regulatory purposes only, are expected to complete Part B in Q3, 2023. Based on the Part A data, Calliditas received accelerated approval

from the U.S Food and Drug Administration (FDA) in December 2021 and conditional marketing authorization from the European Commission

(EC) in July 2022, marking the first time a drug was approved for the treatment of IgAN in the US and the European Economic Area (EEA).

Nefecon is being marketed by Calliditas in the US under the brand name TARPEYO , and by STADA Arzneimittel AG in the EEA, Switzerland

and the UK under the brand name Kinpeygo .

"I am delighted with the positive outcome of the NefIgArd trial.

This important milestone is the culmination of many years of hard work and dedication from so many people involved in the study. I would

like to extend my thanks in particular to the investigators and site staff involved in the study, as well as of course the participating

patients," said Calliditas' CMO, Dr. Richard Philipson.

On the basis of this data, Calliditas plans to file for full approval

from the FDA, and support filing for full approval with EC and UK MHRA during 2023 for patients with primary IgAN based on the Phase

NefIgArd Topline Results

The analysis included 364 patients diagnosed with primary IgAN and

who were on a background of optimized and stable renin-angiotensin system (RAS) inhibitor therapy. The patients were randomized in a

1:1 ratio into one of two treatment groups - Nefecon 16 mg/day orally or placebo - and treated for 9 months daily, and then

monitored for 15 months off-drug.

The key primary endpoint, eGFR over 2 years, was on average 5.05 mL/min/1.73

m2 higher with Nefecon compared to placebo (p<0.0001). Mean change in eGFR over the 2-year period was -2.47 mL/min/1.73

m2 for Nefecon 16 mg versus -7.52 mL/min/1.73 m2 for placebo.

The results indicate that Nefecon was generally well-tolerated and

the safety profile was consistent with that observed in Part A of the trial.

The global clinical trial NefIgArd is an ongoing Phase 3, randomized,

double-blind, placebo- controlled, multicenter study to evaluate the efficacy and safety of TARPEYO 16 mg once daily vs placebo in adult

patients with primary IgAN as an addition to optimized RAS inhibitor therapy.

Part A of the study included a 9-month blinded treatment period and

a 3-month follow-up period. The primary endpoint was UPCR, and eGFR was a secondary endpoint. Part B included a 12-month observational

period off drug and assessed eGFR over the entire 2-year period for patients who were treated with the TARPEYO or placebo regimen in

Part A in a total population of 360 patients.

The trial met its primary objective in Part A of demonstrating a statistically

significant reduction in urine protein creatinine ratio (UPCR) or proteinuria after 9 months of treatment with 16 mg once daily of TARPEYO

compared to placebo. Patients taking TARPEYO plus RAS inhibition (n=97) showed a statistically significant 34% reduction from baseline

vs 5% with RASi alone (n=102) at 9 months, resulting in UPCR reduction of 31% (16% to 42%) p=0.0001.3

At 9 months, there was a 3.87 mL/min/1.73 m2 difference in eGFR absolute

change with TARPEYO plus RASi vs RASi alone (-0.17 vs. -4.04).4

Topline data of the NefIgArd study were reported on March 12, 2023

in which the primary endpoint of eGFR was met as per above. The trial is expected to conclude in Q3 of 2023 when the final 29 patients

in China (not required for global submission purposes) have completed 9 months of treatment and 15 months of observation.

The Company will host a live webcast for investors on Monday 13th

March 2023 at 8 A.M. ET (13:00 CET).

Interested participants may register for the webcast here: https://lifescievents.com/event/calliditas-webcast/

Indication and important safety information

Indication: TARPEYO (budesonide), named Kinpeygo in the

EEA, a 4mg delayed release capsule, is a corticosteroid indicated in the US to reduce proteinuria in adults with primary immunoglobulin

A nephropathy (IgAN) at risk of rapid disease progression, generally a urine protein-to-creatinine ratio (UPCR) 1.5 g/g and in the

EEA for the treatment of IgAN in adults at risk of rapid disease progression with a urine protein-to-creatinine ratio (UPCR) 1.5

This indication is approved by the FDA in the US under an accelerated

approval and as a conditional marketing authorisation by the European Commission for the EEA based on a reduction in proteinuria. It

has not been established whether TARPEYO/Kinpeygo slows kidney function decline in patients with IgAN. Continued approval for this indication

may be contingent upon verification and description of clinical benefit in a confirmatory clinical trial.

Important Safety Information

Contraindications: TARPEYO/Kinpeygo is contraindicated in patients

with hypersensitivity to budesonide or any of the ingredients of TARPEYO/Kinpeygo. Serious hypersensitivity reactions, including anaphylaxis,

have occurred with other budesonide formulations.

Warnings and Precautions

Hypercorticism and adrenal axis suppression: When corticosteroids

are used chronically, systemic effects such as hypercorticism and adrenal suppression may occur. Corticosteroids can reduce the response

of the hypothalamus-pituitary-adrenal (HPA) axis to stress. In situations where patients are subject to surgery or other stress situations,

supplementation with a systemic corticosteroid is recommended. When discontinuing therapy [see Dosing and Administration] or switching

between corticosteroids, monitor for signs of adrenal axis suppression.

Patients with moderate to severe hepatic impairment (Child-Pugh Class

B and C, respectively) could be at an increased risk of hypercorticism and adrenal axis suppression due to an increased systemic exposure

to oral budesonide. Avoid use in patients with severe hepatic impairment (Child-Pugh Class C). Monitor for increased signs and/or symptoms

of hypercorticism in patients with moderate hepatic impairment (Child-Pugh Class B).

Risks of Immunosuppression: Patients who are on drugs that

suppress the immune system are more susceptible to infection than healthy individuals. Chicken pox and measles, for example, can have

a more serious or even fatal course in susceptible patients or patients on immunosuppressive doses of corticosteroids. Avoid corticosteroid

therapy in patients with active or quiescent tuberculosis infection; untreated fungal, bacterial, systemic viral, or parasitic infections;

or ocular herpes simplex. Avoid exposure to active, easily transmitted infections (eg, chicken pox, measles). Corticosteroid therapy

may decrease the immune response to some vaccines.

Other corticosteroid effects: TARPEYO is a systemically available

corticosteroid and is expected to cause related adverse reactions. Monitor patients with hypertension, prediabetes, diabetes mellitus,

osteoporosis, peptic ulcer, glaucoma, cataracts, a family history of diabetes or glaucoma, or with any other condition in which corticosteroids

may have unwanted effects.

Adverse reactions: In clinical studies, the most common adverse

reactions with TARPEYO (occurring in 5% of TARPEYO/Kinpeygo patients and 2% higher than placebo) were hypertension (16%), peripheral

edema (14%), muscle spasms (13%), acne (11%), dermatitis (7%), weight increase (7%), dyspnea (6%), face edema (6%), dyspepsia (5%), fatigue

(5%), and hirsutism (5%).

Drug interactions: Budesonide is a substrate for CYP3A4. Avoid

use with potent CYP3A4 inhibitors, such as ketoconazole, itraconazole, ritonavir, indinavir, saquinavir, erythromycin, and cyclosporine.