Liposomal doxorubicin (Dox) plus pomalidomide (Pom) was safe and active in heavily pretreated patients with Kaposi sarcoma, according to results from a phase 1/2 trial.
Dr. Ramya Ramaswami
“The results of our phase 1/2 study suggest pomalidomide and liposomal doxorubicin is safe with evidence of activity among patients with Kaposi sarcoma,” said investigator Ramya Ramaswami, MBBS, MPH, of the HIV & AIDS malignancy branch at the National Cancer Institute. The results were presented at the Conference on Retroviruses and Opportunistic Infections.
The researchers evaluated the safety and tolerability of Pom/Dox in two groups of patients with Kaposi sarcoma: group 1 included patients with Kaposi sarcoma alone and group 2 included patients with Kaposi sarcoma–associated herpesvirus and concurrent multicentric Castleman disease (KSHV-MCD) and KSHV inflammatory cytokine syndrome (KICS).
“Kaposi sarcoma can be challenging to treat when it co-occurs with KSHV-MCD or KICS, resulting in high mortality rates,” Dr. Ramaswami explained.
Study participants received IV liposomal Dox at 20 mg/m2 on day 1 of a 28-day cycle, in addition to oral Pom once daily on days 1-21 at three escalating dose levels (2 mg, 3 mg, or 4 mg, respectively) using a standard 3 + 3 design until plateau of response, progression, dose-limiting toxicities (DLTs) or patient preference. Some eligibility criteria differed between groups 1 and 2. Participants in group 1 were required to be on antiretroviral therapy for at least 1 month and had a performance status of 2 or less, while those in group 2 had a performance status of 3 or less and could be antiretroviral therapy naive.
All participants received oral aspirin thromboprophylaxis (81 mg daily) and could have received prior Kaposi sarcoma therapy.
With respect to outcomes, Kaposi sarcoma responses were assessed using the modified AIDS Clinical Trial Group criteria and KICS and KSHV-MCD responses were evaluated using an NCI clinical benefit criteria.
Results
Overall, 34 cisgender men were enrolled in the study: 21 (62%) in group 1 and 13 (38%) in group 2. All participants had severe (T1) Kaposi sarcoma; 32 (94%) participants were HIV-infected and 22 (65%) had prior chemotherapy for Kaposi sarcoma.
While the HIV viral load was largely controlled in both groups, the CD4 count differed, with median CD4 counts of 286 and 92 cells/mcL in groups 1 and 2, respectively.
With respect to safety, no DLTs were observed in group 1. As a result, 12 participants were treated at the maximum tolerated dose (MTD) of 4 mg of Pom. However, two DLTs (grade 3 rash and pharyngeal edema) were observed in group 2 at the 3 mg dose level.
A median of six cycles were administered for all participants and the most common grade 3/4 toxicity was neutropenia; nine patients with grade 3 neutropenia required dose reduction and three patients had febrile neutropenia requiring hospitalization. Other Pom-related adverse events were rash, constipation, and fatigue.
Among evaluable participants receiving two or more cycles, 17 (81%) patients in group 1 had a response (95% confidence interval, 58-95%; 16 partial response and 1 complete response) and 5 (50%) patients in group 2 had a response (95% CI, 19-81%; 4 PR and 1 CR).
“Our waterfall plots indicated that the vast majority of patients in group 1 had a positive change in nodular lesions at baseline,” Dr. Ramaswami said. “Participants in group 2 showed some decrease in nodular lesions, but this was usually temporary.”
Among seven participants with KICS responses, four participants (57%) experienced a CR or PR in symptoms and lab abnormalities associated with KICS; three of six participants (50%) with KSHV-MCD responses experienced a PR as per response criteria.
“While activity was noted, the combination was less well tolerated in patients with Kaposi sarcoma and concurrent KSHV-MCD or KICS,” Dr. Ramaswami said.
During a live discussion, Ronald T. Mitsuyasu, MD, of the University of California, Los Angeles, asked Dr. Ramaswami about the use of liposomal doxorubicin alone in patients with Kaposi sarcoma and concurrent KSHV-MCD or KICS.
While there is currently no data on the use of doxorubicin alone in this population, Dr. Ramaswami noted that she was more confident administering Pom/Dox combination therapy for these patients.
Dr. Ramaswami disclosed financial relationships with the National Cancer Institute, Celgene/Bristol-Myers Squibb, EMD Serono, Merck, CTI Biopharma, and Janssen. The study was funded by a cooperative research and drug development agreement between the National Cancer Institute and Celgene/BMS, EMD Serono, Merck, CTI Biopharma, and Janssen.