Current chemotherapy drugs cause strong systemic side effects outside of the tumor.


We develop photoswitchable small molecule drugs that can simply be activated by local light application at the tumor. We can therefore reduce systemic side effects compared to conventional chemotherapy.


CytoSwitch is developing its lead candidates through early preclinical studies towards the clinical stages. CytoSwitch is also validating the platform technology, being first-in-class to develop photoswitchable small molecule therapeutics.

ABOUT CytoSwitch

We have developed a targeted antimitotic molecule called Photostatin (PST), published in the high profile scientific journal Cell and featured in various mainstream media. PST has a unique selectivity advantage over all other antimitotics: it can be targeted to affect specific tissues and avoid all the others, just by specifically illuminating the tissue where it should be active. We aim to develop PST as a novel chemotherapeutic that targets cancer tumors while sparing healthy tissues, delivering effective tumor therapy with much reduced side-effects compared to standard-of-care (SoC) chemotherapies.

Potential treatment applications:

  • PSTs could tackle refractory tumors, which do not respond to tolerable doses of current drugs.
  • PSTs could treat weaker patients, who cannot tolerate the side-effects of current treatments.

CytoSwitch is currently in the pre-seed phase and is funded through the EXIST governmental grant by the German Ministry of Economics (BMWi).


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Our Team

Tilmann Petersen

Tilmann Petersen

Business Officer, Project Leader

Tilmann Petersen manages the business related side of CytoSwitch. He has 10 years of experience as co-founder and manager in various Biotech and High-Tech Startups. He worked as Head of Finance in the VivoCell Biosolutions AG group, as CFO for and as CEO of Nu Emotions.

Dr. Wen-Hsin Liu

Dr. Wen-Hsin Liu

Translational Biologist

Dr. Wen-Hsin Liu carries out the in vivo validation for the new drug candidates at CytoSwitch. During her PhD in molecular biology at the Sun Yat-Sen Univ., she focused on signaling mechanisms involved in cancer development. She did her postdocs at the MPI and at the Helmholtz Zentrum where she developed leukemia mouse models and performed preclinical drug testing in vivo.

Dr. Marcel Klingenberg

Dr. Marcel Klingenberg

Translational Biologist

Dr. Marcel Klingenberg manages the in vitro assays of CytoSwitch. Besides, he is involved in the study design (strategy and operations) for preclinical drug testing in vivo in collaboration with CROs as well as in regulatory affairs.
During his PhD at the DKFZ in Heidelberg, he performed basic research with a focus on genetics in liver cancer.

Dr. Elena Longhi

Dr. Elena Longhi

Medicinal Chemist

Dr. Elena Longhi leads the synthetic efforts for the development of new compounds at CytoSwitch. She received her Ph.D. in industrial chemistry with a focus on organic chemistry from the Univ. of Milan. She then worked as a postdoc at M√ľnster and Strasbourg universities, developing immunoassays for diagnostics, followed by a postdoc at Georgia Tech in organic electronics.


Dr. Oliver Thorn-Seshold

Dr. Oliver Thorn-Seshold

Medicinal Chemistry, Academic Group Leader

Dr. Oliver Thorn-Seshold is the chemist behind the compound pipeline design for CytoSwitch. He leads a junior research group at the LMU Munich, developing small molecule inhibitors as reagents and cancer therapeutics. After a PhD in fluorescent probes at the University of Lyon, he began research into turning known cancer drugs into light-sensitive analogues.


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