Stockholm, Sweden

Calliditas Therapeutics and STADA partner to register and commercialize specialty therapy for IgA Nephropathy in Europe

Stockholm, Sweden; Bad Vilbel, Germany.

21 July 2021 - Calliditas Therapeutics AB (Nasdaq: CALT, Nasdaq Stockholm: CALTX) ("Calliditas") and STADA Arzneimittel

AG ("STADA") announced today that they have entered into a license agreement to register and commercialize a novel specialty

drug candidate for the treatment of the chronic autoimmune kidney disease Immunoglobulin A Nephropathy (IgAN) in the European Economic

Area (EEA) member states, Switzerland and the UK.

Under the terms of the agreement, Calliditas

is entitled receive an initial upfront payment of 20M EUR ($24m) upon signing and up to an additional 77.5M EUR ($91m) in future payments

linked to pre-defined regulatory and commercialization milestones. STADA is also obligated pay tiered royalties on net sales expressed

as a percentage between the low twenties and the low thirties.

The partnership relates to a novel oral

formulation, developed under the project name Nefecon', of a potent and well-known active substance - budesonide -

designed to target down regulation of IgA1 with a view to be disease modifying. If approved, this value-added specialty medicine, which

received an EU orphan-drug designation in 2016, would be the first treatment authorized in the European Union for IgAN, a rare autoimmune

disease. IgAN, also known as Berger s disease, is a serious progressive autoimmune disease in which up to 50% of patients end up

at risk of developing end stage renal disease and thus requiring dialysis or a kidney transplant. Prevalence in Europe is estimated at

4 in 10,000, translating into approximately 200,000 patients.

"We are excited to be entering

into this partnership with STADA to bring this IgAN therapy to market in Europe, where there is a significant unmet medical need for

this patient population. We look forward to working in close collaboration with STADA to pursue marketing authorization with the goal

of bringing the first ever EU-approved medication in IgAN to patients as soon as possible, utilizing STADA's extensive marketing

and sales platform throughout Europe," said Ren e Aguiar-Lucander, CEO of Calliditas.

"This partnership, which leverages

Calliditas' drug-delivery expertise and clinical data in this under-served patient population, further validates STADA's

position as a go-to-partner for specialty pharmaceuticals, as well as for generics and consumer health products," commented STADA

CEO Peter Goldschmidt. "This value-added novel formulation for a large orphan indication will complement STADA's offerings

in nephrology, where we have built strong expertise over more than a decade through our epoetin zeta biosimilar and where we continue

to place a clear strategic focus on seeking further opportunities to bring new options to patients."

The novel 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. The formulation uses a unique two-step 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 ileum in the lower small intestine.

In addition to its potent local effect, another advantage of using this active substance is that it has very low bioavailability, with

around 90% being inactivated in the liver before it reaches the systemic circulation. This means that a high concentration can be applied

locally where needed, whilst limiting systemic exposure.

On May 28, 2021, Calliditas announced

that the company had, under the drug-development candidate name Nefecon, submitted a Marketing Authorisation Application (MAA) to the

European Medicines Agency (EMA) for a novel oral formulation of budesonide targeting down regulation of IgA1 for the treatment of primary

IgAN. The company also filed an application for accelerated approval in the US on March 15, 2021 and was granted priority review in April

2021. The commercial brand name for this therapy in Europe will be determined and disclosed at a later date.

Calliditas oral formulation has

been granted Accelerated Assessment procedure by the Committee for Human Medicinal Products (CHMP) within the European Medicines Agency,

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).

IgAN is designated as an orphan disease

in both the US and Europe. In Europe, an orphan disease is defined as a disease or condition affecting no more than five in 10,000 European

citizens with no satisfactory method of diagnosis, prevention or treatment. Orphan incentives consist of ten years of market exclusivity

from the grant date of marketing approval in the EU, protocol assistance and scientific advice, fee reductions on EMA procedural activities

and eligibility for EU grants.

If approved, the product could be available

to patients in Europe in the first half of 2022 and would become the first therapy specifically designed and approved for the treatment

of IgAN, and which has the potential to be disease modifying.

Torreya acted as exclusive financial

advisor to Calliditas on the transaction.

For further information, please contact:

Marie Galay, IR Manager, Calliditas

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

STADA Arzneimittel AG

61118 Bad Vilbel - Germany

Phone: +49 (0) 6101 603-165

Fax: +49 (0) 6101 603-215

For Media Relations, email: press@stada.de

Or visit us on the Internet at www.stada.com/press

For Investor & Creditor Relations,

Or visit us on the Internet at www.stada.com/investor-relations

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 Calliditas contact person set out above, on July 21, 2021 at 8:45 a.m. CET.

AG is headquartered in Bad Vilbel, Germany. The company focuses on a three-pillar strategy consisting of generics, specialty pharma and

non-prescription consumer healthcare products. Worldwide, STADA Arzneimittel AG sells its products in approximately 120 countries. In

financial year 2020, STADA achieved group sales of EUR 3,010.3 million and adjusted earnings before interest, taxes, depreciation and

amortization (EBITDA) of EUR 713.3 million. As of December 31, 2020, STADA employed 12,301 people worldwide.

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.

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, as well as Calliditas's partnership with

STADA, the parties' plans with respect to registration and commercialization of the specialty therapy, the terms of the collaboration

and the intended benefits therefrom, the regulatory pathway and interactions for Nefecon, including timing of review and assessment of

the candidate, and the intended benefits of regulatory designations such as Accelerated Assessment and orphan disease. 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 conduct of Calliditas's partnership with STADA,

the potential for regulatory 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.