Intralesionals for melanoma - some new reports

I was a fan of intralesional therapies for melanoma long before they were used with any frequency in real live melanoma peeps! I first posted about Rose Bengal (the name I much prefer to the current PV-10) in 2012!!  Rose Bengal sustains high response rate in Melanoma patients!!!  These days the medications used intralesionally for melanoma patients has grown.  Even this list isn't comprehensive:

CAVATAK - derived from the Coxsackievirus
T-VEC - also called OncoVEX, Imlygic,  or Talimogene Laherparepvec - uses the herpes virus with GM-CSF
PV-10 - derived from Rose Bengal
HF10 - also derived from HSV
SD101 - a TLR9 agonist
IL-2 and IL-12 (tavo) -  are also being used

This link, including an update from June of this year, will give you - A zillion more posts on all things intralesional  Now, there are these ~

False positive FDG uptake in melanoma patients treated with talimogene laherparepvec (T-VEC).  Mulder, Stahlie, Verver, et al.  J Surg Oncol.  Jul 2021.

Talimogene laherparepvec (T-VEC) is a genetically modified herpes simplex virus-1-based oncolytic immunotherapy and has been approved for the local treatment of unresectable (stage IIIB/C and IVM1a) cutaneous melanoma. During T-VEC treatment, tumor response is often evaluated using [18F]2-fluoro-2-deoxy- d-glucose(FDG) positron emission tomography/computed tomography (PET/CT). In a Dutch cohort (n = 173), almost one-third of patients developed new-onset FDG uptake in uninjected locoregional lymph nodes during T-VEC. In 36 out of 53 (68%) patients with new nodal FDG uptake, nuclear medicine physicians classified this FDG uptake as "suspected metastases" without clinical or pathological confirmation in the majority of patients. These false positive results indicate that new-onset FDG uptake in locoregional lymph nodes during T-VEC treatment does not necessarily reflect progressive disease, but may be associated with immune infiltration. In current clinical practice, physicians should be aware of the high false positive rate of FDG uptake during treatment with T-VEC in patients with melanoma. Therefore, pathological examination of lymph node lesions with new FDG uptake is recommended to differentiate between progressive disease and immune infiltration after treatment with T-VEC.

Given the real (and wonderful) possibility of "by-stander response" - ie the positive response in lesions NOT injected when intralesional therapy is used - why oh why would you assume that uptake visible on scans is progression you silly silly radiology peeps???!!!!  Live and learn people!  Live and learn!

Durability of Complete Response to Intralesional Interleukin-2 for In-Transit Melanoma.  Khoury, Knapp, Fyfe, et al.  J Cutan Med Surg.  Jul-Aug 2021.

Background: Intralesional injection of interleukin-2 (IL-2) for in-transit melanoma (ITM) is associated with a high rate of complete response. However, there is a paucity of data on treatment durability and long-term outcomes.

Methods: Consecutive patients with ITM, treated with intralesional IL-2 therapy, at the Tom Baker Cancer Center were identified from April 2009 to August 2019. All patients received at least 4 cycles (every 2 weeks) of IL-2 (5 MIU/mL). Complete response was defined as sustained (ie, 3 months) clinical complete remission of all known in-transit disease.

Results: Sixty-five patients were treated with curative intent for in-transit disease with intralesional IL-2. Complete clinical response was identified in 44.6% (29/65). In this subset of patients, the median number of lesions per patient was 9 (range 1-40). The median total dose of IL-2 was 0.8 mL (IQR 0.4-1.5) per lesion. One patient received isolated limb infusion and 13.8% (4/29) received systemic immunotherapy as part of their initial management. At a median follow-up of 27 months (IQR 16-59), 34.5% (10/29) developed recurrent disease. Of these patients, 50.0% (5/10) presented with synchronous in-transit and distant metastases. The median time to recurrence was 10.5 months (IQR 5.8-16.3).

