This morning, CytRx announced updated data from their Ph3 clinical trial evaluating the efficacy of Aldoxorubicin as second-line therapy for soft tissue sarcoma (STS) patients. This updated data included several subset analyses that showed Aldoxorubicin conferred a statistically significant clinical benefit. The market initially responded very favorably showing peak premarket activity ~+50%. However, this sentiment changed after market open and at this time is around +7%.
In the announcement, the company indicates that Aldoxorubicin performed better than the investigator’s choice, but missed statistical significance (p=0.12, HR=0.71). They went on to further elaborate that in certain tumor subsets, efficacy was more pronounced. In patients with either liposarcoma or leiomyosarcoma, Aldoxorubicin caused a significant increase in progression free survival (PFS), p=0.007; HR=0.62. During the call, CytRx management reminded listeners that this improvement was relative to the standard of care, not placebo.
Further subset analysis can be viewed on their press release here: http://www.cytrx.com/press_releases.
Subset analysis, when not predefined, is generally seen as data cherry picking. Indeed, using these subset analyses when seeking approval with the FDA represents a much steeper uphill climb. However, if CytRx can justify scientifically why Aldoxorubicin has improved efficacy in these specific STS tumor types, there may be a smoother path to approval. It remains possible that these tumor types are more accessible with Aldoxorubicin. This accessibility could be a result of differential acidity within the tumor that occurs secondary to the intratumor hypoxic environment. Regardless, without justification, and sound scientific rationale, additional data will likely be required by the FDA prior to approval.
The markets are skeptical of the data cherry picking by management. An article was published by thestreet.com that questions the integrity of CYTR’s CEO (https://www.thestreet.com/story/13907339/1/cytrx-ceo-pockets-millions-of-dollars-as-failed-sarcoma-drug-moves-to-fda.html). We are not that impressed with the management team but feel that doxorubicin appears to have value, At a minimum the study published today supports aldoxorubicin as a more tolerable yet active form of doxorubicin. Therefore, at this valuation and with upcoming phase 3 lung cancer data next year, CYTR remains an interesting very high risk/high reward play.