Data from a phase 2 clinical trial by Antisense Therapeutics (ASX: ANP) on the immunomodulatory therapy ATL1102 for Duchenne muscular dystrophy has confirmed the drug can have positive effects on progression of the disease.
The trial aimed to assess the safety and tolerability of 25 milligram doses of ATL1102 administered to nine wheelchair-bound young male participants once a week via subcutaneous injection over six months.
It measured the effects of the drug on immune cell numbers in the blood as well as functional capacity and upper limb strength in participants as evaluated under the industry standard Performance of Upper Limb (PUL2.0) test used to assess disease improvement, stabilisation or progression in non-ambulant DMD patients.
At the end of the trial period, ATL1102 was found to have an “excellent safety profile”, appearing to be “generally safe and well tolerated” with no serious adverse effects reported and no safety concerns expressed by the Australian Data Safety Monitoring Board.
Most notably, participant immune cell data showed consistent mean reductions in the number and type of lymphocytes measured from baseline to week 24, with a return to around starting levels two weeks after the trial ended.
Antisense said this data was supportive of the drug’s positive effects on modulating CD49d+ T cells in the blood.
Antisense’s ATL1102 drug has been developed as an inhibitor of the alpha4 chain (CD49d) expression on certain immune cells such as T lymphocytes.
DMD patients displaying a greater number of T cells with high levels of CD49d have more severe and rapid disease progression.
ATL1102 is the only drug in clinical development for DMD which targets CD49d, and one of a very limited number of treatments being tested on male children at a more advanced stage of the disease.
Antisense is now consulting with internationally-recognised DMD experts to analyse the phase 2 clinical trial data and evaluate the response to therapy.
Phase 2b trial
The phase 2 results have been considered “highly supportive” of Antisense’s plans for a phase 2b clinical trial of ATL1102.
Chief executive officer Mark Diamond said meetings have been held with three European regulatory authorities to discuss trial design, dose escalation plans, study duration and applicability of the study endpoints.
“There was general acceptance by the agencies at the meetings on the proposed trial efficacy endpoints (being PUL2.0 and Myoset), a safety monitoring plan, a 12-month dosing duration and the use of higher doses,” he said.
“Encouraging clarification was provided by the agencies that this could be a path to an early regulatory approval on positive phase 2b results.”
Antisense plans to discuss the trial’s development plan with the European Medicines Agency and engage with the US Food and Drug Administration on development plans for ATL1102 in that region.
“We are moving forward with all deliberate speed to advance ATL1102 through the clinic, with specific view to a blinded controlled study in the European Union which, based upon recent and ongoing guidance, may lead directly to early approval,” Mr Diamond said.
Options mostly underwritten
Antisense today confirmed that $5.5 million will be raised with the exercising of options to fund the advancement of the phase 2b clinical trial.
The options are due to expire on 19 December and $4.1 million of the total will be underwritten by Morgans Corporate at a price of $0.08 each.
There are currently 57 million listed options as of 16 December 2019.
“Taking into account the underwritten amount and commitments received from a number of optionholders, including key management personnel and advisors, [our] understanding is that [we] will receive full options exercise of $5.5 million,” the company said.
Funds raised from the issue of the options will be used to advance plans for the phase 2b trial and for general working capital and corporate purposes.
Early childhood disease
DMD is a genetic disorder characterised by progressive muscle degeneration and weakness due to alterations of the dystrophin protein which helps keep muscle cells intact.
The disease primarily affects boys, with early childhood symptoms affecting the proximal muscles (those close to the core of the body) and later the distal limb muscles (those close to the extremities).
DMD patients often have difficulty jumping, running and walking, and can also display enlarged calves, a waddling gait and lumbar lordosis (or inward curve of the spine).
Progressive weakness and scoliosis result in impaired pulmonary function, which can eventually cause acute respiratory failure.
At midday, shares in Antisense were up 17.07% to $0.096.