Stockholm, Sweden

Calliditas Announces Submission of Marketing

Authorisation Application for Nefecon to the European Medicines Agency

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

("Calliditas") today announced that the company submitted a Marketing Authorisation Application (MAA) to the European Medicines

Agency (EMA) for Nefecon, a novel oral formulation targeting down regulation of IgA1 for the treatment of primary IgA Nephropathy (IgAN).

The submission is based on positive data from Part A of the NefIgArd

pivotal Phase 3 study, a randomized, double-blind, placebo-controlled, international multicenter study designed to evaluate the efficacy

and safety of Nefecon compared to placebo in 200 adult patients with IgAN. The study achieved its primary endpoint of proteinuria reduction

compared to placebo, and also showed a renal protective effect by way of stabilization of eGFR at 9 months.

The submission also includes clinical data from the Phase 2 NEFIGAN

trial, which met the same primary and secondary endpoint as the NefIgArd study. The NefIgArd trial also showed that Nefecon was generally

well-tolerated, with a safety profile in keeping with the Phase 2b results. Calliditas is the only company which has achieved positive

data in randomized, double-blind, placebo-controlled Phase 2b and Phase 3 clinical trials in IgAN.

"This is another important step forward in our endeavors to bring

the first approved medication to patients suffering from IgAN. We look forward to engaging with the agency with the target of achieving

an approval in Q1 next year," said CEO Ren e Aguiar-Lucander

As previously reported, the MAA for Nefecon has been granted Accelerated

Assessment procedure by EMA's Committee for Human Medicinal Products (CHMP), which is intended to expedite access to drugs that

the CHMP considers to be of major therapeutic interest from the point of view of public health and in particular from the viewpoint of

therapeutic innovation. Accelerated assessment reduces the maximum timeframe for review of the MAA to 150 days (excluding clock-stops).

If approved, Nefecon could be available to patients in Europe in H1

2022 and would become the first therapy specifically designed and approved for the treatment of IgAN, and which has the potential to be

For further information, please contact:

Marie Galay, IR Manager, Calliditas

Tel.: +44 79 55 12 98 45, email: marie.galay@calliditas.com

The information in the press release is information that Calliditas

is obliged to make public pursuant to the EU Market Abuse Regulation. The information was sent for publication, through the agency of

the contact persons set out above, on May 28, 2021 at 2:40

Calliditas Therapeutics is a biopharma company based in

Stockholm, Sweden focused on identifying, developing and commercializing novel treatments in orphan indications, with an initial

focus on renal and hepatic diseases with significant unmet medical needs. Calliditas' lead product candidate, Nefecon, is a

proprietary, novel oral formulation of budesonide, an established, highly potent local immunosuppressant, for the treatment of

adults with the autoimmune renal disease primary IgA nephropathy (IgAN), for which there is a high unmet medical need and there are

no approved treatments. Calliditas has recently read out topline data from Part A of its global Phase 3 study in IgAN and, if

approved, aims to commercialize Nefecon in the United States. Calliditas is also planning to start clinical trials with NOX

inhibitors in primary biliary cholangitis and head and neck cancer. Calliditas is listed on Nasdaq Stockholm (ticker: CALTX) and the

Nasdaq Global Select Market (ticker: CALT). Visit www.calliditas.com for further information.

About the NefIgArd Study

The global Phase 3 clinical trial NefIgArd, which investigated the

effect of Nefecon versus placebo in patients with primary IgA nephropathy (IgAN), consists of two parts.

Part A, which was designed to provide the basis for regulatory submissions

and approvals, evaluates data on the efficacy and safety of Nefecon. The first patient in the NefIgArd trial was randomized by Calliditas

in November 2018, and in December 2019, Calliditas announced the full recruitment of Part A, across approximately 146 sites in 19 countries.

Calliditas read out topline data for Part A in November 2020.

