At ASCO, Merck KGAA shows how its medication treats it as a treatment for rare types of tumors
Patients with adrenaline giant cell tumors know that this rare tumor that affects joints will not kill them. But this does not make life in illness easier. Merck KGAA’s data comes from a pivotal study showing that its once daily pills helped reduce pain and improve physical exercise. Regulatory submission is now planned. But first, data from the drug’s key research will be shared at the world’s largest cancer conference.
Tenosynovial giant cell tumors or TGCTs are not considered cancer because the tumor does not spread. Even so, the tumor is painful and disfigured. Surgery is a treatment option, but tumors often regenerate. The surgery also introduces complication risks and has limitations. Even if the TGCT tumor is successfully removed, the surgery may impair the patient’s joint function.
TGCT is driven by a genetic abnormality that leads to overexpression of stimulating factor 1 (CSF-1), a protein that recruits tumor-promoting cells. Merck’s pimitinib is an oral small molecule designed to inhibit CSF-1. The drug was evaluated in a placebo-controlled phase 3 study that recruited nearly 100 patients who had not received treatment for CSF-1 before.
The results of the third phase showed that at 25 weeks, 54% of those who received pimicotinib received an objective response, compared with 3.2% of those who received a placebo. Darmstadt, headquartered in the German company, also met the secondary goal of assessing tumor volume, range of motion, stiffness and body function. Each trial measure for pimitinib was statistically significant. The results were presented Sunday at the Annual Meeting of the American Society of Clinical Oncology in Chicago.
CSF-1 inhibitors are already available for TGCT. The first is Turalio, a Daiichi Sankyo product that was approved by the FDA in 2019. However, this twice-daily drug may cause liver toxicity, which is a risk of marking in the black box warning on the product’s label. European pharmaceutical agencies rejected the drug in 2020, citing limited ability to improve pain and use joints. The institution also noted the risk of hepatotoxicity.
Ono Pharma entered the TGCT market earlier this year, with its CSF-1 inhibitor Romvimza approved the FDA. The two twice-week capsules come from Ono’s $2.4 billion acquisition of Deciphera Pharmaceuticals. Although Romvimza’s label does not have a black box warning, it advises against people who already have high blood liver enzymes. Chemotherapy provides another drug option for TGCT, but it does not solve CSF-1 and brings tolerance issues. Ravi noted that no hepatotoxicity was observed in Pimiconini’s study. This aspect of drug characteristics may drive use in patients with joint pain, but avoid TGCT medication due to concerns about the risk of liver damage.
“We are used to the wide range of side effects through chemotherapy due to limited toxicity and welcomed by disease sites,” Ravi said.
Pimitinib was developed by Abbisko Therapeutics. In 2023, Merck began a commercialization agreement with Abbisko on assets, which has reached three-stage testing. Earlier this year, Merck paid $85 million to exercise its choice to commercialize the drug in the United States and elsewhere in the world. Not long after, Merck struck a $3.9 billion deal to acquire Springworks Therapeutics, a FDA-approved drug Ogsiveo and Gomekli to treat other types of rare tumors.
Victoria Zazulina, head of Oncology Development at Merck’s healthcare business, said in a media briefing that Pimicotinib paves the way for the smaller tumor subtypes that affect smaller patient populations in ways that the company works differently from the disease. She added that cancer is a sign of many rare diseases. Merck plans to go later this year
“In many countries, there is no choice, no approved systemic therapy,” Zazulina said. “Europe, China does not approve the drugs on the market.”
Photo: Hannelore Foerster/Bloomberg, via Getty Images
