An additional FDA hold has been placed on Mersana Therapeutics in connection with the passing of a patient. This time, the government has placed restrictions on the primary antibody-drug conjugate (ADC) that the biotech company produces because of bleeding events that have occurred in patients, among whom there have been five deaths.
The company revealed that trials of its primary asset, UpRi, had found a greater risk of major bleeding events in treated individuals with platinum-resistant ovarian cancer compared to the background group. This prompted authorities to place two studies currently underway by the ADC on partial hold. As of Thursday’s revelation, around 560 individuals had received doses of Mersana.
Both the company’s phase 3 UP-NEXT study and its phase 1 dosage expansion trial, UPGRADE-A, have been placed on partial holds, which has resulted in the cessation of recruitment. After finishing enrollment in October, Mersana’s registrational single-arm study known as UPLIFT has emerged unharmed. Patients who are already participating in one of the three studies have the opportunity to continue receiving treatment.
The developer of the ADC-focused medicine presented a new batch of safety data to the regulatory bodies, which included information on the five fatal bleeding incidents. This is when the news of the holds became public. According to the firm, an inquiry into what caused the problem is currently underway
Mersana has stated that it is currently awaiting official written notification from authorities on the holds, and it anticipates that the FDA will request further extensive safety data. Additionally, the biotechnology company intends to submit data about the experiment’s effectiveness and safety. Topline results from the UPLIFT trial are expected to be made public in August.
After closing on Wednesday at $9.55 a share, the price of the company’s stock plummeted to an all-time low just after the market opened, falling to $4.06, a decrease of almost 60% from the previous day’s price. This wipes away practically all of the gains that Mersana had made in the preceding seven weeks, a time period in which the firm was heartened by the possibility that it would file an approval petition for UpRi by the end of the year. However, given the current uncertainty over the safety profile, it is clear that investors are cutting back on their bets.
The collaborations with GSK, Janssen, and Merck KGaA over the past year and a half have contributed to the growth of Mersana’s potential. The total value for all three transactions exceeds $3 billion. However, in March, an individual participating in the first trial of the two firms’ partnered asset, XMT-2056, died from a significant adverse event thought to be connected to the medication, casting doubt on the cooperation with GSK.
Mersana’s bigger clinical development strategy and the resources to pay for it remain unknown as a result of recruiting delays in the two affected studies of UpRi. As of the end of March, the firm had approximately $280 million in the bank, which should see it through into the second half of 2024. Due in part to a rise in staff as well as increased manufacturing and clinical expenditures, Mersana reported a 32% rise in R&D spending in the first quarter of 2023 compared to the same period last year.