Biogen’s adeno-associated virus-based gene therapy for treatment of the degenerative blindness choroideremia has failed at Phase III, the second ophthalmic gene therapy trial to fail for the company.
Biogen acquired British biotech Nightstar Therapeutics, plus its two main ophthalmic gene therapy candidates, in the summer of 2019 in a deal worth over $800 million. The lead Nightstar candidate was for treatment of choroideremia and the second therapeutic for X-linked retinitis pigmentosa.
Both therapies have since failed to reach their primary endpoints in late-stage trials, perhaps casting doubt on the Nightstar approach and the value of the acquisition.
Last month, Biogen announced that cotoretigene toliparvovec, being investigated as a one-time therapy for patients with X-linked retinitis pigmentosa, had failed to reach its primary endpoint in a Phase II/III trial, although some visual improvement was seen.
“Although the Phase II/III XIRIUS study of cotoretigene toliparvovec did not meet its primary endpoint, we are encouraged by positive trends in other pre-specified clinically relevant endpoints, such as a measure of visual acuity under low light conditions,” said Katherine Dawson, M.D., head of the therapeutics development unit at Biogen, in a press statement.
This week the company released the disappointing news that timrepigene emparvovec, for the potential treatment of choroideremia, had also failed to reach its primary endpoint in a Phase III study.
The multicenter, randomized, three-arm, parallel-controlled group STAR study enrolled 169 men with a genetic diagnosis of choroideremia. The participants received a single sub-retinal injection of the gene therapy and were then followed up for 12 months. The primary endpoint was an improvement of at least 15 letters from baseline in best corrected visual acuity score in the treatment compared with the control group, but this was not achieved.
Secondary endpoints in the trial were also not achieved, but safety was consistent with previous studies testing the therapy, according to the company.
“We extend our deepest gratitude to all those who contributed to the STAR study, including the participants, investigators, site staff and the broader choroideremia community,” said Dawson in a new press statement.
“While we are disappointed by the results of the STAR study, we are hopeful that the clinical insights gleaned from this study may help to shape therapeutic innovation for inherited retinal diseases including choroideremia, so that in the future there may be treatment options for the community affected by these debilitating disorders.”
The company said further information would be released about the trial and future plans for timrepigene emparvovec clinical development after the full data set from the trial had undergone further analysis.
This announcement comes only weeks after the company’s controversial Alzheimer’s drug approval by the FDA. Since the Aduhelm (aducanumab) approval was announced last week Biogen’s stock price went up by more than 50%.
While the announcement of a second gene therapy failure for the company is not good news, so far it does not seem to have had a massive impact on share price with only a small dip from $434 to around the $405 mark since the trial results were announced.