VSC 4 SC AG

4SC AG (Frankfurt, Prime Standard: VSC) the German drug discovery and development company, in conjunction with Royal Marsden Hospital in Sutton, England, today announced that it will present Phase I data on 4SC-201, an innovative histone deacetylase (HDAC) inhibitor, at the 45th Annual Meeting of the American Society of Clinical Oncology (ASCO) in Orlando, Florida, USA, from May 29 to June 2, 2009. The Phase I data, generated in advanced solid tumors will form the basis of 4SC's drug development program in oncology.

In the Phase I trial, 4SC 201 was orally administered to 18 patients and was applied in therapy cycles, consisting of a once daily oral dose over five consecutive days, followed by a nine day treatment free period. The resulting 14 day cycle (5 + 9) was repeated four times in the main part of the trial. The daily doses tested in this trial ranged from 100 mg to 800 mg, all of which were generally well tolerated. Patients who benefitted from treatment with 4SC-201 were offered the option of a follow-up treatment beyond the first four cycles. Three patients with stable disease entered this follow-up treatment phase, of which two continued therapy over seven and 19 cycles respectively. The third, an advanced liposarcoma patient, remains stable and has now been on treatment for over a year (currently cycle 28) at the 400 mg daily dose, thereby indicating exciting anti-tumor activity and valuable additional long-term safety data for 4SC-201.

Stable disease according to RECIST was observed in 11 of 18 patients. Of these 11 patients, eight were treated at the two highest dose levels (600 mg and 800 mg oral daily dose), suggesting a correlation between dose and disease stabilization. The degree of HDAC enzyme inhibition was also dose-dependent and ranged from 50% to 100%. The complete block of these target enzymes was reached at the 400 mg dose level and higher. A favorable pharmacokinetic (PK) profile of 4SC-201 was observed with dose-proportionality, high plasma exposure and low inter-subject variability, indicating good bioavailability of the compound. Based on these Phase I results, the recommended Phase II dosing of 4SC-201 as monotherapy treatment will be 600 mg orally once-daily, given in a '5 + 9' dosing schedule.

Dr Bernd Hentsch, Chief Development Officer at 4SC commented, 'We are very excited about the Phase I results of 4SC-201, an innovative HDAC inhibitor. In addition, it is very encouraging to see that one patient has now completed one year of treatment and remains stable. We look forward to commencing our Phase II trial of 4SC-201 in Hepatocellular Carcinoma (HCC) in the second half of this year and continue to evaluate an additional indication for a further trial this year'.

Details of the ASCO poster presentation

Abstract #3530 (Temp. Abst. ID: 33511)A first-in-human Phase I study of 4SC-201, an oral histone deacetylase (HDAC) inhibitor, in patients with solid tumors

Session date and time: 05/29/2009, 2:00PM - 6:00PMSession title: Developmental Therapeutics: Molecular TherapeuticsSession type: Poster Discussion PosterPresenter: Dr A.T. Brunetto (Phase I Co-Investigator)

Notes to Editor

About 4SC-201

4SC-201 is an innovative substance from the histone deacetylase (HDAC) class of inhibitors (former designation BYK408740). The candidate has shown a promising pharmacokinetic profile upon oral application in a Phase I trial in multiple cancers. In addition, an encouraging safety and efficacy profile has been observed in multiple pre-clinical models. 4SC is planning to develop 4SC-201 for the treatment of a number of solid tumors, with a Phase II trial in Hepatocellular Carcinoma (HCC) planned in 2009.

About 4SC

4SC AG (Frankfurt, Prime Standard: VSC/ISIN DE0005753818) is a drug discovery and development company focused on autoimmune and cancer indications. The company currently has three clinical programs, with three further clinical trials planned in 2009. The lead autoimmune compound, 4SC-101, has completed a Phase IIa trial in Rheumatoid Arthritis, and recently entered a Phase IIa trial in Morbus Crohn's. The lead oncology compound, 4SC-201, recently completed a Phase I trial in multiple cancer indications and will commence a Phase II trial in Hepatocellular Carcinoma (HCC) in the second half of 2009. Drug candidates are developed until proof of concept and subsequently partnered with the pharmaceutical industry in return for advance and milestone payments as well as royalties.

4SC was founded in 1997, has 90 employees, and was listed on the Prime Standard of Frankfurt Stock Exchange in December 2005.

Further information, please visit www.4sc.com.

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ISIN: DE0005753818 WKN: 575381 Listed: Regulierter Markt in Frankfurt (Prime Standard); Freiverkehr in Berlin, D�sseldorf, M�nchen, Stuttgart