The trial met its primary objective of demonstrating a statistically

significant reduction in urine protein creatinine ratio, UPCR or proteinuria, after 9 months of treatment with 16 mg of Nefecon compared

to placebo, with significant continued improvement at 12 months. The primary endpoint analysis showed a 31% mean reduction in the 16 mg

arm versus baseline, with placebo showing a 5% mean reduction versus baseline, resulting in a 27% mean reduction at 9 months (p=0.0005)

of the 16 mg arm versus placebo. The trial also met the key secondary endpoint, showing a statistically significant difference in estimated

glomerular filtration rate or eGFR after 9 months of treatment with Nefecon compared to placebo. The key secondary endpoint, eGFR, showed

a treatment benefit of 7% versus placebo at 9 months, reflecting stabilization in the treatment arm and a 7% decline of eGFR in the placebo

arm (p=0.0029). This reflected an absolute decline of 4.04 ml/min/1.73m2 in the placebo group over 9 months compared to a 0.17 ml/min/1.73m2

decline in the treatment group. Nefecon was also generally well-tolerated, and the safety profile was in keeping with the Phase 2b results

and consistent with the known safety profile of budesonide.

Part B of the NefIgArd study is designed to be a confirmatory post-market

observational trial to confirm long-term renal protection and assess the difference in kidney function between treated and placebo patients

as measured by eGFR over a two-year period from the start of dosing of each patient. The 360-patient population of the complete Phase

3 trial includes another 160 patients enrolled in addition to the 200 patients from Part A. The trial was fully recruited in January 2021,

and aims to read out data in early 2023, after all patients have completed 2 years in the trial.

Nefecon is a patented oral formulation of a potent and well-known active

substance - budesonide - for targeted release. The formulation is designed to deliver the drug to the Peyer's patch

region of the lower small intestine, where the disease originates, as per the predominant pathogenesis models. Nefecon is derived from

the TARGIT technology, which allows for the substance to pass through the stomach and intestine without being absorbed, and to be released

in a pulse like fashion only when it reaches the lower small intestine.

The combination of dose and optimized release profile is required to

be effective in patients with IgAN, as shown in a large Phase 2b trial, completed by Calliditas. In addition to its potent local effect,

another advantage of using this active substance is that it has very low bioavailability, i.e. around 90% of it is inactivated in the

liver before it reaches the systemic circulation. This means that a high concentration can be applied locally where needed but with only

very limited systemic exposure and side effects.

Forward-Looking Statements

This press release contains forward-looking statements within the

meaning of the Private Securities Litigation Reform Act of 1995, as amended, including, without limitation, statements regarding

Calliditas' strategy, business plans, regulatory submissions and focus. The words "may," "will,"

"could," "would," "should," "expect," "plan," "anticipate,"

"intend," "believe," "estimate," "predict," "project,"

"potential," "continue," "target" and similar expressions are intended to identify

forward-looking statements, although not all forward-looking statements contain these identifying words. Any forward-looking

statements in this press release are based on management's current expectations and beliefs and are subject to a number of

risks, uncertainties and important factors that may cause actual events or results to differ materially from those expressed or

implied by any forward-looking statements contained in this press release, including, without limitation, any related to

Calliditas' business, operations, the potential for FDA acceptance for and the success and timeline of its regulatory

marketing application for Nefecon, clinical trials, supply chain, strategy, goals and anticipated timelines, competition from other

biopharmaceutical companies, and other risks identified in the section entitled "Risk Factors" in Calliditas'

reports filed with the Securities and Exchange Commission. Calliditas cautions you not to place undue reliance on any

forward-looking statements, which speak only as of the date they are made. Calliditas disclaims any obligation to publicly update or

revise any such statements to reflect any change in expectations or in events, conditions or circumstances on which any such

statements may be based, or that may affect the likelihood that actual results will differ from those set forth in the

forward-looking statements. Any forward-looking statements contained in this press release represent Calliditas' views only as

of the date hereof and should not be relied upon as representing its views as of any subsequent date. conditions or circumstances on

which any such statements may be based, or that may affect the likelihood that actual results will differ from those set forth in

the forward-looking statements. Any forward-looking statements contained in this press release represent Calliditas' views

only as of the date hereof and should not be relied upon as representing its views as of any subsequent date.