Conclusion: With long-term follow-up, 65.5% of complete responders have a durable response to intralesional IL-2 therapy. In this cohort of patients, local in-transit recurrence is most likely to occur within 12 months and is often associated with concomitant distant disease.

Treatment of in-transit melanoma metastases using intralesional PV-10.  Thompson, Saw, Dalton, et al.  Melanoma Res.  June 2021.

Melanoma in-transit metastases (ITMs) can sometimes be difficult to manage by surgical excision due to their number, size or location. Treatment by intralesional injection of PV-10, a 10% solution of rose bengal, has been reported to be a simple, safe and effective alternative, but more outcome data are required to confirm its value in the management of ITMs. Two hundred and twenty-six melanoma ITMs in 48 patients were treated with intralesional PV-10 supplied under a special-access scheme. By 8 weeks a complete response in all injected ITMs was achieved in 22 patients (46%) and a partial response in 19 patients (40%). Of 19 patients who had uninjected metastases, 3 (16%) had a response in these. The most common adverse event was transient localised pain in injected tumours. New ITMs developed in 25 patients within 8 weeks, and later in another 8 patients. Repeat injection cycles were given to 21 patients: 13 of these received repeat injection into partially responding or nonresponding tumours, 5 had new ITMs, as well as partially-responding lesions injected, and 3 received injection into new ITMs only. Twenty-two patients received subsequent systemic therapy. At 1 year 37 of the 48 patients were alive, 28 with melanoma, and at 2 years 27 were alive, and 19 with melanoma. Injection of PV-10 was simple and safe and resulted in tumour involution in most patients and sometimes in noninjected tumours. However, many patients developed new lesions; these were treated by further PV-10 injections or with alternative therapies.

T-VEC for stage IIIB-IVM1a melanoma achieves high rates of complete and durable responses and is associated with tumor load: a clinical prediction model.  Stahlie, Franke, Zuur, et al.  Cancer Immunol Immunother.  August 2021.

Background: Talimogene laherparepvec (T-VEC) is a genetically modified herpes simplex type 1 virus and known as an effective oncolytic immunotherapy for injectable cutaneous, subcutaneous and nodal melanoma lesions in stage IIIB-IVM1a patients. This study set out to identify prognostic factors for achieving a complete response that can be used to optimize patient selection for T-VEC monotherapy.

Methods: Patients with stage IIIB-IVM1a melanoma, treated with T-VEC at the Netherlands Cancer Institute between 2016-12 and 2020-01 with a follow-up time greater than 6 months, were included. Data were collected on baseline characteristics, responses and adverse events (AEs). Uni- and multivariable analyses were conducted, and a prediction model was developed to identify prognostic factors associated with CR.

Results: A total of 93 patients were included with a median age of 69 years, median follow-up time was 16.6 months. As best response, 58 patients (62%) had a CR, and the overall response rate was 79%. The durable response rate (objective response lasting greater than 6 months) was 51%. Grade 1-2 AEs occurred in almost every patient. Tumor size, type of metastases, prior treatment with systemic therapy and stage (8Th AJCC) were independent prognostic factors for achieving CR. The prediction model includes the predictors tumor size, type of metastases and number of lesions.

Conclusions: This study shows that intralesional T-VEC monotherapy is able to achieve high complete and durable responses. The prediction model shows that use of T-VEC in patients with less tumor burden is associated with better outcomes, suggesting use earlier in the course of the disease.

Much like every other treatment in the melanoma arsenal, intralesional therapy (no matter the type you choose) is not a 100% cure nirvana.  Still, to my mind, it is a valuable weapon available to melanoma patients with in-transit lesions and as a supplement to Stage III and IV patients being treated simultaneously with systemic therapy.  As ever, those with the lowest tumor burden do best.  And sadly, nobody does the Even Steven clinical trials I want to see, placing similar patients on the various intralesionals - with and without equivalent systemic therapies - and THEN comparing outcomes!!!!  Why not, oh brilliant researchers?  WHY?????

For what it's worth - c