Subcutaneous isatuximab administration in combination with pomalidomide-dexamethasone in RRMM can improve convenience and relieve burden for patients

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Published: 13 Jun 2022
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Prof Hang Quach - St.Vincent’s Hospital, Sydney, Australia

Prof Hang Quach speaks to ecancer at EHA 2022 about a study looking at the subcutaneous isatuximab administration in combination with pomalidomide-dexamethasone in relapsed/refractory multiple myeloma (RRMM).

She explains that currently intravenous isatuximab in combination with pomalidomide-dexamethasone is approved for RRMM patients but that a subcutaneous administration would improve convenience and relieve burden for patients.

Prof Quach reports that adverse events were similar across cohorts and that the efficacy seen was also comparable.

The study I’ll be discussing today is an interim result of the phase Ib study of subcutaneous
isatuximab delivered via an on-body delivery system, so OBDS, in combination with pomalidomide
and dexamethasone in patients with relapsed/refractory multiple myeloma. Currently IV isatuximab is
approved for the treatment of relapsed/refractory myeloma in combination with pomalidomide and
dexamethasone based on the pivotal results of the ICARIA study. Now, subcutaneous isatuximab is
more convenient and will result in less burden on resource in the hospital system.

So this phase Ib study compares subcutaneous isatuximab with IV isatuximab in combination with
pomalidomide and dexamethasone. Previously, in fact, we’ve reported the result of the first cohort of
this study that demonstrated that subcutaneous isatuximab resulted in a similar efficacy and safety
compared to IV isatuximab. In this study what we’re doing is reporting the result of the expanded
cohort of patients receiving subcutaneous isatuximab via an on-body delivery system, so that’s an
OBDS, at the recommended phase II dose of 1,400mg. The OBDS is a wearable, injectable bolus
injector that can be applied on the abdomen.

Overall, 56 patients were enrolled into the study: 12 were in the IV cohort, 12 were in the subcut
1,000mg cohort, 10 patients were in the subcut 1,400mg cohort and overall 22 patients were in the
OBDS cohort. Both IV and subcut isatuximab were given weekly for four weeks, then every two
weeks until disease progression. The primary endpoint of the study was safety, including injection site
reaction, as well as PK. The secondary endpoints of the study, the main ones, were overall response
rate and progression free survival.

In terms of safety, the total all causality grade 3 or more treatment related adverse events were very
similar across all cohorts. Injections or infusion reactions were quite low, occurring in less than 10% in
each cohort. All were grade 2 and all occurred only during the first administration. What was important
was that the subgroup of patients in the OBDS cohort did not have any injection reactions at all. Local
tolerability was excellent in the OBDS cohort in that only five out of the 22 patients experienced local
site injection reactions and seven episodes overall out of the 305 administrations, so that was quite
impressive. The median time of injections via the OBDS was ten minutes for the first injections and
subsequent injections.

In terms of efficacy, for the cohort of patients who received the recommended phase II dose i.e. the
subcut 1,400mg plus the OBDS cohort, the overall response rate was 78%. The median progression
free survival for the IV cohort of patients was 22 months; it was 12 months for the subcut 1,00mg and
not reached for the cohort of patients who received the 1,400mg via subcut injections or the OBDS
cohort of patients.

Overall this data can allow us to conclude that subcutaneous isatuximab administered at the
recommended phase II dose of 1,400mg via OBDS had similar efficacy to the IV isatuximab and with
no injection reactions and with excellent local tolerability and with efficacy that was similar to what we
would expect with IV isatuximab in the phase III ICARIA study.

So, in summary, subcutaneous isatuximab via OBDS is very feasible with a very short injection time
and can provide a very convenient, hands-free, alternative option for our patients with
relapsed/refractory multiple myeloma.

In terms of where we go from here, follow-up for this study is still ongoing and the final results in the
near future will hopefully pave the way for the availability of subcutaneous isatuximab administered
via the OBDS device which will significantly improve quality of life for our patients with myeloma and
reduce the resource burden on our hospitals.